from Cryptodome.Cipher import AES
from Cryptodome.Random import get_random_bytes
import hashlib
import base64
def decrypt(enc, key_hash): # To decrypt data
print("\nIn Decryption method\n")
unpad = lambda s: s[:-ord(s[-1:])]
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(key_hash, AES.MODE_CFB, iv)
ciper_text = cipher.decrypt(enc[AES.block_size:])
ciper_text = ciper_text.decode('utf-16')
ciper_text = unpad(ciper_text)
return ciper_text
def encrypt(ID, temperature, key_hash): # To encrypt data
print("\nIn Encryption method\n")
BS = AES.block_size
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
ID = pad(ID)
ID = ID.encode('utf-16')
temperature = pad(temperature)
temperature = temperature.encode('utf-16')
iv = get_random_bytes(AES.block_size)
cipher = AES.new(key= key_hash, mode= AES.MODE_CFB, iv= iv)
ID_cipher = base64.b64encode(iv + cipher.encrypt(ID))
temperature_cipher = base64.b64encode(iv + cipher.encrypt(temperature))
print("Id cipher is '{0}'".format(ID_cipher))
print("temp cipher is '{0}'".format(temperature_cipher))
return (ID_cipher, temperature_cipher)
no = int(input("enter no of records"))
key_hash = hashlib.sha256(b"charaka").digest() # Creating key for cipher
for i in range(no):
ID = input("enter ID\n")
temperature = input("enter temperature\n")
(ID_cipher, temperature_cipher) = encrypt(ID, temperature, key_hash)
print("Decyrpted ID is '{0}'".format((decrypt(ID_cipher, key_hash))))
print("Decyrpted temp is '{0}'".format((decrypt(temperature_cipher, key_hash))))
When I want to enter a record i.e "ID, temperature" and trying to decrypt both ID is decrypting fine but temperature is not decrypting. Sometimes it produces utf-16 error i.e
ciper_text = ciper_text.decode('utf-16') UnicodeDecodeError: 'utf-16-le' codec can't decode bytes in position 4-5: illegal UTF-16 surrogate
sometimes, output is not displayed properly
In Decryption method Decyrpted temp is '勼⼋'
My doubt is when ID is decrypting well why am I getting problem in decrypting temperature value. I have explored other tutorials about encoding techniques but the problem is same.
I used pycryptodome library to encrypt strings using AES. Thank you
