Anti-collision of 1. hash algorithm

That is, it is difficult to find two different original texts m0, m 1, and let their abstracts Hash(m0) = Hash(m 1).

Example: SHA-3 is safer than MD5 and SHA-2, and it is difficult to collide.

2. Difficulties in forging digital signatures

That is to say, for the "fresh" original abstract hash (m*), it is difficult to calculate a legal signature on it unless the server private key is mastered.

The so-called "fresh" means that this digest hash (m*) has not been signed by the server. (The original signature pair of the signature is meaningless, it was originally signed by the server)

So, in theory, there are two typical attacks:

1. Finding the original text with the same abstract value as the "old" original text is equivalent to attacking the hash algorithm and finding the conflict. If you use the rainbow table or other means mentioned by the subject.

2. Directly forge the digital signature.

In fact, to forge any signature, it can be said that this digital signature system has been completely broken. ...

Why software needs digital signature: network link