Mock a private/public key in a unit test?

Question

Currently I have a code base that uses openssl_public_encrypt/openssl_private_decrypt. Now I would like to test my encryption and decryption methods with a unit test, since these are pretty vital.

To really test them I think I would like to simply mock the private and public keys. Is this viable and how would I go about mocking these keys without putting any sensitive information in my code base?

Of course I could circumvent the openssl public/private part and mock the outcome of that but this logic also throws some exceptions, etc. which I would like to test.

Answer 1

If you have PHP's OpenSSL extension installed and enabled then you can generate your public/private key pair with OpenSSL Functions:

openssl_pkey_new, for the private key with:

$private_key = openssl_pkey_new([
    'digest_alg' => 'sha256',
    'private_key_bits' => 1024,
    'private_key_type' => OPENSSL_KEYTYPE_RSA
]);

Then pass the private key to openssl_pkey_get_details to get details about the key including the public key:

$details = openssl_pkey_get_details($private_key);
$public_key = $details['key'];