AES
Plugin > Security

Description

AES decryption functionality for bootloader.

Data Structures

struct AesContext
Context variable type for AES-ECB.
struct AesCtrContext
Context variable type for AES-CTR (and AES-CCM)

Typedefs

typedef struct AesContext AesContext_t
Context variable type for AES-ECB.
typedef struct AesCtrContext AesCtrContext_t
Context variable type for AES-CTR (and AES-CCM)

Functions

void btl_initAesContext (void *ctx)
void btl_setAesKey (void *ctx, const uint8_t *key, unsigned int keySize, bool encryptNotDecrypt)
void btl_processAesBlock (void *ctx, uint8_t *inputBlock, uint8_t *outputBlock, bool encryptNotDecrypt)
void btl_initAesCcm (void *ctx, uint8_t flags, uint8_t *nonce, uint32_t counter, const uint8_t *key, unsigned int keySize)
void btl_processAesCtrData (void *ctx, const uint8_t *input, uint8_t *output, size_t length)

Function Documentation

void btl_initAesContext ( void * ctx )

Initialize AES context.

Wipes the AES context struct before use.

Parameters
ctx Context variable of type AesContext_t
void btl_setAesKey ( void * ctx,
const uint8_t * key,
unsigned int keySize,
bool encryptNotDecrypt
)

Set AES key to use for encryption/decryption.

Initializes the AES context struct with the key to use.

Parameters
ctx Context variable of type AesContext_t
key Pointer to the AES key
keySize Size of the key in bits. Can be 128 or 256.
encryptNotDecrypt True if using this context for encryption, false if using for decryption.
void btl_processAesBlock ( void * ctx,
uint8_t * inputBlock,
uint8_t * outputBlock,
bool encryptNotDecrypt
)

Process one block of data using AES-ECB.

Runs one block of data through the AES algorithm. In-place encryption/ decryption is supported.

Parameters
ctx Context variable of type AesContext_t
inputBlock 128-bit (16 byte) buffer/block of data to be en/decrypted
outputBlock 128-bit (16 byte) buffer/block of data to put the result of the en/decryption in.
encryptNotDecrypt True for encryption, false for decryption
void btl_initAesCcm ( void * ctx,
uint8_t flags,
uint8_t * nonce,
uint32_t counter,
const uint8_t * key,
unsigned int keySize
)

Set up the AES-CTR context structure in CCM mode.

Initializes an AES-CTR context struct with parameters used in AES-CCM mode. Data can then be en/decrypted using btl_processAesCtrData.

Parameters
ctx Context variable of type AesCtrContext_t
flags CCM flags
nonce 12-byte nonce specific to this transmission
counter 3-byte running block counter
key Pointer to the AES key
keySize Size of the key in bits. Can be 128 or 256.
void btl_processAesCtrData ( void * ctx,
const uint8_t * input,
uint8_t * output,
size_t length
)

Process data using AES-CTR.

Runs data for encryption or decryption (which uses the same function) through the AES-CTR algorithm. In-place encryption/decryption is supported.

Parameters
ctx Context variable of type AesCtrContext_t
input Raw data to en/decrypt
output Output buffer to put en/decrypted data
length Size (in bytes) of the input/output buffers