phpBitMessageCrawler/ecc.php at master · SavageTiger/phpBitMessageCrawler · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
<?php

class Ecc
{
    protected $secp256k1;
    protected $secp256k1_G;

    function __construct()
    {
        if (extension_loaded('gmp') === false) {
            trigger_error('PHP GMP extension required for ECC', E_USER_ERROR);
        }

        if (!defined('USE_EXT')) {
            define('USE_EXT', 'GMP');
        }

        $this->secp256k1 = new CurveFp(
            '115792089237316195423570985008687907853269984665640564039457584007908834671663',
            '0', '7'
        );

        $this->secp256k1_G = new Point(
            $this->secp256k1,
            '55066263022277343669578718895168534326250603453777594175500187360389116729240',
            '32670510020758816978083085130507043184471273380659243275938904335757337482424',
            '115792089237316195423570985008687907852837564279074904382605163141518161494337'
        );
    }

    public function ECDSA($binary, $key, $signature)
    {
        $signature = $this->decodeSignature($signature);
        $signature = new Signature(
            gmp_Utils::gmp_hexdec('0x' . $signature['r']),
            gmp_Utils::gmp_hexdec('0x' . $signature['s'])
        );

        $pubKey = $this->loadPublicKey($key);

        return $pubKey->verifies($this->digest_integer($binary), $signature);
    }

    public function Decrypt($binary)
    {
        // https://bitmessage.org/wiki/Protocol_specification#Encrypted_payload
        $initVector = substr($binary, 0, 16);

        $binary = substr($binary, 16);
        $pubKey = $this->decodePubkey($binary);

        if ($pubKey['curveType'][1] === 714) {
            $body = substr($binary, $pubKey['len']);
            //$body = substr($body, 0, strlen($body) - 32);

            $ecDh = new EcDH(
                new Point(
                    $this->secp256k1,
                    gmp_Utils::gmp_hexdec('0x' . $pubKey['x']),
                    gmp_Utils::gmp_hexdec('0x' . $pubKey['y'])
                )
            );

            die(var_dump($ecDh->decrypt($body, $initVector)));
        }

        return false;
    }

    private function digest_integer($message)
    {
        // Copy't from the phpecc library, not sure why, there implementation might be broken
        // That was a nice 5 hours of searching :P
        return PrivateKey::string_to_int(hash('sha1', $message, true));
    }


    protected function loadPublicKey($key)
    {
        $key =
            hex2bin('02ca0020') .
            substr($key, 1, 32) .
            hex2bin('0020') .
            substr($key, 33, 32);

        $pubKey = $this->decodePubKey($key);
        $pubKey = new PublicKey(
            $this->secp256k1_G,
            new Point(
                $this->secp256k1,
                gmp_Utils::gmp_hexdec('0x' . $pubKey['x']),
                gmp_Utils::gmp_hexdec('0x' . $pubKey['y'])
            )
        );

        return $pubKey;
    }

    protected function decodeSignature($signature)
    {
        $rLength = unpack('C', substr($signature, 3, 1));
        $rLength = $rLength[1];

        $r = substr($signature, 4, $rLength);

        $sLength = unpack('C', substr($signature, 5 + $rLength, 1));
        $sLength = $sLength[1];

        $s = substr($signature, 6 + $rLength, $sLength + 1);

        return array(
            'r' => bin2hex($r),
            's' => bin2hex($s)
        );
    }

    protected function decodePubKey($key)
    {
        $curveType = substr($key, 0, 2);
        $curveType = unpack('n', $curveType);

        $pointLength = substr($key, 2, 2);
        $pointLength = unpack('n', $pointLength);

        $x = substr($key, 4, $pointLength[1]);

        $pointLength = substr($key, $pointLength[1] + 4);
        $pointLength = unpack('n', $pointLength);

        $y = substr($key, strlen($x) + 6, $pointLength[1]);

        return array(
            'len' => (strlen($x) + 6 + $pointLength[1]),
            'curveType' => $curveType,
            'x' => bin2hex($x),
            'y' => bin2hex($y)
        );
    }
}