[RC5] RC5 Block Names

Dan Oetting dan_oetting at uswest.net
Wed Mar 28 09:32:16 EST 2001

on 3/27/01 10:50 AM, R J Booysen wrote:

>I was wondering if anyone could explain how the keys work in RC5.  For
>Example the keys that are cracked what do the 0x65... mean.  I have a
>general idea just wanted to know if someone could explain the whole idea to

A key in RC5-64 is a 64 bit number that when used in the encryption 
algorithm will unlock the secret message. Keys are distributed to the 
d.net clinets in blocks of consecutive keys so only the first key and the 
size of the block need to be specified. The 0x65... is the starting value 
of a block of keys written in hexadecimal (hex) notation. Hex numbers 
work just like decimal numbers except in addition to the digits 0..9 
there are also digits A..F. [0x is used in the C programming language to 
specify that the following number is hex] Each digit in hex is 4 bits so 
to specify a 64 bit value requires 16 hex digits. 64 bit values are 
sometimes written as two 32 bit values separated by a ":".

-- Dan O.
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