A hash collision is when the result of hashinng two different values is equal.

A partial hash collision is when a part of two hashes collide. Example:

  • 0000000a5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824

In the above hash, there’s a partial hash collision (0000000) against the zero-string.

cryptography