SSL RC4 challenge

Hal hfinney at shell.portal.com
Thu Jul 13 12:46:37 PDT 1995


From: Hal <hfinney at shell.portal.com>
> Here is a challenge to try breaking SSL using the default exportable
> encryption mode, 40-bit RC4.
> [...]

It has been pointed out to me that I made a mistake in my analysis of the
SSL packets.  The MAC at the beginning of the encrypted packets is itself
RC4 encrypted.  That means that the 17 bytes of known plaintext start 16
bytes into the stream, not at the beginning as I thought.  This just
means that after key setup, RC4 has to be cycled 16 times before we start
comparing its output with the XOR of the known plaintext and ciphertext.

I'll produce a revision of my "challenge".  If no other mistakes are
found I'll post it to sci.crypt.

Hal






More information about the cypherpunks-legacy mailing list