(Perl) Duplicate PHP's openssl_encrypt and openssl_random_pseudo_bytes

Demonstrates how to duplicate PHP's openssl_encrypt function. (https://www.php.net/manual/en/function.openssl-encrypt.php)

For more information, see https://www.php.net/manual/en/function.openssl-encrypt.php

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Duplicates thw following PHP script:

# $text = "This is a test";
# $passphrase = "my password";
# $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("AES-256-CBC"));
# $crypted = base64_encode($iv.openssl_encrypt($text, "AES-256-CBC", $passphrase, OPENSSL_RAW_DATA, $iv));
# echo $crypted;

$crypt = chilkat::CkCrypt2->new();

$text = "This is a test";
$passphrase = "my password";

# AES is a block cipher.  The IV size for any block cipher is the size of the block, which is defined by the encryption algorithm. 
# For AES, the block size is always 16 bytes, regardless of key size (i.e. 128-bits, 192-bits, or 256-bits).
# Therefore, generate 16 random bytes for the IV.
$crypt->put_EncodingMode("base64");
$ivBase64 = $crypt->genRandomBytesENC(16);

print "Generated IV = " . $ivBase64 . "\r\n";

# Because we're doing AES-256-CBC, the key length must be 256-bits (i.e. 32 bytes).
# Given that our passphrase is a us-ascii string that can be shorter or longer than 32-bytes, we need to 
# somehow transform the passphrase to a 32-byte secret key.  We need to know what openssl_encrypt does.
# Here's the answer from the openssl_encrypt documentation:
# 
# "If the passphrase is shorter than expected, it is silently padded with NUL characters; 
# if the passphrase is longer than expected, it is silently truncated."

# OK.... so let's pad or shorten to get a 32-byte key.
$bdKey = chilkat::CkBinData->new();
$bdKey->AppendString($passphrase,"utf-8");

$sz = $bdKey->get_NumBytes();
if ($sz > 32) {
    $bdKey->RemoveChunk(32,$sz - 32);
}
else {
    $bdKey->Clear();
    $bdKey->AppendPadded($passphrase,"utf-8",0,32);
}

# Setup for encryption.
$crypt->put_CryptAlgorithm("aes");
$crypt->put_KeyLength(256);
$crypt->SetEncodedIV($ivBase64,"base64");
$crypt->SetEncodedKey($bdKey->getEncoded("base64"),"base64");

# Encrypt and base64 encode.
$cipherText64 = $crypt->encryptStringENC($text);

# The PHP code fragment above returns the base64 encoded bytes of the IV and the encrypted text.
# So let's do that..
$bd = chilkat::CkBinData->new();
$bd->AppendEncoded($ivBase64,"base64");
$bd->AppendEncoded($cipherText64,"base64");
$result = $bd->getEncoded("base64");

print "result = " . $result . "\r\n";

# Sample output:
# dN0vS1O0cWi5BbLAAY+NTf7bs3S27xzPf11RkG47sjs=

# Now let's decrypt from the output...

# Setup for decryption.
$crypt->put_CryptAlgorithm("aes");
$crypt->put_KeyLength(256);
$crypt->SetEncodedKey($bdKey->getEncoded("base64"),"base64");

$bdResult = chilkat::CkBinData->new();
$bdResult->AppendEncoded($result,"base64");
$crypt->SetEncodedIV($bdResult->getEncodedChunk(0,16,"base64"),"base64");

# Remove the IV (first 16 bytes) from the result.
$bdResult->RemoveChunk(0,16);
$success = $crypt->DecryptBd($bdResult);
$originalText = $bdResult->getString("utf-8");

print "original text = " . $originalText . "\r\n";