php man page for openssl_sign

OPENSSL_SIGN(3) 							 1							   OPENSSL_SIGN(3)

openssl_sign - Generate signature

SYNOPSIS
       bool openssl_sign (string  $data, string  &$signature, mixed  $priv_key_id, [mixed  $signature_alg = OPENSSL_ALGO_SHA1])

DESCRIPTION
       openssl_sign(3)	computes a signature for the specified $data by generating a cryptographic digital signature using the private key associ-
       ated with $priv_key_id. Note that the data itself is not encrypted.

PARAMETERS
	      o $data
		- The string of data you wish to sign

	      o $signature
		- If the call was successful the signature is returned in $signature.

	      o $priv_key_id
		- resource - a key, returned by openssl_get_privatekey(3) string - a PEM formatted key

	      o $signature_alg
		-  int	-  one	of  these  Signature  Algorithms.   string  -  a  valid  string  returned  by  openssl_get_md_methods(3)  example,
		"sha256WithRSAEncryption" or "sha384".

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

EXAMPLES
       Example #1

	      openssl_sign(3) example

	      <?php
	      // $data is assumed to contain the data to be signed

	      // fetch private key from file and ready it
	      $pkeyid = openssl_pkey_get_private("file://src/openssl-0.9.6/demos/sign/key.pem");

	      // compute signature
	      openssl_sign($data, $signature, $pkeyid);

	      // free the key from memory
	      openssl_free_key($pkeyid);
	      ?>

       Example #2

	      openssl_sign(3) example

	      <?php
	      //data you want to sign
	      $data = 'my data';

	      //create new private and public key
	      $new_key_pair = openssl_pkey_new(array(
		  "private_key_bits" => 2048,
		  "private_key_type" => OPENSSL_KEYTYPE_RSA,
	      ));
	      openssl_pkey_export($new_key_pair, $private_key_pem);

	      $details = openssl_pkey_get_details($new_key_pair);
	      $public_key_pem = $details['key'];

	      //create signature
	      openssl_sign($data, $signature, $private_key_pem, OPENSSL_ALGO_SHA256);

	      //save for later
	      file_put_contents('private_key.pem', $private_key_pem);
	      file_put_contents('public_key.pem', $public_key_pem);
	      file_put_contents('signature.dat', $signature);

	      //verify signature
	      $r = openssl_verify($data, $signature, $public_key_pem, "sha256WithRSAEncryption");
	      var_dump($r);
	      ?>

SEE ALSO
       openssl_verify(3).

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