Secure Digest Functions
Secure digest functions are famously known as Cryptographic hash functions. It is a mathematical function that takes an input value and converts it into a meaningless output called a hash. The input to the hash function can differ to the occasion but the output always has a fixed length. when it comes to cryptographic hashing functions, hash, hash value, Message digest or Digital fingerprint, are all the same.
Properties of Hash Functions
· One way function: Hashing is based on a one-way mathematical function which is really hard to reverse. That means, using the hash value that generated, it is really hard to find the input value.
· Collision Resistance: This means, two different inputs of any lengths are not resulting in the same hash.
Hashing does not provide the security to transmitted data. So, hashing is vulnerable to man in the middle attacks.
The most famous examples of hashing functions are, MD5 and SHA256.
MD5
MD5 refers to message digest 5 algorithm. It came out to the public as the MD4 is identified as a vulnerable algorithm. After some time this MD5 is also announced as a not secure algorithm because it was cracked by collision attacks. After this MD5, MD6 came out addressing all those weaknesses in MD5.
SHA-1
SHA refers to the secure hash algorithm. SHA-1 came after the issues identified in the initial algorithm which is SHA-0. But SHA-1 is not suitable to use it is now deprecated algorithm because NIST announced that it is vulnerable for the collision attacks. Bitcoin- bitcoin uses the SHA256 hashing function which is a highly secured algorithm for the security of its block mining process.
