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Diffie Hellman Key Secrets for OpenID

I am trying to create an open source library for OpenID that will be used as a Wordpress plugin. I have a problem when I try to calculate the secret value using the openssl function openssl_dh_compute_key . Curious if anyone has any steps that I could try, tips, etc.

Thank!

Constants ...

const DH_DEFAULT_PRIME = "dcf93a0b883972ec0e19989ac5a2ce310e1d37717e8d9571bb7623731866e61ef75a2e27898b057f9891c2e27a639c3f29b60814581cd3b2ca3986d2683705577d45c2e7e52dc81c7a171876e5cea74b1448bfdfaf18828efd2519f14e45e3826634af1949e5b535cc829a483b8a76223e5d490a257f05bdff16f2fb22c583ab";
const DH_DEFAULT_GENERATOR = '02';

Creating a Diffie-Hellman Key

private function createDHKey($priv_key = false) {
    if (!$priv_key) {
        $details = array();
        $details['p'] = pack('H*', self::DH_DEFAULT_PRIME);
        $details['g'] = pack('H*', self::DH_DEFAULT_GENERATOR);
        $this->dh = openssl_pkey_new(array(
            'dh' => $details,
        ));
        if ($this->dh) {
            return true;
        } else {
            error('OpenSSL failed to export your private key, ensure you have a valid configuration file, and PHP can find it.');
        }
    } else {
        $this->dh = openssl_pkey_get_private($priv_key);
        return false;
    }
}

First run of function

Recalling exported private key

Ag == on the button of both images is the base64 encoded dh ['g'] value.

Then I save the generated private key to the database for saving, which allows me to re-create the key later through the openssl_pkey_get_private function.

, openid.dh_server_public , , , false

var_dump(openssl_dh_compute_key($this->op_pubkey, $this->dh));
+5
1

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dh_server_public
   Value: base64(btwoc(g ^ xb mod p))
   Description: The OP Diffie-Hellman public key.

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, ...

openssl_dh_compute_key(base64_decode($this->op_pubkey), $this->dh);
+4

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