It is a sub-block of the RIPEMD-160 hash algorithm. The message is

processed by compression function in blocks of 5 12 bits and passed

through two streams of this sub-block by using five different versions

in which the value of constant “k” is also different.

3 . Message-digest Algorithm 5 (MD5)

Developed by Ron Rivest in 19 9 1 to produce a 128-bit or 16 bytes

message digest is MD5 , a hash function used in cryptography, the fifth

version of the message digest algorithm, which is faster than any other

version of message digest (MD). This algorithm or function takes an

input message of arbitrary length to produce a 128-bits hash value or

message digest.

A big file must first be safely “compressed”, before being encrypted

with a secret key, and MD5 was developed for this purpose.

Working

A 5 12-bit string is divided into 16 words of 3 2 bits, each using the

MD5 message-digest hashing method. MD5 generates a 128-bit

message digest as a result of the operation. There are four steps

involved in producing a message digest:

1. Appending padding bits to the original message

When you receive the input string, you have to make sure the size

is 64 bits short of a multiple of 5 12. When it comes to padding

the bits, you must add one (1) first, followed by zeroes to round

out the extra characters.

2. Appending length bits

You need to add a few more characters to make your final string a

multiple of 5 12. To do so, take the length of the initial input and

express it in the form of 64 bits. On combining the two, the final

string is ready to be hashed.

3 . Initializing MD or message digest buffer

The entire string is converted into multiple blocks of 5 12 bits

each. You also need to initialize four different buffers, namely, K ,

L, M, and N. These buffers are 3 2 bits each and are initialized as

follows: