mirror of
https://github.com/kokke/tiny-AES-c
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92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
#ifndef _AES_H_
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#define _AES_H_
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#include <stdint.h>
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// #define the macros below to 1/0 to enable/disable the mode of operation.
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//
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// CBC enables AES encryption in CBC-mode of operation.
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// CTR enables encryption in counter-mode.
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// ECB enables the basic ECB 16-byte block algorithm. All can be enabled simultaneously.
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// The #ifndef-guard allows it to be configured before #include'ing or at compile time.
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#ifndef CBC
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#define CBC 1
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#endif
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#ifndef ECB
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#define ECB 1
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#endif
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#ifndef CTR
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#define CTR 1
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#endif
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#define AES128 1
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//#define AES192 1
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//#define AES256 1
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#define AES_BLOCKLEN 16 //Block length in bytes AES is 128b block only
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#if defined(AES256) && (AES256 == 1)
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#define AES_KEYLEN 32
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#define AES_keyExpSize 240
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#elif defined(AES192) && (AES192 == 1)
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#define AES_KEYLEN 24
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#define AES_keyExpSize 208
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#else
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#define AES_KEYLEN 16 // Key length in bytes
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#define AES_keyExpSize 176
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#endif
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struct AES_ctx {
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uint8_t RoundKey[AES_keyExpSize];
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#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1))
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uint8_t Iv[AES_BLOCKLEN];
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#endif
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};
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void AES_init_ctx(struct AES_ctx *ctx,const uint8_t* key);
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#if defined(CBC) && (CBC == 1)
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void AES_init_ctx_iv(struct AES_ctx *ctx,const uint8_t* key,const uint8_t* iv);
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void AES_ctx_set_iv(struct AES_ctx *ctx,const uint8_t* iv);
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#endif
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#if defined(ECB) && (ECB == 1)
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// buffer size is exactly AES_BLOCKLEN bytes;
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// you need only AES_init_ctx as Iv is not used in ECB
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// NB: ECB s considered insecure
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void AES_ECB_encrypt(struct AES_ctx *ctx, const uint8_t* input, uint8_t *output);
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void AES_ECB_decrypt(struct AES_ctx *ctx, const uint8_t* input, uint8_t *output);
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#endif // #if defined(ECB) && (ECB == !)
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#if defined(CBC) && (CBC == 1)
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// buffer size MUST be mutile of AES_BLOCKLEN;
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// We suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 if you need one
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// you need to set iv in ctx via AES_init_ctx_iv or AES_ctx_set_iv
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// NB: no IV should ever be reused with the same key
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void AES_CBC_encrypt_buffer(struct AES_ctx *ctx, uint8_t* output, uint8_t* input, uint32_t length);
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void AES_CBC_decrypt_buffer(struct AES_ctx *ctx, uint8_t* output, uint8_t* input, uint32_t length);
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#endif // #if defined(CBC) && (CBC == 1)
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#if defined(CTR) && (CTR == 1)
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// Same function for encrypting as for decrypting.
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// iv is incremented for every block, and usesd after encryption as xor compliment for output
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// buffer size MUST be mutile of AES_BLOCKLEN;
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// We suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 if you need one
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// you need to set iv in ctx via AES_init_ctx_iv or AES_ctx_set_iv
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// NB: no IV should ever be reused with the same key
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void AES_CTR_xcrypt_buffer(struct AES_ctx *ctx, uint8_t* output, uint8_t* input, uint32_t length);
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#endif // #if defined(CTR) && (CTR == 1)
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#endif //_AES_H_
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