CODEWITHSUNDEEP
pythongoencryption
GraphicalDot
GraphicalDot

Reputation: 2831

AES-GCM decryption in python

I am trying to decrypt cipher text generated from AES_GCM. The cipher text was generated from "crypto/aes" library in golang. Now, I am trying to decipher the encrypted text in python using cryptodome library.

func AESEncryption(key []byte, plaintext []byte)([]byte, error){
   c, err := aes.NewCipher(key)
   if err != nil {
      log.Printf("Error ocurred in generating AES key %s", err)
      return nil,  err
   }

   gcm, err := cipher.NewGCM(c)
   if err != nil {
      return nil,  err
   }

  nonce := make([]byte, gcm.NonceSize())
  if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
    log.Printf("Error ocurred in generating AES key %s", err)
      return nil, err
  }

  return gcm.Seal(nonce, nonce, plaintext, nil), nil

}

plainText := "I will become what I deserve, Is there anything like freewil?"

Hex encoded key : e629ed98829a893899ddda67f582ede72e2a187dd1ddd5ada54f49cfe2c8675f

hex encoded encypted text = 9012a33bfb0a51dec4f96404cdd7300ec6afca1fa0d6679a7c036652d014a38faf909e9c44d08dffac121aa85d48b7256fa74542e2545e27dc070adfc03af26f2a32f50c2c311d5c91ff6de2ca3b4347da70669575c9b198f4 Deciphering the encrypted text in golang executes successfully but not in python.

Code for decryption in python.

cipher = AES.new(binascii.unhexlify(key), AES.MODE_GCM)
cipher.nonce = binascii.unhexlify(nonce)
cipher.decrypt(binascii.unhexlify(hex_encoded_encrypted_hex))

Upvotes: 5

Views: 17295

Answers (1)

President James K. Polk
President James K. Polk

Reputation: 42009

Worked like a charm for me.

from Crypto.Cipher import AES
import binascii

key = binascii.unhexlify('e629ed98829a893899ddda67f582ede72e2a187dd1ddd5ada54f49cfe2c8675f')
data = binascii.unhexlify('9012a33bfb0a51dec4f96404cdd7300ec6afca1fa0d6679a7c036652d014a38faf909e9c44d08dffac121aa85d48b7256fa74542e2545e27dc070adfc03af26f2a32f50c2c311d5c91ff6de2ca3b4347da70669575c9b198f4')
nonce, tag = data[:12], data[-16:]
cipher = AES.new(key, AES.MODE_GCM, nonce)
cipher.decrypt_and_verify(data[12:-16], tag)

displays

b'I will become what I deserve, Is there anything like freewil?'

Upvotes: 8

Related Questions