Description
bool 
openssl_sign ( string data, string &signature, mixed priv_key_id [, int signature_alg] )
     Returns TRUE on success or FALSE on failure.
     If successful the signature is returned in
     signature. 
    
     openssl_sign() computes a signature for the
     specified data by using SHA1 for hashing
     followed by encryption using the private key associated with
     priv_key_id. Note that the data itself is
     not encrypted.
    
Note: 
      Optional 4th parameter signature_alg was added in
      version 5.0.0. Its default value is
      OPENSSL_ALGO_SHA1. For more information see the
      list of Signature Algorithms.
     
     
Example 1. openssl_sign() example <?php
// $data is assumed to contain the data to be signed
// fetch private key from file and ready it
$fp = fopen("/src/openssl-0.9.6/demos/sign/key.pem", "r");
$priv_key = fread($fp, 8192);
fclose($fp);
$pkeyid = openssl_get_privatekey($priv_key);
// compute signature
openssl_sign($data, $signature, $pkeyid);
// free the key from memory
openssl_free_key($pkeyid);
?> |  
  | 
    
     See also openssl_verify().