Re: Designing a secure message format

Thanks for the info, I wasn't aware that RC4 was no longer considered
secure. Is there a place I can go (other than Wikipedia, Google, ...)
to track the current security ratings of various protocols. Books have
this funny thing about going out of date :)

Thanks again.

rossum wrote:
On 29 Jun 2006 20:57:24 -0700, "imposterrific@xxxxxxxxx"
<imposterrific@xxxxxxxxx> wrote:

The passphrase would be used to generate a pseudo-random data stream
(S1) which would be used to decrypt a message header, which contains
additional information needed to decrypt the body of the message. (I
plan on using RC4 for S1 and including an initialization vector in the
message.) I have had a few ideas about what to put in this header.
Perhaps it could contain several symmetric keys which were used to
encrypt the message body (3DES, AES, etc.) or maybe it could contain
initialization vectors for a series of pseudo random streams spawned
from the original data stream (S1).
RC4 is very easy to program, but no longer secure. MARC4 is better,
but still iffy. Given that you will have 3DES and/or AES available,
why not use AES in CTR mode to produce the pseudo random stream S1?

rossum

.

Relevant Pages

  • Re: Cipher advice
    ... I am involved in a software project that requires a degree of secure ... We have tried an AES implementation but ... My limited understanding of RC4 is ... I am looking for an algorithm that is not much slower than ...
    (sci.crypt)
  • Re: RC4 on AMD64
    ... I'm totally agree with Guy Macon: Why RC4 has a so bad reputation? ... has few known security weak you can avoid if you use it ... just imagine AES *is* secure. ...
    (sci.crypt)
  • Re: Needle in a haystack--or is this just stupid?
    ... >> reasonably secure if used correctly. ... Regardless RC4 is actually harder to use correctly than that. ... > 3) You demonstrated a lack of understanding of how the attacks actually work ... The lack of understanding goes both ways, ...
    (sci.crypt)
  • Re: Needle in a haystack--or is this just stupid?
    ... > reasonably secure if used correctly. ... Regardless RC4 is actually harder to use correctly than that. ... because the first byte has a substantial bias, and 256 makes sense for RC4. ... You demonstrated a lack of understanding of how the attacks actually work ...
    (sci.crypt)
  • Re: RC4, With Homebrew MAC...
    ... Though MD5 and SHA-1 would be faster than AES I think AES in CTR ... RC4 is shown to be very fast here because the machine I ran this on ... > your software discard some of the first outputs of the stream. ... > About your MAC, literature says that is not easy to get a good MAC ...
    (sci.crypt)