Editing 153: Cryptography
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==Explanation== | ==Explanation== | ||
− | This comic | + | This comic, as the name implies, is relevant to the study of {{w|cryptography}}. At the podium, [[Cueball]] is describing a proposed crypto system (a computer program that turns a very large number, called the "{{w|key (cryptography)|key}}", and a message into an encrypted form that can only be read by using the same key), based on the model of a {{w|Feistel cipher}}. Part of any Feistel cipher is the "round function", which determines how the key is applied to the original message; this is applied multiple times with a variety of tricks and techniques to insure the process can eventually be reversed. One common component of round functions is the {{w|S-box}}, a simple table that converts input bytes into output bytes, preferably in a way that doesn't correspond to any mathematical rules. |
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Here, the S-box would be implemented by doing the following (with the computer operation actually shown in the diagrams indicated in parentheses): | Here, the S-box would be implemented by doing the following (with the computer operation actually shown in the diagrams indicated in parentheses): | ||
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#Reverse it (run the bits in the opposite order) | #Reverse it (run the bits in the opposite order) | ||
− | This would be run on each round of the cipher to further scramble the message for the next round. As the caption implies, the steps are based on a line from the {{w|Missy Elliott}} song ''{{w|Work It (Missy Elliott song)|Work It}}'': | + | This would be run on each round of the cipher to further scramble the message for the next round. As the caption implies, the steps are based on a line from the {{w|Missy Elliott}} song ''{{w|Work It (Missy Elliott song)|Work It}}'': "I put my thing down, flip it and reverse it." |
− | The {{w|Key space (cryptography)|keyspace}} for a cryptographic algorithm is the number of possible keys the algorithm can possibly accept. For example, {{w|Advanced Encryption Standard|AES-256}} has a keyspace of 2<sup>256</sup> (roughly 1.1579209e+77) possible keys, simply because the algorithm specifies that each key is 256 bits wide. The title text is referring to "searching a keyspace, | + | The {{w|Key space (cryptography)|keyspace}} for a cryptographic algorithm is the number of possible keys the algorithm can possibly accept. For example, {{w|Advanced Encryption Standard|AES-256}} has a keyspace of 2<sup>256</sup> (roughly 1.1579209e+77) possible keys, simply because the algorithm specifies that each key is 256 bits wide. The title text is referring to "searching a keyspace", which is to say, simply trying every key until you find one that works. (For reference, a computer would require roughly the energy of a billion billion supernovas to even count to 2<sup>256</sup>, let alone actually try each one.) The precise wording "If you got a big keyspace, let me search it" is, of course, another reference to the same song: "If you got a big **** let me search ya." (The **** in the song is apparently the sound of an elephant, but it is heavily implied from context to be "penis".) |
− | + | Cueball is banned from multiple conferences for similar pranks ([[541: TED Talk]]) and so is the author Randall Munroe at [http://pycon.blogspot.com/2009/02/randall-munroe.html PyCon]. | |
==Transcript== | ==Transcript== | ||
− | :[ | + | :[Cueball at a podium.] |
− | : | + | :Cueball: My cryptosystem is like any Feistel cipher, except in the S-Boxes we simply take the bitstring down, flip it, and reverse it. |
− | + | :I've been barred from speaking at any major cryptography conferences ever since it became clear that all my algorithms were just thinly disguised Missy Elliot songs. | |
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− | :I've been barred from speaking at any major cryptography conferences ever since it became clear that all my algorithms were just thinly disguised Missy | ||
{{comic discussion}} | {{comic discussion}} | ||
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[[Category:Comics featuring Cueball]] | [[Category:Comics featuring Cueball]] | ||
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