Javascript not decrypt, laravel RSA encrypted string

Question

Problem Statement

I need to encrypt details in Laravel using RSA algorithm and then decrypt in Javascript.

Efforts Done

In laravel I am using phpseclib library to encrypt. Laravel code to encrypt string is given below...

$publicKey= file_get_contents(storage_path('app/' . $disk .'/'. $filename));
$rsa = new RSA();
$rsa->loadKey($publicKey); // public key
$plaintext = 'hello world';
$ciphertext = $rsa->encrypt($plaintext);
$ciphertext = base64_encode($ciphertext);

echo '<br>base64_encode = '. $ciphertext;

Given below is the output of this script.

base64_encode = FDtZ1XAzW6yH7LIwIBb9VjL64KQb/UPclpV4Stc2xSoiAdIQc2r1dYFgrsJflkQfLtA/7ZJ5IHWQUWjNUuUTWmMYKk2xRmCjShTEhSkI9JEJC70ltjhxB7BXPRLIofpFdc8HVq8koEZOFTvtZ5YmJt86/iqLby0t41VhlDqkN2U=

Private Key

I am using jsencrypt library to decrypt RSA string.

var crypt = new JSEncrypt();
crypt.setKey('-----BEGIN RSA PRIVATE KEY----- MIICXgIBAAKBgQDNIdcnHmDD+XzO+nBTt2VOjcCfJQs2kefZbVWzSgczLeYBfPsg MNX5r/q5oB65pfs07iMO9fBi5mpIG9fQ8sEbGfEupDQjBdPE6v2TCn/FR0JmH6OO tbKZVmn2mC2KxmB2PDluUM3dN5YJtezZnJn/vGYCTse4W8AYL9ljYTnRbQIDAQAB AoGAOHWV+EheLdJfTcCUZhZWJdbSK3tQqMZj3+495kj7zlRVuBckL2oBmuWaxriR fFt41sqsj5OVhEMTAaHYNsR57XMaZa+Frv49vv8TO3YK41oI4fIhdI9hxbc5zcYR GJMVnRrzxKcAQ7gxZzxDvjqnS3Qv6gAuX+ohBNeYNJoFdSkCQQD4Wutn852uRDIW DJiIizp1zW4wyRYtXUk684z1GpXYnnyFStvtnVMwNxx+fS19up89Ur13uq275Qo1 DQDrA8lHAkEA03JRD0zGkhuMZ74pouBXUMlbH179BQWQsj95cvMvdH8SCDZ5tdxX KECmASawUN1NqAsI4/0sVo24rOy9fNopqwJBALglKeDE2IiLFhwVMNAlc64/KNHR d7khLxgf18cw9CROtwNaEyHnAfSBGIaNKDrOMh4VCFkLOKBV3jChuKmJACcCQQDR YOHjxKLdC2p9UFDqeDv+Q2V4KxdhYaFm4HPi3+yd7zZr64WaEBY+RcYcXbM6X+oF /OdQ2+KL0sqMceExQNcBAkEAwtV3+J7fIJ5TJIlCN6WZRbfLo3g8DzzzEkyA3CcS nSO4ZQoCclINsZWJBTk31eEVA4+Sna5MpOtGSFK2+5h8ew== -----END RSA PRIVATE KEY-----');  

var text = 'FDtZ1XAzW6yH7LIwIBb9VjL64KQb/UPclpV4Stc2xSoiAdIQc2r1dYFgrsJflkQfLtA/7ZJ5IHWQUWjNUuUTWmMYKk2xRmCjShTEhSkI9JEJC70ltjhxB7BXPRLIofpFdc8HVq8koEZOFTvtZ5YmJt86/iqLby0t41VhlDqkN2U=';
text = atob(text);
var dec = crypt.decrypt(text);
console.log(dec);

Output of js code in console is given below...

null

Requirement

This is required to decrypt string in separate offline system. I am not going to decrypt with javascript on live website. Rather decryption with javascript will be done on offline system.

The posted _private_ key seems to be rather an OpenSSH _public_ key, can that be? This can be tested e.g. with `ssh-keygen -l -f`. — Topaco, Jul 27 '20 at 13:29
@Topaco you are right. I have updated private key now. But still results are same in browser console. — shujat132, Jul 27 '20 at 14:01
Both codes use different paddings, OAEP in the PHP code (which is the phpseclib default for RSA) and PKCS#1 v1.5 in the JSEncrypt code. JSEncrypt doesn't support OAEP. So you have to change the padding used in the PHP code or switch to another JavaScript library. Furthermore, `JSEncrypt#decrypt` expects the ciphertext Base64 encoded. — Topaco, Jul 27 '20 at 14:27
To followup on what Topaco said, the padding, in phpseclib, can be changed by doing `$rsa->setEncryptionMode(RSA::ENCRYPTION_PKCS1);` Base64 can be enabled by doing `base64_encode(...)`. — neubert, Jul 28 '20 at 13:17
check this link http://www-cs-students.stanford.edu/~tjw/jsbn/rsa2.js here find RSADecrypt — Gaurav Gupta, Jul 28 '20 at 13:30
@GauravGupta where I can find documentation of this library ? — shujat132, Jul 28 '20 at 18:18

Javascript not decrypt, laravel RSA encrypted string

0 Answers0