<?php

if (class_exists('ParagonIE_Sodium_Core32_XSalsa20', false)) {
    return;
}
abstract class ParagonIE_Sodium_Core32_XSalsa20 extends ParagonIE_Sodium_Core32_HSalsa20
{
    public static function xsalsa20($len, $nonce, $key)
    {
        $ret = self::salsa20($len, self::substr($nonce, 16, 8), self::hsalsa20($nonce, $key));
        return $ret;
    }
    public static function xsalsa20_xor($message, $nonce, $key)
    {
        return self::xorStrings($message, self::xsalsa20(self::strlen($message), $nonce, $key));
    }
}