Create README.md

Author: GtechGovind

README.md

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+# DesfireCMAC
+
+DesfireCMAC is a C++ library that provides an implementation of the CMAC (Cipher-based Message Authentication Code) algorithm using AES (Advanced Encryption Standard) encryption.
+
+## Table of Contents
+- [Introduction](#introduction)
+- [Installation](#installation)
+- [Usage](#usage)
+- [API Reference](#api-reference)
+- [Author](#author)
+
+## Introduction
+
+DesfireCMAC is designed to generate a CMAC for a given data input using AES encryption. It utilizes the AES algorithm to generate subkeys and perform the necessary operations to calculate the CMAC.
+
+The library provides the following functions:
+- `initCMAC`: Initializes the CMAC algorithm with a key and initialization vector (IV).
+- `getCMAC`: Calculates the CMAC for a given data input.
+- `leftShift`: Performs a left shift operation on a vector.
+- `vecPrint`: Prints a vector in hexadecimal format.
+- `xorVec`: Performs an XOR operation between two vectors.
+
+## Installation
+
+To use DesfireCMAC in your project, follow these steps:
+
+1. Clone the DesfireCMAC repository from GitHub: `git clone https://github.com/GtechGovind/DesfireCMAC.git`.
+2. Include the `CMAC.h` header file in your C++ source code.
+3. Make sure to link against the required dependencies, such as the AES library.
+
+## Usage
+
+Here's an example of how to use the DesfireCMAC library:
+
+```cpp
+#include "CMAC.h"
+
+int main() {
+    // Initialize CMAC with a key and IV
+    vector<uint8_t> key = {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF};
+    vector<uint8_t> iv = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    CMAC cmac;
+    cmac.initCMAC(key, iv);
+
+    // Calculate CMAC for data
+    vector<uint8_t> data = {0x01, 0x02, 0x03, 0x04, 0x05};
+    vector<uint8_t> cmacResult = cmac.getCMAC(data);
+
+    // Print the CMAC
+    CMAC::vecPrint("CMAC", cmacResult);
+
+    return 0;
+}
+```
+
+## API Reference
+
+### CMAC Class
+
+#### `void initCMAC(const vector<uint8_t>& _key, const vector<uint8_t>& _iv)`
+
+Initializes the CMAC algorithm with a key and IV.
+
+- `_key`: The key for CMAC initialization.
+- `_iv`: The initialization vector for CMAC initialization.
+
+#### `vector<uint8_t> getCMAC(const vector<uint8_t>& _data)`
+
+Calculates the CMAC for a given data input.
+
+- `_data`: The input data for which the CMAC is to be calculated.
+- Returns: The calculated CMAC as a vector of bytes.
+
+#### `static void leftShift(const vector<uint8_t>& inputBuffer, vector<uint8_t>& outputBuffer)`
+
+Performs a left shift operation on a vector.
+
+- `inputBuffer`: The input vector to be left-shifted.
+- `outputBuffer`: The output vector to store the left-shifted result.
+
+#### `static void vecPrint(const string& message, const vector<unsigned char>& data)`
+
+Prints a vector in hexadecimal format.
+
+- `message`: The message to be printed before the vector.
+- `data`: The
+
+ vector to be printed.
+
+#### `static void xorVec(const vector<uint8_t>& vector1, const vector<uint8_t>& vector2, vector<uint8_t>& result)`
+
+Performs an XOR operation between two vectors and stores the result in a third vector.
+
+- `vector1`: The first vector for XOR operation.
+- `vector2`: The second vector for XOR operation.
+- `result`: The resultant vector to store the XOR result.
+
+## Author
+
+DesfireCMAC is developed by Govind Yadav.