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Diffstat (limited to 'src/tiny-AES-c/aes.h')
-rw-r--r-- | src/tiny-AES-c/aes.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/src/tiny-AES-c/aes.h b/src/tiny-AES-c/aes.h new file mode 100644 index 0000000..87f1471 --- /dev/null +++ b/src/tiny-AES-c/aes.h @@ -0,0 +1,90 @@ +#ifndef _AES_H_ +#define _AES_H_ + +#include <stdint.h> + +// #define the macros below to 1/0 to enable/disable the mode of operation. +// +// CBC enables AES encryption in CBC-mode of operation. +// CTR enables encryption in counter-mode. +// ECB enables the basic ECB 16-byte block algorithm. All can be enabled simultaneously. + +// The #ifndef-guard allows it to be configured before #include'ing or at compile time. +#ifndef CBC + #define CBC 1 +#endif + +#ifndef ECB + #define ECB 1 +#endif + +#ifndef CTR + #define CTR 1 +#endif + + +#define AES128 1 +//#define AES192 1 +//#define AES256 1 + +#define AES_BLOCKLEN 16 //Block length in bytes AES is 128b block only + +#if defined(AES256) && (AES256 == 1) + #define AES_KEYLEN 32 + #define AES_keyExpSize 240 +#elif defined(AES192) && (AES192 == 1) + #define AES_KEYLEN 24 + #define AES_keyExpSize 208 +#else + #define AES_KEYLEN 16 // Key length in bytes + #define AES_keyExpSize 176 +#endif + +struct AES_ctx +{ + uint8_t RoundKey[AES_keyExpSize]; +#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1)) + uint8_t Iv[AES_BLOCKLEN]; +#endif +}; + +void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key); +#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1)) +void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, const uint8_t* iv); +void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv); +#endif + +#if defined(ECB) && (ECB == 1) +// buffer size is exactly AES_BLOCKLEN bytes; +// you need only AES_init_ctx as IV is not used in ECB +// NB: ECB is considered insecure for most uses +void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf); +void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf); + +#endif // #if defined(ECB) && (ECB == !) + + +#if defined(CBC) && (CBC == 1) +// buffer size MUST be mutile of AES_BLOCKLEN; +// Suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme +// NOTES: you need to set IV in ctx via AES_init_ctx_iv() or AES_ctx_set_iv() +// no IV should ever be reused with the same key +void AES_CBC_encrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); +void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); + +#endif // #if defined(CBC) && (CBC == 1) + + +#if defined(CTR) && (CTR == 1) + +// Same function for encrypting as for decrypting. +// IV is incremented for every block, and used after encryption as XOR-compliment for output +// Suggesting https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme +// NOTES: you need to set IV in ctx with AES_init_ctx_iv() or AES_ctx_set_iv() +// no IV should ever be reused with the same key +void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); + +#endif // #if defined(CTR) && (CTR == 1) + + +#endif //_AES_H_ |