EFM32 Gecko Software Documentation
efm32g-doc-5.1.2
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Advanced Encryption Standard Accelerator (AES) Peripheral API.
The AES peripheral supports AES block cipher encryption and decryption with 128 bit and 256 bit keys. The following block cipher modes are supported:
The following input/output notations should be noted:
It is up to the user to use a cipher mode according to its requirements in order to not break security. Please refer to specific cipher mode theory for details.
References:
E.g. the following example shows how to perform an AES-128 CBC encryption:
Enable clocks:
Execute AES-128 CBC encryption:
Typedefs | |
typedef void(* | AES_CtrFuncPtr_TypeDef) (uint8_t *ctr) |
AES counter modification function pointer. More... | |
Functions | |
void | AES_CBC128 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv, bool encrypt) |
Cipher-block chaining (CBC) cipher mode encryption/decryption, 128 bit key. More... | |
void | AES_CBC256 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv, bool encrypt) |
Cipher-block chaining (CBC) cipher mode encryption/decryption, 256 bit key. More... | |
void | AES_CFB128 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv, bool encrypt) |
Cipher feedback (CFB) cipher mode encryption/decryption, 128 bit key. More... | |
void | AES_CFB256 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv, bool encrypt) |
Cipher feedback (CFB) cipher mode encryption/decryption, 256 bit key. More... | |
void | AES_CTR128 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, uint8_t *ctr, AES_CtrFuncPtr_TypeDef ctrFunc) |
Counter (CTR) cipher mode encryption/decryption, 128 bit key. More... | |
void | AES_CTR256 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, uint8_t *ctr, AES_CtrFuncPtr_TypeDef ctrFunc) |
Counter (CTR) cipher mode encryption/decryption, 256 bit key. More... | |
void | AES_CTRUpdate32Bit (uint8_t *ctr) |
Update last 32 bits of 128 bit counter, by incrementing with 1. More... | |
void | AES_DecryptKey128 (uint8_t *out, const uint8_t *in) |
Generate 128 bit decryption key from 128 bit encryption key. The decryption key is used for some cipher modes when decrypting. More... | |
void | AES_DecryptKey256 (uint8_t *out, const uint8_t *in) |
Generate 256 bit decryption key from 256 bit encryption key. The decryption key is used for some cipher modes when decrypting. More... | |
void | AES_ECB128 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, bool encrypt) |
Electronic Codebook (ECB) cipher mode encryption/decryption, 128 bit key. More... | |
void | AES_ECB256 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, bool encrypt) |
Electronic Codebook (ECB) cipher mode encryption/decryption, 256 bit key. More... | |
__STATIC_INLINE void | AES_IntClear (uint32_t flags) |
Clear one or more pending AES interrupts. More... | |
__STATIC_INLINE void | AES_IntDisable (uint32_t flags) |
Disable one or more AES interrupts. More... | |
__STATIC_INLINE void | AES_IntEnable (uint32_t flags) |
Enable one or more AES interrupts. More... | |
__STATIC_INLINE uint32_t | AES_IntGet (void) |
Get pending AES interrupt flags. More... | |
__STATIC_INLINE uint32_t | AES_IntGetEnabled (void) |
Get enabled and pending AES interrupt flags. Useful for handling more interrupt sources in the same interrupt handler. More... | |
__STATIC_INLINE void | AES_IntSet (uint32_t flags) |
Set one or more pending AES interrupts from SW. More... | |
void | AES_OFB128 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv) |
Output feedback (OFB) cipher mode encryption/decryption, 128 bit key. More... | |
void | AES_OFB256 (uint8_t *out, const uint8_t *in, unsigned int len, const uint8_t *key, const uint8_t *iv) |
Output feedback (OFB) cipher mode encryption/decryption, 256 bit key. More... | |
typedef void(* AES_CtrFuncPtr_TypeDef) (uint8_t *ctr) |
void AES_CBC128 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv, | ||
bool | encrypt | ||
) |
Cipher-block chaining (CBC) cipher mode encryption/decryption, 128 bit key.
Encryption:
* Plaintext Plaintext * | | * V V * InitVector ->XOR +-------------->XOR * | | | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | encryption | | | encryption | * +--------------+ | +--------------+ * |---------+ | * V V * Ciphertext Ciphertext *
Decryption:
* Ciphertext Ciphertext * |----------+ | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | decryption | | | decryption | * +--------------+ | +--------------+ * | | | * V | V * InitVector ->XOR +-------------->XOR * | | * V V * Plaintext Plaintext *
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | When doing encryption, this is the 128 bit encryption key. When doing decryption, this is the 128 bit decryption key. The decryption key may be generated from the encryption key with AES_DecryptKey128(). On devices supporting key buffering this argument can be null, if so, the key will not be loaded, as it is assumed the key has been loaded into KEYHA previously. |
[in] | iv | 128 bit initalization vector to use. |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 124 of file em_aes.c.
References AES, AES_CTRL_DATASTART, AES_CTRL_DECRYPT, AES_CTRL_KEYBUFEN, AES_CTRL_XORSTART, and AES_STATUS_RUNNING.
void AES_CBC256 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv, | ||
bool | encrypt | ||
) |
Cipher-block chaining (CBC) cipher mode encryption/decryption, 256 bit key.
Please see AES_CBC128() for CBC figure.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | When doing encryption, this is the 256 bit encryption key. When doing decryption, this is the 256 bit decryption key. The decryption key may be generated from the encryption key with AES_DecryptKey256(). |
[in] | iv | 128 bit initalization vector to use. |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 289 of file em_aes.c.
References AES, AES_CTRL_AES256, AES_CTRL_DATASTART, AES_CTRL_DECRYPT, AES_CTRL_XORSTART, and AES_STATUS_RUNNING.
void AES_CFB128 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv, | ||
bool | encrypt | ||
) |
Cipher feedback (CFB) cipher mode encryption/decryption, 128 bit key.
Encryption:
* InitVector +----------------+ * | | | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | encryption | | | encryption | * +--------------+ | +--------------+ * | | | * V | V * Plaintext ->XOR | Plaintext ->XOR * |---------+ | * V V * Ciphertext Ciphertext *
Decryption:
* InitVector +----------------+ * | | | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | encryption | | | encryption | * +--------------+ | +--------------+ * | | | * V | V * XOR<- Ciphertext XOR<- Ciphertext * | | * V V * Plaintext Plaintext *
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 128 bit encryption key is used for both encryption and decryption modes. |
[in] | iv | 128 bit initalization vector to use. |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 453 of file em_aes.c.
References AES, AES_CTRL_DATASTART, AES_CTRL_KEYBUFEN, and AES_STATUS_RUNNING.
void AES_CFB256 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv, | ||
bool | encrypt | ||
) |
Cipher feedback (CFB) cipher mode encryption/decryption, 256 bit key.
Please see AES_CFB128() for CFB figure.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 256 bit encryption key is used for both encryption and decryption modes. |
[in] | iv | 128 bit initalization vector to use. |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 562 of file em_aes.c.
References AES, AES_CTRL_AES256, AES_CTRL_DATASTART, and AES_STATUS_RUNNING.
void AES_CTR128 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
uint8_t * | ctr, | ||
AES_CtrFuncPtr_TypeDef | ctrFunc | ||
) |
Counter (CTR) cipher mode encryption/decryption, 128 bit key.
Encryption:
* Counter Counter * | | * V V * +--------------+ +--------------+ * Key ->| Block cipher | Key ->| Block cipher | * | encryption | | encryption | * +--------------+ +--------------+ * | | * Plaintext ->XOR Plaintext ->XOR * | | * V V * Ciphertext Ciphertext *
Decryption:
* Counter Counter * | | * V V * +--------------+ +--------------+ * Key ->| Block cipher | Key ->| Block cipher | * | encryption | | encryption | * +--------------+ +--------------+ * | | * Ciphertext ->XOR Ciphertext ->XOR * | | * V V * Plaintext Plaintext *
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 128 bit encryption key. On devices supporting key buffering this argument can be null, if so, the key will not be loaded, as it is assumed the key has been loaded into KEYHA previously. |
[in,out] | ctr | 128 bit initial counter value. The counter is updated after each AES block encoding through use of ctrFunc . |
[in] | ctrFunc | Function used to update counter value. |
Definition at line 687 of file em_aes.c.
References AES, AES_CTRL_DATASTART, AES_CTRL_KEYBUFEN, and AES_STATUS_RUNNING.
void AES_CTR256 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
uint8_t * | ctr, | ||
AES_CtrFuncPtr_TypeDef | ctrFunc | ||
) |
Counter (CTR) cipher mode encryption/decryption, 256 bit key.
Please see AES_CTR128() for CTR figure.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 256 bit encryption key. |
[in,out] | ctr | 128 bit initial counter value. The counter is updated after each AES block encoding through use of ctrFunc . |
[in] | ctrFunc | Function used to update counter value. |
Definition at line 785 of file em_aes.c.
References AES, AES_CTRL_AES256, AES_CTRL_DATASTART, and AES_STATUS_RUNNING.
void AES_CTRUpdate32Bit | ( | uint8_t * | ctr | ) |
Update last 32 bits of 128 bit counter, by incrementing with 1.
Notice that no special consideration is given to possible wrap around. If 32 least significant bits are 0xFFFFFFFF, they will be updated to 0x00000000, ignoring overflow.
Please refer to general comments on layout and byte ordering of parameters.
[in,out] | ctr | Buffer holding 128 bit counter to be updated. |
void AES_DecryptKey128 | ( | uint8_t * | out, |
const uint8_t * | in | ||
) |
Generate 128 bit decryption key from 128 bit encryption key. The decryption key is used for some cipher modes when decrypting.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place 128 bit decryption key. Must be at least 16 bytes long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding 128 bit encryption key. Must be at least 16 bytes long. |
Definition at line 873 of file em_aes.c.
References AES, AES_CMD_START, AES_IF_DONE, AES_IntClear(), and AES_STATUS_RUNNING.
void AES_DecryptKey256 | ( | uint8_t * | out, |
const uint8_t * | in | ||
) |
Generate 256 bit decryption key from 256 bit encryption key. The decryption key is used for some cipher modes when decrypting.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place 256 bit decryption key. Must be at least 32 bytes long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding 256 bit encryption key. Must be at least 32 bytes long. |
Definition at line 918 of file em_aes.c.
References AES, AES_CMD_START, AES_CTRL_AES256, and AES_STATUS_RUNNING.
void AES_ECB128 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
bool | encrypt | ||
) |
Electronic Codebook (ECB) cipher mode encryption/decryption, 128 bit key.
Encryption:
* Plaintext Plaintext * | | * V V * +--------------+ +--------------+ * Key ->| Block cipher | Key ->| Block cipher | * | encryption | | encryption | * +--------------+ +--------------+ * | | * V V * Ciphertext Ciphertext *
Decryption:
* Ciphertext Ciphertext * | | * V V * +--------------+ +--------------+ * Key ->| Block cipher | Key ->| Block cipher | * | decryption | | decryption | * +--------------+ +--------------+ * | | * V V * Plaintext Plaintext *
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | When doing encryption, this is the 128 bit encryption key. When doing decryption, this is the 128 bit decryption key. The decryption key may be generated from the encryption key with AES_DecryptKey128(). |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 1001 of file em_aes.c.
References AES, AES_CTRL_DATASTART, AES_CTRL_DECRYPT, AES_CTRL_KEYBUFEN, and AES_STATUS_RUNNING.
void AES_ECB256 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
bool | encrypt | ||
) |
Electronic Codebook (ECB) cipher mode encryption/decryption, 256 bit key.
Please see AES_ECB128() for ECB figure.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | When doing encryption, this is the 256 bit encryption key. When doing decryption, this is the 256 bit decryption key. The decryption key may be generated from the encryption key with AES_DecryptKey256(). |
[in] | encrypt | Set to true to encrypt, false to decrypt. |
Definition at line 1102 of file em_aes.c.
References AES, AES_CTRL_AES256, AES_CTRL_DATASTART, AES_CTRL_DECRYPT, and AES_STATUS_RUNNING.
__STATIC_INLINE void AES_IntClear | ( | uint32_t | flags | ) |
Clear one or more pending AES interrupts.
[in] | flags | Pending AES interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the AES module (AES_IF_nnn). |
Definition at line 200 of file em_aes.h.
References AES.
Referenced by AES_DecryptKey128().
__STATIC_INLINE void AES_IntDisable | ( | uint32_t | flags | ) |
__STATIC_INLINE void AES_IntEnable | ( | uint32_t | flags | ) |
Enable one or more AES interrupts.
[in] | flags | AES interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the AES module (AES_IF_nnn). |
Definition at line 233 of file em_aes.h.
References AES.
__STATIC_INLINE uint32_t AES_IntGet | ( | void | ) |
__STATIC_INLINE uint32_t AES_IntGetEnabled | ( | void | ) |
Get enabled and pending AES interrupt flags. Useful for handling more interrupt sources in the same interrupt handler.
Definition at line 270 of file em_aes.h.
References AES.
__STATIC_INLINE void AES_IntSet | ( | uint32_t | flags | ) |
void AES_OFB128 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv | ||
) |
Output feedback (OFB) cipher mode encryption/decryption, 128 bit key.
Encryption:
* InitVector +----------------+ * | | | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | encryption | | | encryption | * +--------------+ | +--------------+ * | | | * |---------+ | * V V * Plaintext ->XOR Plaintext ->XOR * | | * V V * Ciphertext Ciphertext *
Decryption:
* InitVector +----------------+ * | | | * V | V * +--------------+ | +--------------+ * Key ->| Block cipher | | Key ->| Block cipher | * | encryption | | | encryption | * +--------------+ | +--------------+ * | | | * |---------+ | * V V * Ciphertext ->XOR Ciphertext ->XOR * | | * V V * Plaintext Plaintext *
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 128 bit encryption key. |
[in] | iv | 128 bit initalization vector to use. |
Definition at line 1213 of file em_aes.c.
References AES, AES_CMD_START, AES_CTRL_KEYBUFEN, and AES_STATUS_RUNNING.
void AES_OFB256 | ( | uint8_t * | out, |
const uint8_t * | in, | ||
unsigned int | len, | ||
const uint8_t * | key, | ||
const uint8_t * | iv | ||
) |
Output feedback (OFB) cipher mode encryption/decryption, 256 bit key.
Please see AES_OFB128() for OFB figure.
Please refer to general comments on layout and byte ordering of parameters.
[out] | out | Buffer to place encrypted/decrypted data. Must be at least len long. It may be set equal to in , in which case the input buffer is overwritten. |
[in] | in | Buffer holding data to encrypt/decrypt. Must be at least len long. |
[in] | len | Number of bytes to encrypt/decrypt. Must be a multiple of 16. |
[in] | key | 256 bit encryption key. |
[in] | iv | 128 bit initalization vector to use. |
Definition at line 1299 of file em_aes.c.
References AES, AES_CMD_START, AES_CTRL_AES256, and AES_STATUS_RUNNING.