Re: RC5 algorithm

'b' is the length of the key. In this case it will always be 9 bytes long.
RC5 is a stream algorithm. I should be able to encode the first two
blocks [64 bits, 8 bytes] and get the same output. There is nothing in
the algorithm which cares about the rest of the message. I could be
wrong, but I don't think I am [of course].
--
Martin

Michael Meeuwisse wrote:

> AFAIK because you're not using the entire plaintext input, but only
> the first bit, the end cipher is different from what you see on the
> RSA web page.
> This is because your keytable (S[]) is builded with a messed up input
> (key[]) in L[], which in turn will be different depending on the
> length (b) of your input.
> That's also why John didn't end up with an error, since the algorithm
> used is still correct. :)
>
> [: wacco :]
>
>> From: Martin Klingensmith <[email protected]>
>>
>> The ciphertext should match the ciphertext on the RSA website, should it
>> not? Check here:
>> <http://www.rsasecurity.com/rsalabs/node.asp?id=2105>
>> "RC5-32/12/9-test"
>>
>> key: c9 0c 03 53 c0 d4 e1 fe 85
>> plaintext, first two 32-bit words: 54 68 65 20 75 6e 6b 6e
>> ciphertext: 5a 28 2d 56 2a 85 b7 2f
>>
>> -- 
>> Martin Klingensmith
>>
>> John L. Bass wrote:
>>
>> >What architecture cpu are you running your tests on?
>> >
>> >Works fine from:
>> >
>> >    [jbass@dmsd ~]$ uname -a
>> >    Linux dmsd.com 2.6.10-1.770_FC3smp #1 SMP Thu Feb 24 14:20:06
>> EST 2005 i686 i686 i386 GNU/Linux
>> >    [jbass@dmsd ~]$ vi rc5ref.c
>> >    [jbass@dmsd ~]$ make rc5ref
>> >    cc     rc5ref.c   -o rc5ref
>> >    [jbass@dmsd ~]$ ./rc5ref
>> >    key = C9 0C 03 53 C0 D4 E1 FE 85
>> >       plaintext 54686520 756E6B6E  --->  ciphertext E61759B8 36808E74
>> >
>> >John
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