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File: src/Core/Salsa20.php

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File: src/Core/Salsa20.php
Role: Class source
Content type: text/plain
Description: Class source
Class: PHP Sodium Compat
Cryptographic functions of libsodium in pure PHP
Author: By
Last change: Type safety
Date: 6 months ago
Size: 8,233 bytes
 

Contents

Class file image Download
<?php

if (class_exists('ParagonIE_Sodium_Core_Salsa20', false)) {
    return;
}

/**
 * Class ParagonIE_Sodium_Core_Salsa20
 */
abstract class ParagonIE_Sodium_Core_Salsa20 extends ParagonIE_Sodium_Core_Util
{
    const
ROUNDS = 20;

   
/**
     * Calculate an salsa20 hash of a single block
     *
     * @internal You should not use this directly from another application
     *
     * @param string $in
     * @param string $k
     * @param string|null $c
     * @return string
     * @throws TypeError
     */
   
public static function core_salsa20($in, $k, $c = null)
    {
        if (
self::strlen($k) < 32) {
            throw new
RangeException('Key must be 32 bytes long');
        }
        if (
$c === null) {
           
$j0 = $x0 = 0x61707865;
           
$j5 = $x5 = 0x3320646e;
           
$j10 = $x10 = 0x79622d32;
           
$j15 = $x15 = 0x6b206574;
        } else {
           
$j0 = $x0 = self::load_4(self::substr($c, 0, 4));
           
$j5 = $x5 = self::load_4(self::substr($c, 4, 4));
           
$j10 = $x10 = self::load_4(self::substr($c, 8, 4));
           
$j15 = $x15 = self::load_4(self::substr($c, 12, 4));
        }
       
$j1 = $x1 = self::load_4(self::substr($k, 0, 4));
       
$j2 = $x2 = self::load_4(self::substr($k, 4, 4));
       
$j3 = $x3 = self::load_4(self::substr($k, 8, 4));
       
$j4 = $x4 = self::load_4(self::substr($k, 12, 4));
       
$j6 = $x6 = self::load_4(self::substr($in, 0, 4));
       
$j7 = $x7 = self::load_4(self::substr($in, 4, 4));
       
$j8 = $x8 = self::load_4(self::substr($in, 8, 4));
       
$j9 = $x9 = self::load_4(self::substr($in, 12, 4));
       
$j11 = $x11 = self::load_4(self::substr($k, 16, 4));
       
$j12 = $x12 = self::load_4(self::substr($k, 20, 4));
       
$j13 = $x13 = self::load_4(self::substr($k, 24, 4));
       
$j14 = $x14 = self::load_4(self::substr($k, 28, 4));

        for (
$i = self::ROUNDS; $i > 0; $i -= 2) {
           
$x4 ^= self::rotate($x0 + $x12, 7);
           
$x8 ^= self::rotate($x4 + $x0, 9);
           
$x12 ^= self::rotate($x8 + $x4, 13);
           
$x0 ^= self::rotate($x12 + $x8, 18);

           
$x9 ^= self::rotate($x5 + $x1, 7);
           
$x13 ^= self::rotate($x9 + $x5, 9);
           
$x1 ^= self::rotate($x13 + $x9, 13);
           
$x5 ^= self::rotate($x1 + $x13, 18);

           
$x14 ^= self::rotate($x10 + $x6, 7);
           
$x2 ^= self::rotate($x14 + $x10, 9);
           
$x6 ^= self::rotate($x2 + $x14, 13);
           
$x10 ^= self::rotate($x6 + $x2, 18);

           
$x3 ^= self::rotate($x15 + $x11, 7);
           
$x7 ^= self::rotate($x3 + $x15, 9);
           
$x11 ^= self::rotate($x7 + $x3, 13);
           
$x15 ^= self::rotate($x11 + $x7, 18);

           
$x1 ^= self::rotate($x0 + $x3, 7);
           
$x2 ^= self::rotate($x1 + $x0, 9);
           
$x3 ^= self::rotate($x2 + $x1, 13);
           
$x0 ^= self::rotate($x3 + $x2, 18);

           
$x6 ^= self::rotate($x5 + $x4, 7);
           
$x7 ^= self::rotate($x6 + $x5, 9);
           
$x4 ^= self::rotate($x7 + $x6, 13);
           
$x5 ^= self::rotate($x4 + $x7, 18);

           
$x11 ^= self::rotate($x10 + $x9, 7);
           
$x8 ^= self::rotate($x11 + $x10, 9);
           
$x9 ^= self::rotate($x8 + $x11, 13);
           
$x10 ^= self::rotate($x9 + $x8, 18);

           
$x12 ^= self::rotate($x15 + $x14, 7);
           
$x13 ^= self::rotate($x12 + $x15, 9);
           
$x14 ^= self::rotate($x13 + $x12, 13);
           
$x15 ^= self::rotate($x14 + $x13, 18);
        }

       
$x0 += $j0;
       
$x1 += $j1;
       
$x2 += $j2;
       
$x3 += $j3;
       
$x4 += $j4;
       
$x5 += $j5;
       
$x6 += $j6;
       
$x7 += $j7;
       
$x8 += $j8;
       
$x9 += $j9;
       
$x10 += $j10;
       
$x11 += $j11;
       
$x12 += $j12;
       
$x13 += $j13;
       
$x14 += $j14;
       
$x15 += $j15;

        return
self::store32_le($x0) .
           
self::store32_le($x1) .
           
self::store32_le($x2) .
           
self::store32_le($x3) .
           
self::store32_le($x4) .
           
self::store32_le($x5) .
           
self::store32_le($x6) .
           
self::store32_le($x7) .
           
self::store32_le($x8) .
           
self::store32_le($x9) .
           
self::store32_le($x10) .
           
self::store32_le($x11) .
           
self::store32_le($x12) .
           
self::store32_le($x13) .
           
self::store32_le($x14) .
           
self::store32_le($x15);
    }

   
/**
     * @internal You should not use this directly from another application
     *
     * @param int $len
     * @param string $nonce
     * @param string $key
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
   
public static function salsa20($len, $nonce, $key)
    {
        if (
self::strlen($key) !== 32) {
            throw new
RangeException('Key must be 32 bytes long');
        }
       
$kcopy = '' . $key;
       
$in = self::substr($nonce, 0, 8) . str_repeat("\0", 8);
       
$c = '';
        while (
$len >= 64) {
           
$c .= self::core_salsa20($in, $kcopy, null);
           
$u = 1;
           
// Internal counter.
           
for ($i = 8; $i < 16; ++$i) {
               
$u += self::chrToInt($in[$i]);
               
$in[$i] = self::intToChr($u & 0xff);
               
$u >>= 8;
            }
           
$len -= 64;
        }
        if (
$len > 0) {
           
$c .= self::substr(
               
self::core_salsa20($in, $kcopy, null),
               
0,
               
$len
           
);
        }
        try {
           
ParagonIE_Sodium_Compat::memzero($kcopy);
        } catch (
SodiumException $ex) {
           
$kcopy = null;
        }
        return
$c;
    }

   
/**
     * @internal You should not use this directly from another application
     *
     * @param string $m
     * @param string $n
     * @param int $ic
     * @param string $k
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
   
public static function salsa20_xor_ic($m, $n, $ic, $k)
    {
       
$mlen = self::strlen($m);
        if (
$mlen < 1) {
            return
'';
        }
       
$kcopy = self::substr($k, 0, 32);
       
$in = self::substr($n, 0, 8);
       
// Initialize the counter
       
$in .= ParagonIE_Sodium_Core_Util::store64_le($ic);

       
$c = '';
        while (
$mlen >= 64) {
           
$block = self::core_salsa20($in, $kcopy, null);
           
$c .= self::xorStrings(
               
self::substr($m, 0, 64),
               
self::substr($block, 0, 64)
            );
           
$u = 1;
            for (
$i = 8; $i < 16; ++$i) {
               
$u += self::chrToInt($in[$i]);
               
$in[$i] = self::intToChr($u & 0xff);
               
$u >>= 8;
            }

           
$mlen -= 64;
           
$m = self::substr($m, 64);
        }

        if (
$mlen) {
           
$block = self::core_salsa20($in, $kcopy, null);
           
$c .= self::xorStrings(
               
self::substr($m, 0, $mlen),
               
self::substr($block, 0, $mlen)
            );
        }
        try {
           
ParagonIE_Sodium_Compat::memzero($block);
           
ParagonIE_Sodium_Compat::memzero($kcopy);
        } catch (
SodiumException $ex) {
           
$block = null;
           
$kcopy = null;
        }

        return
$c;
    }

   
/**
     * @internal You should not use this directly from another application
     *
     * @param string $message
     * @param string $nonce
     * @param string $key
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
   
public static function salsa20_xor($message, $nonce, $key)
    {
        return
self::xorStrings(
           
$message,
           
self::salsa20(
               
self::strlen($message),
               
$nonce,
               
$key
           
)
        );
    }

   
/**
     * @internal You should not use this directly from another application
     *
     * @param int $u
     * @param int $c
     * @return int
     */
   
public static function rotate($u, $c)
    {
       
$u &= 0xffffffff;
       
$c %= 32;
        return (int) (
0xffffffff & (
                (
$u << $c)
                    |
                (
$u >> (32 - $c))
            )
        );
    }
}