Is there a protocol that uses MD5 Hashing?

Question

I have a program that I am reverse engineering for learning purposes about protocols (and to sharpen my assembly skills). I have reversed the whole protocol, and know where encryption takes place and all. The program uses an CBC(chain block cipher) but the packets keep going through an MD5 Hash before they are sent.

I know this is not possible(or is it?) I searched Google for a long time and couldn't find any information. So does anyone else know if a protocol like this is possible, and the name of it?

Are you sure the MD5 hashing is not just used for signing or used as a checksum ? (You're right that this is impossibly, you can't use hash functions to encrypt stuff) — nos, Jan 13 '12 at 12:21
What are the difference between MD5 signing and checksum? The information I see after it gets out of the MD5_Hash actually gets sent. — user954753, Jan 13 '12 at 12:29
SSL can use md5. But it's unlikely that it does negotiate md5 given a relatively recent implementation. — CodesInChaos, Jan 13 '12 at 14:02
@CodeInChaos: TLS 1.0 and SSL 3.0 *must* use MD5+SHA1. It is not negotiable. — President James K. Polk, Jan 14 '12 at 00:32

score 1 · Accepted Answer · answered Jan 13 '12 at 12:22

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As a very obvious and well-known example, the SSL/TLS protocol uses MD5 (but not exclusively MD5).

answered Jan 13 '12 at 12:22

President James K. Polk

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Thank you. I figured out the program. It MD5s the packet and sticks it on the end. It then goes into blowfish to be encrypted. Now the only part I need is the blowfish key. – user954753 Jan 13 '12 at 16:05

Is there a protocol that uses MD5 Hashing?

1 Answers1