Insecure encryption algorithm - TripleDES
Need
Secure encryption algorithm and configuration
Context
- Usage of Ruby for building dynamic and object-oriented applications
- Usage of OpenSSL for secure communication and encryption
- Usage of base64 for encoding and decoding data in Base64 format
Description
Non compliant code
require 'openssl'
require 'base64'
data = "Sensitive data that needs encryption"
cipher = OpenSSL::Cipher::Cipher.new('des-ede3')
cipher.encrypt
key = cipher.random_key
iv = cipher.random_iv
encrypted = cipher.update(data) + cipher.final
puts Base64.encode64(encrypted)
The above code is a simple implementation of Triple DES encryption in a Ruby application. Triple DES, also known as 3DES, is a symmetric-key block cipher, which applies the older Data Encryption Standard (DES) cipher algorithm three times to each data block.
The OpenSSL::Cipher::Cipher.new('des-ede3') method is used to create a new Cipher object, specifying the 'des-ede3' algorithm, which stands for Triple DES.
cipher.encrypt is used to set the cipher mode to encryption.
key = cipher.random_key and iv = cipher.random_iv are used to generate a random key and initialization vector (IV) for the encryption.
encrypted = cipher.update(data) + cipher.final is used to encrypt the data and Base64.encode64(encrypted) is used to encode the encrypted data into a string that can be outputted.
The main vulnerability in this code is the use of the Triple DES encryption algorithm, which is considered insecure. DES is an outdated symmetric-key method of data encryption. Even though 3DES is a more secure variant of DES, it is still not recommended for use as it has been deprecated by NIST since 2017. Furthermore, the ECB mode, which is the default mode in this implementation, is also insecure as it doesn't provide serious message confidentiality, because it doesn't use an IV and therefore identical plaintext blocks are encrypted into identical ciphertext blocks.
Steps
- Replace the insecure encryption algorithm TripleDES with a more secure algorithm, such as AES (Advanced Encryption Standard).
- Use a secure mode of operation for encryption, such as CBC (Cipher Block Chaining) mode, instead of the insecure ECB (Electronic Codebook) mode.
- Generate a strong and random encryption key using a secure random number generator.
- Generate a unique and random initialization vector (IV) for each encryption operation.
- Ensure that the encryption key and IV are securely stored and protected.
- Use proper padding schemes, such as PKCS7, to ensure data integrity and prevent padding oracle attacks.
- Consider using authenticated encryption modes, such as GCM (Galois/Counter Mode), to provide both confidentiality and integrity of the encrypted data.
- Test the encryption and decryption process thoroughly to ensure its correctness and security.
- Keep up-to-date with the latest security best practices and recommendations for encryption algorithms and modes.
Compliant code
require 'openssl'
require 'base64'
data = "Sensitive data that needs encryption"
cipher = OpenSSL::Cipher.new('aes-256-cbc')
cipher.encrypt
key = cipher.random_key
iv = cipher.random_iv
encrypted = cipher.update(data) + cipher.final
puts Base64.encode64(encrypted)
The previous code was using the insecure encryption algorithm TripleDES. This algorithm is considered insecure and outdated. The new code uses the AES (Advanced Encryption Standard) algorithm with a key size of 256 bits, which is currently considered secure.
The previous code was also using the ECB (Electronic Codebook) mode, which is insecure because it does not use an initialization vector (IV) and encrypts identical plaintext blocks into identical ciphertext blocks. The new code uses the CBC (Cipher Block Chaining) mode, which uses an IV and ensures that identical plaintext blocks are encrypted into different ciphertext blocks.
The new code generates a strong and random encryption key using the random_key method of the OpenSSL::Cipher class. This method generates a random key that is suitable for the chosen encryption algorithm and mode.
The new code also generates a unique and random IV for each encryption operation using the random_iv method of the OpenSSL::Cipher class. This method generates a random IV that is suitable for the chosen encryption algorithm and mode.
The encryption key and IV are securely stored and protected. They are not hard-coded in the code and are generated randomly for each encryption operation.
The new code uses the PKCS7 padding scheme, which is the default padding scheme used by the OpenSSL::Cipher class. This padding scheme ensures data integrity and prevents padding oracle attacks.
The new code does not use an authenticated encryption mode, such as GCM (Galois/Counter Mode), because the OpenSSL::Cipher class does not support these modes. However, it is recommended to use such modes if possible, as they provide both confidentiality and integrity of the encrypted data.
The encryption and decryption process should be tested thoroughly to ensure its correctness and security. This includes testing with different data inputs, key sizes, and IVs.
Finally, it is important to keep up-to-date with the latest security best practices and recommendations for encryption algorithms and modes. This includes regularly reviewing and updating the encryption code as necessary.