1<?php
  2
  3if (class_exists('ParagonIE_Sodium_Core_XChaCha20', false)) {
  4    return;
  5}
  6
  7/**
  8 * Class ParagonIE_Sodium_Core_XChaCha20
  9 */
 10class ParagonIE_Sodium_Core_XChaCha20 extends ParagonIE_Sodium_Core_HChaCha20
 11{
 12    /**
 13     * @internal You should not use this directly from another application
 14     *
 15     * @param int $len
 16     * @param string $nonce
 17     * @param string $key
 18     * @return string
 19     * @throws SodiumException
 20     * @throws TypeError
 21     */
 22    public static function stream($len, $nonce, $key)
 23    {
 24        if (self::strlen($nonce) !== 24) {
 25            throw new SodiumException('Nonce must be 24 bytes long');
 26        }
 27        return self::encryptBytes(
 28            new ParagonIE_Sodium_Core_ChaCha20_Ctx(
 29                self::hChaCha20(
 30                    self::substr($nonce, 0, 16),
 31                    $key
 32                ),
 33                self::substr($nonce, 16, 8)
 34            ),
 35            str_repeat("\x00", $len)
 36        );
 37    }
 38
 39    /**
 40     * @internal You should not use this directly from another application
 41     *
 42     * @param int $len
 43     * @param string $nonce
 44     * @param string $key
 45     * @return string
 46     * @throws SodiumException
 47     * @throws TypeError
 48     */
 49    public static function ietfStream($len, $nonce, $key)
 50    {
 51        if (self::strlen($nonce) !== 24) {
 52            throw new SodiumException('Nonce must be 24 bytes long');
 53        }
 54        return self::encryptBytes(
 55            new ParagonIE_Sodium_Core_ChaCha20_IetfCtx(
 56                self::hChaCha20(
 57                    self::substr($nonce, 0, 16),
 58                    $key
 59                ),
 60                "\x00\x00\x00\x00" . self::substr($nonce, 16, 8)
 61            ),
 62            str_repeat("\x00", $len)
 63        );
 64    }
 65
 66    /**
 67     * @internal You should not use this directly from another application
 68     *
 69     * @param string $message
 70     * @param string $nonce
 71     * @param string $key
 72     * @param string $ic
 73     * @return string
 74     * @throws SodiumException
 75     * @throws TypeError
 76     */
 77    public static function streamXorIc($message, $nonce, $key, $ic = '')
 78    {
 79        if (self::strlen($nonce) !== 24) {
 80            throw new SodiumException('Nonce must be 24 bytes long');
 81        }
 82        return self::encryptBytes(
 83            new ParagonIE_Sodium_Core_ChaCha20_Ctx(
 84                self::hChaCha20(self::substr($nonce, 0, 16), $key),
 85                self::substr($nonce, 16, 8),
 86                $ic
 87            ),
 88            $message
 89        );
 90    }
 91
 92    /**
 93     * @internal You should not use this directly from another application
 94     *
 95     * @param string $message
 96     * @param string $nonce
 97     * @param string $key
 98     * @param string $ic
 99     * @return string
100     * @throws SodiumException
101     * @throws TypeError
102     */
103    public static function ietfStreamXorIc($message, $nonce, $key, $ic = '')
104    {
105        if (self::strlen($nonce) !== 24) {
106            throw new SodiumException('Nonce must be 24 bytes long');
107        }
108        return self::encryptBytes(
109            new ParagonIE_Sodium_Core_ChaCha20_IetfCtx(
110                self::hChaCha20(self::substr($nonce, 0, 16), $key),
111                "\x00\x00\x00\x00" . self::substr($nonce, 16, 8),
112                $ic
113            ),
114            $message
115        );
116    }
117}
118