1<?php
  2
  3if (class_exists('ParagonIE_Sodium_Core32_HChaCha20', false)) {
  4    return;
  5}
  6
  7/**
  8 * Class ParagonIE_Sodium_Core_HChaCha20
  9 */
 10class ParagonIE_Sodium_Core32_HChaCha20 extends ParagonIE_Sodium_Core32_ChaCha20
 11{
 12    /**
 13     * @param string $in
 14     * @param string $key
 15     * @param string|null $c
 16     * @return string
 17     * @throws SodiumException
 18     * @throws TypeError
 19     */
 20    public static function hChaCha20($in = '', $key = '', $c = null)
 21    {
 22        $ctx = array();
 23
 24        if ($c === null) {
 25            $ctx[0] = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));
 26            $ctx[1] = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));
 27            $ctx[2] = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));
 28            $ctx[3] = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));
 29        } else {
 30            $ctx[0] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 0, 4));
 31            $ctx[1] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 4, 4));
 32            $ctx[2] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 8, 4));
 33            $ctx[3] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 12, 4));
 34        }
 35        $ctx[4]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 0, 4));
 36        $ctx[5]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 4, 4));
 37        $ctx[6]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 8, 4));
 38        $ctx[7]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 12, 4));
 39        $ctx[8]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 16, 4));
 40        $ctx[9]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 20, 4));
 41        $ctx[10] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 24, 4));
 42        $ctx[11] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 28, 4));
 43        $ctx[12] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 0, 4));
 44        $ctx[13] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 4, 4));
 45        $ctx[14] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 8, 4));
 46        $ctx[15] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 12, 4));
 47
 48        return self::hChaCha20Bytes($ctx);
 49    }
 50
 51    /**
 52     * @param array $ctx
 53     * @return string
 54     * @throws SodiumException
 55     * @throws TypeError
 56     */
 57    protected static function hChaCha20Bytes(array $ctx)
 58    {
 59        /** @var ParagonIE_Sodium_Core32_Int32 $x0 */
 60        $x0  = $ctx[0];
 61        /** @var ParagonIE_Sodium_Core32_Int32 $x1 */
 62        $x1  = $ctx[1];
 63        /** @var ParagonIE_Sodium_Core32_Int32 $x2 */
 64        $x2  = $ctx[2];
 65        /** @var ParagonIE_Sodium_Core32_Int32 $x3 */
 66        $x3  = $ctx[3];
 67        /** @var ParagonIE_Sodium_Core32_Int32 $x4 */
 68        $x4  = $ctx[4];
 69        /** @var ParagonIE_Sodium_Core32_Int32 $x5 */
 70        $x5  = $ctx[5];
 71        /** @var ParagonIE_Sodium_Core32_Int32 $x6 */
 72        $x6  = $ctx[6];
 73        /** @var ParagonIE_Sodium_Core32_Int32 $x7 */
 74        $x7  = $ctx[7];
 75        /** @var ParagonIE_Sodium_Core32_Int32 $x8 */
 76        $x8  = $ctx[8];
 77        /** @var ParagonIE_Sodium_Core32_Int32 $x9 */
 78        $x9  = $ctx[9];
 79        /** @var ParagonIE_Sodium_Core32_Int32 $x10 */
 80        $x10 = $ctx[10];
 81        /** @var ParagonIE_Sodium_Core32_Int32 $x11 */
 82        $x11 = $ctx[11];
 83        /** @var ParagonIE_Sodium_Core32_Int32 $x12 */
 84        $x12 = $ctx[12];
 85        /** @var ParagonIE_Sodium_Core32_Int32 $x13 */
 86        $x13 = $ctx[13];
 87        /** @var ParagonIE_Sodium_Core32_Int32 $x14 */
 88        $x14 = $ctx[14];
 89        /** @var ParagonIE_Sodium_Core32_Int32 $x15 */
 90        $x15 = $ctx[15];
 91
 92        for ($i = 0; $i < 10; ++$i) {
 93            # QUARTERROUND( x0,  x4,  x8,  x12)
 94            list($x0, $x4, $x8, $x12) = self::quarterRound($x0, $x4, $x8, $x12);
 95
 96            # QUARTERROUND( x1,  x5,  x9,  x13)
 97            list($x1, $x5, $x9, $x13) = self::quarterRound($x1, $x5, $x9, $x13);
 98
 99            # QUARTERROUND( x2,  x6,  x10,  x14)
100            list($x2, $x6, $x10, $x14) = self::quarterRound($x2, $x6, $x10, $x14);
101
102            # QUARTERROUND( x3,  x7,  x11,  x15)
103            list($x3, $x7, $x11, $x15) = self::quarterRound($x3, $x7, $x11, $x15);
104
105            # QUARTERROUND( x0,  x5,  x10,  x15)
106            list($x0, $x5, $x10, $x15) = self::quarterRound($x0, $x5, $x10, $x15);
107
108            # QUARTERROUND( x1,  x6,  x11,  x12)
109            list($x1, $x6, $x11, $x12) = self::quarterRound($x1, $x6, $x11, $x12);
110
111            # QUARTERROUND( x2,  x7,  x8,  x13)
112            list($x2, $x7, $x8, $x13) = self::quarterRound($x2, $x7, $x8, $x13);
113
114            # QUARTERROUND( x3,  x4,  x9,  x14)
115            list($x3, $x4, $x9, $x14) = self::quarterRound($x3, $x4, $x9, $x14);
116        }
117
118        return $x0->toReverseString() .
119            $x1->toReverseString() .
120            $x2->toReverseString() .
121            $x3->toReverseString() .
122            $x12->toReverseString() .
123            $x13->toReverseString() .
124            $x14->toReverseString() .
125            $x15->toReverseString();
126    }
127}
128