The openssl_verify() function is an inbuilt function in PHP which is used to verifies that if the signature is correct for the specified data using the public key associated with public_key or not. This must be the public key corresponding to the private key used for signing.
Syntax:
openssl_verify( $data, $signature,
$public_key, $algorithm ): int|false
Parameters: This function accept four parameters which are listed below –
- data: The string of data used to generate the signature previously.
- signature: A raw binary string, generated by openssl_sign() or similar means.
- public_key: string – a PEM formatted key, example, “—–BEGIN PUBLIC KEY—– MIIBCgK…”
- algorithm: A valid string returned by openssl_get_md_methods() function.
Return Value: It returns 1 if the signature is correct, 0 if it is incorrect, and -1 or false on error.
Note: The public key comes from a certificate in any of the support formats.
Listed below are examples illustrating the use of openssl_verify() function:
Example 1:
PHP
<?php // Data you want to sign $data = 'neveropen for neveropen'; // Create a new pair of private and public key $private_key_rsa = openssl_pkey_new(array( "private_key_bits" => 2048, "private_key_type" => OPENSSL_KEYTYPE_RSA, )); $details = openssl_pkey_get_details($private_key_rsa); $public_key_rsa = openssl_pkey_get_public($details['key']); // Create signature for your data openssl_sign($data, $signature, $private_key_rsa, "sha256WithRSAEncryption"); // Verify signature obtained for your data $result = openssl_verify($data, $signature, $public_key_rsa, OPENSSL_ALGO_SHA256); if ($result == 1) { echo "signature is valid for given data."; } elseif ($ok == 0) { echo "signature is invalid for given data."; } else { echo "error: ".openssl_error_string(); } ?> |
Output:
signature is valid for given data.
Example 2:
PHP
<?php // Data you want to sign $data = 'neveropen for neveropen'; // Create a new pair of private and public key $private_key_rsa = openssl_pkey_new(array( "private_key_bits" => 2048, "private_key_type" => OPENSSL_KEYTYPE_RSA, )); $details = openssl_pkey_get_details($private_key_rsa); $public_key_rsa = openssl_pkey_get_public($details['key']); // Create signature for your data openssl_sign($data, $signature, $private_key_rsa, "sha256WithRSAEncryption"); // Change the data $data = 'neveropen and neveropen'; // Verify signature obtained for your data $result = openssl_verify($data, $signature, $public_key_rsa, OPENSSL_ALGO_SHA256); if ($result == 1) { echo "signature is valid for given data."; } elseif ($ok == 0) { echo "signature is invalid for given data."; } else { echo "error: ".openssl_error_string(); } ?> |
Output:
signature is invalid for given data.
Reference: https://www.php.net/manual/en/function.openssl-verify.php
