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<?phpdeclare(strict_types=1);
 
 if (class_exists('ParagonIE_Sodium_Core_HSalsa20', false)) {
 return;
 }
 
 /**
 * Class ParagonIE_Sodium_Core_HSalsa20
 */
 abstract class ParagonIE_Sodium_Core_HSalsa20 extends ParagonIE_Sodium_Core_Salsa20
 {
 /**
 * Calculate an hsalsa20 hash of a single block
 *
 * HSalsa20 doesn't have a counter and will never be used for more than
 * one block (used to derive a subkey for xsalsa20).
 *
 * @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 hsalsa20(
 string $in,
 #[SensitiveParameter]
 string $k,
 ?string $c = null
 ): string {
 if ($c === null) {
 $x0  = 0x61707865;
 $x5  = 0x3320646e;
 $x10 = 0x79622d32;
 $x15 = 0x6b206574;
 } else {
 $x0  = self::load_4(self::substr($c, 0, 4));
 $x5  = self::load_4(self::substr($c, 4, 4));
 $x10 = self::load_4(self::substr($c, 8, 4));
 $x15 = self::load_4(self::substr($c, 12, 4));
 }
 $x1  = self::load_4(self::substr($k, 0, 4));
 $x2  = self::load_4(self::substr($k, 4, 4));
 $x3  = self::load_4(self::substr($k, 8, 4));
 $x4  = self::load_4(self::substr($k, 12, 4));
 $x11 = self::load_4(self::substr($k, 16, 4));
 $x12 = self::load_4(self::substr($k, 20, 4));
 $x13 = self::load_4(self::substr($k, 24, 4));
 $x14 = self::load_4(self::substr($k, 28, 4));
 $x6  = self::load_4(self::substr($in, 0, 4));
 $x7  = self::load_4(self::substr($in, 4, 4));
 $x8  = self::load_4(self::substr($in, 8, 4));
 $x9  = self::load_4(self::substr($in, 12, 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);
 }
 
 return self::store32_le($x0) .
 self::store32_le($x5) .
 self::store32_le($x10) .
 self::store32_le($x15) .
 self::store32_le($x6) .
 self::store32_le($x7) .
 self::store32_le($x8) .
 self::store32_le($x9);
 }
 }
 
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