The md5() function calculates the MD5 hash of a string.The md5() function uses the RSA Data Security, Inc. MD5 Message-Digest Algorithm.
From RFC 1321 - The MD5 Message-Digest Algorithm: "The MD5 message-digest algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input. The MD5 algorithm is intended for digital signature applications, where a large file must be "compressed" in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA."
string md5 ( string $str [, bool $raw_output = FALSE ] )
To calculate the MD5 hash of a file, use the md5_file() function.
| Parameter | Description |
|---|---|
| str | Required. The string to be calculated |
| raw_output | If the optional raw_output is set to TRUE, then the md5 digest is instead returned in raw binary format with a length of 16. |
Returns the hash as a 32-character hexadecimal number.