aessw.h File Reference

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Functions
void	aes_setupStream (aes_data_stream_t *stream_ptr, const uint8_t *key128_ptr, const uint8_t *iv_ctr_ptr)
	Setup generic AES128 CTR mode stream. More...
void	aes_initOmac1 (aes_omac1_state_t *state_ptr, const uint8_t *mic_key_ptr)
	Initializes an OMAC1 state. More...
void	aes_omac1 (aes_omac1_state_t *state, uint8_t *mic_out_ptr, uint_fast8_t mic_out_bytes, const uint8_t *intext_ptr, size_t intext_bytes)
	Calculate and write out OMAC1 (CMAC) MIC for input text. More...
void	aes_crypto128Ctr (aes_data_stream_t *stream_ptr, const uint8_t *intext_ptr, uint8_t *outtext_ptr, size_t bytecount)
	Run the AES128 cryptography in CTR mode. More...

Data Structures
union	aes_128_t
	For storing 128bit keys, IVs, MACs etc. Allows both byte and faster 32-bit word-aligned access. More...
struct	aes_data_stream_t
	AES-128 key, input data and output data. More...
struct	aes_omac1_state_t
	AES-128 OMAC1 state. More...
union	aes_data_stream_t.__unnamed__

Macros
#define	AES_128_KEY_BLOCK_SIZE   16
	AES 128 block size in bytes. More...

Function Documentation

aes_crypto128Ctr()

void aes_crypto128Ctr	(	aes_data_stream_t *	stream_ptr,
		const uint8_t *	intext_ptr,
		uint8_t *	outtext_ptr,
		size_t	bytecount
	)

Run the AES128 cryptography in CTR mode.

Note

This is a software implementation based on tiny AES. The same algorithm handles both encryption and decryption. The receiver must know the initial iv_ctr for decryption. The stream.iv_ctr is autoincremented after every AES block exec. Supports partial operation: data can be split to consecutive parts, provided that the splits are done at 16-byte boundaries.

Parameters

stream_ptr	Pointer to aes_data_stream_t to be used
intext_ptr	Pointer to input text
outtext_ptr	Pointer to output text. Supports intext overwrite
bytecount	Number of bytes to handle

Examples

aes/app.c.

aes_initOmac1()

void aes_initOmac1	(	aes_omac1_state_t *	state_ptr,
		const uint8_t *	mic_key_ptr
	)

Initializes an OMAC1 state.

Parameters

state_ptr	Pointer to aes_omac1_state_t to be set up
mic_key_ptr	Pointer to the secret 16-byte MIC key, which is no longer needed after this function returns

Examples

aes/app.c.

aes_omac1()

void aes_omac1	(	aes_omac1_state_t *	state,
		uint8_t *	mic_out_ptr,
		uint_fast8_t	mic_out_bytes,
		const uint8_t *	intext_ptr,
		size_t	intext_bytes
	)

Calculate and write out OMAC1 (CMAC) MIC for input text.

Note

This is a software implementation based on tiny AES. NIST recommends using at least 8 byte MICs. See "NIST Special Publication 800-38B" appendix A and B.

Parameters

state	Pointer to OMAC1 AES-128 state
mic_out_ptr	Pointer for writing MIC
mic_out_bytes	Amount of MIC bytes wanted (1...16)
intext_ptr	Pointer to input text
intext_bytes	Length of input text

Examples

aes/app.c.

aes_setupStream()

void aes_setupStream	(	aes_data_stream_t *	stream_ptr,
		const uint8_t *	key128_ptr,
		const uint8_t *	iv_ctr_ptr
	)

Setup generic AES128 CTR mode stream.

Parameters

stream_ptr	Pointer to aes_data_stream_t to be set up
key128_ptr	Pointer to key, copied to the stream struct
iv_ctr_ptr	Pointer to iv_ctr, copied to the stream struct

Examples

aes/app.c.

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Data Structure Documentation

aes_128_t

union aes_128_t

For storing 128bit keys, IVs, MACs etc. Allows both byte and faster 32-bit word-aligned access.

Definition at line 19 of file aessw.h.

Data Fields
uint8_t	bytes[16]
uint32_t	words[4]

aes_data_stream_t

struct aes_data_stream_t

AES-128 key, input data and output data.

Every independent stream cipher flow should have one of these. This structure layout was created specifically for the Nordic nRF51822 AES ECB peripheral. However, this software implementations also use the same structure, for symmetry.

Examples

aes/app.c.

Definition at line 33 of file aessw.h.

Data Fields
union aes_data_stream_t	__unnamed__
uint32_t	aes_out[4]
uint32_t	key[4]

aes_omac1_state_t

struct aes_omac1_state_t

AES-128 OMAC1 state.

This state contains the HL1 and HL2 subkeys, so that they don't need to be recalculated when switching between authentication keys.

Examples

aes/app.c.

Definition at line 50 of file aessw.h.

Data Fields
aes_data_stream_t	data
aes_128_t	hl1
aes_128_t	hl2

aes_data_stream_t.__unnamed__

union aes_data_stream_t.__unnamed__

Definition at line 36 of file aessw.h.

Data Fields
uint32_t	aes_in[4]
uint32_t	iv_ctr[4]

Macro Definition Documentation

AES_128_KEY_BLOCK_SIZE

#define AES_128_KEY_BLOCK_SIZE   16

AES 128 block size in bytes.

Examples

aes/app.c.

Definition at line 13 of file aessw.h.