Myujth

The following script works fine. The zip is encrypted, txt file created, and immediately decrypted successfully, and the new zip is created successfully.

However, if I run the decrypt portion only subsequently, it fails to decrypt the txt file. It returns an empty $original_plaintext variable and the final zip has size 0. The $key and $iv are not changed for the second run. Security is not the issue - I just need a scrambled text file and then need to be able to decrypt it later.

$key = "sometext"; 
$iv = "someothertext"; 
$cipher = "aes-128-gcm";
$tag = NULL;

$fileRoot = "sql_2018_11_10";

if (in_array($cipher, openssl_get_cipher_methods())) 
 // Encrypt
 $plaintext = file_get_contents("tmp/$fileRoot.zip");
 $ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
 file_put_contents("tmp/enc_$fileRoot.txt", $ciphertext);

 // Decrypt
 $ciphertext = file_get_contents("tmp/enc_$fileRoot.txt"); 
 $original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
 file_put_contents("tmp/uenc_$fileRoot.zip", $original_plaintext);