ge_scalarmult_base example

/** * @internal You should not use this directly from another application * * @param string $sk * @return string * @throws SodiumException * @throws TypeError */
    public static function sk_to_pk($sk)
    {
        return self::ge_p3_tobytes(
            self::ge_scalarmult_base(
                self::substr($sk, 0, 32)
            )
        );
    }

    /** * @internal You should not use this directly from another application * * @param string $message * @param string $sk * @return string * @throws SodiumException * @throws TypeError */

# e[0] &= 248;         $e[0] = self::intToChr(
            self::chrToInt($e[0]) & 248
        );

        # e[31] &= 127;         # e[31] |= 64;         $e[31] = self::intToChr(
            (self::chrToInt($e[31]) & 127) | 64
        );

        $A = self::ge_scalarmult_base($e);
        if (
            !($A->Y instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
                ||
            !($A->Z instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
        ) {
            throw new TypeError('Null points encountered');
        }
        $pk = self::edwards_to_montgomery($A->Y, $A->Z);
        return self::fe_tobytes($pk);
    }
}

/** * @internal You should not use this directly from another application * * @param string $sk * @return string * @throws SodiumException * @throws TypeError */
    public static function sk_to_pk($sk)
    {
        return self::ge_p3_tobytes(
            self::ge_scalarmult_base(
                self::substr($sk, 0, 32)
            )
        );
    }

    /** * @internal You should not use this directly from another application * * @param string $message * @param string $sk * @return string * @throws SodiumException * @throws TypeError */

    /** * @param string $n * @return string * @throws SodiumException */
    public static function scalarmult_ristretto255_base($n)
    {
        $t = self::stringToIntArray($n);
        $t[31] &= 0x7f;
        $Q = self::ge_scalarmult_base(self::intArrayToString($t));
        $q = self::ristretto255_p3_tobytes($Q);
        if (ParagonIE_Sodium_Compat::is_zero($q)) {
            throw new SodiumException('An unknown error has occurred');
        }
        return $q;
    }
}

# e[0] &= 248;         $e[0] = self::intToChr(
            self::chrToInt($e[0]) & 248
        );

        # e[31] &= 127;         # e[31] |= 64;         $e[31] = self::intToChr(
            (self::chrToInt($e[31]) & 127) | 64
        );

        $A = self::ge_scalarmult_base($e);
        if (
            !($A->Y instanceof ParagonIE_Sodium_Core32_Curve25519_Fe)
                ||
            !($A->Z instanceof ParagonIE_Sodium_Core32_Curve25519_Fe)
        ) {
            throw new TypeError('Null points encountered');
        }
        $pk = self::edwards_to_montgomery($A->Y, $A->Z);
        return self::fe_tobytes($pk);
    }
}

/** @var string $nonceHash */
        $nonceHash = hash_final($hs, true);

        /** @var string $pk */
        $pk = self::substr($secretKey, 32, 32);

        /** @var string $nonce */
        $nonce = ParagonIE_Sodium_Core_Ed25519::sc_reduce($nonceHash) . self::substr($nonceHash, 32);

        /** @var string $sig */
        $sig = ParagonIE_Sodium_Core_Ed25519::ge_p3_tobytes(
            ParagonIE_Sodium_Core_Ed25519::ge_scalarmult_base($nonce)
        );

        $hs = hash_init('sha512');
        self::hash_update($hs, self::substr($sig, 0, 32));
        self::hash_update($hs, self::substr($pk, 0, 32));
        /** @var resource $hs */
        $hs = self::updateHashWithFile($hs, $fp, $size);

        /** @var string $hramHash */
        $hramHash = hash_final($hs, true);