Purposes for hash functions Data Integrity Ex: Tripwire Message digest h(x). y is called the message digest 160 bits in size -"birthday attack Message source Digital signatures Message Authentication Codes(mac)3 Purposes for hash functions • Data Integrity – Ex: Tripwire – Message digest • y = h(x). y is called the message digest. • 160 bits in size – “birthday attack” • Message Source • Digital Signatures • Message Authentication Codes (MAC)