PHP

AES and CHACHA20 Encrypt/Decrypt Text

See more Encryption Examples

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

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

Chilkat2 PHP

<?php

use Chilkat2\BinData;
use Chilkat2\Crypt2;
use Chilkat2\StringBuilder;

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

// First build a string to be encrypted
$sb = new StringBuilder();
$i = 1;
while ($i < 10) {
    $sb->AppendInt($i);
    $sb->Append(" the quick brown fox jumped over the lazy dog.\r\n");
    $i = $i + 1;
}

echo $sb->GetAsString(), "\n";

// The string to be encrypted looks like this:

// 1 the quick brown fox jumped over the lazy dog.
// 2 the quick brown fox jumped over the lazy dog.
// 3 the quick brown fox jumped over the lazy dog.
// 4 the quick brown fox jumped over the lazy dog.
// 5 the quick brown fox jumped over the lazy dog.
// 6 the quick brown fox jumped over the lazy dog.
// ...

$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');

// When EncryptSb is called, the contents of the source (sb)
// remains unmodified.  The encrypted bytes are written into bdEncrypted.
// If bdEncrypted already contained data, it is replaced with the encrypted bytes.
$bdEncrypted = new BinData();
try {
    $crypt->EncryptSb($sb, $bdEncrypted);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Examine the encrypted bytes:
echo $bdEncrypted->GetEncoded('base64_mime'), "\n";

// Sample encrypted data:

// 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
// df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
// EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
// g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
// PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
// 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
// eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
// H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

// Decrypt to restore back to the original:
$sbOriginal = new StringBuilder();
try {
    $crypt->DecryptSb($bdEncrypted, $sbOriginal);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Examine the original data:
echo $sbOriginal->GetAsString(), "\n";

// ----------------------------------------------------------------------------------
// 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;

// EncryptSb completely replaces the contents of bdEncrypted.
$crypt->EncryptSb($sb, $bdEncrypted);

// However.. DecryptSb appends the decrypted text to whatever may
// have already existed within sbOriginal.
$crypt->DecryptSb($bdEncrypted, $sbOriginal);

echo "----\n";
echo "The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt.\n";
echo $sbOriginal->GetAsString(), "\n";
echo "Success.\n";