Difference b/w Hash function & Keyed Hash function? And HMAC with Matyas-Meyer-Oseas hash function I am looking for hash functions. In this process i came across hash &amp; keyed hash functions(HAMC). In which it uses some has function to generate MAC.

And also Matyas-Meyer-Oseas hash function, which is of block cipher hash function.

I would like to know the difference between HMAC, and hash functions?

And about Matyas-Meyer-Oseas hash function, how hash will be calculated?

At least where can i find proper solution for this?
Intuitively a MAC is essentially the symmetric cryptography variant of a signature. To calculate a MAC a secret key which is shared between sender and receiver is used. This means that somebody who does not have the key cannot calculate the MAC.

A hash function on the other hand can be computed by anybody, uses no secrets and is simply used to get a shorter representation of data. For example, if somebody wants to sign an e-mail they usually hash it first and then sign the hash.

The Matyas–Meyer–Oseas construction is a way to construct a one-way compression function from a block cipher. This can then be used in the construction of a hash function, for example, using the Merkle–Damgård construction.

In particular, this means that the Matyas–Meyer–Oseas construction doesn't actually specify a complete hash function in an implementable way.