CCM Mode AES Encryption and Decryption

This project provides a Java implementation of Counter with CBC-MAC (CCM) mode for AES encryption and decryption. CCM mode combines Counter (CTR) mode for encryption with CBC-MAC for tag generation, supporting additional authenticated data (AAD) along with plaintext.

Overview

The project consists of several classes:

• CCM: Implements AES encryption and decryption in CCM mode, including methods for encrypting plaintext, decrypting ciphertext, generating and verifying authentication tags, and formatting input for tag generation.
• Utils: Provides utility methods for hexadecimal string to byte array conversion and vice versa, essential for cryptographic operations.
• Main Class (Example): A main class demonstrating sample usage scenarios for encrypting and decrypting data using CCM mode with AES.

Usage

To use the CCM mode AES encryption and decryption:

1. Create an instance of the CCM class with a secret key represented by a SecretKey.
2. Use the encryptAndGenerateTag method to encrypt plaintext along with generating an authentication tag, and the decryptAndVerifyTag method to decrypt ciphertext and verify the appended authentication tag.

Example:

String keyHexadecimal = "404142434445464748494A4B4C4D4E4F";
byte[] keyBytes = Utils.hexadecimalStringToByteArray(keyHexadecimal);
SecretKey secretKey = new SecretKeySpec(keyBytes, "AES");

CCM ccm = new CCM(secretKey);

String nonceHexadecimal = "10111213141516";
String associatedDataHexadecimal = "0001020304050607";
String plainTextHexadecimal = "20212223";
int tagLength = 4;

byte[] nonce = Utils.hexadecimalStringToByteArray(nonceHexadecimal);
byte[] associatedData = Utils.hexadecimalStringToByteArray(associatedDataHexadecimal);
byte[] plainText = Utils.hexadecimalStringToByteArray(plainTextHexadecimal);

byte[] cipher = ccm.encryptAndGenerateTag(nonce, associatedData, plainText, tagLength);
byte[] decrypted = ccm.decryptAndVerifyTag(nonce, associatedData, cipher, tagLength);

System.out.println("Nonce: " + Utils.byteArrayToHexadecimalString(nonce));
System.out.println("Associated data: " + Utils.byteArrayToHexadecimalString(associatedData));
System.out.println("Plain text: " + Utils.byteArrayToHexadecimalString(plainText));
System.out.println("Tag Length: " + (tagLength * 8) + " bits");
System.out.println("\nEncrypted Hexadecimal: " + Utils.byteArrayToHexadecimalString(cipher));
System.out.println("Decrypted Hexadecimal: " + Utils.byteArrayToHexadecimalString(decrypted));

Contributors

• Ricardo BOKA - ricardo.boka@dauphine.eu
• Sébastien GIRET-IMHAUS - sebastien.giret-imhaus@dauphine.eu
• Nelson PROIA - nelson.proia@dauphine.eu
• Mathieu ANDRIN - mathieu.andrin@dauphine.eu

License

This project is licensed under the MIT License. See the LICENSE file for details.