The Rise of Contactless Payments:...
In recent years, contactless payments have surged in popularity, driven...
<?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))
)
);
}
}
Blog Section
Dive into our blog to explore the cutting-edge trends in digital payments and NFC technology. Stay updated on the innovations that are revolutionizing transactions, boosting security, and making payments quicker and more convenient. Learn how these advancements are shaping the future of financial interactions and driving the global transition towards a cashless world.
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