hash function

1. summary

• Encryption is bidirectional , That is, plaintext can be encrypted into ciphertext by key , The ciphertext can also be decrypted into plaintext through the key
• Hash is one-way , That is, only from plaintext to

2. usage

3. characteristic

3.1 Arbitrary-length message to fixed-length digest

3.2 Antigenic image Preimage resistant (One-way property)

3.3 Anti second primary image Second preimage resistant (Weak collision resistant)

3.4 Anti conflict Collision resistant (Strong collision resistance)