# AES128_CMAC_Algorithm

**Repository Path**: GarryMeng/AES128_CMAC_Algorithm

## Basic Information

- **Project Name**: AES128_CMAC_Algorithm
- **Description**: CMAC AES 128算法研究
- **Primary Language**: C
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-07-29
- **Last Updated**: 2025-08-01

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# AES128_CMAC_Algorithm

# `aes128`: A fresh, dependency-free and cross-platform implementation of AES-128 and AES-CMAC (OMAC1)

# Installation:

Copy both [aes128.c](aes128.c) and [aes128.h](aes128.h) into your project and include the header where needed.

# Usage:

The opaque `aes128_t` type is used to maintain contexts for both AES encryption / decryption and CMAC generation.

Contexts are initialized using
```C
void aes128_init(aes128_t *ctx, const uint8_t *iv, const uint8_t *key);
```
and
```C
void aes128_init_cmac(aes128_t *ctx, const uint8_t *key);
```

Initializing a context for encryption / decryption requires an Initialization Vector (IV) to be provided. This *usually does not* have to be kept secret, but it **absolutely does** need to be random.

Once initialized, data can be encrypted and decrypted in-place using
```C
void aes128_encrypt(aes128_t *ctx, uint8_t *chunk, size_t length);
```
and
```C
void aes128_decrypt(aes128_t *ctx, uint8_t *chunk, size_t length);
```
where `chunk` points to `length` (at least 16) bytes to be encrypted or decrypted using the provided `aes128_t` context.

Initialization of a CMAC context only requires a key to be provided. Once initialized, a tag can be computed using
```C
void aes128_cmac(const aes128_t *ctx, const uint8_t *msg, size_t length, uint8_t *mac);
```
where `msg` points to `length` bytes to be used, computing a tag at `mac`. Unlike with aes128_encrypt() and aes128_decrypt(), `length` does not have to be a minimum of 16-bytes.

See [aes128.h](aes128.h) for additional API reference

# Sample Usage:

See [validation.c](validation.c) for a usage example.