$header = "What is md5?"; include("header.inc.php"); ?>
What is Md5?
In cryptography, MD5 (Message-Digest algorithm 5) is a widely-used cryptographic hash function with a 128-bit hash value. As an Internet standard (RFC 1321), MD5 has been employed in a wide variety of security applications, and is also commonly used to check the integrity of files.
MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function, MD4. In 1996, a flaw was found with the design of MD5; while it was not a clearly fatal weakness, cryptographers began to recommend using other algorithms, such as SHA-1 (recent claims suggest that SHA-1 has been broken, however). In 2004, more serious flaws were discovered making further use of the algorithm for security purposes questionable.
//Note: All variables are unsigned 32 bits and wrap modulo 2^32 when calculating
//Define r as the following
//Use binary integer part of the sines of integers as constants:
//Process the message in successive 512-bit chunks:
//Initialize hash value for this chunk:
//Add this chunk's hash to result so far:
var int digest := h0 append h1 append h2 append h3 //(expressed as little-endian)