def get_gcm_decoded_private_key(encrypted_key_str: str, password: str,
b58_address: str, salt: str, n: int,
scheme: SignatureScheme) -> str:
"""
This interface is used to decrypt an private key which has been encrypted.
:param encrypted_key_str: an gcm encrypted private key in the form of string.
:param password: the secret pass phrase to generate the keys from.
:param b58_address: a base58 encode address which should be correspond with the private key.
:param salt: a string to use for better protection from dictionary attacks.
:param n: CPU/memory cost parameter.
:param scheme: the signature scheme.
:return: a private key in the form of string.
"""
r = 8
p = 8
dk_len = 64
scrypt = Scrypt(n, r, p, dk_len)
derivedkey = scrypt.generate_kd(password, salt)
iv = derivedkey[0:12]
derivedhalf2 = derivedkey[32:64]
encrypted_key = base64.b64decode(encrypted_key_str).hex()
mac_tag = a2b_hex(encrypted_key[64:96])
cipher_text = a2b_hex(encrypted_key[0:64])
private_key = AESHandler.aes_gcm_decrypt_with_iv(
cipher_text, b58_address.encode(), mac_tag, derivedhalf2, iv)
if len(private_key) == 0:
raise SDKException(ErrorCode.decrypt_encrypted_private_key_error)
private_key = b2a_hex(private_key).decode('ascii')
acct = Account(private_key, scheme)
if acct.get_address().b58encode() != b58_address:
raise RuntimeError
return private_key
def test_aes_gcm_with_iv(self):
key = b'Sixteen byte key'
plain_text = b'Attack at dawn'
hdr = b'To your eyes only'
iv = Random.new().read(AES.block_size)
mac, cipher_text = AESHandler.aes_gcm_encrypt_with_iv(plain_text, hdr, key, iv)
decrypt_out = AESHandler.aes_gcm_decrypt_with_iv(cipher_text, hdr, mac, key, iv)
self.assertEqual(plain_text, decrypt_out)
def get_gcm_decoded_private_key(encrypted_key_str: str, password: str, address: str, salt: str, n: int,
scheme: SignatureScheme) -> str:
r = 8
p = 8
dk_len = 64
scrypt = Scrypt(n, r, p, dk_len)
derivedkey = scrypt.generate_kd(password, salt)
iv = derivedkey[0:12]
derivedhalf2 = derivedkey[32:64]
encrypted_key = base64.b64decode(encrypted_key_str).hex()
mac_tag = a2b_hex(encrypted_key[64:96])
cipher_text = a2b_hex(encrypted_key[0:64])
pri_key = AESHandler.aes_gcm_decrypt_with_iv(cipher_text, address.encode(), mac_tag, derivedhalf2, iv)
pri_key = b2a_hex(pri_key).decode('ascii')
acct = Account(pri_key, scheme)
if acct.get_address().b58encode() != address:
raise RuntimeError
return pri_key
