PHP OpenSSL Public Key Encryption With String Public Key

Question

I have a public key

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwKMDEDjbP5v/9kcvpQKf
IG3nU5Yid/tUNIeXBSDlxqhTEOKs8iQHXk0T17C4g7KHmrT2hxUomaAa2wwbfL+Z
4ppqvZZ4cu7CO6jaA0HyoBCU96siSuE0mPt8kU/PRA9+nAwu9lu9oYZUiVVJ3D4f
o2bc+jWWL4GGY+PdSlz81ZW5cW/LOmNs9D0jJIxbwNocHxGgJ+xTZ3JKp6AO4MvL
zXyipXu562N8wVc7UIgYYnvr63zFU8vzRL180X5x5MiJbjTYbfLH3z7qINPMZZLv
A5vzJ0HX3J8rG96tmFuUzopCnvf+WVLvaS2T5uMxieK9dfA32CFQp4i3cj39c2b7
NwIDAQAB
-----END PUBLIC KEY-----

stored as a base64 encoded string (in MySQL, set as $row['public_key'])

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 

in PHP. I'm trying to use this string to encrypt string data, but it just fails without telling me why when I use the following code:

$success = openssl_public_encrypt($data, $encrypted, base64_decode($row['public_key']));

When the above is run, $success is always false and $encrypted is blank. I've tried running the public key through openssl_pkey_get_public() and sending the resource to openssl_public_encrypt() with no luck either. Writing to a file is not an option, nor is storing the private key.

Does anyone know how to get this to work? (or does it work for everyone else and it's just a weird server issue?)

EDIT: Since there seems to be some confusion about my issue, here is the testing code I'm using and its output. (Note: I've removed the base64 encoding, just to see if that made any difference)

$pubkey = openssl_get_publickey($row['public_key']);
$publicKey = openssl_pkey_get_details($res);
$encrypted = null;
$success = openssl_public_encrypt($data, $encrypted, $pubkey);
print "\npubkey1 " . $row['public_key'];
print "\npubkey2 " . $pubkey;
print "\npubkey3 " . $publicKey;
print "\npubkey4 " . $publicKey["key"];
print "\nencryption " . ($success ? 'true' : 'false') . ' "' . $encrypted . '"';
$success = openssl_public_encrypt($data, $encrypted, $row['public_key']);
print "\nencryption2 " . ($success ? 'true' : 'false') . ' "' . $encrypted . '"';   

Output:

pubkey1 -----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA89FgfElm36q7iAf8frqa
o58naoROsAljaFbmztfnqlmzXfyijK5CNJFdkUCgsu2zGxN7UlGiBOassTd4ijWm
1rz6/ad9fGXplfMGxZxyPCz31VreSWXmTG/PeSIYs1Co+dibV3imYt5jTxfLs7BZ
WsT8nuLxGPw/o/gyKut0Ru+jXI2GgT4s3SylXinn/IbIA497SohqYA7/ViQnBwSL
ZKUysOx2QgBmc9m0viRqDSKNUtDw7+L7bjhlwgZUGr6fxfTuNj9PWo97aPSE74CD
owYYl2ToTboKSjZUszeNwQKpUnlHY/DBkwmYUJ7SAYDY70VNooadN5dZ4ehjdaka
6QIDAQAB
-----END PUBLIC KEY-----

pubkey2 Resource id #50
pubkey3 
pubkey4 
encryption false ""
encryption2 false ""

Answer 1

So the issue actually relates to the data. PKI for php has a really small length restriction and can't be used to encrypt large amounts of data. Instead you're supposed to use PKI to encrypt a symmetric key which is then used to encrypt/decrypt data.

See more @ How to encrypt long strings in PHP?

Answer 2

The key that you should pass to this function is a PHP resource object, and not the string representation of the key itself.

$pubkey = openssl_get_publickey(base64_decode($row['public_key']));
$success = openssl_public_encrypt($data, $encrypted, $pubkey);