php man page for sha1

SHA1(3) 								 1								   SHA1(3)

sha1 - Calculate the sha1 hash of a string

SYNOPSIS
       string sha1 (string  $str, [bool  $raw_output = false])

DESCRIPTION
	Calculates the sha1 hash of $str using the US Secure Hash Algorithm 1.

PARAMETERS
	      o $str
		- The input string.

	      o $raw_output
		-  If  the optional $raw_output is set to TRUE, then the sha1 digest is instead returned in raw binary format with a length of 20,
		otherwise the returned value is a 40-character hexadecimal number.

RETURN VALUES
	Returns the sha1 hash as a string.

EXAMPLES
       Example #1

	      A sha1(3) example

	      <?php
	      $str = 'apple';

	      if (sha1($str) === 'd0be2dc421be4fcd0172e5afceea3970e2f3d940') {
		  echo "Would you like a green or red apple?";
	      }
	      ?>

NOTES
       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
       sha1_file(3), crc32(3), md5(3), hash(3), crypt(3), password_hash(3).

PHP Documentation Group 														   SHA1(3)