KeyPair.py 文件源码

def ExportNEP2(self, passphrase):
        """
        Export the encrypted private key in NEP-2 format.

        Args:
            passphrase (str): The password to encrypt the private key with, as unicode string

        Returns:
            str: The NEP-2 encrypted private key
        """
        if len(passphrase) < 2:
            raise ValueError("Passphrase must have a minimum of 2 characters")

        # Hash address twice, then only use the first 4 bytes
        address_hash_tmp = hashlib.sha256(self.GetAddress().encode('utf-8')).digest()
        address_hash_tmp2 = hashlib.sha256(address_hash_tmp).digest()
        address_hash = address_hash_tmp2[:4]

        # Normalize password and run scrypt over it with the address_hash
        pwd_normalized = bytes(unicodedata.normalize('NFC', passphrase), 'utf-8')
        derived = scrypt.hash(pwd_normalized, address_hash,
                              N=SCRYPT_ITERATIONS,
                              r=SCRYPT_BLOCKSIZE,
                              p=SCRYPT_PARALLEL_FACTOR,
                              buflen=SCRYPT_KEY_LEN_BYTES)

        # Split the scrypt-result into two parts
        derived1 = derived[:32]
        derived2 = derived[32:]

        # Run XOR and encrypt the derived parts with AES
        xor_ed = xor_bytes(bytes(self.PrivateKey), derived1)
        cipher = AES.new(derived2, AES.MODE_ECB)
        encrypted = cipher.encrypt(xor_ed)

        # Assemble the final result
        assembled = bytearray()
        assembled.extend(NEP_HEADER)
        assembled.extend(NEP_FLAG)
        assembled.extend(address_hash)
        assembled.extend(encrypted)

        # Finally, encode with Base58Check
        encrypted_key_nep2 = base58.b58encode_check(bytes(assembled))
        return encrypted_key_nep2