PHP

Example for both AES-128 and ChaCha20 to Encrypt Binary Data

See more Encryption Examples

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt binary bytes.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat2 PHP

<?php

use Chilkat2\BinData;
use Chilkat2\Crypt2;

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

// Load a small JPG file to be encrypted/decrypted.
$jpgBytes = new BinData();
try {
    $jpgBytes->LoadFile('qa_data/jpg/starfish.jpg');
} catch (\Chilkat2\Exception $e) {
    echo "Failed to load JPG file.\n";
    exit;
}

// Show the unencrypted JPG bytes in Base64 format.
// (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
// The "base64" encoding emits a single line of base64, whereas
// "base64_mime" will emit multi-line base64 as it would appear
// in MIME.)
echo $jpgBytes->GetEncoded('base64_mime'), "\n";

// Sample base64_mime JPG data:

//     /9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
//     AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
//     AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
//     MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
//     ...

$crypt = new Crypt2();

// Specify the encryption to be used.
// First we'll do AES-128 CBC
$crypt->CryptAlgorithm = 'aes';
$crypt->CipherMode = 'cbc';
$crypt->KeyLength = 128;

$ivHex = '000102030405060708090A0B0C0D0E0F';
$crypt->SetEncodedIV($ivHex, 'hex');

$keyHex = '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F';
$crypt->SetEncodedKey($keyHex, 'hex');

// Do the in-place 128-bit AES CBC encryption.
// The contents of jpgBytes are replaced with the encrypted bytes.
try {
    $crypt->EncryptBd($jpgBytes);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Examine the JPG bytes again.  The bytes should be different because they are encrypted:
echo $jpgBytes->GetEncoded('base64_mime'), "\n";

// Sample base64_mime encrypted JPG data:

//     sbz0babt1WCkQf5xKMdg/baZAcUBO5GVUUDF2BjVqmd+HrqKN+t6hAcqakL/bdo0q9hYmow0Tp1e
//     AQ9V9DOiifQUZqWVkR+kL/c45bq8JGFDvgNl0djPt+yYhV789IB/fPH0upx+/ad++WNOlv1IxGMr
//     Y1x1oERU/IsiEzafUJdI4kZ6FQo2IPGMF/Rm1h79I7hP1yYUFxvJyz+PzaySAUH1nLsNHyDVY5VY
//     O90aH3steRSYbz8C8UF9wQ3qqEIXQNnnixvoNDnmHyY39VoVBI5F6rnPwYDfAk2t8tmuryFqvwAu
//     ...

// Decrypt to restore back to the original:
try {
    $crypt->DecryptBd($jpgBytes);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $jpgBytes->GetEncoded('base64_mime'), "\n";

//     /9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
//     AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
//     AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
//     MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
//     ...

// ----------------------------------------------------------------------------------
// To do chacha20 encryption, just change the settings:

$crypt->CryptAlgorithm = 'chacha20';
$crypt->KeyLength = 256;
// The initial count is the initial block counter for the chacha20 algorithm.
// It can be any integer, but must be set to the same when decrypting.
$crypt->InitialCount = 22;

$crypt->EncryptBd($jpgBytes);
// jpgBytes now contains chacha20 encrypted bytes.

$crypt->DecryptBd($jpgBytes);
// jpgBytes is now restored back to the original unencrypted by bytes.

// Save the bytes to a file..
$jpgBytes->WriteFile('qa_output/starfish.jpg');

echo "Success.\n";