How to generate a string containing private and public key in PhP?

Question

I saw this code:

<?php
class MyEncryption
{

    public $pubkey = '...public key here...';
    public $privkey = '...private key here...';

    public function encrypt($data)
    {
        if (openssl_public_encrypt($data, $encrypted, $this->pubkey))
            $data = base64_encode($encrypted);
        else
            throw new Exception('Unable to encrypt data. Perhaps it is bigger than the key size?');

        return $data;
    }

    public function decrypt($data)
    {
        if (openssl_private_decrypt(base64_decode($data), $decrypted, $this->privkey))
            $data = $decrypted;
        else
            $data = '';

        return $data;
    }
}


?>

What are samples of public_key? What kind of public key should be put on $pubkey? Should it be base_64encoded or not? How do I generate one?

I added:

$privKey = openssl_pkey_new();

And all I got is $privKey==false

I just want to use a simple private and public. No need for anything complicated. — user4951, Dec 18 '12 at 10:44
The code appears to have been posted previously in these answers: http://stackoverflow.com/a/2806742 and http://stackoverflow.com/a/4484258 — Simon East, Aug 10 '13 at 12:42

score 2 · Accepted Answer · answered Dec 18 '12 at 10:11

The keys have to be generated together, as the public key is the "non-secret" key that can encrypt information so that only the private key is able to decrypt it. This is an example of Public-key cryptography.

If openssl_pkey_new fails (it will not return the key itself, only a resource that you can use to retrieve the actual keys), see the examples and links to alternatives in the comment section of the manual page.

And no, the keys should not base64-encoded. This is only done to the encrypted data in your methods. The reason that this is done in the class is probably because the original author wanted to transfer the encrypted data through some sort of non-binary-safe environment.

How to generate a string containing private and public key in PhP?

1 Answers1