Any one see this Cryptographic?

[winndy]

Originally Posted by Lunar_Dust

RSA doesn't have collision, but usually what's encrypted isn't the actual document, it's the hash of the document. Since asymetric crypto is too slow usually they just take a hash of the doc and then encrypt the hash with RSA with private key. Then the end user uses public key to decrypt hash, takes hash themselves of the document, and compares hashes. If they match this means document hasn't been changed. If MD5 (the most common hash) has collision (still very rare I think) then that is why you may see it because possibly they are RSA the hash only.

-Lunar

Thanks for your explanation.
I am still in the mist.
RSA(hash1)=RSA(hash2)
Whether the hash1 or hash2 are MD5 hash is not important.
What's important is that two different hash arrived the same RSA value.

Anyway,I generally agree with you that RSA has no collision.
Maybe when the program apis32 v2.5 checks the regcode,
It is not the standand RSA_Decipher procedure,so I could
got different Regcode for the same username.

You could look at the apis32 v2.5.
And I will provide more keys for the same username.

Regards