Talk:Affine cipher

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Good changes thus far. I really like the python script you added for the encryption method. One thing that would be nice would be if you tried to make it a little less esoteric, or even better, supplement the really esoteric parts with further explanations of the concepts. Good stuff otherwise. --Arjun X3nodox (talk) 04:31, 14 April 2009 (UTC)

Stuart-I think that the changes you have made to the page on the Affine Cipher are good. I like that you added the examples for encryption and decryption because it makes it much easier to understand how the cipher works. The only part of that section that I think is a bit confusing is why the numbers 5 and 8 are chosen for that formula. If you know why, maybe you could find a way to just explain that on the page. I also couldn't tell if you were the one who added the section on the weaknesses, but that section is good and should remain on the page. The only other information I would add to the page is maybe how the cipher first came about (who created it or when the cipher was first used) if you happen to know these details. ~Sam~ 123samantha (talk) 21:04, 13 April 2009 (UTC)

So, is this cipher actually secure or not? The article is ambiguous --Az 19:17, 18 October 2006 (UTC)

Not: monoalphabetic substitution ciphers are normally quite insecure. The article references substitution cipher for more detail on the security of these sorts of schemes. — Matt Crypto 19:28, 18 October 2006 (UTC)

286?

Where does the number 286 come from for non-trivial English affine ciphers? 72.197.74.80 (talk) 04:55, 10 August 2008 (UTC)

286 is correct. It is 11 * 26. There are only eleven co-primes of 26 that are also less than 26. The text shows 312, which is 12 * 26. Of the twenty-five integers less than 26, twelve are even (and not co-prime because of the shared factor of 2), one (the integer 1) is not prime, and one (the integer 13) is not co-prime (with a shared factor of 13). This leaves eleven (3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25). The page should be edited, but I don't feel confident enough to do that, yet, as I'm not sure that I understand how the value for other factor (26, for "b") makes sense. 175.45.146.223 (talk) 06:55, 15 April 2017 (UTC)

Development?

Who developed this cipher, and where has it been used? By the way the Examples section seems to be lifted from the handout in the References. Not sure if that is okay... Rofflebuster (talk) 14:56, 13 April 2009 (UTC)

~Sam~ The reasons why 5 & 8 are chosen for the example are these. The number 5 is a coprime of 26, which is the modulo. Coprime is a pair of numbers whose Greatest Common Divisor is 1. Being 5 → 1 and 5; 26 → 1, 2, 13, and 26. If you do not use a coprime number of your modulo, you won't be able to decipher your ciphertext because you cannot get the multiplicative inverse modulo of ${\displaystyle a}$.

Number 8 is just a random number chosen to shift the letters, like in Ceasar's Cipher. Actually you can omitt this or give it a value of 0 but do not use 1 as your value for ${\displaystyle a}$ because your plaintext won't be enciphered. Karyuudo Ketsueki (talk) 14:22, 17 April 2009 (UTC)