Python Crypto.Cipher.AES.MODE_OFB Examples

def triple_des_encrypt(
        self,
        key: str,
        iv: str = "0000000000000000",
        mode: str = "CBC",
        hex_key: bool = False,
        hex_iv: bool = True,
    ):
        """Encrypt raw state with Triple DES

        Triple DES applies DES three times to each block to increase key size. Key: 
        Triple DES uses a key length of 24 bytes (192 bits).<br>DES uses a key length 
        of 8 bytes (64 bits).<br><br>You can generate a password-based key using one 
        of the KDF operations. IV: The Initialization Vector should be 8 bytes long. 
        If not entered, it will default to 8 null bytes. Padding: In CBC and ECB 
        mode, PKCS#7 padding will be used.
        
        Args:
            key (str): Required. The secret key
            iv (str, optional): IV for certain modes only. Defaults to '0000000000000000'.
            mode (str, optional): Encryption mode. Defaults to 'CBC'.
            hex_key (bool, optional): If the secret key is a hex string. Defaults to False.
            hex_iv (bool, optional): If the IV is a hex string. Defaults to True.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> Chepy("some data").triple_des_encrypt("super secret password !!", mode="ECB").o
            b"f8b27a0d8c837edc8fb00ea85f502fb4"
        """

        self.__check_mode(mode)

        key, iv = self._convert_key(key, iv, hex_key, hex_iv)

        if mode == "CBC":
            cipher = DES3.new(key, mode=DES3.MODE_CBC, iv=iv)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "ECB":
            cipher = DES3.new(key, mode=DES3.MODE_ECB)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "CTR":
            cipher = DES3.new(key, mode=DES3.MODE_CTR, nonce=b"")
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self
        elif mode == "OFB":
            cipher = DES3.new(key, mode=DES3.MODE_OFB, iv=iv)
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self 

def des_encrypt(
        self,
        key: str,
        iv: str = "0000000000000000",
        mode: str = "CBC",
        hex_key: bool = False,
        hex_iv: bool = True,
    ):
        """Encrypt raw state with DES

        DES is a previously dominant algorithm for encryption, and was published 
        as an official U.S. Federal Information Processing Standard (FIPS). It is 
        now considered to be insecure due to its small key size. DES uses a key 
        length of 8 bytes (64 bits).<br>Triple DES uses a key length of 24 bytes. 
        You can generate a password-based key using one of the KDF operations. 
        The Initialization Vector should be 8 bytes long. If not entered, it will 
        default to 8 null bytes. Padding: In CBC and ECB mode, PKCS#7 padding will be used.
        
        Args:
            key (str): Required. The secret key
            iv (str, optional): IV for certain modes only. Defaults to '0000000000000000'.
            mode (str, optional): Encryption mode. Defaults to 'CBC'.
            hex_key (bool, optional): If the secret key is a hex string. Defaults to False.
            hex_iv (bool, optional): If the IV is a hex string. Defaults to True.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> Chepy("some data").des_encrypt("70617373776f7264", hex_key=True).o
            b"1ee5cb52954b211d1acd6e79c598baac"

            To encrypt using a differnt mode

            >>> Chepy("some data").des_encrypt("password", mode="CTR").o
            b"0b7399049b0267d93d"
        """

        self.__check_mode(mode)

        key, iv = self._convert_key(key, iv, hex_key, hex_iv)

        if mode == "CBC":
            cipher = DES.new(key, mode=DES.MODE_CBC, iv=iv)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "ECB":
            cipher = DES.new(key, mode=DES.MODE_ECB)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "CTR":
            cipher = DES.new(key, mode=DES.MODE_CTR, nonce=b"")
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self
        elif mode == "OFB":
            cipher = DES.new(key, mode=DES.MODE_OFB, iv=iv)
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self 

def encrypt( raw, key, iv ):
    """
    Encrypt the raw data using the provided key and initial IV.  Data will be 
    encrypted using AES OFB mode.
    
    Args:
        raw: plaintext data to be encrypted
        key: AES key used for encryption
        iv: Initial IV used for encryption
    """
    result = ''
    tmp_iv = iv 
    text = pad(raw)

    for i in xrange(0, len(text) / BS):
        lower_bound = i * 16
        upper_bound = (i+1) * 16
        
        tmp = AES.new(key, AES.MODE_OFB, tmp_iv).decrypt( text[lower_bound:upper_bound] )
        tmp_iv = tmp
        result += tmp

    return result 

def get_encrypted_data(self, secret, data):
        data = data[27:]
        header = data[:2]
        salt = data[2:6]
        iv = data[6:22]
        encrypted_data = data[22:42]

        if header != self.RECOVERY_TOKEN_HEADER:
            raise Exception('Header mismatch')

        key = self.get_key(secret, salt)
        cipher = AES.new(key, AES.MODE_OFB, iv)

        return cipher.decrypt(encrypted_data) 

def test_aes_256(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'dc7e84bfda79164b7ecd8486985d3860' +\
                        '4febdc6740d20b3ac88f6ad82a4fb08d' +\
                        '71ab47a086e86eedf39d1c5bba97c408' +\
                        '0126141d67f37be8538f5a8be740e484'
        key =           '603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def test_aes_192(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'cdc80d6fddf18cab34c25909c99a4174' +\
                        'fcc28b8d4c63837c09e81700c1100401' +\
                        '8d9a9aeac0f6596f559c6d4daf59a5f2' +\
                        '6d9f200857ca6c3e9cac524bd9acc92a'
        key =           '8e73b0f7da0e6452c810f32b809079e562f8ead2522c6b7b'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def test_aes_128(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    '3b3fd92eb72dad20333449f8e83cfb4a' +\
                        '7789508d16918f03f53c52dac54ed825' +\
                        '9740051e9c5fecf64344f7a82260edcc' +\
                        '304c6528f659c77866a510d9c1d6ae5e'
        key =           '2b7e151628aed2a6abf7158809cf4f3c'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def test_aes_256(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'dc7e84bfda79164b7ecd8486985d3860' +\
                        '4febdc6740d20b3ac88f6ad82a4fb08d' +\
                        '71ab47a086e86eedf39d1c5bba97c408' +\
                        '0126141d67f37be8538f5a8be740e484'
        key =           '603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def test_aes_192(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'cdc80d6fddf18cab34c25909c99a4174' +\
                        'fcc28b8d4c63837c09e81700c1100401' +\
                        '8d9a9aeac0f6596f559c6d4daf59a5f2' +\
                        '6d9f200857ca6c3e9cac524bd9acc92a'
        key =           '8e73b0f7da0e6452c810f32b809079e562f8ead2522c6b7b'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def test_aes_128(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    '3b3fd92eb72dad20333449f8e83cfb4a' +\
                        '7789508d16918f03f53c52dac54ed825' +\
                        '9740051e9c5fecf64344f7a82260edcc' +\
                        '304c6528f659c77866a510d9c1d6ae5e'
        key =           '2b7e151628aed2a6abf7158809cf4f3c'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8]) 

def setup(self):
        from Crypto.Cipher import AES
        self.cipher = AES.new(self.key, AES.MODE_OFB, iv=self.iv) 

def decrypt( raw, key, iv ):
    """
    Decrypt the raw data using the provided key and iv.  
    Netwire encrypts data using AES OFB mode.  Initial IV is sent in the key exchange
    packet.  This iv will decrypt the initial block of 16 bytes of data, each 
    subsequent block will use the previous block as an IV.
    
    Args:
        raw: raw data to be decrypted
        key: AES key used to decrypt the data
        iv: initial IV used for decryption
    """
    result = ''
    tmp_iv = iv 
    ciphertext = pad(raw)

    for i in xrange(0, len(ciphertext) / BS):
        lower_bound = i * 16
        upper_bound = (i+1) * 16
        
        tmp = AES.new(key, AES.MODE_OFB, tmp_iv).decrypt( ciphertext[lower_bound:upper_bound] )
        tmp_iv = ciphertext[lower_bound:upper_bound]
        result += tmp

    return result 

def decrypt( raw, key, iv ):
    """
    Decrypt the raw data using the provided key and iv.  
    Netwire encrypts data using AES OFB mode.  Initial IV is sent in the key exchange
    packet.  This iv will decrypt the initial block of 16 bytes of data, each 
    subsequent block will use the previous block as an IV.
    
    Args:
        raw: raw data to be decrypted
        key: AES key used to decrypt the data
        iv: initial IV used for decryption
    """
    result = ''
    tmp_iv = iv 
    ciphertext = pad(raw)

    for i in xrange(0, len(ciphertext) / BS):
        lower_bound = i * 16
        upper_bound = (i+1) * 16
        
        tmp = AES.new(key, AES.MODE_OFB, tmp_iv).decrypt( ciphertext[lower_bound:upper_bound] )
        tmp_iv = ciphertext[lower_bound:upper_bound]
        result += tmp

    return result 

def encrypt( raw, key, iv ):
    """
    Encrypt the raw data using the provided key and initial IV.  Data will be 
    encrypted using AES OFB mode.
    
    Args:
        raw: plaintext data to be encrypted
        key: AES key used for encryption
        iv: Initial IV used for encryption
    """
    result = ''
    tmp_iv = iv 
    text = pad(raw)

    for i in xrange(0, len(text) / BS):
        lower_bound = i * 16
        upper_bound = (i+1) * 16
        
        tmp = AES.new(key, AES.MODE_OFB, tmp_iv).decrypt( text[lower_bound:upper_bound] )
        tmp_iv = tmp
        result += tmp

    return result 

def blowfish_encrypt(
        self,
        key: str,
        iv: str = "0000000000000000",
        mode: str = "CBC",
        hex_key: bool = False,
        hex_iv: bool = True,
    ):
        """Encrypt raw state with Blowfish

        Blowfish is a symmetric-key block cipher designed in 1993 by 
        Bruce Schneier and included in a large number of cipher suites 
        and encryption products. AES now receives more attention.
        IV: The Initialization Vector should be 8 bytes long.

        Args:
            key (str): Required. The secret key
            iv (str, optional): IV for certain modes only. Defaults to '0000000000000000'.
            mode (str, optional): Encryption mode. Defaults to 'CBC'.
            hex_key (bool, optional): If the secret key is a hex string. Defaults to False.
            hex_iv (bool, optional): If the IV is a hex string. Defaults to True.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> Chepy("some data").blowfish_encrypt("password", mode="ECB").o
            b"d9b0a79853f139603951bff96c3d0dd5"
        """

        self.__check_mode(mode)

        key, iv = self._convert_key(key, iv, hex_key, hex_iv)

        if mode == "CBC":
            cipher = Blowfish.new(key, mode=Blowfish.MODE_CBC, iv=iv)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "ECB":
            cipher = Blowfish.new(key, mode=Blowfish.MODE_ECB)
            self.state = cipher.encrypt(pad(self._convert_to_bytes(), 8))
            return self
        elif mode == "CTR":
            cipher = Blowfish.new(key, mode=Blowfish.MODE_CTR, nonce=b"")
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self
        elif mode == "OFB":
            cipher = Blowfish.new(key, mode=Blowfish.MODE_OFB, iv=iv)
            self.state = cipher.encrypt(self._convert_to_bytes())
            return self 

def triple_des_decrypt(
        self,
        key: str,
        iv: str = "0000000000000000",
        mode: str = "CBC",
        hex_key: bool = False,
        hex_iv: bool = True,
    ):
        """Decrypt raw state encrypted with DES. 

        Triple DES applies DES three times to each block to increase key size. Key: 
        Triple DES uses a key length of 24 bytes (192 bits).<br>DES uses a key length 
        of 8 bytes (64 bits).<br><br>You can generate a password-based key using one 
        of the KDF operations. IV: The Initialization Vector should be 8 bytes long. 
        If not entered, it will default to 8 null bytes. Padding: In CBC and ECB 
        mode, PKCS#7 padding will be used.
        
        Args:
            key (str): Required. The secret key
            iv (str, optional): IV for certain modes only. Defaults to '0000000000000000'.
            mode (str, optional): Encryption mode. Defaults to 'CBC'.
            hex_key (bool, optional): If the secret key is a hex string. Defaults to False.
            hex_iv (bool, optional): If the IV is a hex string. Defaults to True.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> c = Chepy("f8b27a0d8c837edce87dd13a1ab41f96")
            >>> c.hex_to_str()
            >>> c.triple_des_decrypt("super secret password !!")
            >>> c.o
            b"some data"
        """

        self.__check_mode(mode)

        key, iv = self._convert_key(key, iv, hex_key, hex_iv)

        if mode == "CBC":
            cipher = DES3.new(key, mode=DES3.MODE_CBC, iv=iv)
            self.state = unpad(cipher.decrypt(self._convert_to_bytes()), 8)
            return self
        elif mode == "ECB":
            cipher = DES3.new(key, mode=DES3.MODE_ECB)
            self.state = unpad(cipher.decrypt(self._convert_to_bytes()), 8)
            return self
        elif mode == "CTR":
            cipher = DES3.new(key, mode=DES3.MODE_CTR, nonce=b"")
            self.state = cipher.decrypt(self._convert_to_bytes())
            return self
        elif mode == "OFB":
            cipher = DES3.new(key, mode=DES3.MODE_OFB, iv=iv)
            self.state = cipher.decrypt(self._convert_to_bytes())
            return self 

def des_decrypt(
        self,
        key: str,
        iv: str = "0000000000000000",
        mode: str = "CBC",
        hex_key: bool = False,
        hex_iv: bool = True,
    ):
        """Decrypt raw state encrypted with DES. 

        DES is a previously dominant algorithm for encryption, and was published 
        as an official U.S. Federal Information Processing Standard (FIPS). It is 
        now considered to be insecure due to its small key size. DES uses a key 
        length of 8 bytes (64 bits).<br>Triple DES uses a key length of 24 bytes. 
        You can generate a password-based key using one of the KDF operations. 
        The Initialization Vector should be 8 bytes long. If not entered, it will 
        default to 8 null bytes. Padding: In CBC and ECB mode, PKCS#7 padding will be used.
        
        Args:
            key (str): Required. The secret key
            iv (str, optional): IV for certain modes only. Defaults to '0000000000000000'.
            mode (str, optional): Encryption mode. Defaults to 'CBC'.
            hex_key (bool, optional): If the secret key is a hex string. Defaults to False.
            hex_iv (bool, optional): If the IV is a hex string. Defaults to True.
        
        Returns:
            Chepy: The Chepy object. 

        Examples:
            >>> Chepy("1ee5cb52954b211d1acd6e79c598baac").hex_to_str().des_decrypt("password").o
            b"some data"
        """

        self.__check_mode(mode)

        key, iv = self._convert_key(key, iv, hex_key, hex_iv)

        if mode == "CBC":
            cipher = DES.new(key, mode=DES.MODE_CBC, iv=iv)
            self.state = unpad(cipher.decrypt(self._convert_to_bytes()), 8)
            return self
        elif mode == "ECB":
            cipher = DES.new(key, mode=DES.MODE_ECB)
            self.state = unpad(cipher.decrypt(self._convert_to_bytes()), 8)
            return self
        elif mode == "CTR":
            cipher = DES.new(key, mode=DES.MODE_CTR, nonce=b"")
            self.state = cipher.decrypt(self._convert_to_bytes())
            return self
        elif mode == "OFB":
            cipher = DES.new(key, mode=DES.MODE_OFB, iv=iv)
            self.state = cipher.decrypt(self._convert_to_bytes())
            return self 

def decrypt(self, password):
        """decrypt "secret_secret" from the ini file with the given password.
        This will return false if decryption did not seem to be successful.
        After this menthod succeeded the application can access the secret"""

        key = self.config.get_string("api", "secret_key")
        sec = self.config.get_string("api", "secret_secret")
        if sec == "" or key == "":
            return self.S_NO_SECRET

        hashed_pass = hashlib.sha512(password.encode("utf-8")).digest()
        crypt_key = hashed_pass[:32]
        crypt_ini = hashed_pass[-16:]
        aes = AES.new(crypt_key, AES.MODE_OFB, crypt_ini)
        try:
            encrypted_secret = base64.b64decode(sec.strip().encode("ascii"))
            self.secret = aes.decrypt(encrypted_secret).strip()
            self.key = key.strip()
        except ValueError:
            return self.S_FAIL

        # now test if we now have something plausible
        try:
            print("testing secret...")
            # is it plain ascii? (if not this will raise exception)
            # dummy = self.secret.decode("ascii")
            # can it be decoded? correct size afterwards?
            if len(base64.b64decode(self.secret)) != 64:
                raise Exception("Decrypted secret has wrong size")
            if not self.secret:
                raise Exception("Unable to decrypt secret")

            print("testing key...")
            # key must be only hex digits and have the right size
            # hex_key = self.key.replace("-", "").encode("ascii")
            # if len(binascii.unhexlify(hex_key)) != 16:
            #     raise Exception("key has wrong size")
            if not self.key:
                raise Exception("Unable to decrypt key")

            print("OK")
            return self.S_OK

        except Exception as exc:
            # this key and secret do not work
            self.secret = ""
            self.key = ""
            print("### Error occurred while testing the decrypted secret:")
            print("    '%s'" % exc)
            print("    This does not seem to be a valid API secret")
            return self.S_FAIL 

def prompt_encrypt(self):
        """ask for key, secret and password on the command line,
        then encrypt the secret and store it in the ini file."""
        print("Please copy/paste key and secret from exchange and")
        print("then provide a password to encrypt them.")
        print("")

        key = input("             key: ").strip()
        secret = input("          secret: ").strip()
        while True:
            password1 = getpass.getpass("        password: ").strip()
            if password1 == "":
                print("aborting")
                return
            password2 = getpass.getpass("password (again): ").strip()
            if password1 != password2:
                print("you had a typo in the password. try again...")
            else:
                break

        hashed_pass = hashlib.sha512(password1.encode("utf-8")).digest()
        crypt_key = hashed_pass[:32]
        crypt_ini = hashed_pass[-16:]
        aes = AES.new(crypt_key, AES.MODE_OFB, crypt_ini)

        # since the secret is a base64 string we can just just pad it with
        # spaces which can easily be stripped again after decryping
        print(len(secret))
        secret += " " * (16 - len(secret) % 16)
        print(len(secret))
        secret = base64.b64encode(aes.encrypt(secret)).decode("ascii")

        self.config.set("api", "secret_key", key)
        self.config.set("api", "secret_secret", secret)
        self.config.save()

        print("encrypted secret has been saved in %s" % self.config.filename)