PHP

Duplicate SQL Server ENCRYPTBYPASSPHRASE

See more Encryption Examples

Demonstrates how to duplicate SQL Server's ENCRYPTBYPASSPHRASE. Chilkat2 PHP

<?php

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

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

// For SQL Server 2008 - SQL Server 2016 we must use TripleDES with SHA1
// For SQL Server 2017 and later, use AES256 / SHA256.

$password = 'tEst1234';
$encryptedHex_v1 = '0x010000001E8E7DCDBD4061B951999E25D18445D2305474D2D71EEE98A241C755246F58AB';

// Here's an encrypted string using AES256/SHA256
$encryptedHex_v2 = '0x02000000FFE880C0354780481E64EF25B6197A02E2A854A4BA9D8D9BDDFDAB27EB56537ABDA0B1D9C4D1050C91B313550DECF429';

$sbEncHex = new StringBuilder();
$sbEncHex->Append($encryptedHex_v1);

// If present, we don't want the leading "0x"
if ($sbEncHex->StartsWith('0x', false)) {
    $sbEncHex->RemoveCharsAt(0, 2);
}

$crypt = new Crypt2();
$crypt->EncodingMode = 'hex';

// The encrypted hex string will begin with either 01000000 or 02000000
// version 1 is produced by SQL Server 2008 to SQL Server 2016, and we must use TripleDES with SHA1
// version 2 is for SQL Server 2017 and later, and uses AES256 / SHA256.
$v1 = $sbEncHex->StartsWith('01', false);

$ivLen = 0;
$hashAlg = '';

if ($v1) {
    $crypt->CryptAlgorithm = '3des';
    $crypt->CipherMode = 'cbc';
    $crypt->KeyLength = 168;
    $ivLen = 8;
    $hashAlg = 'sha1';
} else {
    $crypt->CryptAlgorithm = 'aes';
    $crypt->CipherMode = 'cbc';
    $crypt->KeyLength = 256;
    $ivLen = 16;
    $hashAlg = 'sha256';
}

// Remove the SQL Server version info (i.e. the "01000000")
$sbEncHex->RemoveCharsAt(0, 8);

// Get the IV part of the sbEncHex, and also remove it from the StringBuilder.
$ivHex = $sbEncHex->GetRange(0, $ivLen * 2, true);
echo 'IV = ', $ivHex, "\n";
$crypt->SetEncodedIV($ivHex, 'hex');

$sbPassword = new StringBuilder();
$sbPassword->Append($password);
$pwd_hash = $sbPassword->GetHash($hashAlg, 'hex', 'utf-16');
$sbKey = new StringBuilder();
$sbKey->Append($pwd_hash);
if ($v1) {
    // For v1, we only want the 1st 16 bytes of the 20 byte hash.
    // (remember, the hex encoding uses 2 chars per byte, so we remove the last 8 chars)
    $sbKey->Shorten(8);
}

echo 'crypt key: ', $sbKey->GetAsString(), "\n";

$crypt->SetEncodedKey($sbKey->GetAsString(), 'hex');

// Decrypt
$bd = new BinData();
$bd->AppendEncoded($sbEncHex->GetAsString(), 'hex');
$crypt->DecryptBd($bd);

// The result is composed of a header of 8 bytes which we can discard.
// The remainder is the decrypted text.

// The header we are discarding is composed of:
// Bytes 0-3: Magic number equal to 0DF0ADBA
// Bytes 4-5: Number of integrity bytes, which is 0 unless an authenticator is used. We're assuming no authenticator is used.
// Bytes 6-7: Number of plain-text bytes. We really don't need this because the CBC padding takes care of it.

// Therefore, just return the data after the 1st 8 bytes.
// Assuming the encrypted string was utf-8 text...
$bd->RemoveChunk(0, 8);
$plainText = $bd->GetString('utf-8');
echo 'decrypted plain text: ', $plainText, "\n";

// The output:

// IV = 1E8E7DCDBD4061B9
// crypt key: 710B9C2E61ACCC9570D4112203BD9738
// decrypted plain text: Hello world.

// ------------------------------------------------------------------------------------------
// To encrypt, do the reverse...

// Let's do v1 with TripleDES with SHA1

$encryptor = new Crypt2();
$encryptor->EncodingMode = 'hex';

$encryptor->CryptAlgorithm = '3des';
$encryptor->CipherMode = 'cbc';
$encryptor->KeyLength = 168;

// Generate a random 8-byte IV
$prng = new Prng();
$ivHex = $prng->GenRandom(8, 'hex');
$encryptor->SetEncodedIV($ivHex, 'hex');

// The binary password is generated the same as above.
// We'll use the same password (and same binary password)
$encryptor->SetEncodedKey($sbKey->GetAsString(), 'hex');

$plainTextLen = 8;
$plainText = 'ABCD1234';

// Encrypt the header + the plain-text.
$bdData = new BinData();
$bdData->AppendEncoded('0DF0ADBA', 'hex');
$bdData->AppendEncoded('0000', 'hex');
$bdData->AppendInt2($plainTextLen, true);
echo 'header: ', $bdData->GetEncoded('hex'), "\n";
$bdData->AppendString($plainText, 'utf-8');
$encryptor->EncryptBd($bdData);

// Compose the result..
$sbEnc = new StringBuilder();
$sbEnc->Append('0x01000000');
$sbEnc->Append($ivHex);
$sbEnc->Append($bdData->GetEncoded('hex'));

echo 'result: ', $sbEnc->GetAsString(), "\n";