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seen Nov 6 '11 at 0:27

Nov
4
comment How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?
Perfect - thanks very much for that confirmation. I had suspected that, but couldn't quite wrap my head around it - thanks for your explanation which makes sense. Agreed that there is a very minor performance hit, but in this case I'm only tossing about 1.5% of the potential values, so that doesn't concern me. Thanks for your help.
Nov
4
comment How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?
Thanks for the comments. It is possible that I might transition to a different stream cipher. RC4 was easily to implement at this stage in the prototype for testing purposes. Any thoughts on the impact on security from doing the mapping of the output, which effectively reduces the number of output values? Is there a nice statistical explanation of how the security is impacted? Thanks.
Nov
4
comment How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?
I was careful to not introduce any new bias, but is it apparent that by working with only 36 possible outputs, rather than the full 256, that I would be reducing the security level? I can't quite wrap my mind around that part.
Nov
4
comment How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?
Agreed about the initial discard. As noted on the Wikipedia article about RC4-drop, I'm tossing the first 3072 outputs.
Nov
3
awarded  Student
Nov
3
comment How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?
Micro-controller application (so limited capabilities). It is to encrypt a text stream which consists of A-Z and 0-9. The plain will be added mod 36 to the adjusted RC4 output. The result will be output as the cipher text.
Nov
3
asked How does one measure the decrease in security, if any, of RC4 when mapping to a specific range of values?