1<?php
  2
  3if (class_exists('ParagonIE_Sodium_Core32_XChaCha20', false)) {
  4    return;
  5}
  6
  7/**
  8 * Class ParagonIE_Sodium_Core32_XChaCha20
  9 */
 10class ParagonIE_Sodium_Core32_XChaCha20 extends ParagonIE_Sodium_Core32_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 = 64, $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_Core32_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 string $message
 43     * @param string $nonce
 44     * @param string $key
 45     * @param string $ic
 46     * @return string
 47     * @throws SodiumException
 48     * @throws TypeError
 49     */
 50    public static function streamXorIc($message, $nonce = '', $key = '', $ic = '')
 51    {
 52        if (self::strlen($nonce) !== 24) {
 53            throw new SodiumException('Nonce must be 24 bytes long');
 54        }
 55        return self::encryptBytes(
 56            new ParagonIE_Sodium_Core32_ChaCha20_Ctx(
 57                self::hChaCha20(self::substr($nonce, 0, 16), $key),
 58                self::substr($nonce, 16, 8),
 59                $ic
 60            ),
 61            $message
 62        );
 63    }
 64
 65    /**
 66     * @internal You should not use this directly from another application
 67     *
 68     * @param string $message
 69     * @param string $nonce
 70     * @param string $key
 71     * @param string $ic
 72     * @return string
 73     * @throws SodiumException
 74     * @throws TypeError
 75     */
 76    public static function ietfStreamXorIc($message, $nonce = '', $key = '', $ic = '')
 77    {
 78        return self::encryptBytes(
 79            new ParagonIE_Sodium_Core32_ChaCha20_IetfCtx(
 80                self::hChaCha20(self::substr($nonce, 0, 16), $key),
 81                "\x00\x00\x00\x00" . self::substr($nonce, 16, 8),
 82                $ic
 83            ),
 84            $message
 85        );
 86    }
 87}
 88