What are the consequences, in terms of security, of using a padding rule at the beginning of the message? Instead of the end?
For instance, in most hash functions, we are using the following padding rule: appending of a bit 1, followed by a number of 0 such that the total length is a multiple of the block length.
What happens if we change this rule in: prepend a bit 1. Then, prepend a number of 0 such that the total length is a multiple of the block length.
I would like to know if the various security properties that can have a hash function are preserved.