text:
Talk:Berlin

Metropolitan region vs. “Capital” region
Please don’t confuse the Berlin metropolitan area as Wikipedia defines a Metropolitan area with the “Capital” region as some officials/agencies in Berlin-Brandenburg would like to define the region. According to Wikipedia: “A metropolitan area, metro area or metro is a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing” – note that farming and other distant rural areas are not included. The metro area is shown for example as the yellow parts of the maps and by the lists of towns. Personally, I would also say it’s the area you can reach by public transport with a Berlin ABC ticket. The given reference http://www.berlin-brandenburg.de/daten-fakten/ also refers this as “Berliner Umland”.

The “Capital Region Berlin-Brandenburg” is a construction that government agencies are trying to push, but it simply includes all of Brandenburg with Berlin. It is true, that in the wider sense Brandenburg’s economy is generally, but not exclusively, oriented towards Berlin. Some day they may even become politically united. However, it is stretching it a bit far to say that vast rural areas such as the forests of the Uckermark or the swamps of the Spreewald belong to the metropolitan area of Berlin. It would be like saying all of Connecticut is part of the Hartford metropolitan area.

So, please adhere to the definition set by Wikipedia and do not follow some megalomaniac political redefinition. Alandeus (talk) 13:35, 7 February 2013 (UTC)

 * Hello :) It is not up to us or Wikipedia to define Berlin metropolitan, that is up to The state of Berlin and Brandenburg, or the German Federal State. If the official numbers are 6 million then it is 6 million, we are not the judgers of that, we follow the official figures, and fact is that Berlin metropolitan are Berlin-Brandenburg. and the links clearly defines the Berlin-Brandenburg as Berlins metro area.  — Preceding unsigned comment added by 86.52.81.168 (talk) 18:25, 7 February 2013 (UTC)

 * I’m sorry User 86.52.81.168, but in the encyclopedic realm of Wikipedia, its definitions are quite sound (see above). If some well-meaning government officials for the Berlin/Brandenburg Metropolitan Region have a different idea of what a metropolitan area is, they are welcome to espouse something else on their own “official” websites, no matter how off the mark they are. What they are actually advocating is simply a much larger regional area with a real metropolitan area in the middle as a focal point. The faraway fields of Brandenburg only belong to the Berlin area in so far as that is where the Berliners get their vegetables from for example or where they go for a weekend getaway. Greetings from Berlin, yours Alandeus (talk) 09:12, 8 February 2013 (UTC)

 * Official definitions are all we need with reliable links, the figure of 4.5 mio people don't have any link, but the claims of 6 mio people does, so that is the guideline and what we can use as a reliable source.
 * Wikipedia is not a place to make definitions, but a encyclopedia, to put reliable content. At least let's change the figure to include 6 mio people.
 * But is must say that you don't recognize the official figures from the states of Berlin and Brandenburg plus IKM (Initiativkreises Europäische Metropolregionen in Deutschland) are not in the spirit if Wikipedia, where reliable sources are all we recognized. The German language site on Wikipedia Metropolregion Berlin/Brandenburg recognized the links, why not on the English language site? — Preceding unsigned comment added by 86.52.81.168 (talk) 22:43, 8 February 2013 (UTC)

 * Wikipedia is a place to make definitions. When reviewing Metropolitan Areas it must have a fundamental definition as a benchmark when collecting and comparing data from many different sources. Some “official” sites seem to make their area larger than what actual metropolitan are for whatever interests they may have. Sure, information from these sites is useful, but only insofar as it does not distort encyclopedic evaluation.
 * About those 4.5 million inhabitants: The “Daten und Fakten zur Hauptstadtregion“ page (http://www.berlin-brandenburg.de/daten-fakten/) has those population figures in the middle and at the bottom of the page: about 3.5 for Berlin, 900 thousand for the area around Berlin (“Berliner Umland”) and 1.6 million for the rest of Brandenburg. I’m sure these latter, more distant Brandenburgers would be appalled to be considered being part of Berlin. Alandeus (talk) 10:01, 11 February 2013 (UTC)

 * The same site say that "Berlin und Brandenburg bilden zusammen die deutsche Hauptstadtregion mit 6 million menschen" In English - "Berlin and Brandenburg together form the German capital region with 6 million people", fact.
 * You write "more distant Brandenburgers would be appalled to be considered being part of Berlin" Personal feelings are not relevant, the States of Berlin and Brandenburg say it is Berlin metro area, then it is what it is, fact. — Preceding unsigned comment added by 86.52.84.231 (talk) 18:13, 11 February 2013 (UTC)

 * Dear 86.52.84.231: Back to basics once more: The quoted source says “Hauptstadtregion” or “capital region”. Granted, that is the whole region around the capital including all of rural Brandenburg. When Wikipedia talks about metropolitan areas, however, that is a concentration on exclusively urban areas and that is what we ought to stick to when evaluating the Berlin metro area, including the 4½ population figure. My opinion on the Brandenburgers, by the way, was not meant to be taken as a fact of course; it was just a tongue-in-the-cheek afterthought. Alandeus (talk) 07:50, 12 February 2013 (UTC)

Hello Alandeus :) my point is that the only figures we have are the 6 million people, no source are mentioning 4½. And recarding metropolitan areas, a metro area are not only urban, but can contain large rural areas who are afffected by the urban area in terms of commuting and influence.. As stated in Wikipedia's own site - A metropolitan area combines an urban agglomeration (the contiguous, built-up area) with zones not necessarily urban in character, but closely bound to the center by employment or other commerce. These outlying zones are sometimes known as a commuter belt, and may extend well beyond the urban zone.

Metro areas with large rural areas are common, here are some.

Seattle metropolitan area 3.5 mio people - 21,202 km2

Phoenix metropolitan area 4.2 mio people - 37,744 km2

Hamburg Metropolitan Region 5.2 mio people - 26,000 km2. — Preceding unsigned comment added by 86.52.84.231 (talk) 12:07, 12 February 2013 (UTC)

 * The quaint Brandenburg towns of Wusterhausen, Schwedt and Lübbenau for example are each about an hour’s drive from Berlin and are therefore not really in the defined ‘commuter belt’ of or otherwise ‘closely bound’ in a Berlin metro area, i.e. that yellow area on the metro area map. And although that 4½ million figure is not mentioned explicitly on the aforementioned source page, it is pretty easy to come to this total from the data provided there. And those other examples; maybe those need to be reexamined as well. Alandeus (talk) 14:24, 12 February 2013 (UTC)

 * The map you are mentioning are self made by a wikipedia user called Broadway, so the definitions on that map are not any official status. — Preceding unsigned comment added by 86.52.84.231 (talk) 19:07, 12 February 2013 (UTC)

 * Of course Broadway’s excellent map of the Berlin/Brandenburg Metropolitan Region is not “official”. It visualises perfectly well though the area as correctly defined by the rest of the Berlin/Brandenburg Metropolitan Region article. Please, 86.52.84.231 (are you from Berlin or Brandenburg?), get off the idea that everything must have or rely only on an official source. Alandeus (talk) 09:50, 13 February 2013 (UTC)

 * It seems that we are not going anywhere :) lets at least mentioning the 6 mio, when the official sources claims it. What about this line, "the Berlin-Brandenburg Metropolitan Region, whit a population ranging from 4,5 to 6 mio people according to different sources.  — Preceding unsigned comment added by 86.52.84.231 (talk) 22:19, 13 February 2013 (UTC)

 * No need to muddle up or bloat the lead paragraph with references to differing sources. Various population figures can already be found in the Demographics section. For the sake of completeness though, I’ve added “The entire Berlin-Brandenburg region has a population then of 6 million.” there with reference to Hauptstadtregion Berlin-Brandenburg. Hope this is a satisfactory compromise. Alandeus (talk) 09:04, 14 February 2013 (UTC)

West Berlin
West Berlin was not legally part of West Germany and to state that it was compromises the factual accuracy of this article. Paul Austin (talk) 13:44, 29 April 2013 (UTC)

 * Although the Allies maintained their role as the highest executive authority - West Berlin did de facto become a "Bundesland" of the FRG, and was represented in the Bundestag and Bundesrat. West Berlins' residents were citizens of the FRG. There is no need to go into depth about West Berlins' complicated legal status - at least not in the lead. After all, this article is about Berlin and not West Berlin. More detailed information is given in the appropriate section (History, 2.2 20th century) of this article.--77.181.5.160 (talk) 17:58, 29 April 2013 (UTC)

 * de facto and de jure are important distinctions. To include wrong information in the lede is not good. It is possible to simplify without distorting.158.181.66.104 (talk) 22:59, 16 June 2013 (UTC)

 * "The constitution of West Berlin, as it came into force on 1 September 1950, maintained that West Berlin is a constituent Land of the Federal Republic, where the Basic Law of the Federal Republic is binding ... Under its 1950 constitution, West Berlin is a state of the Federal Republic..."Dorothy Elkins, T. H. Elkins, B. Hofmeister, Berlin: The Spatial Structure of a Divided City, 1988, p.40-41 --82.113.99.196 (talk) 16:41, 1 August 2013 (UTC)

One of the Bundesländer?
In this article's second paragraph I find it stated that West Berlin was one of the states of the Federal Republic before the re-unification of Germany. In the 1980s I actually believed that to be the be the case. I know that Willi Brandt, who resided in West Berlin, served as chancellor of the Federal Republic before the re-unification. However, I also know that West Germany's laws allowed even citizens of East Germany to hold that office and others in West Germany, since they refused to recognize any distinction between different German citizenships. I think it was from reading Wikipedia's article on Germany's re-unification and its article on the Federal Republic that I came to think that Berlin was never incorporated in the Federal Republic until 1990. Is there a source for the assertion? Michael Hardy (talk) 11:49, 1 August 2013 (UTC)

 * West Berlin did de facto become a "Bundesland" of the FRG, and was represented in the Bundestag and Bundesrat. West Berlins' residents were citizens of the FRG. --77.181.244.33 (talk) 16:07, 1 August 2013 (UTC)

 * "The constitution of West Berlin, as it came into force on 1 September 1950, maintained that West Berlin is a constituent Land of the Federal Republic, where the Basic Law of the Federal Republic is binding ... Under its 1950 constitution, West Berlin is a state of the Federal Republic..."Dorothy Elkins, T. H. Elkins, B. Hofmeister, Berlin: The Spatial Structure of a Divided City, 1988, p.40-41 --82.113.99.196 (talk) 16:40, 1 August 2013 (UTC)

"federal state"?
Early in this article we find this:
 * and federal state of the Federal Republic of Germany.

I've always thought "federal state" is a lousy way to translate the German word Bundesland. The prefix bundes- does generally mean "federal", but in English the term "federal state" is often taken to mean a federated state, like the U.S.A. or like Germany or Brazil or any of various others (Switzerland, Canada, Australia, Mexico,....), i.e. a state composed of a union of smaller states.

But a difficulty arises: I don't know if the English language has any good term that refers to the concept that Bundesland refers to. It would be a common noun whose referents include things like Schleswig-Holstein, Wisconsin, and Alagoas.

Is there some reasonable term that could be used here instead of the misleading term "federal state"? Michael Hardy (talk) 17:41, 5 August 2013 (UTC)

 * I believe just "state" would be fine to use. "Federal state" is not correct for Berlin, or for West Berlin like in the quote. Actually West Berlin was not even a proper state, more something of a de facto-state tightly connected to West Germany. --JohanahoJ (talk) 18:39, 5 August 2013 (UTC)

Name of Berlin / Etymology
The Etymology section should be redone, according to that of the German article. Cheers, Horst-schlaemma (talk) 16:28, 3 December 2013 (UTC)

 * In ancient Slavic languages (Protoslavic language) word "ber" means "a bear". Hence Russian "берлога" (berloga) - "a bears lair". In the same time I never heard there would be a Slavic word "berl" which means "a swamp" according to this article. So, I think there is a fair chance name "Berlin" was derived from the ancient Slavic word "ber" which means "a bear". And this version has to be researched and included in Wikipedia. — Preceding unsigned comment added by 192.222.146.79 (talk) 12:50, 19 November 2017 (UTC)

 * No, it hasn't. The issue was researched pretty intensely and no one ever mentioned an "ancient Slavic word ber". --j.budissin (talk) 11:42, 30 November 2020 (UTC)

Articles needed for cultural/musical festivals
Hi! I think the following topics should be covered by at least some compact articles, as they're relevant not just for Berlin:

 * Karneval der Kulturen (Carnival of Cultures), see de:Karneval der Kulturen
 * Berlin Festival (web), see de:Berlin Festival
 * Berlin Music Week (web), see de:Berlin Music Week

Thanks & all the best, Horst-schlaemma (talk) 12:44, 2 April 2014 (UTC)

Incorrect Google Earth Icon Coordinate
Hello -

A Wikipedia Icon for Berlin linked to the Wikipedia article for Berlin is show in Google Earth in the Sierra Nevada mountains of the United States at the approximate coordinate of 38°45'N 119°22'W. Can this be fixed or can you tell me who I should notify? Thanks VFF0347 (talk) 15:59, 9 April 2014 (UTC) VFF0347

 * The coordinates at the top are perfectly OK: |latd=52 |latm=31 |lats= |longd=13 |longm=23 . Don't know where you got the Sierra Nevada mountains coordinates from. No correction necessary. Alandeus (talk) 05:58, 10 April 2014 (UTC)

 * There is nothing incorrect with the coordinates referenced in your article. However there is a Wikipedia icon shown in Google Earth (in the Sierra Nevadas at the coordinates which I mentioned) that is linked to your article. When a reader double clicks the icon in Google Earth it brings the reader to your article. From your response I take it that you didn't have anything to do with placing the icon in Google Earth. Is that correct? Would you have any knowledge of how Wikipedia icons are set-up and/or controlled in Google Earth? Thanks so much VFF0347  — Preceding unsigned comment added by VFF0347 (talk • contribs) 20:27, 12 April 2014 (UTC)

Copy edit template
It appears that someone close to Berlin, who might also not be a native English speaker, has been editing the page, and other copyeditors need to review the content for both grammar and tone. I have made numerous corrections today and also needed to add citations—I will continue to monitor the page.--Soulparadox (talk) 14:39, 30 August 2014 (UTC)

 * Would be great if you were able to proofread some sections. FinnishDriver (talk) 11:26, 31 August 2014 (UTC)

London Crest
The article showing the sister cities and such, shows London with a crest. That is not the crest of London, is the crest of the City of London. — Preceding unsigned comment added by 200.237.96.9 (talk) 18:46, 11 December 2014 (UTC)

Inconsistency: Weather data
It appears that there is a sizable difference between the weather data listed on this page and the weather data listed on the Geography of Berlin page. Maybe I'm missing something, but comparing the two pages it appears that the mean annual sunshine hours for Berlin are a) 1,625.6; and b) 2,025.6.

Is someone interested in looking into this, determining which is more accurate, and then making the appropriate changes if necessary?

54.68.59.137 (talk) 07:53, 11 January 2015 (UTC)

Timeline of Berlin
What is missing from the recently created city timeline article? Please add relevant content. Contributions welcome. Thank you. -- M2545 (talk) 15:33, 19 May 2015 (UTC)

Döner myth
"The Döner kebab was invented in Berlin in 1971" is a common misperception in Germany. The "berlin style" of Döner kebab sandwich, not surprisingly, developed in Berlin, through the 70s and 80s. But the legend that the Döner was "invented" there is highly misleading. The Döner meat itself has been served in Turkey for more than a century, and Döner sandwiches as snack or street food have been sold in Turkey since at least the 1950s. Statement needs clarification or removal. Discussion in Talk:Doner_kebab IamNotU (talk) 18:16, 17 February 2016 (UTC)

There, I fixed it. -- IamNotU (talk) 17:07, 6 May 2016 (UTC)

 * The case was already clarified with a source. BTW, this article is neither about Döner Kebab nor the history of Döner Kebab. Your additions are out of place. Sorry. FinnishDriver (talk) 16:05, 9 May 2016 (UTC)

 * FinnishDriver, you're right, that was too much information... I've moved it to Doner kebab. I did rewrite the one sentence about Döners here though, as it was inaccurate, and the Telegraph source was unreliable. Not only did they contradict their own report here:, but they still didn't check their facts - although Kadir Nurman is still dead, de:Mehmet Aygün is not! -- IamNotU (talk) 01:33, 12 May 2016 (UTC)

 * I still believe that mentioning the Döner myth is misplaced here. Its not the article about Döner Kebab. FinnishDriver (talk) 06:36, 5 June 2016 (UTC)

 * , I appreciate your efforts to improve the article. Nevertheless, please do not continue to reintroduce the citation declaring the death of Mehmet Aygün. It was a false report (see ) and its inclusion without adequate context violates multiple Wikipedia guidelines and policies. I have replaced it with another one from the Wall Street Journal, which should be more than sufficient. Thank-you. -- IamNotU (talk) 03:47, 6 June 2016 (UTC)

Removal of images

I added the two files shown at right to illustrate how Berlin has changed since its reunification. They show the same location, as evidenced by the signpost marking the intersection of Charlottenstraße and Zimmerstraße, and, in my opinion, deliver the full value of a thousand words in what they depict. I am certain, having taken the 1986 picture myself, that no arrangement of prose could have titillated my imagination nearly as much as it was upon seeing the changes in 2D.

They were subsequently removed for the following summarized reason: "one division pic is enough here". I would agree, except these images were not illustrating the division of Berlin, but instead: how drastically it changed upon reunification, and by all reasonable measure, how quickly as well. I think they improve the article, and am keen to know if others agree. Best regards.--John Cline (talk) 05:17, 3 July 2016 (UTC)

West Berlin and East Berlin post-German reunification
I think there should be an article on how "West" and "East" co-exist in the post-reunification era, and why it's perhaps a misnomer to talk about just "Berlin". There's a bunch of fascinating sources on this topic; here's a sample: --Coin945 (talk) 05:40, 26 January 2017 (UTC)

 * https://www.washingtonpost.com/news/worldviews/wp/2014/10/31/the-berlin-wall-fell-25-years-ago-but-germany-is-still-divided/
 * https://www.theguardian.com/world/2015/oct/02/german-reunification-25-years-on-how-different-are-east-and-west-really
 * https://www.libertarianism.org/publications/essays/east-west-berlin-study-free-vs-controlled-economy
 * http://www.visitberlin.de/en/article/living-in-a-divided-city-west-berlin
 * http://fortune.com/2014/11/09/germany-east-west-economy/

Contradicting statements in the ingress
This is from the ingress:

"Berlin is the second most populous city proper in the European Union and the seventh most populous urban area in the European Union. Located in northeastern Germany on the banks of the rivers Spree and Havel, it is the centre of the Berlin-Brandenburg Metropolitan Region, which has roughly 6 million residents from more than 180 nations, making it the sixth most populous urban area in the European Union."

So its the seventh most populous, then in the next sentence its the sixth. Seems both is based on the same source and the same year. I don't read French so I can't say what is right, but it should be corrected. Ulflarsen (talk) 12:33, 1 August 2017 (UTC)

 * So fix it! That's a nine year old dead link with no archive. You'll need to find a new source, start with the List of urban areas in the European Union page, which lists it in either seventh or third place, depending how you look at it... --IamNotU (talk) 15:01, 2 August 2017 (UTC)

Coordinate error
Be aware! This edit might anger or frustrate the reader because the issue it addresses is so minor it could be called irrelevant. I would have edited the article myself, but unfortunately I don't understand how to obtain coordinates from the source used in all articles on cities.

The following coordinate fix is needed for Berlin:

- The coordinate on the page is located outside the city borders.

The following coordinate fix is needed in general:

- Coordinates are presented in all articles on cities. It should be noted why this exact location is chosen. Coordinates represent a point (non-dimensional) on the earths surface (two dimensional). This raises the question: "What point within the area covered by the city is chosen coordinate?". Does it represent location of some important building, or the cities historical or geometrical center, etc?

—CreatorOfYellow (talk) 21:08, 27 September 2017 (UTC)

 * I've changed the coordinates to reflect a point nearer the "geometrical center" of the city. The center, either the geographical center or a "business center", is usually where we put the coordinates of a settlement, although there are some exceptions in special cases. And we try to avoid too much precision relative to the place's size. Deor (talk) 21:35, 27 September 2017 (UTC)

East Side Gallery photo in lead
There's been a photo of the East Side Gallery in the lead photomontage since at least February 2015 (though not always the same photo). A few weeks ago, it was replaced with a photo of a monument at the Berlin Wall Memorial. Several people have tried to put it back, but the editor always reverts them. I'd like to discuss some kind of consensus about it. Which site do you prefer, and which photo?

Personally, I support the East Side Gallery as being a world-famous emblem of Berlin. The Berlin Wall Memorial is important in its own way, but just doesn't have that kind of status. For the photo, I'd like to see one of the more well-known artworks, ideally from before the fence that's now there. Some suggestions:

 * Your choice of representation for my city looks like a really, really bad joke to me! --Kharon (talk) 18:10, 23 February 2018 (UTC)

 * Die Zitadelle at Spandau is nice, but Landskrona Citadell is even better preserved, from the moats' point of view at least. There is one well preserved in Belgium also (Antwerpen ?). Kastellet at Copenhagen also worth mentioning, and with a rather central location. I like the gallery above. But I would like to have added both Unter den Linden and Kurfürstendamm - too, not instead. Famous streets. Boeing720 (talk) 23:42, 16 August 2018 (UTC)

 * with all due respect, but you can find this sort of scenery in any German city, especially in the failed industry zones at the outskirt of a German city. The graffiti is a urban youth-culture phenomenon in Germany.--MedRobo (talk) 20:55, 9 December 2023 (UTC)

Capital of Prussia as of 1701 ...
I'm certain to have seen 1701 as the year Berlin became Prussia's capital before. But can anyone find a source ? Had a look in our Prussia article. The year is 1701, but no source there either. A German encyclopedia or book on the history of Berlin perhaps ? (Why the American flag, by the way ? Germany is after all not very far away from England - and I think we should use real English here)Boeing720 (talk) 23:27, 16 August 2018 (UTC)

 * Maybe check out our article Margraviate of Brandenburg and Holy Roman Empire for a grand sketch of the european history and later the part of Berlin in it, starting with Charles the Great in the year 800. There was allot of turmoil, many small and some bigger wars in between which makes it hard to pin down the history of Berlin appropriately to single events and dates. I have no clue what flag you are referring to. --Kharon (talk) 03:22, 22 August 2018 (UTC)

Demographics - table of nationalities
I have added figures for "other" totals - calculated by subtracting the figures for the countries in each region that are displayed in the table, from the total given for each region in the source (Europa zusammen pg. 18, Amerika zusammen pg. 20, Asien zusammen pg. 21). and, I appreciate your contributions to updating the table with new figures. In the future it would also be good if you or others are updating the table, to update the "other figures as well. Otherwise a skewed picture of the demographics is given, with over 235,000 people missing... --IamNotU (talk) 13:57, 23 February 2019 (UTC)

Population density
Why is not the population density listed as under most other major cities in Europe?

https://en.wikipedia.org/wiki/List_of_European_Union_cities_proper_by_population_density

The fact that Berlin is a vast city by area is known. As every city can define it´s borders to it´s own liking. What is the reason for the population density not to be shown? Most peculiar. — Preceding unsigned comment added by 83.150.9.77 (talk) 18:57, 7 November 2019 (UTC)

 * WP:SOFIXIT. This might help: https://www.stadtentwicklung.berlin.de/umwelt/umweltatlas/edn606_01.htm --IamNotU (talk) 14:57, 8 November 2019 (UTC)

Climate - disputed edit
, in this edit:, has changed the "Climate" section from:

to:

There are multiple issues with this edit, the main ones being:
 * 1) The added statement fails verification in the added source. The cited article is about Berlin's "rich" groundwater and drinking water resources. It does not mention Berlin's oceanic climate, nor Köppen climate classification, nor climate in general.
 * 2) The added statement is false. The fact that Berlin has an oceanic climate is clearly not in any way because of being rich in groundwater resources.

For these reasons, I removed the added statement, in accordance with WP:V and WP:NOR. Rather than just delete the reference, I moved it to the "Topography" section and added some information about groundwater from it. See this edit:.

In addition, the citation's URL pointed to a Google Translate machine translation of the article. It's my understanding that the consensus reached in this rfc: Village pump (policy)/Archive 130, which specifically addressed this question, was that citations should not link to Google Translate. I changed this, and made some other corrections to the citation (wrong website, poorly-formatted title, etc.).

Kharon reverted my edit as "nonsense", reinstating theirs:. I'm asking for others' opinions and a consensus about this. In the meantime, I have restored the article to the previous status-quo, pending outcome of this discussion. --IamNotU (talk) 23:51, 1 December 2019 (UTC)

Pinging, who has made significant contributions to the "Climate" section recently, and to that sentence. Also pinging, who deleted part of the same sentence earlier that day, without explanation, could you explain why? --IamNotU (talk) 00:26, 2 December 2019 (UTC)

 * I cited the chapter 2 headline of my SOURCE ("Berlin is a water rich federal state") with "because Berlin is a very water rich federal state" to clarify why Berlin is categorized as "oceanic climate" no matter it is in fact not near any ocean.
 * Also i don't care about who thinks what about Google-translate-pages as reference in this case as it is a nonsense complacently argument that actually messes up the source instead of showing the connection (which you consequently missed on top). --Kharon (talk) 03:06, 2 December 2019 (UTC)

 * It has nothing to do with the hydrography of the country, but with patterns and air masses coming from the west but from larger bodies of water such as seas and ocean (North Sea, Baltic Ocean, Atlantic Ocean ...).Kubaski (talk) 23:34, 2 December 2019 (UTC)

Histories of intolerance and racism
I wonder why the article lacks information about the role the city plays within histories of genocides (the Holocaust), racism (as the capital of Germany) and European White Supremacy in general. Instead, the article seems to paint a rosy picture of a post-race paradise for a reason that I could only attribute to self-promoting marketing-oriented Berlin-based and German Wikipedia editors. --2600:1010:B048:BD91:848E:37DE:A1BA:A8C8 (talk) 03:31, 4 March 2020 (UTC)

 * Didn't you read the history section? Alandeus (talk) 10:31, 4 March 2020 (UTC)

Etymology
Changed the intro a bit. Heading east of the confluence of Elbe and Saale, one passes south of Berlin, so the claim of Berlin being to the east of the Saale is a bit tall imho. North to Northeast would be more like it, but given the geography, not east. Keeping in mind that banal facts do not have to be referenced. Berlin is commonly referred to as being east of the Elbe, if a riverine reference is used. Referring the location relative to the Saale as a main description is OR, if not by the author, then by the source. Gotta go now - have to mention in the article of Edinburgh that place's north of the Thames. If you catch my drift. No offense intended, --G-41614 (talk) 08:20, 11 March 2020 (UTC)

Brandenburg Gate
This structure may be iconic, but of european history as suggested in the text? I wouldn't be surprised if there were a lot of europeans who'd beg to differ. As a symbol of change after the Cold War, it would be an icon of global history, and it certainly is such regarding to german history. But explicitly european? Hm. Who said that? Regards, --G-41614 (talk) 06:11, 21 May 2020 (UTC)

 * As there is no reference, you can rephrase it, if you like. --GodeNehler (talk) 05:26, 24 May 2020 (UTC)

No complete darkness
When I was in Germany a couple years ago it only got as far as astronomical twilight, it was astronomical twilight at solar midnight rather than complete darkness. Does Berlin get complete darkness at winter solstice?, Berlin's latitude is 52.5 degrees therefore it falls in astronomical twilight on the summer solstice, complete darkness doesn't occur within 41.5 degrees of either pole on summer solstice.

--98.31.29.4 (talk) 00:22, 16 October 2020 (UTC)

 * How does this relate to the article exactly? If you want to ask a specific scientific question, then please visit Reference desk/Science instead. Best, ɴᴋᴏɴ21  ❯❯❯  talk  00:31, 16 October 2020 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion: Participate in the deletion discussion at the. —Community Tech bot (talk) 19:51, 17 June 2022 (UTC)
 * BER-Destinations.png

Population of Berlin missing
On the side panel Population of city is missing even though it shows on the edit page. 104.3.143.81 (talk) 14:56, 31 January 2023 (UTC)

Date of Hitler’s Berlin design contest seems wrong
I don’t edit Wikipedia so apologies if this isn’t proper procedure but in the 20th-21st century section of the page it says Hitler announced the results of his design contest in 1910. Not sure what the real year is but it should be sometime in the 1930s. 46.183.103.8 (talk) 18:19, 27 May 2023 (UTC)

 * Removed that dubious and rather insignificant passage. Alandeus (talk) 11:58, 30 May 2023 (UTC)

Lua error: not enough memory
This article has around 180 "Lua error: not enough memory" errors at the bottom, currently starting in Berlin. I asked about the issue at Module talk:Mapframe pointing out that it is due to the complex maplink in the infobox. A reply suggested removing the Germany map. Any thoughts on that? WP:VPT could be used to ask if other solutions might work. Johnuniq (talk) 04:38, 23 July 2023 (UTC)
 * I just removed the Germany map and it has resolved the problem. The article HTML source contains a NewPP report with "Lua memory usage: 33158319/52428800 bytes" meaning the memory used is 19MB less than maximum whereas before it was over the maximum. Johnuniq (talk) 08:22, 27 July 2023 (UTC)

Area of Berlin over 1,000 square kilometer?
The German Wikipedia and official sources give the area as 891.7 square kilometers. What's going on here? 2A02:8109:B60F:B300:60E3:E2C4:BB5:E05A (talk) 22:27, 9 November 2023 (UTC)

 * Done Kgfleischmann (talk) 20:03, 10 November 2023 (UTC)

title: Talk:Berlin


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Braille embosser

A braille embosser is an impact printer that renders text as tactile braille cells. Using braille translation software, a document or digital text can be embossed with relative ease. This makes braille production efficient and cost-effective. Braille translation software may be free and open-sourced or paid. Braille embossers can emboss single-sided or double-sided (called interpoint) and can produce 6- or 8-dot braille.

Blind users tend to call other printers "ink printers," to distinguish them from their braille counterparts. This is often the case regardless of the type of printer being discussed (e.g., thermal printers being called "ink printers" even though they use no ink).

As with ink printers and presses, embossers range from those intended for consumers to those used by large publishers. The price of embossers increase with the volume of braille it produces.

Types
The fastest industrial braille embosser is probably the $92,000 Belgian-made NV Interpoint 55, first produced in 1991, which uses a separate air compressor to drive the embossing head and can output up to 800 braille characters per second. Adoption was slow at first; in 2000 the National Federation of the Blind said there were only three of these in the US, one owned by the NFB itself and the other two by the Watchtower Bible and Tract Society. As of 2008, there are more than 60 in use across the world.

Smaller desktop braille embossers are more common and can be found in libraries, universities, and specialist education centers, as well as being privately owned by blind individuals. It may be necessary to use an acoustic cabinet or hood to dampen the noise level.

Braille embossers usually need special braille paper which is thicker and more expensive than normal paper. Some high-end embossers are capable of printing on normal paper. Embossers can be either one-sided or two-sided. Two-sided embossing requires lining up the dots so they do not overlap (called "interpoint" because the points on the other side are placed in between the points on the first side). Two-sided embossing uses less paper and reduces the size of the output.

Once one copy of a document has been produced, printing further copies is often quicker by means of a device called a thermoform, which produces copies on soft plastic. However, the resulting braille is not as easily readable as braille that has been freshly embossed, in much the same way that a poor-quality photocopy is not as readable as the original. Hence large publishers do not generally use thermoforms.

Some embossers can produce "dotty Moon", i.e., Moon type shapes formed by dots.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Braille embosser


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Basic Role-Playing

Basic Role-Playing (BRP) is a tabletop role-playing game which originated in the RuneQuest fantasy role-playing game. Chaosium released the BRP standalone booklet in 1980 in the boxed set release of the second edition of RuneQuest. Greg Stafford and Lynn Willis are credited as the authors. Chaosium used the percentile skill-based system as the basis for most of their games, including Call of Cthulhu, Stormbringer, and Elfquest.

History
The core rules were written by Steve Perrin as part of his game RuneQuest. It was Greg Stafford's idea to simplify the rules (eliminating such mechanics as Strike Ranks and Hit Locations) and issue them in a 16-page booklet called Basic Role-Playing. Since the first BRP release, designers including Sandy Petersen, Lynn Willis, and Steve Henderson, have contributed to the system.

The system was notable for being the first role-playing game system to introduce a full skill system to characters regardless of their profession. This was developed in RuneQuest but was also later adopted by the more skill-oriented Call of Cthulhu RPG.

BRP was conceived of as a generic system. Specific rule systems for support differing genres could be added to the core rules in a modular fashion. In order to underscore this, in 1982 Chaosium released the Worlds of Wonder box set, which contained a revised main booklet and several booklets providing the additional rules for playing in specific genres. The superhero-themed Superworld originated as part of this set. A third edition of the core booklet, now entitled Basic Roleplaying: The Chaosium System, was released in 2002.

In 2004, Chaosium began publishing the Basic Roleplaying monographs, a series of paperback booklets. The first four monographs (Players Book, Magic Book, Creatures Book, and Gamemaster Book) was the same as RuneQuest 3rd Edition, but with trademarked elements removed, as Chaosium had lost the rights to the name but retained copyright to the rules text. Additional monographs allowing for new mechanics, thereby extending the system to other genres, were released in the following years. Many of these monographs reproduced rules from other Chaosium-published BRP games that had gone out of print.

Jason Durall and Sam Johnson gathered up previous works and updated them to a new edition. published in 2008. This comprehensive book, Basic Roleplaying: The Chaosium System nicknamed the "Big Gold Book". It allowed game masters to build their own game out of the included subsystems. A quickstart booklet for new players accompanied it. In 2011, it was updated to a second edition.

In 2020, Chaosium released Basic Roleplaying as a System Reference Document (SRD).

A new edition, entitled Basic Roleplaying: Universal Game Engine, appeared in 2023, initially as a PDF and later as a hardbound book.

Licensed adaptations
Preexisting RPG and fiction settings converted to the system by Chaosium using the BRP ruleset include Ringworld, Hawkmoon, and an adaptation of the French RPG Nephilim.

Rules system
BRP is similar to other generic systems such as GURPS, Hero System, or Savage Worlds in that it uses a simple resolution method which can be broadly applied. It uses a core set of seven characteristics: Size, Strength, Dexterity, Constitution, Intelligence, Power, and Appearance or Charisma. From these, a character derives scores in various skills, expressed as percentages. These skill scores are the basis of play. When attempting an action, the player rolls percentile dice to attempt to get a result equal to or lower than the character's skill score. Each incarnation of the BRP rules changed or added to the core ideas and mechanics, so that games are not identical. For example, in Call of Cthulhu, skills may never be over 100%, while in Stormbringer skills in excess of 100% are within reach for all characters. Scores can increase through experience checks, the mechanics of which vary in an individual game.

The system treats armor and defense as separate: the act of parrying is a defensive skill that reduces an opponent's chance to successfully land an attack, and the purpose of armor is to absorb damage.

In most BRP games there is no difference between the player character race systems and that of monsters or other opponents. By varying ability scores, the same system is used for a human hero as a troll villain. This approach allows for players to play a variety of nonhuman species.

Adaptations of the system
Chaosium was an early adopter of licensing out its BRP system to other companies, something that was unique at the time they began but commonplace now thanks to the d20 licenses. This places BRP in the notable position of being one of the first products to allow other game companies to develop games or game aids for their work. For example, Other Suns, published by Fantasy Games Unlimited, used them under license. BRP was also used as the base for the Swedish game Drakar och Demoner from Target Games.

Reception
In the July 1981 edition of The Space Gamer (Issue No. 41), Ronald Pehr commented that "Basic Role-Playing is too little too late. RuneQuest is long established, does an adequate job of teaching role-playing, and there are now even more games to choose from. If you want to teach role-playing to a very young, but literate, child, Basic Role-Playing is excellent. Otherwise, for all its charm, it's not much use.".

In the August 1981 edition of Dragon (Issue 52), John Sapienza noted that Basic Roleplaying was "not a fantasy role-playing game as such, but a handbook on how to role-play and a simple combat system to help the beginner get into the act." Despite this, Sapienza called it "one of the best introductions to the practical social interactions in gaming that I have read, and will give beginning gamers the kind of guidance they typically do not get in the full-scale games they will graduate to, since game writers usually spend their time on mechanics instead of on the proper relationships between player and player, player and referee, or player and character." He concluded, "Basic Role-Playing is a truly universal introduction to the hobby — highly recommended."

Awards
The BRP itself has been the recipient, via its games, of many awards. Most notable was the 1981 Origins Award for Best Roleplaying Rules of 1981 for Call of Cthulhu. Other editions of Call of Cthulhu have also won Origins Awards including the Hall of Fame award. The BRP Character Generation software has also won awards for its design.

title: Basic Role-Playing


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Block cipher

In cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called blocks. Block ciphers are the elementary building blocks of many cryptographic protocols. They are ubiquitous in the storage and exchange of data, where such data is secured and authenticated via encryption.

A block cipher uses blocks as an unvarying transformation. Even a secure block cipher is suitable for the encryption of only a single block of data at a time, using a fixed key. A multitude of modes of operation have been designed to allow their repeated use in a secure way to achieve the security goals of confidentiality and authenticity. However, block ciphers may also feature as building blocks in other cryptographic protocols, such as universal hash functions and pseudorandom number generators.

Definition
A block cipher consists of two paired algorithms, one for encryption, E, and the other for decryption, D. Both algorithms accept two inputs: an input block of size n bits and a key of size k bits; and both yield an n-bit output block. The decryption algorithm D is defined to be the inverse function of encryption, i.e., $E^{−1}$. More formally, a block cipher is specified by an encryption function
 * $$E_K(P) := E(K,P): \{0,1\}^k \times \{0,1\}^n \rightarrow \{0,1\}^n,$$

which takes as input a key K, of bit length k (called the key size), and a bit string P, of length n (called the block size), and returns a string C of n bits. P is called the plaintext, and C is termed the ciphertext. For each K, the function EK(P) is required to be an invertible mapping on ${0,1}^{ serif$. The inverse for E is defined as a function
 * $$E_K^{-1}(C) := D_K(C) = D(K,C): \{0,1\}^k \times \{0,1\}^n \rightarrow \{0,1\}^n,$$

taking a key K and a ciphertext C to return a plaintext value P, such that
 * $$\forall P: D_K(E_K(P)) = P.$$

For example, a block cipher encryption algorithm might take a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext. The exact transformation is controlled using a second input – the secret key. Decryption is similar: the decryption algorithm takes, in this example, a 128-bit block of ciphertext together with the secret key, and yields the original 128-bit block of plain text.

For each key K, EK is a permutation (a bijective mapping) over the set of input blocks. Each key selects one permutation from the set of $$(2^n)!$$ possible permutations.

History
The modern design of block ciphers is based on the concept of an iterated product cipher. In his seminal 1949 publication, Communication Theory of Secrecy Systems, Claude Shannon analyzed product ciphers and suggested them as a means of effectively improving security by combining simple operations such as substitutions and permutations. Iterated product ciphers carry out encryption in multiple rounds, each of which uses a different subkey derived from the original key. One widespread implementation of such ciphers named a Feistel network after Horst Feistel is notably implemented in the DES cipher. Many other realizations of block ciphers, such as the AES, are classified as substitution–permutation networks.

The root of all cryptographic block formats used within the Payment Card Industry Data Security Standard (PCI DSS) and American National Standards Institute (ANSI) standards lies with the Atalla Key Block (AKB), which was a key innovation of the Atalla Box, the first hardware security module (HSM). It was developed in 1972 by Mohamed M. Atalla, founder of Atalla Corporation (now Utimaco Atalla), and released in 1973. The AKB was a key block, which is required to securely interchange symmetric keys or PINs with other actors in the banking industry. This secure interchange is performed using the AKB format. The Atalla Box protected over 90% of all ATM networks in operation as of 1998, and Atalla products still secure the majority of the world's ATM transactions as of 2014.

The publication of the DES cipher by the United States National Bureau of Standards (subsequently the U.S. National Institute of Standards and Technology, NIST) in 1977 was fundamental in the public understanding of modern block cipher design. It also influenced the academic development of cryptanalytic attacks. Both differential and linear cryptanalysis arose out of studies on DES design. , there is a palette of attack techniques against which a block cipher must be secure, in addition to being robust against brute-force attacks.

Iterated block ciphers
Most block cipher algorithms are classified as iterated block ciphers which means that they transform fixed-size blocks of plaintext into identically sized blocks of ciphertext, via the repeated application of an invertible transformation known as the round function, with each iteration referred to as a round.

Usually, the round function R takes different round keys Ki as a second input, which is derived from the original key:
 * $$M_i = R_{K_i}(M_{i-1})$$

where $$M_0$$ is the plaintext and $$M_r$$ the ciphertext, with r being the number of rounds.

Frequently, key whitening is used in addition to this. At the beginning and the end, the data is modified with key material (often with XOR):
 * $$ M_0 = M \oplus K_0 $$
 * $$M_i = R_{K_i}(M_{i-1})\; ; \; i = 1 \dots r$$
 * $$C = M_r \oplus K_{r+1}$$

Given one of the standard iterated block cipher design schemes, it is fairly easy to construct a block cipher that is cryptographically secure, simply by using a large number of rounds. However, this will make the cipher inefficient. Thus, efficiency is the most important additional design criterion for professional ciphers. Further, a good block cipher is designed to avoid side-channel attacks, such as branch prediction and input-dependent memory accesses that might leak secret data via the cache state or the execution time. In addition, the cipher should be concise, for small hardware and software implementations.

Substitution–permutation networks

One important type of iterated block cipher known as a substitution–permutation network (SPN) takes a block of the plaintext and the key as inputs and applies several alternating rounds consisting of a substitution stage followed by a permutation stage—to produce each block of ciphertext output. The non-linear substitution stage mixes the key bits with those of the plaintext, creating Shannon's confusion. The linear permutation stage then dissipates redundancies, creating diffusion.

A substitution box (S-box) substitutes a small block of input bits with another block of output bits. This substitution must be one-to-one, to ensure invertibility (hence decryption). A secure S-box will have the property that changing one input bit will change about half of the output bits on average, exhibiting what is known as the avalanche effect—i.e. it has the property that each output bit will depend on every input bit.

A permutation box (P-box) is a permutation of all the bits: it takes the outputs of all the S-boxes of one round, permutes the bits, and feeds them into the S-boxes of the next round. A good P-box has the property that the output bits of any S-box are distributed to as many S-box inputs as possible.

At each round, the round key (obtained from the key with some simple operations, for instance, using S-boxes and P-boxes) is combined using some group operation, typically XOR.

Decryption is done by simply reversing the process (using the inverses of the S-boxes and P-boxes and applying the round keys in reversed order).

Feistel ciphers

In a Feistel cipher, the block of plain text to be encrypted is split into two equal-sized halves. The round function is applied to one half, using a subkey, and then the output is XORed with the other half. The two halves are then swapped.

Let $${\rm F}$$ be the round function and let $$K_0,K_1,\ldots,K_{n}$$ be the sub-keys for the rounds $$0,1,\ldots,n$$ respectively.

Then the basic operation is as follows:

Split the plaintext block into two equal pieces, ($$L_0$$, $$R_0$$)

For each round $$i =0,1,\dots,n$$, compute

 * $$L_{i+1} = R_i\,$$
 * $$R_{i+1}= L_i \oplus {\rm F}(R_i, K_i)$$.

Then the ciphertext is $$(R_{n+1}, L_{n+1})$$.

The decryption of a ciphertext $$(R_{n+1}, L_{n+1})$$ is accomplished by computing for $$i=n,n-1,\ldots,0$$

 * $$R_{i} = L_{i+1}\,$$
 * $$L_{i} = R_{i+1} \oplus {\rm F}(L_{i+1}, K_{i})$$.

Then $$(L_0,R_0)$$ is the plaintext again.

One advantage of the Feistel model compared to a substitution–permutation network is that the round function $${\rm F}$$ does not have to be invertible.

Lai–Massey ciphers

The Lai–Massey scheme offers security properties similar to those of the Feistel structure. It also shares the advantage that the round function $$\mathrm F$$ does not have to be invertible. Another similarity is that it also splits the input block into two equal pieces. However, the round function is applied to the difference between the two, and the result is then added to both half blocks.

Let $$\mathrm F$$ be the round function and $$\mathrm H$$ a half-round function and let $$K_0,K_1,\ldots,K_n$$ be the sub-keys for the rounds $$0,1,\ldots,n$$ respectively.

Then the basic operation is as follows:

Split the plaintext block into two equal pieces, ($$L_0$$, $$R_0$$)

For each round $$i =0,1,\dots,n$$, compute

 * $$(L_{i+1}',R_{i+1}') = \mathrm H(L_i' + T_i,R_i' + T_i),$$

where $$T_i = \mathrm F(L_i' - R_i', K_i)$$ and $$(L_0',R_0') = \mathrm H(L_0,R_0)$$

Then the ciphertext is $$(L_{n+1}, R_{n+1}) = (L_{n+1}',R_{n+1}')$$.

The decryption of a ciphertext $$(L_{n+1}, R_{n+1})$$ is accomplished by computing for $$i=n,n-1,\ldots,0$$

 * $$(L_i',R_i') = \mathrm H^{-1}(L_{i+1}' - T_i, R_{i+1}' - T_i)$$

where $$T_i = \mathrm F(L_{i+1}' - R_{i+1}',K_i)$$ and $$(L_{n+1}',R_{n+1}')=\mathrm H^{-1}(L_{n+1},R_{n+1})$$

Then $$(L_0,R_0) = (L_0',R_0')$$ is the plaintext again.

ARX (add–rotate–XOR)
Many modern block ciphers and hashes are ARX algorithms—their round function involves only three operations: (A) modular addition, (R) rotation with fixed rotation amounts, and (X) XOR. Examples include ChaCha20, Speck, XXTEA, and BLAKE. Many authors draw an ARX network, a kind of data flow diagram, to illustrate such a round function.

These ARX operations are popular because they are relatively fast and cheap in hardware and software, their implementation can be made extremely simple, and also because they run in constant time, and therefore are immune to timing attacks. The rotational cryptanalysis technique attempts to attack such round functions.

Other operations
Other operations often used in block ciphers include data-dependent rotations as in RC5 and RC6, a substitution box implemented as a lookup table as in Data Encryption Standard and Advanced Encryption Standard, a permutation box, and multiplication as in IDEA.

Modes of operation
A block cipher by itself allows encryption only of a single data block of the cipher's block length. For a variable-length message, the data must first be partitioned into separate cipher blocks. In the simplest case, known as electronic codebook (ECB) mode, a message is first split into separate blocks of the cipher's block size (possibly extending the last block with padding bits), and then each block is encrypted and decrypted independently. However, such a naive method is generally insecure because equal plaintext blocks will always generate equal ciphertext blocks (for the same key), so patterns in the plaintext message become evident in the ciphertext output.

To overcome this limitation, several so-called block cipher modes of operation have been designed and specified in national recommendations such as NIST 800-38A and BSI TR-02102 and international standards such as ISO/IEC 10116. The general concept is to use randomization of the plaintext data based on an additional input value, frequently called an initialization vector, to create what is termed probabilistic encryption. In the popular cipher block chaining (CBC) mode, for encryption to be secure the initialization vector passed along with the plaintext message must be a random or pseudo-random value, which is added in an exclusive-or manner to the first plaintext block before it is encrypted. The resultant ciphertext block is then used as the new initialization vector for the next plaintext block. In the cipher feedback (CFB) mode, which emulates a self-synchronizing stream cipher, the initialization vector is first encrypted and then added to the plaintext block. The output feedback (OFB) mode repeatedly encrypts the initialization vector to create a key stream for the emulation of a synchronous stream cipher. The newer counter (CTR) mode similarly creates a key stream, but has the advantage of only needing unique and not (pseudo-)random values as initialization vectors; the needed randomness is derived internally by using the initialization vector as a block counter and encrypting this counter for each block.

From a security-theoretic point of view, modes of operation must provide what is known as semantic security. Informally, it means that given some ciphertext under an unknown key one cannot practically derive any information from the ciphertext (other than the length of the message) over what one would have known without seeing the ciphertext. It has been shown that all of the modes discussed above, with the exception of the ECB mode, provide this property under so-called chosen plaintext attacks.

Padding
Some modes such as the CBC mode only operate on complete plaintext blocks. Simply extending the last block of a message with zero bits is insufficient since it does not allow a receiver to easily distinguish messages that differ only in the number of padding bits. More importantly, such a simple solution gives rise to very efficient padding oracle attacks. A suitable padding scheme is therefore needed to extend the last plaintext block to the cipher's block size. While many popular schemes described in standards and in the literature have been shown to be vulnerable to padding oracle attacks, a solution that adds a one-bit and then extends the last block with zero-bits, standardized as "padding method 2" in ISO/IEC 9797-1, has been proven secure against these attacks.

Brute-force attacks
This property results in the cipher's security degrading quadratically, and needs to be taken into account when selecting a block size. There is a trade-off though as large block sizes can result in the algorithm becoming inefficient to operate. Earlier block ciphers such as the DES have typically selected a 64-bit block size, while newer designs such as the AES support block sizes of 128 bits or more, with some ciphers supporting a range of different block sizes.

Linear cryptanalysis
A linear cryptanalysis is a form of cryptanalysis based on finding affine approximations to the action of a cipher. Linear cryptanalysis is one of the two most widely used attacks on block ciphers; the other being differential cryptanalysis.

The discovery is attributed to Mitsuru Matsui, who first applied the technique to the FEAL cipher (Matsui and Yamagishi, 1992).

Integral cryptanalysis
Integral cryptanalysis is a cryptanalytic attack that is particularly applicable to block ciphers based on substitution–permutation networks. Unlike differential cryptanalysis, which uses pairs of chosen plaintexts with a fixed XOR difference, integral cryptanalysis uses sets or even multisets of chosen plaintexts of which part is held constant and another part varies through all possibilities. For example, an attack might use 256 chosen plaintexts that have all but 8 of their bits the same, but all differ in those 8 bits. Such a set necessarily has an XOR sum of 0, and the XOR sums of the corresponding sets of ciphertexts provide information about the cipher's operation. This contrast between the differences between pairs of texts and the sums of larger sets of texts inspired the name "integral cryptanalysis", borrowing the terminology of calculus.

Other techniques
In addition to linear and differential cryptanalysis, there is a growing catalog of attacks: truncated differential cryptanalysis, partial differential cryptanalysis, integral cryptanalysis, which encompasses square and integral attacks, slide attacks, boomerang attacks, the XSL attack, impossible differential cryptanalysis, and algebraic attacks. For a new block cipher design to have any credibility, it must demonstrate evidence of security against known attacks.

Provable security
When a block cipher is used in a given mode of operation, the resulting algorithm should ideally be about as secure as the block cipher itself. ECB (discussed above) emphatically lacks this property: regardless of how secure the underlying block cipher is, ECB mode can easily be attacked. On the other hand, CBC mode can be proven to be secure under the assumption that the underlying block cipher is likewise secure. Note, however, that making statements like this requires formal mathematical definitions for what it means for an encryption algorithm or a block cipher to "be secure". This section describes two common notions for what properties a block cipher should have. Each corresponds to a mathematical model that can be used to prove properties of higher-level algorithms, such as CBC.

This general approach to cryptography – proving higher-level algorithms (such as CBC) are secure under explicitly stated assumptions regarding their components (such as a block cipher) – is known as provable security.

Standard model
Informally, a block cipher is secure in the standard model if an attacker cannot tell the difference between the block cipher (equipped with a random key) and a random permutation.

To be a bit more precise, let E be an n-bit block cipher. We imagine the following game:
 * 1) The person running the game flips a coin.
 * 2) * If the coin lands on heads, he chooses a random key K and defines the function f = EK.
 * 3) * If the coin lands on tails, he chooses a random permutation $\pi$ on the set of n-bit strings and defines the function f = π.
 * 4) The attacker chooses an n-bit string X, and the person running the game tells him the value of f(X).
 * 5) Step 2 is repeated a total of q times. (Each of these q interactions is a query.)
 * 6) The attacker guesses how the coin landed. He wins if his guess is correct.

The attacker, which we can model as an algorithm, is called an adversary. The function f (which the adversary was able to query) is called an oracle.

Note that an adversary can trivially ensure a 50% chance of winning simply by guessing at random (or even by, for example, always guessing "heads"). Therefore, let PE(A) denote the probability that adversary A wins this game against E, and define the advantage of A as 2(PE(A) − 1/2). It follows that if A guesses randomly, its advantage will be 0; on the other hand, if A always wins, then its advantage is 1. The block cipher E is a pseudo-random permutation (PRP) if no adversary has an advantage significantly greater than 0, given specified restrictions on q and the adversary's running time. If in Step 2 above adversaries have the option of learning f−1(X) instead of f(X) (but still have only small advantages) then E is a strong PRP (SPRP). An adversary is non-adaptive if it chooses all q values for X before the game begins (that is, it does not use any information gleaned from previous queries to choose each X as it goes).

These definitions have proven useful for analyzing various modes of operation. For example, one can define a similar game for measuring the security of a block cipher-based encryption algorithm, and then try to show (through a reduction argument) that the probability of an adversary winning this new game is not much more than PE(A) for some A. (The reduction typically provides limits on q and the running time of A.) Equivalently, if PE(A) is small for all relevant A, then no attacker has a significant probability of winning the new game. This formalizes the idea that the higher-level algorithm inherits the block cipher's security.

Practical evaluation
Block ciphers may be evaluated according to multiple criteria in practice. Common factors include:
 * Key parameters, such as its key size and block size, both of which provide an upper bound on the security of the cipher.
 * The estimated security level, which is based on the confidence gained in the block cipher design after it has largely withstood major efforts in cryptanalysis over time, the design's mathematical soundness, and the existence of practical or certificational attacks.
 * The cipher's complexity and its suitability for implementation in hardware or software. Hardware implementations may measure the complexity in terms of gate count or energy consumption, which are important parameters for resource-constrained devices.
 * The cipher's performance in terms of processing throughput on various platforms, including its memory requirements.
 * The cost of the cipher refers to licensing requirements that may apply due to intellectual property rights.
 * The flexibility of the cipher includes its ability to support multiple key sizes and block lengths.

Lucifer / DES
Lucifer is generally considered to be the first civilian block cipher, developed at IBM in the 1970s based on work done by Horst Feistel. A revised version of the algorithm was adopted as a U.S. government Federal Information Processing Standard: FIPS PUB 46 Data Encryption Standard (DES). It was chosen by the U.S. National Bureau of Standards (NBS) after a public invitation for submissions and some internal changes by NBS (and, potentially, the NSA). DES was publicly released in 1976 and has been widely used.

DES was designed to, among other things, resist a certain cryptanalytic attack known to the NSA and rediscovered by IBM, though unknown publicly until rediscovered again and published by Eli Biham and Adi Shamir in the late 1980s. The technique is called differential cryptanalysis and remains one of the few general attacks against block ciphers; linear cryptanalysis is another but may have been unknown even to the NSA, prior to its publication by Mitsuru Matsui. DES prompted a large amount of other work and publications in cryptography and cryptanalysis in the open community and it inspired many new cipher designs.

DES has a block size of 64 bits and a key size of 56 bits. 64-bit blocks became common in block cipher designs after DES. Key length depended on several factors, including government regulation. Many observers in the 1970s commented that the 56-bit key length used for DES was too short. As time went on, its inadequacy became apparent, especially after a special-purpose machine designed to break DES was demonstrated in 1998 by the Electronic Frontier Foundation. An extension to DES, Triple DES, triple-encrypts each block with either two independent keys (112-bit key and 80-bit security) or three independent keys (168-bit key and 112-bit security). It was widely adopted as a replacement. As of 2011, the three-key version is still considered secure, though the National Institute of Standards and Technology (NIST) standards no longer permit the use of the two-key version in new applications, due to its 80-bit security level.

IDEA
The International Data Encryption Algorithm (IDEA) is a block cipher designed by James Massey of ETH Zurich and Xuejia Lai; it was first described in 1991, as an intended replacement for DES.

IDEA operates on 64-bit blocks using a 128-bit key and consists of a series of eight identical transformations (a round) and an output transformation (the half-round). The processes for encryption and decryption are similar. IDEA derives much of its security by interleaving operations from different groups – modular addition and multiplication, and bitwise exclusive or (XOR) – which are algebraically "incompatible" in some sense.

The designers analysed IDEA to measure its strength against differential cryptanalysis and concluded that it is immune under certain assumptions. No successful linear or algebraic weaknesses have been reported. , the best attack which applies to all keys can break a full 8.5-round IDEA using a narrow-bicliques attack about four times faster than brute force.

RC5

RC5 is a block cipher designed by Ronald Rivest in 1994 which, unlike many other ciphers, has a variable block size (32, 64, or 128 bits), key size (0 to 2040 bits), and a number of rounds (0 to 255). The original suggested choice of parameters was a block size of 64 bits, a 128-bit key, and 12 rounds.

A key feature of RC5 is the use of data-dependent rotations; one of the goals of RC5 was to prompt the study and evaluation of such operations as a cryptographic primitive. RC5 also consists of a number of modular additions and XORs. The general structure of the algorithm is a Feistel-like a network. The encryption and decryption routines can be specified in a few lines of code. The key schedule, however, is more complex, expanding the key using an essentially one-way function with the binary expansions of both e and the golden ratio as sources of "nothing up my sleeve numbers". The tantalizing simplicity of the algorithm together with the novelty of the data-dependent rotations has made RC5 an attractive object of study for cryptanalysts.

12-round RC5 (with 64-bit blocks) is susceptible to a differential attack using 244 chosen plaintexts. 18–20 rounds are suggested as sufficient protection.

Rijndael / AES
The Rijndael cipher developed by Belgian cryptographers, Joan Daemen and Vincent Rijmen was one of the competing designs to replace DES. It won the 5-year public competition to become the AES, (Advanced Encryption Standard).

Adopted by NIST in 2001, AES has a fixed block size of 128 bits and a key size of 128, 192, or 256 bits, whereas Rijndael can be specified with block and key sizes in any multiple of 32 bits, with a minimum of 128 bits. The block size has a maximum of 256 bits, but the key size has no theoretical maximum. AES operates on a 4×4 column-major order matrix of bytes, termed the state (versions of Rijndael with a larger block size have additional columns in the state).

Blowfish
Blowfish is a block cipher, designed in 1993 by Bruce Schneier and included in a large number of cipher suites and encryption products. Blowfish has a 64-bit block size and a variable key length from 1 bit up to 448 bits. It is a 16-round Feistel cipher and uses large key-dependent S-boxes. Notable features of the design include the key-dependent S-boxes and a highly complex key schedule.

It was designed as a general-purpose algorithm, intended as an alternative to the aging DES and free of the problems and constraints associated with other algorithms. At the time Blowfish was released, many other designs were proprietary, encumbered by patents, or were commercial/government secrets. Schneier has stated that "Blowfish is unpatented, and will remain so in all countries. The algorithm is hereby placed in the public domain, and can be freely used by anyone." The same applies to Twofish, a successor algorithm from Schneier.

Tweakable block ciphers
M. Liskov, R. Rivest, and D. Wagner have described a generalized version of block ciphers called "tweakable" block ciphers. A tweakable block cipher accepts a second input called the tweak along with its usual plaintext or ciphertext input. The tweak, along with the key, selects the permutation computed by the cipher. If changing tweaks is sufficiently lightweight (compared with a usually fairly expensive key setup operation), then some interesting new operation modes become possible. The disk encryption theory article describes some of these modes.

Format-preserving encryption
Block ciphers traditionally work over a binary alphabet. That is, both the input and the output are binary strings, consisting of n zeroes and ones. In some situations, however, one may wish to have a block cipher that works over some other alphabet; for example, encrypting 16-digit credit card numbers in such a way that the ciphertext is also a 16-digit number might facilitate adding an encryption layer to legacy software. This is an example of format-preserving encryption. More generally, format-preserving encryption requires a keyed permutation on some finite language. This makes format-preserving encryption schemes a natural generalization of (tweakable) block ciphers. In contrast, traditional encryption schemes, such as CBC, are not permutations because the same plaintext can encrypt multiple different ciphertexts, even when using a fixed key.

Relation to other cryptographic primitives
Block ciphers can be used to build other cryptographic primitives, such as those below. For these other primitives to be cryptographically secure, care has to be taken to build them the right way.

 * Stream ciphers can be built using block ciphers. OFB mode and CTR mode are block modes that turn a block cipher into a stream cipher.
 * Cryptographic hash functions can be built using block ciphers. See the one-way compression function for descriptions of several such methods. The methods resemble the block cipher modes of operation usually used for encryption.
 * Cryptographically secure pseudorandom number generators (CSPRNGs) can be built using block ciphers.
 * Secure pseudorandom permutations of arbitrarily sized finite sets can be constructed with block ciphers; see Format-Preserving Encryption.
 * A publicly known unpredictable permutation combined with key whitening is enough to construct a block cipher -- such as the single-key Even–Mansour cipher, perhaps the simplest possible provably secure block cipher.
 * Message authentication codes (MACs) are often built from block ciphers. CBC-MAC, OMAC, and PMAC are such MACs.
 * Authenticated encryption is also built from block ciphers. It means to both encrypt and MAC at the same time. That is to both provide confidentiality and authentication. CCM, EAX, GCM, and OCB are such authenticated encryption modes.

Just as block ciphers can be used to build hash functions, like SHA-1 and SHA-2 are based on block ciphers which are also used independently as SHACAL, hash functions can be used to build block ciphers. Examples of such block ciphers are BEAR and LION.

title: Block cipher


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Wireless broadband

Wireless broadband is a telecommunications technology that provides high-speed wireless Internet access or computer networking access over a wide area. The term encompasses both fixed and mobile broadband.

The term broadband
Originally the word "broadband" had a technical meaning, but became a marketing term for any kind of relatively high-speed computer network or Internet access technology. According to the 802.16-2004 standard, broadband means "having instantaneous bandwidths greater than 1 MHz and supporting data rates greater than about 1.5 Mbit/s." The Federal Communications Commission (FCC) recently re-defined the definition to mean download speeds of at least 25 Mbit/s and upload speeds of at least 3 Mbit/s.

Technology and speeds
A wireless broadband network is an outdoor fixed and/or mobile wireless network providing point-to-multipoint or point-to-point terrestrial wireless links for broadband services.

Wireless networks can feature data rates exceeding 1 Gbit/s. Many fixed wireless networks are exclusively half-duplex (HDX), however, some licensed and unlicensed systems can also operate at full-duplex (FDX) allowing communication in both directions simultaneously.

Outdoor fixed wireless broadband networks commonly utilize a priority TDMA based protocol   in order to divide communication into timeslots. This timeslot technique eliminates many of the issues common to 802.11 Wi-Fi protocol in outdoor networks such as the hidden node problem.

Few wireless Internet service providers (WISPs) provide download speeds of over 100 Mbit/s; most broadband wireless access (BWA) services are estimated to have a range of 50 km from a tower. Technologies used include Local Multipoint Distribution Service (LMDS) and Multichannel Multipoint Distribution Service (MMDS), as well as heavy use of the industrial, scientific and medical (ISM) radio bands and one particular access technology was standardized by IEEE 802.16, with products known as WiMAX.

WiMAX is highly popular in Europe but has not met full acceptance in the United States because cost of deployment does not meet return on investment figures. In 2005 the Federal Communications Commission adopted a Report and Order that revised the FCC's rules to open the 3650 MHz band for terrestrial wireless broadband operations.

Another system that is popular with cable internet service providers uses point-to-multipoint wireless links that extend the existing wired network using a transparent radio connection. This allows the same DOCSIS modems to be used for both wired and wireless customers.

Development of Wireless Broadband in the United States
On November 14, 2007 the Commission released Public Notice DA 07–4605 in which the Wireless Telecommunications Bureau announced the start date for licensing and registration process for the 3650–3700 MHz band. In 2010 the FCC adopted the TV White Space Rules (TVWS) and allowed some of the better no line of sight frequency (700 MHz) into the FCC Part-15 Rules. The Wireless Internet Service Providers Association, a national association of WISPs, petitioned the FCC and won.

Initially, WISPs were only found in rural areas not covered by cable or DSL. These early WISPs would employ a high-capacity T-carrier, such as a T1 or DS3 connection, and then broadcast the signal from a high elevation, such as at the top of a water tower. To receive this type of Internet connection, consumers mount a small dish to the roof of their home or office and point it to the transmitter. Line of sight is usually necessary for WISPs operating in the 2.4 and 5 GHz bands with 900 MHz offering better NLOS (non-line-of-sight) performance.

Residential Wireless Internet
Providers of fixed wireless broadband services typically provide equipment to customers and install a small antenna or dish somewhere on the roof. This equipment is usually deployed as a service and maintained by the company providing that service. Fixed wireless services have become particularly popular in many rural areas where cable, DSL or other typical home internet services are not available.

Business Wireless Internet
Many companies in the US and worldwide have started using wireless alternatives to incumbent and local providers for internet and voice service. These providers tend to offer competitive services and options in areas where there is a difficulty getting affordable Ethernet connections from terrestrial providers such as ATT, Comcast, Verizon and others. Also, companies looking for full diversity between carriers for critical uptime requirements may seek wireless alternatives to local options.

Demand for spectrum
To cope with increased demand for wireless broadband, increased spectrum would be needed. Studies began in 2009, and while some unused spectrum was available, it appeared broadcasters would have to give up at least some spectrum. This led to strong objections from the broadcasting community. In 2013, auctions were planned, and for now any action by broadcasters is voluntary.

Mobile wireless broadband
Called mobile broadband, wireless broadband technologies include services from mobile phone service providers such as Verizon Wireless, Sprint Corporation, and AT&T Mobility, and T-Mobile which allow a more mobile version of Internet access. Consumers can purchase a PC card, laptop card, USB equipment, or mobile broadband modem, to connect their PC or laptop to the Internet via cell phone towers. This type of connection would be stable in almost any area that could also receive a strong cell phone connection. These connections can cost more for portable convenience as well as having speed limitations in all but urban environments.

On June 2, 2010, after months of discussion, AT&T became the first wireless Internet provider in the US to announce plans to charge according to usage. As the only iPhone service in the United States, AT&T experienced the problem of heavy Internet use more than other providers. About 3 percent of AT&T smart phone customers account for 40 percent of the technology's use. 98 percent of the company's customers use less than 2 gigabytes (4000 page views, 10,000 emails or 200 minutes of streaming video), the limit under the $25 monthly plan, and 65 percent use less than 200 megabytes, the limit for the $15 plan. For each gigabyte in excess of the limit, customers would be charged $10 a month starting June 7, 2010, though existing customers would not be required to change from the $30 a month unlimited service plan. The new plan would become a requirement for those upgrading to the new iPhone technology later in the summer.

Licensing
A wireless connection can be either licensed or unlicensed. In the US, licensed connections use a private spectrum the user has secured rights to from the Federal Communications Commission (FCC). The unlicensed mobile wireless broadband, in US operates on CBRS Which has three tiers. Tier 1 – Incumbent Access, reserved for US Federals Government, Tier 2 – Priority Access, a paid access with priority on the spectrum, Tier 3 – General Authorized Access (GAA), a shared spectrum. In other countries, spectrum is licensed from the country's national radio communications authority (such as the ACMA in Australia or Nigerian Communications Commission in Nigeria (NCC)). Licensing is usually expensive and often reserved for large companies who wish to guarantee private access to spectrum for use in point to point communication. Because of this, most wireless ISP's use unlicensed spectrum which is publicly shared.

title: Wireless broadband