Talk:Blowfish (cipher)
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[edit] Endianness
Anyone inclined to talk about endianness issues with implementations? Including efficiency questions about using htonl() and ntohl() or equivalent?
[edit] Disambiguation?
Isn't a blowfish a kind of, well, fish? And what about Hootie and the?
Errr, possibly, but not in my country. I guess this is the reason that the data compression algorithms are all subpages. Maybe encryption algorithms should be too, to make sure they don't clash with more mundane topics of the same name. Not a problem for RC4 and triple-Des, but there is a Tiger and a Serpent. Anyway, i just wrote this because there was an open link to it from one of the crypto pages. Better track that down and fix it if this moves.
Added a note on the same. The fish is usually called a puffer, so the collision between the two isn't too bad. :)
[edit] Question
What does "symmetric, secret key, block cypher" mean? --LMS
- "symmetric, and secret key" means that it uses the same secret key for both encryption and decryption (compare public key cryptography), and "block cipher" means it encrypts data a block at a time (compare stream cipher).
What is the time complexity of the blowfish encryption/decryption algorithm? --DWB
- Quite obviously, O(1) for a single block, O(n) for n blocks since the number of rounds is constant regardless of key size. -- intgr 22:25, 27 September 2006 (UTC)
[edit] The removal of cryptoanalysis result by Schmidt
On an email correspondense, I pointed out to Dieter Schmidt that the conclusion of his cryptoanalysis paper is wrong, and after this he retracted his article. The problem is, that while subkeys P3 and P4 do not depend on P1 and P2 (and this is a somewhat interesting observation), this does not mean that P3 and P4 do not depend on 64 bits of userkey. This is because the userkey bits will be cycled into the P-array, before any subkey encryptions take place. So if, for example, the userkey is 448 bits long, the first 64 bits will go to P1 and P2, and ALSO into P15 and P16. Then, P15 and P16 (and thus the first 64 bits) WILL affect the encryption iteration whose final value will be put into P3 and P4. -- 84.251.21.229 13:04, 28 August 2006 (UTC)
- Thanks for letting us know. (The paper has been withdrawn from ePrint: [1]). — Matt Crypto 13:31, 28 August 2006 (UTC)
[edit] "Diagram on the right" isn't
Somewhere along the line a diagram went missing. The second paragraph refers to "the diagram on the right" that describes the F-function, but there is only one diagram. --Joe Sewell 20:58, 27 September 2006 (UTC)
- I can see two diagrams - one on the right in the infobox, and the other on the left under the "The algorithm" section. This particular paragraph refers to the image in the infobox. Now that I see it, I agree that it can be confusing. Unfortunately, moving infobox around is out of the question, and duplicating the image would be silly as well. Any ideas how to improve it? -- intgr 22:16, 27 September 2006 (UTC)
[edit] Why is this algorithm called 'blowfish'?
If I look at the image, I would think it's called 'blowfish' because it blows up the plaintext while encrypting (the S-boxes have an 8-bit input and a 32-bit output). If someone knows the official reason or explanation why this algorithm is called 'blowfish', please add it to the article. --Bernard François 15:37, 15 October 2006 (UTC)
- My memory is that the analogy was to the pufferfish which defends itself well by both armed and poisonous. A good cypher algorithm would do something similar, metaphorically. Having said that, however, I can't connect it to any particular source, and so I'm not sure it belongs in the article. ww 02:18, 16 October 2006 (UTC)
- Actually the pufferfish is also called blowfish. It blows itself up like a balloon to impress. The input of the S-boxes gets blown up in a similar way... --Bernard François 15:52, 5 January 2007 (UTC)