Perl

AES Encrypt and Decrypt a File

_LANGUAGE_ demonstrates how to AES encrypt a file of any size, and then decrypt. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

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

my $crypt = Chilkat2::Crypt2->new;

$crypt->CryptAlgorithm('aes');

# CipherMode may be "ecb" or "cbc"
$crypt->CipherMode('cbc');

# KeyLength may be 128, 192, 256
$crypt->KeyLength(256);

# The padding scheme determines the contents of the bytes
# that are added to pad the result to a multiple of the
# encryption algorithm's block size.  AES has a block
# size of 16 bytes, so encrypted output is always
# a multiple of 16.
$crypt->PaddingScheme(0);

# An initialization vector is required if using CBC mode.
# ECB mode does not use an IV.
# The length of the IV is equal to the algorithm's block size.
# It is NOT equal to the length of the key.
my $ivHex = '000102030405060708090A0B0C0D0E0F';
$crypt->SetEncodedIV($ivHex, 'hex');

# The secret key must equal the size of the key.  For
# 256-bit encryption, the binary secret key is 32 bytes.
# For 128-bit encryption, the binary secret key is 16 bytes.
my $keyHex = '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F';
$crypt->SetEncodedKey($keyHex, 'hex');

# Encrypt a file, producing the .aes as output.
# The input file is unchanged, the output .aes contains the encrypted
# contents of the input file.

# Note: The .aes output file has no file format.  It is simply a stream
# of bytes that resembles random binary data.
my $inFile = '/Users/chilkat/testData/pdf/sample.pdf';
my $outFile = '/Users/chilkat/testData/p7m/sample.pdf.aes';
my $success = $crypt->CkEncryptFile($inFile, $outFile);
if (!$success) {
    print $crypt->LastErrorText, "\n";
    exit;
}

# For demonstration purposes, a different instance of the object will be used
# for decryption.
my $decrypt = Chilkat2::Crypt2->new;

# All settings must match to be able to decrypt:
$decrypt->CryptAlgorithm('aes');
$decrypt->CipherMode('cbc');
$decrypt->KeyLength(256);
$decrypt->PaddingScheme(0);
$decrypt->SetEncodedIV($ivHex, 'hex');
$decrypt->SetEncodedKey($keyHex, 'hex');

# Decrypt the .aes
$inFile = '/Users/chilkat/testData/p7m/sample.pdf.aes';
$outFile = '/Users/chilkat/testData/pdf/recovered.pdf';
$success = $decrypt->CkDecryptFile($inFile, $outFile);
if (!$success) {
    print $decrypt->LastErrorText, "\n";
    exit;
}

print "Success!\n";