(PHP 4, PHP 5)

md5Calculate the md5 hash of a string


string md5 ( string $str [, bool $raw_output = false ] )

Calculates the MD5 hash of str using the » RSA Data Security, Inc. MD5 Message-Digest Algorithm, and returns that hash.



The string.


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.

Return Values

Returns the hash as a 32-character hexadecimal number.


Version Description
5.0.0 The raw_output parameter was added.


Example #1 A md5() example


if (
md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
"Would you like a green or red apple?";


Note: Secure password hashing

It is not recommended to use this function to secure passwords, due to the fast nature of this hashing algorithm. See here for details.

See Also

  • md5_file() - Calculates the md5 hash of a given file
  • sha1_file() - Calculate the sha1 hash of a file
  • crc32() - Calculates the crc32 polynomial of a string
  • sha1() - Calculate the sha1 hash of a string
  • hash() - Generate a hash value (message digest)