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Convert an Ed25519 secret key to a Curve25519 secret key
Syntax Syntax
Parameters Parameters
- $sk
-
(Required)
Return Return
(string)
Source Source
File: wp-includes/sodium_compat/src/Compat.php
public static function crypto_sign_ed25519_sk_to_curve25519($sk)
{
/* Type checks: */
ParagonIE_Sodium_Core_Util::declareScalarType($sk, 'string', 1);
/* Input validation: */
if (ParagonIE_Sodium_Core_Util::strlen($sk) < self::CRYPTO_SIGN_SEEDBYTES) {
throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_SEEDBYTES long.');
}
if (self::useNewSodiumAPI()) {
if (is_callable('crypto_sign_ed25519_sk_to_curve25519')) {
return sodium_crypto_sign_ed25519_sk_to_curve25519($sk);
}
}
if (self::use_fallback('crypto_sign_ed25519_sk_to_curve25519')) {
return (string) call_user_func('\\Sodium\\crypto_sign_ed25519_sk_to_curve25519', $sk);
}
$h = hash('sha512', ParagonIE_Sodium_Core_Util::substr($sk, 0, 32), true);
$h[0] = ParagonIE_Sodium_Core_Util::intToChr(
ParagonIE_Sodium_Core_Util::chrToInt($h[0]) & 248
);
$h[31] = ParagonIE_Sodium_Core_Util::intToChr(
(ParagonIE_Sodium_Core_Util::chrToInt($h[31]) & 127) | 64
);
return ParagonIE_Sodium_Core_Util::substr($h, 0, 32);
}