|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
/** |
|
4
|
|
|
* OpensslBridge.php |
|
5
|
|
|
* |
|
6
|
|
|
* PHP version 7 |
|
7
|
|
|
* |
|
8
|
|
|
* @category Dcrypt |
|
9
|
|
|
* @package Dcrypt |
|
10
|
|
|
* @author Michael Meyer (mmeyer2k) <[email protected]> |
|
11
|
|
|
* @license http://opensource.org/licenses/MIT The MIT License (MIT) |
|
12
|
|
|
* @link https://github.com/mmeyer2k/dcrypt |
|
13
|
|
|
*/ |
|
14
|
|
|
|
|
15
|
|
|
namespace Dcrypt; |
|
16
|
|
|
|
|
17
|
|
|
/** |
|
18
|
|
|
* Provides functionality common to the dcrypt AES block ciphers. Extend this class to customize your cipher suite. |
|
19
|
|
|
* |
|
20
|
|
|
* @category Dcrypt |
|
21
|
|
|
* @package Dcrypt |
|
22
|
|
|
* @author Michael Meyer (mmeyer2k) <[email protected]> |
|
23
|
|
|
* @license http://opensource.org/licenses/MIT The MIT License (MIT) |
|
24
|
|
|
* @link https://github.com/mmeyer2k/dcrypt |
|
25
|
|
|
* @link https://apigen.ci/github/mmeyer2k/dcrypt/namespace-Dcrypt.html |
|
26
|
|
|
*/ |
|
27
|
|
|
class OpensslBridge |
|
28
|
|
|
{ |
|
29
|
|
|
/** |
|
30
|
|
|
* Decrypt cyphertext |
|
31
|
|
|
* |
|
32
|
|
|
* @param string $data Cyphertext to decrypt |
|
33
|
|
|
* @param string $pass Password that should be used to decrypt input data |
|
34
|
|
|
* @return string |
|
35
|
|
|
*/ |
|
36
|
|
|
public static function decrypt(string $data, string $pass): string |
|
37
|
|
|
{ |
|
38
|
|
|
// Calculate the hash checksum size in bytes for the specified algo |
|
39
|
|
|
$hsz = Str::hashSize(static::CHKSUM); |
|
40
|
|
|
|
|
41
|
|
|
// Ask openssl for the IV size needed for specified cipher |
|
42
|
|
|
$isz = OpensslWrapper::ivsize(static::CIPHER); |
|
43
|
|
|
|
|
44
|
|
|
// Find the IV at the beginning of the cypher text |
|
45
|
|
|
$ivr = Str::substr($data, 0, $isz); |
|
46
|
|
|
|
|
47
|
|
|
// Gather the checksum portion of the ciphertext |
|
48
|
|
|
$sum = Str::substr($data, $isz, $hsz); |
|
49
|
|
|
|
|
50
|
|
|
// Gather the iterations portion of the cipher text as packed/encrytped unsigned long |
|
51
|
|
|
$itr = Str::substr($data, $isz + $hsz, 4); |
|
52
|
|
|
|
|
53
|
|
|
// Gather message portion of ciphertext after iv and checksum |
|
54
|
|
|
$msg = Str::substr($data, $isz + $hsz + 4); |
|
55
|
|
|
|
|
56
|
|
|
// Calculate verification checksum |
|
57
|
|
|
$chk = \hash_hmac(static::CHKSUM, ($msg . $itr . $ivr), $pass, true); |
|
58
|
|
|
|
|
59
|
|
|
// Verify HMAC before decrypting |
|
60
|
|
|
if (!Str::equal($chk, $sum)) { |
|
61
|
|
|
throw new \InvalidArgumentException('Decryption can not proceed due to invalid cyphertext checksum.'); |
|
62
|
|
|
} |
|
63
|
|
|
|
|
64
|
|
|
// Decrypt and unpack the cost parameter to match what was used during encryption |
|
65
|
|
|
$cost = \unpack('N', $itr ^ \hash_hmac(static::CHKSUM, $ivr, $pass, true))[1]; |
|
66
|
|
|
|
|
67
|
|
|
// Derive key from password |
|
68
|
|
|
$key = \hash_pbkdf2(static::CHKSUM, ($pass . static::CIPHER), $ivr, $cost, 0, true); |
|
69
|
|
|
|
|
70
|
|
|
// Decrypt message and return |
|
71
|
|
|
return OpensslWrapper::decrypt($msg, static::CIPHER, $key, $ivr); |
|
72
|
|
|
} |
|
73
|
|
|
|
|
74
|
|
|
/** |
|
75
|
|
|
* Encrypt plaintext |
|
76
|
|
|
* |
|
77
|
|
|
* @param string $data Plaintext string to encrypt. |
|
78
|
|
|
* @param string $pass Password used to encrypt data. |
|
79
|
|
|
* @param int $cost Number of extra HMAC iterations to perform on key |
|
80
|
|
|
* @return string |
|
81
|
|
|
*/ |
|
82
|
|
|
public static function encrypt(string $data, string $pass, int $cost = 1): string |
|
83
|
|
|
{ |
|
84
|
|
|
// Generate IV of appropriate size. |
|
85
|
|
|
$ivr = \random_bytes(OpensslWrapper::ivsize(static::CIPHER)); |
|
86
|
|
|
|
|
87
|
|
|
// Derive key from password with hash_pbkdf2 function. |
|
88
|
|
|
// Append CIPHER to password beforehand so that cross-method decryptions will fail at checksum step |
|
89
|
|
|
$key = \hash_pbkdf2(static::CHKSUM, ($pass . static::CIPHER), $ivr, $cost, 0, true); |
|
90
|
|
|
|
|
91
|
|
|
// Encrypt the plaintext data |
|
92
|
|
|
$msg = OpensslWrapper::encrypt($data, static::CIPHER, $key, $ivr); |
|
93
|
|
|
|
|
94
|
|
|
// Convert cost integer into 4 byte string and XOR it with a newly derived key |
|
95
|
|
|
$itr = \pack('N', $cost) ^ \hash_hmac(static::CHKSUM, $ivr, $pass, true); |
|
96
|
|
|
|
|
97
|
|
|
// Generate the ciphertext checksum to prevent bit tampering |
|
98
|
|
|
$chk = \hash_hmac(static::CHKSUM, ($msg . $itr . $ivr), $pass, true); |
|
99
|
|
|
|
|
100
|
|
|
// Return iv + checksum + iterations + cyphertext |
|
101
|
|
|
return $ivr . $chk . $itr . $msg; |
|
102
|
|
|
} |
|
103
|
|
|
} |
|
104
|
|
|
|
mmeyer2k /
dcrypt
