Cryptography is the only powerful tool for achieving high levels
of information security in a computer networks environment. The ISO have
proposed five security service groups including, confidentiality,
authentication, data integrity, non-repudiation, and access control.
Cryptography can support implementation of all these security services,
by using various cryptographic techniques, which
... [Show full abstract] include among other
things conventional secret key algorithms, public-key algorithms,
authentication procedures, and different digital signature schemes. Hash
functions, in cryptography, are used for digital signature applications
and authentication procedures. It is advisable, for cryptographic
reasons, to sign only hashed messages. A secure hash function must be a
one-way and collision-free function. Cryptographic security of hash
functions could be evaluated, so far, either by conducting detailed
cryptanalysis, or by using computational complexity theory. Each of
these methods has its own shortcomings. A new scheme for evaluating the
cryptographic security of hash functions is proposed. The proposed
scheme is simple, fast, and based on a solid mathematical model offered
by Markov process. The proposed scheme is used to evaluate the
cryptographic security of the Message Digest MD-4 algorithm. The results
are in accordance with what was conjectured and published