Calculates an MD5 128-bit checksum for the string. It can still be used as a checksum to verify data integrity, but only against unintentional corruption.Syntax. Although MD5 was initially designed to be used as a cryptographic hash function, it has been found to suffer from extensive vulnerabilities. The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value.

Note thatThe function H is the bit-wise 'xor' or 'parity' function of itsAt this point the message is passed in blocks of 512 bits through the the compression function as seen below:Figure taken from Cryptography and Network Security: Principles and Practice by William StallingsCalculate rounds:After all the 512 bit blocks have been processed a 128 bit message digest is produced, which is a function of all the bits of your message.To produce this digest just sum A, B, C and D and convert it to hexadecimal. They are initialized to the following values:We first define four auxiliary functions that each take as inputThree 32-bit words and produce as output one 32-bit word.In each bit position F acts as a conditional: if X then Y else Z.The function F could have been defined using + instead of v since XYAnd not(X)Z will never have 1's in the same bit position.) It isInteresting to note that if the bits of X, Y, and Z are independentAnd unbiased, the each bit of F(X,Y,Z) will be independent andThe functions G, H, and I are similar to the function F, in that theyAct in 'bitwise parallel' to produce their output from the bits of X,Y, and Z, in such a manner that if the corresponding bits of X, Y,And Z are independent and unbiased, then each bit of G(X,Y,Z),H(X,Y,Z), and I(X,Y,Z) will be independent and unbiased. If you look at the end of message you should be able to identify the added bits.A 128 bit buffer (4 registers, 32 bits each) is used to hold the intermediate and final result of the hash function. So the message after all appending operations are complete will look like,At the bit level the text box below.

Md5