CODEWITHSUNDEEP
aes-gcm
Ankit Bansal
Ankit Bansal

Reputation: 2348

AES 256 GCM with php 5.6

I have taken reference of code from this post : Trying to decrypt with aes-256-gcm with php

Code :

< ?php

    $textToEncrypt = "demo text";
    $password = '3sc3RLrpd17';
    $key = substr(hash('sha256', $password, true), 0, 32);
    $cipher = 'aes-256-gcm';
    $iv_len = openssl_cipher_iv_length($cipher);
    $tag_length = 16;
    $iv = openssl_random_pseudo_bytes($iv_len);

    
    $ciphertext = openssl_encrypt($textToEncrypt, $cipher, $key, OPENSSL_RAW_DATA, $iv);
    $encrypted = base64_encode($iv.$ciphertext);
    
    
    
    $textToDecrypt = $encrypted;
    $encrypted = base64_decode($textToDecrypt);
    $password = '3sc3RLrpd17';
    $key = substr(hash('sha256', $password, true), 0, 32);
    $cipher = 'aes-256-gcm';
    $iv_len = openssl_cipher_iv_length($cipher);
    $iv = substr($encrypted, 0, $iv_len);
    $ciphertext = substr($encrypted, $iv_len);
    $decrypted = openssl_decrypt($ciphertext, $cipher, $key, OPENSSL_RAW_DATA, $iv);
    var_dump (openssl_error_string());
    var_dump($decrypted);
    echo $decrypted;


?>

Running this code on PHP 5.6 Now the issue is I am always getting false as decrypted text.

What is wrong?

Upvotes: 0

Views: 751

Answers (1)

Gareth Foster
Gareth Foster

Reputation: 31

I got this working with AES-256-CBC on PHP 5.6:

$textToEncrypt = "demo text";
$password = '3sc3RLrpd17';
$key = substr(hash('sha256', $password, true), 0, 32);

$cipher = 'aes-256-cbc';
$iv_len = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($iv_len);

$ciphertext = openssl_encrypt($textToEncrypt, $cipher, $key, OPENSSL_RAW_DATA, $iv);
if ($ciphertext === false) {
    // Encryption failed; handle error
    echo "Encryption error: " . openssl_error_string() . "\n";
    exit;
}
$encrypted = base64_encode($iv . $ciphertext);

// Decryption
$textToDecrypt = $encrypted;
$encrypted = base64_decode($textToDecrypt);
$iv = substr($encrypted, 0, $iv_len);
$ciphertext = substr($encrypted, $iv_len);
$decrypted = openssl_decrypt($ciphertext, $cipher, $key, OPENSSL_RAW_DATA, $iv);
if ($decrypted === false) {
    // Decryption failed; handle error
    echo "Decryption error: " . openssl_error_string() . "\n";
    exit;
}

echo "Decrypted text: " . $decrypted . "\n";

You can see it running here: https://onlinephp.io/c/74e59

Upvotes: 1

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