Applied Network Security

Cryptographic hash functions

A cryptographic hash function works by mapping data to a fixed length string of characters. These types of hash functions are used in many ways. They can be used for authentication, indexing data into hashed tables, checksums, and digital signatures. Two of the most used cryptographic hash functions are MD5 and SHA-3. MD5 was created in 1991 by Ronald Rivest. MD5 uses a 128-bits hash value. At first it was considered secure, but today most experts recommend not using MD5 for authentication, because of the many vulnerabilities found over the years. MD5 works by taking variable length data and converting it into a fixed length hash string of 128-bits. SHA is more secure than MD5. The creators of SHA are Guido Bertoni, ...