function openid_verify_assertion_signature

Verify the signature of the response received from the OpenID provider.

Parameters

$service: Array describing the OpenID provider.

$association: Information on the association with the OpenID provider.

$response: Array of response values from the provider.

Return value

TRUE if the signature is valid and covers all fields required to be signed.

See also

http://openid.net/specs/openid-authentication-2_0.html#rfc.section.11.4

File

modules/openid/openid.module, line 908

Code

function openid_verify_assertion_signature($service, $association, $response) {
    if ($service['version'] == 2) {
        // OpenID Authentication 2.0, section 10.1:
        // These keys must always be signed.
        $mandatory_keys = array(
            'op_endpoint',
            'return_to',
            'response_nonce',
            'assoc_handle',
        );
        if (isset($response['openid.claimed_id'])) {
            // If present, these two keys must also be signed. According to the spec,
            // they are either both present or both absent.
            $mandatory_keys[] = 'claimed_id';
            $mandatory_keys[] = 'identity';
        }
    }
    else {
        // OpenID Authentication 1.1. section 4.3.3.
        $mandatory_keys = array(
            'identity',
            'return_to',
        );
    }
    $keys_to_sign = explode(',', $response['openid.signed']);
    if (count(array_diff($mandatory_keys, $keys_to_sign)) > 0) {
        return FALSE;
    }
    return _openid_signature($association, $response, $keys_to_sign) === $response['openid.sig'];
}