aes.h File Reference

(6ab9384e7b)

AES operations for the OpenTitan cryptography library. More...

#include "datatypes.h"

Go to the source code of this file.

Typedefs
typedef enum otcrypto_aes_mode	otcrypto_aes_mode_t
	Enum to define AES mode of operation. More...
typedef enum otcrypto_aes_operation	otcrypto_aes_operation_t
	Enum to define AES operation to be performed. More...
typedef enum otcrypto_aes_padding	otcrypto_aes_padding_t
	Enum to define padding scheme for AES data. More...

Enumerations
enum	otcrypto_aes_mode {   kOtcryptoAesModeEcb = 0x533 ,   kOtcryptoAesModeCbc = 0x45d ,   kOtcryptoAesModeCfb = 0xcd2 ,   kOtcryptoAesModeOfb = 0x39a ,   kOtcryptoAesModeCtr = 0xd2c }
	Enum to define AES mode of operation. More...
enum	otcrypto_aes_operation {   kOtcryptoAesOperationEncrypt = 0x2b6 ,   kOtcryptoAesOperationDecrypt = 0x5f0 }
	Enum to define AES operation to be performed. More...
enum	otcrypto_aes_padding {   kOtcryptoAesPaddingPkcs7 = 0xe7f ,   kOtcryptoAesPaddingIso9797M2 = 0xfac ,   kOtcryptoAesPaddingNull = 0x8ce }
	Enum to define padding scheme for AES data. More...

Functions
otcrypto_status_t	otcrypto_aes_padded_plaintext_length (size_t plaintext_len, otcrypto_aes_padding_t aes_padding, size_t *padded_len)
	Get the number of blocks needed for the plaintext length and padding mode. More...
otcrypto_status_t	otcrypto_aes (const otcrypto_blinded_key_t *key, otcrypto_word32_buf_t iv, otcrypto_aes_mode_t aes_mode, otcrypto_aes_operation_t aes_operation, otcrypto_const_byte_buf_t cipher_input, otcrypto_aes_padding_t aes_padding, otcrypto_byte_buf_t cipher_output)
	Performs the AES operation. More...

Detailed Description

AES operations for the OpenTitan cryptography library.

Definition in file aes.h.

Typedef Documentation

otcrypto_aes_mode_t

typedef enum otcrypto_aes_mode otcrypto_aes_mode_t

Enum to define AES mode of operation.

Values are hardened.

otcrypto_aes_operation_t

typedef enum otcrypto_aes_operation otcrypto_aes_operation_t

Enum to define AES operation to be performed.

Values are hardened.

otcrypto_aes_padding_t

typedef enum otcrypto_aes_padding otcrypto_aes_padding_t

Enum to define padding scheme for AES data.

Values are hardened.

Enumeration Type Documentation

otcrypto_aes_mode

enum otcrypto_aes_mode

Enum to define AES mode of operation.

Values are hardened.

Definition at line 24 of file aes.h.

otcrypto_aes_operation

enum otcrypto_aes_operation

Enum to define AES operation to be performed.

Values are hardened.

Definition at line 42 of file aes.h.

otcrypto_aes_padding

enum otcrypto_aes_padding

Enum to define padding scheme for AES data.

Values are hardened.

Definition at line 54 of file aes.h.

Function Documentation

otcrypto_aes()

otcrypto_status_t otcrypto_aes	(	const otcrypto_blinded_key_t *	key,
		otcrypto_word32_buf_t	iv,
		otcrypto_aes_mode_t	aes_mode,
		otcrypto_aes_operation_t	aes_operation,
		otcrypto_const_byte_buf_t	cipher_input,
		otcrypto_aes_padding_t	aes_padding,
		otcrypto_byte_buf_t	cipher_output
	)

Performs the AES operation.

The input data in the cipher_input is first padded using the aes_padding scheme and the output is copied to cipher_output.

The caller should allocate space for the cipher_output buffer, which is given in bytes by otcrypto_aes_padded_plaintext_length, and set the number of bytes allocated in the len field of the output. If the user-set length and the expected length do not match, an error message will be returned.

Note that, during decryption, the padding mode is ignored. This function will NOT check the padding or return an error if the padding is invalid, since doing so could expose a padding oracle (especially in CBC mode).

Parameters

	key	Pointer to the blinded key struct with key shares.
	iv	Initialization vector, used for CBC, CFB, OFB, CTR modes. May be NULL if mode is ECB.
	aes_mode	Required AES mode of operation.
	aes_operation	Required AES operation (encrypt or decrypt).
	cipher_input	Input data to be ciphered.
	aes_padding	Padding scheme to be used for the data.
[out]	cipher_output	Output data after cipher operation.

Returns

The result of the cipher operation.

Definition at line 241 of file aes.c.

otcrypto_aes_padded_plaintext_length()

otcrypto_status_t otcrypto_aes_padded_plaintext_length	(	size_t	plaintext_len,
		otcrypto_aes_padding_t	aes_padding,
		size_t *	padded_len
	)

Get the number of blocks needed for the plaintext length and padding mode.

This returns the size of the padded plaintext, which is the same as the ciphertext size. Returns kOtcryptoStatusValueBadArgs if the padding mode and length are incompatible (for instance, if the padding mode is "no padding" but the input length is not a multiple of the AES block size).

Parameters

plaintext_len	Plaintext data length in bytes.
aes_padding	Padding scheme to be used for the data.

Returns

Size of the padded input or ciphertext.

Result of the operation.

Definition at line 231 of file aes.c.