Algorithms - AES

Functions
int	wc_AesSetKey (Aes *aes, const byte *key, word32 len, const byte *iv, int dir)
	This function initializes an AES structure by setting the key and then setting the initialization vector. More...
int	wc_AesSetIV (Aes *aes, const byte *iv)
	This function sets the initialization vector for a particular AES object. The AES object should be initialized before calling this function. More...
int	wc_AesCbcEncrypt (Aes *aes, byte *out, const byte *in, word32 sz)
	Encrypts a plaintext message from the input buffer in, and places the resulting cipher text in the output buffer out using cipher block chaining with AES. This function requires that the AES object has been initialized by calling AesSetKey before a message is able to be encrypted. This function assumes that the input message is AES block length aligned, and expects the input length to be a multiple of the block length, which will optionally be checked and enforced if WOLFSSL_AES_CBC_LENGTH_CHECKS is defined in the build configuration. In order to assure block-multiple input, PKCS#7 style padding should be added beforehand. This differs from the OpenSSL AES-CBC methods which add the padding for you. To make the wolfSSL and corresponding OpenSSL functions interoperate, one should specify the -nopad option in the OpenSSL command line function so that it behaves like the wolfSSL AesCbcEncrypt method and does not add extra padding during encryption. More...
int	wc_AesCbcDecrypt (Aes *aes, byte *out, const byte *in, word32 sz)
	Decrypts a cipher from the input buffer in, and places the resulting plain text in the output buffer out using cipher block chaining with AES. This function requires that the AES structure has been initialized by calling AesSetKey before a message is able to be decrypted. This function assumes that the original message was AES block length aligned, and expects the input length to be a multiple of the block length, which will optionally be checked and enforced if WOLFSSL_AES_CBC_LENGTH_CHECKS is defined in the build configuration. This differs from the OpenSSL AES-CBC methods, which add PKCS#7 padding automatically, and so do not require block-multiple input. To make the wolfSSL function and equivalent OpenSSL functions interoperate, one should specify the -nopad option in the OpenSSL command line function so that it behaves like the wolfSSL AesCbcEncrypt method and does not create errors during decryption. More...
int	wc_AesCtrEncrypt (Aes *aes, byte *out, const byte *in, word32 sz)
	Encrypts/Decrypts a message from the input buffer in, and places the resulting cipher text in the output buffer out using CTR mode with AES. This function is only enabled if WOLFSSL_AES_COUNTER is enabled at compile time. The AES structure should be initialized through AesSetKey before calling this function. Note that this function is used for both decryption and encryption. NOTE: Regarding using same API for encryption and decryption. User should differentiate between Aes structures for encrypt/decrypt. More...
int	wc_AesEncryptDirect (Aes *aes, byte *out, const byte *in)
	This function is a one-block encrypt of the input block, in, into the output block, out. It uses the key of the provided AES structure, which should be initialized with wc_AesSetKey before calling this function. wc_AesSetKey should have been called with the iv set to NULL. This is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible. More...
int	wc_AesDecryptDirect (Aes *aes, byte *out, const byte *in)
	This function is a one-block decrypt of the input block, in, into the output block, out. It uses the key of the provided AES structure, which should be initialized with wc_AesSetKey before calling this function. wc_AesSetKey should have been called with the iv set to NULL. This is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible. More...
int	wc_AesSetKeyDirect (Aes *aes, const byte *key, word32 len, const byte *iv, int dir)
	This function is used to set the AES keys for CTR mode with AES. It initializes an AES object with the given key, iv (initialization vector), and encryption dir (direction). It is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Currently wc_AesSetKeyDirect uses wc_AesSetKey internally. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible. More...
int	wc_AesGcmSetKey (Aes *aes, const byte *key, word32 len)
	This function is used to set the key for AES GCM (Galois/Counter Mode). It initializes an AES object with the given key. It is only enabled if the configure option HAVE_AESGCM is enabled at compile time. More...
int	wc_AesGcmEncrypt (Aes *aes, byte *out, const byte *in, word32 sz, const byte *iv, word32 ivSz, byte *authTag, word32 authTagSz, const byte *authIn, word32 authInSz)
	This function encrypts the input message, held in the buffer in, and stores the resulting cipher text in the output buffer out. It requires a new iv (initialization vector) for each call to encrypt. It also encodes the input authentication vector, authIn, into the authentication tag, authTag. More...
int	wc_AesGcmDecrypt (Aes *aes, byte *out, const byte *in, word32 sz, const byte *iv, word32 ivSz, const byte *authTag, word32 authTagSz, const byte *authIn, word32 authInSz)
	This function decrypts the input cipher text, held in the buffer in, and stores the resulting message text in the output buffer out. It also checks the input authentication vector, authIn, against the supplied authentication tag, authTag. More...
int	wc_GmacSetKey (Gmac *gmac, const byte *key, word32 len)
	This function initializes and sets the key for a GMAC object to be used for Galois Message Authentication. More...
int	wc_GmacUpdate (Gmac *gmac, const byte *iv, word32 ivSz, const byte *authIn, word32 authInSz, byte *authTag, word32 authTagSz)
	This function generates the Gmac hash of the authIn input and stores the result in the authTag buffer. After running wc_GmacUpdate, one should compare the generated authTag to a known authentication tag to verify the authenticity of a message. More...
int	wc_AesCcmSetKey (Aes *aes, const byte *key, word32 keySz)
	This function sets the key for an AES object using CCM (Counter with CBC-MAC). It takes a pointer to an AES structure and initializes it with supplied key. More...
int	wc_AesCcmEncrypt (Aes *aes, byte *out, const byte *in, word32 inSz, const byte *nonce, word32 nonceSz, byte *authTag, word32 authTagSz, const byte *authIn, word32 authInSz)
	This function encrypts the input message, in, into the output buffer, out, using CCM (Counter with CBC-MAC). It subsequently calculates and stores the authorization tag, authTag, from the authIn input. More...
int	wc_AesCcmDecrypt (Aes *aes, byte *out, const byte *in, word32 inSz, const byte *nonce, word32 nonceSz, const byte *authTag, word32 authTagSz, const byte *authIn, word32 authInSz)
	This function decrypts the input cipher text, in, into the output buffer, out, using CCM (Counter with CBC-MAC). It subsequently calculates the authorization tag, authTag, from the authIn input. If the authorization tag is invalid, it sets the output buffer to zero and returns the error: AES_CCM_AUTH_E. More...
int	wc_AesXtsSetKey (XtsAes *aes, const byte *key, word32 len, int dir, void *heap, int devId)
	This is to help with setting keys to correct encrypt or decrypt type. It is up to user to call wc_AesXtsFree on aes key when done. More...
int	wc_AesXtsEncryptSector (XtsAes *aes, byte *out, const byte *in, word32 sz, word64 sector)
	Same process as wc_AesXtsEncrypt but uses a word64 type as the tweak value instead of a byte array. This just converts the word64 to a byte array and calls wc_AesXtsEncrypt. More...
int	wc_AesXtsDecryptSector (XtsAes *aes, byte *out, const byte *in, word32 sz, word64 sector)
	Same process as wc_AesXtsDecrypt but uses a word64 type as the tweak value instead of a byte array. This just converts the word64 to a byte array. More...
int	wc_AesXtsEncrypt (XtsAes *aes, byte *out, const byte *in, word32 sz, const byte *i, word32 iSz)
	AES with XTS mode. (XTS) XEX encryption with Tweak and cipher text Stealing. More...
int	wc_AesXtsDecrypt (XtsAes *aes, byte *out, const byte *in, word32 sz, const byte *i, word32 iSz)
	Same process as encryption but Aes key is AES_DECRYPTION type. More...
int	wc_AesXtsFree (XtsAes *aes)
	This is to free up any resources used by the XtsAes structure. More...
int	wc_AesInit (Aes *aes, void *heap, int devId)
	Initialize Aes structure. Sets heap hint to be used and ID for use with async hardware. It is up to the user to call wc_AesFree on the Aes structure when done. More...
int	wc_AesFree (Aes *aes)
	free resources associated with the Aes structure when applicable. Internally may sometimes be a no-op but still recommended to call in all cases as a general best-practice (IE if application code is ported for use on new environments where the call is applicable). More...
int	wc_AesCfbEncrypt (Aes *aes, byte *out, const byte *in, word32 sz)
	AES with CFB mode. More...
int	wc_AesCfbDecrypt (Aes *aes, byte *out, const byte *in, word32 sz)
	AES with CFB mode. More...
int	wc_AesSivEncrypt (const byte *key, word32 keySz, const byte *assoc, word32 assocSz, const byte *nonce, word32 nonceSz, const byte *in, word32 inSz, byte *siv, byte *out)
	This function performs SIV (synthetic initialization vector) encryption as described in RFC 5297. More...
int	wc_AesSivDecrypt (const byte *key, word32 keySz, const byte *assoc, word32 assocSz, const byte *nonce, word32 nonceSz, const byte *in, word32 inSz, byte *siv, byte *out)
	This function performs SIV (synthetic initialization vector) decryption as described in RFC 5297. More...
int	wc_AesCbcDecryptWithKey (byte *out, const byte *in, word32 inSz, const byte *key, word32 keySz, const byte *iv)
	Decrypts a cipher from the input buffer in, and places the resulting plain text in the output buffer out using cipher block chaining with AES. This function does not require an AES structure to be initialized. Instead, it takes in a key and an iv (initialization vector) and uses these to initialize an AES object and then decrypt the cipher text. More...

Detailed Description

Function Documentation

wc_AesCbcDecrypt()

int wc_AesCbcDecrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz
	)

Decrypts a cipher from the input buffer in, and places the resulting plain text in the output buffer out using cipher block chaining with AES. This function requires that the AES structure has been initialized by calling AesSetKey before a message is able to be decrypted. This function assumes that the original message was AES block length aligned, and expects the input length to be a multiple of the block length, which will optionally be checked and enforced if WOLFSSL_AES_CBC_LENGTH_CHECKS is defined in the build configuration. This differs from the OpenSSL AES-CBC methods, which add PKCS#7 padding automatically, and so do not require block-multiple input. To make the wolfSSL function and equivalent OpenSSL functions interoperate, one should specify the -nopad option in the OpenSSL command line function so that it behaves like the wolfSSL AesCbcEncrypt method and does not create errors during decryption.

Returns

0 On successfully decrypting message.

BAD_ALIGN_E may be returned on block align error.

BAD_LENGTH_E will be returned if the input length isn't a multiple of the AES block length, when the library is built with WOLFSSL_AES_CBC_LENGTH_CHECKS.

Parameters

aes	pointer to the AES object used to decrypt data.
out	pointer to the output buffer in which to store the plain text of the decrypted message.
in	pointer to the input buffer containing cipher text to be decrypted.
sz	size of input message.

Example

Aes dec;
int ret = 0;
// initialize dec with AesSetKey, using direction AES_DECRYPTION
byte cipher[AES_BLOCK_SIZE * n]; // some multiple of 16 bytes
// fill cipher with cipher text
byte plain [AES_BLOCK_SIZE * n];
if ((ret = wc_AesCbcDecrypt(&dec, plain, cipher, sizeof(cipher))) != 0 ) {
// block align error
}

See also

wc_AesSetKey

wc_AesCbcEncrypt

wc_AesCbcDecryptWithKey()

int wc_AesCbcDecryptWithKey	(	byte *	out,
		const byte *	in,
		word32	inSz,
		const byte *	key,
		word32	keySz,
		const byte *	iv
	)

Decrypts a cipher from the input buffer in, and places the resulting plain text in the output buffer out using cipher block chaining with AES. This function does not require an AES structure to be initialized. Instead, it takes in a key and an iv (initialization vector) and uses these to initialize an AES object and then decrypt the cipher text.

Returns

0 On successfully decrypting message

BAD_ALIGN_E Returned on block align error

BAD_FUNC_ARG Returned if key length is invalid or AES object is null during AesSetIV

MEMORY_E Returned if WOLFSSL_SMALL_STACK is enabled and XMALLOC fails to instantiate an AES object.

Parameters

out	pointer to the output buffer in which to store the plain text of the decrypted message
in	pointer to the input buffer containing cipher text to be decrypted
inSz	size of input message
key	16, 24, or 32 byte secret key for decryption
keySz	size of key used for decryption

Example

int ret = 0;
byte key[] = { some 16, 24, or 32 byte key };
byte iv[]  = { some 16 byte iv };
byte cipher[AES_BLOCK_SIZE * n]; //n being a positive integer making
cipher some multiple of 16 bytes
// fill cipher with cipher text
byte plain [AES_BLOCK_SIZE * n];
if ((ret = wc_AesCbcDecryptWithKey(plain, cipher, AES_BLOCK_SIZE, key,
AES_BLOCK_SIZE, iv)) != 0 ) {
// Decrypt Error
}

See also

wc_AesSetKey

wc_AesSetIV

wc_AesCbcEncrypt

wc_AesCbcDecrypt

wc_AesCbcEncrypt()

int wc_AesCbcEncrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz
	)

Encrypts a plaintext message from the input buffer in, and places the resulting cipher text in the output buffer out using cipher block chaining with AES. This function requires that the AES object has been initialized by calling AesSetKey before a message is able to be encrypted. This function assumes that the input message is AES block length aligned, and expects the input length to be a multiple of the block length, which will optionally be checked and enforced if WOLFSSL_AES_CBC_LENGTH_CHECKS is defined in the build configuration. In order to assure block-multiple input, PKCS#7 style padding should be added beforehand. This differs from the OpenSSL AES-CBC methods which add the padding for you. To make the wolfSSL and corresponding OpenSSL functions interoperate, one should specify the -nopad option in the OpenSSL command line function so that it behaves like the wolfSSL AesCbcEncrypt method and does not add extra padding during encryption.

Returns

0 On successfully encrypting message.

BAD_ALIGN_E: may be returned on block align error

BAD_LENGTH_E will be returned if the input length isn't a multiple of the AES block length, when the library is built with WOLFSSL_AES_CBC_LENGTH_CHECKS.

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the ciphertext of the encrypted message
in	pointer to the input buffer containing message to be encrypted
sz	size of input message

Example

Aes enc;
int ret = 0;
// initialize enc with AesSetKey, using direction AES_ENCRYPTION
byte msg[AES_BLOCK_SIZE * n]; // multiple of 16 bytes
// fill msg with data
byte cipher[AES_BLOCK_SIZE * n]; // Some multiple of 16 bytes
if ((ret = wc_AesCbcEncrypt(&enc, cipher, message, sizeof(msg))) != 0 ) {
// block align error
}

See also

wc_AesSetKey

wc_AesSetIV

wc_AesCbcDecrypt

wc_AesCcmDecrypt()

int wc_AesCcmDecrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	inSz,
		const byte *	nonce,
		word32	nonceSz,
		const byte *	authTag,
		word32	authTagSz,
		const byte *	authIn,
		word32	authInSz
	)

This function decrypts the input cipher text, in, into the output buffer, out, using CCM (Counter with CBC-MAC). It subsequently calculates the authorization tag, authTag, from the authIn input. If the authorization tag is invalid, it sets the output buffer to zero and returns the error: AES_CCM_AUTH_E.

Returns

0 On successfully decrypting the input message

AES_CCM_AUTH_E If the authentication tag does not match the supplied authentication code vector, authTag.

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the cipher text
in	pointer to the input buffer holding the message to encrypt
sz	length of the input cipher text to decrypt
nonce	pointer to the buffer containing the nonce (number only used once)
nonceSz	length of the nonce
authTag	pointer to the buffer in which to store the authentication tag
authTagSz	length of the desired authentication tag
authIn	pointer to the buffer containing the input authentication vector
authInSz	length of the input authentication vector

Example

Aes dec;
// initialize dec with wc_AesCcmSetKey
 
nonce[] = { initialize nonce };
cipher[] = { encrypted message };
plain[sizeof(cipher)];
 
authIn[] = { some 16 byte authentication input };
tag[AES_BLOCK_SIZE] = { authentication tag received for verification };
 
int return = wc_AesCcmDecrypt(&dec, plain, cipher, sizeof(cipher),
nonce, sizeof(nonce),tag, sizeof(tag), authIn, sizeof(authIn));
if(return != 0) {
// decrypt error, invalid authentication code
}

See also

wc_AesCcmSetKey

wc_AesCcmEncrypt

wc_AesCcmEncrypt()

int wc_AesCcmEncrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	inSz,
		const byte *	nonce,
		word32	nonceSz,
		byte *	authTag,
		word32	authTagSz,
		const byte *	authIn,
		word32	authInSz
	)

This function encrypts the input message, in, into the output buffer, out, using CCM (Counter with CBC-MAC). It subsequently calculates and stores the authorization tag, authTag, from the authIn input.

Returns

none

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the cipher text
in	pointer to the input buffer holding the message to encrypt
sz	length of the input message to encrypt
nonce	pointer to the buffer containing the nonce (number only used once)
nonceSz	length of the nonce
authTag	pointer to the buffer in which to store the authentication tag
authTagSz	length of the desired authentication tag
authIn	pointer to the buffer containing the input authentication vector
authInSz	length of the input authentication vector

Example

Aes enc;
// initialize enc with wc_AesCcmSetKey
 
nonce[] = { initialize nonce };
plain[] = { some plain text message };
cipher[sizeof(plain)];
 
authIn[] = { some 16 byte authentication input };
tag[AES_BLOCK_SIZE]; // will store authentication code
 
wc_AesCcmEncrypt(&enc, cipher, plain, sizeof(plain), nonce, sizeof(nonce),
        tag, sizeof(tag), authIn, sizeof(authIn));

See also

wc_AesCcmSetKey

wc_AesCcmDecrypt

wc_AesCcmSetKey()

int wc_AesCcmSetKey	(	Aes *	aes,
		const byte *	key,
		word32	keySz
	)

This function sets the key for an AES object using CCM (Counter with CBC-MAC). It takes a pointer to an AES structure and initializes it with supplied key.

Returns

none

Parameters

aes	aes structure in which to store the supplied key
key	16, 24, or 32 byte secret key for encryption and decryption
keySz	size of the supplied key

Example

Aes enc;
key[] = { some 16, 24, or 32 byte length key };
 
wc_AesCcmSetKey(&aes, key, sizeof(key));

See also

wc_AesCcmEncrypt

wc_AesCcmDecrypt

wc_AesCfbDecrypt()

int wc_AesCfbDecrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz
	)

AES with CFB mode.

Returns

0 Success and negative error values on failure

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold decrypted text must be at least as large as inputbuffer)
in	input buffer to decrypt
sz	size of input buffer

Example

Aes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
 
//set up key with AES_ENCRYPTION as dir for both encrypt and decrypt
 
if(wc_AesCfbDecrypt(&aes, plain, cipher, SIZE) != 0)
{
    // Handle error
}

See also

wc_AesCfbEncrypt

wc_AesSetKey

wc_AesCfbEncrypt()

int wc_AesCfbEncrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz
	)

AES with CFB mode.

Returns

0 Success and negative error values on failure

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold cipher text must be at least as large as inputbuffer)
in	input plain text buffer to encrypt
sz	size of input buffer

Example

Aes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
 
//set up key with AES_ENCRYPTION as dir for both encrypt and decrypt
 
if(wc_AesCfbEncrypt(&aes, cipher, plain, SIZE) != 0)
{
    // Handle error
}

See also

wc_AesCfbDecrypt

wc_AesSetKey

wc_AesCtrEncrypt()

int wc_AesCtrEncrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz
	)

Encrypts/Decrypts a message from the input buffer in, and places the resulting cipher text in the output buffer out using CTR mode with AES. This function is only enabled if WOLFSSL_AES_COUNTER is enabled at compile time. The AES structure should be initialized through AesSetKey before calling this function. Note that this function is used for both decryption and encryption. NOTE: Regarding using same API for encryption and decryption. User should differentiate between Aes structures for encrypt/decrypt.

Returns

int integer values corresponding to wolfSSL error or success status

Parameters

aes	pointer to the AES object used to decrypt data
out	pointer to the output buffer in which to store the cipher text of the encrypted message
in	pointer to the input buffer containing plain text to be encrypted
sz	size of the input plain text

Example

Aes enc;
Aes dec;
// initialize enc and dec with AesSetKeyDirect, using direction
AES_ENCRYPTION
// since the underlying API only calls Encrypt and by default calling
encrypt on
// a cipher results in a decryption of the cipher
 
byte msg[AES_BLOCK_SIZE * n]; //n being a positive integer making msg
some multiple of 16 bytes
// fill plain with message text
byte cipher[AES_BLOCK_SIZE * n];
byte decrypted[AES_BLOCK_SIZE * n];
wc_AesCtrEncrypt(&enc, cipher, msg, sizeof(msg)); // encrypt plain
wc_AesCtrEncrypt(&dec, decrypted, cipher, sizeof(cipher));
// decrypt cipher text

See also

wc_AesSetKey

wc_AesDecryptDirect()

int wc_AesDecryptDirect	(	Aes *	aes,
		byte *	out,
		const byte *	in
	)

This function is a one-block decrypt of the input block, in, into the output block, out. It uses the key of the provided AES structure, which should be initialized with wc_AesSetKey before calling this function. wc_AesSetKey should have been called with the iv set to NULL. This is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible.

Returns

int integer values corresponding to wolfSSL error or success status

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the plain text of the decrypted cipher text
in	pointer to the input buffer containing cipher text to be decrypted

Example

Aes dec;
// initialize enc with AesSetKey, using direction AES_DECRYPTION
byte cipher [AES_BLOCK_SIZE]; // 16 bytes
// initialize cipher with cipher text to decrypt
byte msg[AES_BLOCK_SIZE];
wc_AesDecryptDirect(&dec, msg, cipher);

See also

wc_AesEncryptDirect

wc_AesSetKeyDirect

wc_AesEncryptDirect()

int wc_AesEncryptDirect	(	Aes *	aes,
		byte *	out,
		const byte *	in
	)

This function is a one-block encrypt of the input block, in, into the output block, out. It uses the key of the provided AES structure, which should be initialized with wc_AesSetKey before calling this function. wc_AesSetKey should have been called with the iv set to NULL. This is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible.

Returns

int integer values corresponding to wolfSSL error or success status

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the cipher text of the encrypted message
in	pointer to the input buffer containing plain text to be encrypted

Example

Aes enc;
// initialize enc with AesSetKey, using direction AES_ENCRYPTION
byte msg [AES_BLOCK_SIZE]; // 16 bytes
// initialize msg with plain text to encrypt
byte cipher[AES_BLOCK_SIZE];
wc_AesEncryptDirect(&enc, cipher, msg);

See also

wc_AesDecryptDirect

wc_AesSetKeyDirect

wc_AesFree()

int wc_AesFree

(

Aes *

aes

)

free resources associated with the Aes structure when applicable. Internally may sometimes be a no-op but still recommended to call in all cases as a general best-practice (IE if application code is ported for use on new environments where the call is applicable).

Returns

no return (void function)

Parameters

aes	aes structure in to free

Example

Aes enc;
void* hint = NULL;
int devId = INVALID_DEVID; //if not using async INVALID_DEVID is default
 
//heap hint could be set here if used
 
wc_AesInit(&enc, hint, devId);
// ... do some interesting things ...
wc_AesFree(&enc);

See also

wc_AesInit

wc_AesGcmDecrypt()

int wc_AesGcmDecrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		const byte *	iv,
		word32	ivSz,
		const byte *	authTag,
		word32	authTagSz,
		const byte *	authIn,
		word32	authInSz
	)

This function decrypts the input cipher text, held in the buffer in, and stores the resulting message text in the output buffer out. It also checks the input authentication vector, authIn, against the supplied authentication tag, authTag.

Returns

0 On successfully decrypting the input message

AES_GCM_AUTH_E If the authentication tag does not match the supplied authentication code vector, authTag.

Parameters

aes	pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the message text
in	pointer to the input buffer holding the cipher text to decrypt
sz	length of the cipher text to decrypt
iv	pointer to the buffer containing the initialization vector
ivSz	length of the initialization vector
authTag	pointer to the buffer containing the authentication tag
authTagSz	length of the desired authentication tag
authIn	pointer to the buffer containing the input authentication vector
authInSz	length of the input authentication vector

Example

Aes enc; //can use the same struct as was passed to wc_AesGcmEncrypt
// initialize aes structure by calling wc_AesGcmSetKey if not already done
 
byte cipher[AES_BLOCK_LENGTH * n]; //n being a positive integer
making cipher some multiple of 16 bytes
// initialize cipher with cipher text to decrypt
byte output[sizeof(cipher)];
byte iv[] = // some 16 byte iv
byte authTag[AUTH_TAG_LENGTH];
byte authIn[] = // Authentication Vector
 
wc_AesGcmDecrypt(&enc, output, cipher, sizeof(cipher), iv, sizeof(iv),
        authTag, sizeof(authTag), authIn, sizeof(authIn));

See also

wc_AesGcmSetKey

wc_AesGcmEncrypt

wc_AesGcmEncrypt()

int wc_AesGcmEncrypt	(	Aes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		const byte *	iv,
		word32	ivSz,
		byte *	authTag,
		word32	authTagSz,
		const byte *	authIn,
		word32	authInSz
	)

This function encrypts the input message, held in the buffer in, and stores the resulting cipher text in the output buffer out. It requires a new iv (initialization vector) for each call to encrypt. It also encodes the input authentication vector, authIn, into the authentication tag, authTag.

Returns

0 On successfully encrypting the input message

Parameters

aes	- pointer to the AES object used to encrypt data
out	pointer to the output buffer in which to store the cipher text
in	pointer to the input buffer holding the message to encrypt
sz	length of the input message to encrypt
iv	pointer to the buffer containing the initialization vector
ivSz	length of the initialization vector
authTag	pointer to the buffer in which to store the authentication tag
authTagSz	length of the desired authentication tag
authIn	pointer to the buffer containing the input authentication vector
authInSz	length of the input authentication vector

Example

Aes enc;
// initialize aes structure by calling wc_AesGcmSetKey
 
byte plain[AES_BLOCK_LENGTH * n]; //n being a positive integer
making plain some multiple of 16 bytes
// initialize plain with msg to encrypt
byte cipher[sizeof(plain)];
byte iv[] = // some 16 byte iv
byte authTag[AUTH_TAG_LENGTH];
byte authIn[] = // Authentication Vector
 
wc_AesGcmEncrypt(&enc, cipher, plain, sizeof(cipher), iv, sizeof(iv),
        authTag, sizeof(authTag), authIn, sizeof(authIn));

See also

wc_AesGcmSetKey

wc_AesGcmDecrypt

wc_AesGcmSetKey()

int wc_AesGcmSetKey	(	Aes *	aes,
		const byte *	key,
		word32	len
	)

This function is used to set the key for AES GCM (Galois/Counter Mode). It initializes an AES object with the given key. It is only enabled if the configure option HAVE_AESGCM is enabled at compile time.

Returns

0 On successfully setting the key.

BAD_FUNC_ARG Returned if the given key is an invalid length.

Parameters

aes	pointer to the AES object used to encrypt data
key	16, 24, or 32 byte secret key for encryption and decryption
len	length of the key passed in

Example

Aes enc;
int ret = 0;
byte key[] = { some 16, 24,32 byte key };
if (ret = wc_AesGcmSetKey(&enc, key, sizeof(key)) != 0) {
// failed to set aes key
}

See also

wc_AesGcmEncrypt

wc_AesGcmDecrypt

wc_AesInit()

int wc_AesInit	(	Aes *	aes,
		void *	heap,
		int	devId
	)

Initialize Aes structure. Sets heap hint to be used and ID for use with async hardware. It is up to the user to call wc_AesFree on the Aes structure when done.

Returns

0 Success

Parameters

aes	aes structure in to initialize
heap	heap hint to use for malloc / free if needed
devId	ID to use with async hardware

Example

Aes enc;
void* hint = NULL;
int devId = INVALID_DEVID; //if not using async INVALID_DEVID is default
 
//heap hint could be set here if used
 
wc_AesInit(&enc, hint, devId);

See also

wc_AesSetKey

wc_AesSetIV

wc_AesFree

wc_AesSetIV()

int wc_AesSetIV	(	Aes *	aes,
		const byte *	iv
	)

This function sets the initialization vector for a particular AES object. The AES object should be initialized before calling this function.

Returns

0 On successfully setting initialization vector.

BAD_FUNC_ARG Returned if AES pointer is NULL.

Parameters

aes	pointer to the AES structure on which to set the initialization vector
iv	initialization vector used to initialize the AES structure. If the value is NULL, the default action initializes the iv to 0.

Example

Aes enc;
// set enc key
byte iv[]  = { some 16 byte iv };
if (ret = wc_AesSetIV(&enc, iv) != 0) {
// failed to set aes iv
}

See also

wc_AesSetKeyDirect

wc_AesSetKey

wc_AesSetKey()

int wc_AesSetKey	(	Aes *	aes,
		const byte *	key,
		word32	len,
		const byte *	iv,
		int	dir
	)

This function initializes an AES structure by setting the key and then setting the initialization vector.

Returns

0 On successfully setting key and initialization vector.

BAD_FUNC_ARG Returned if key length is invalid.

Parameters

aes	pointer to the AES structure to modify
key	16, 24, or 32 byte secret key for encryption and decryption
len	length of the key passed in
iv	pointer to the initialization vector used to initialize the key
dir	Cipher direction. Set AES_ENCRYPTION to encrypt, or AES_DECRYPTION to decrypt. Direction for some modes (CFB and CTR) is always AES_ENCRYPTION.

Example

Aes enc;
int ret = 0;
byte key[] = { some 16, 24 or 32 byte key };
byte iv[]  = { some 16 byte iv };
if (ret = wc_AesSetKey(&enc, key, AES_BLOCK_SIZE, iv,
AES_ENCRYPTION) != 0) {
// failed to set aes key
}

See also

wc_AesSetKeyDirect

wc_AesSetIV

wc_AesSetKeyDirect()

int wc_AesSetKeyDirect	(	Aes *	aes,
		const byte *	key,
		word32	len,
		const byte *	iv,
		int	dir
	)

This function is used to set the AES keys for CTR mode with AES. It initializes an AES object with the given key, iv (initialization vector), and encryption dir (direction). It is only enabled if the configure option WOLFSSL_AES_DIRECT is enabled. Currently wc_AesSetKeyDirect uses wc_AesSetKey internally. Warning: In nearly all use cases ECB mode is considered to be less secure. Please avoid using ECB API’s directly whenever possible.

Returns

0 On successfully setting the key.

BAD_FUNC_ARG Returned if the given key is an invalid length.

Parameters

aes	pointer to the AES object used to encrypt data
key	16, 24, or 32 byte secret key for encryption and decryption
len	length of the key passed in
iv	initialization vector used to initialize the key
dir	Cipher direction. Set AES_ENCRYPTION to encrypt, or AES_DECRYPTION to decrypt. (See enum in wolfssl/wolfcrypt/aes.h) (NOTE: If using wc_AesSetKeyDirect with Aes Counter mode (Stream cipher) only use AES_ENCRYPTION for both encrypting and decrypting)

Example

Aes enc;
int ret = 0;
byte key[] = { some 16, 24, or 32 byte key };
byte iv[]  = { some 16 byte iv };
if (ret = wc_AesSetKeyDirect(&enc, key, sizeof(key), iv,
AES_ENCRYPTION) != 0) {
// failed to set aes key
}

See also

wc_AesEncryptDirect

wc_AesDecryptDirect

wc_AesSetKey

wc_AesSivDecrypt()

int wc_AesSivDecrypt	(	const byte *	key,
		word32	keySz,
		const byte *	assoc,
		word32	assocSz,
		const byte *	nonce,
		word32	nonceSz,
		const byte *	in,
		word32	inSz,
		byte *	siv,
		byte *	out
	)

This function performs SIV (synthetic initialization vector) decryption as described in RFC 5297.

Returns

0 On successful decryption.

BAD_FUNC_ARG If key, SIV, or output buffer are NULL. Also returned if the key size isn't 32, 48, or 64 bytes.

AES_SIV_AUTH_E If the SIV derived by S2V doesn't match the input SIV (see RFC 5297 2.7).

Other Other negative error values returned if AES or CMAC operations fail.

Parameters

key	Byte buffer containing the key to use.
keySz	Length of the key buffer in bytes.
assoc	Additional, authenticated associated data (AD).
assocSz	Length of AD buffer in bytes.
nonce	A number used once. Used by the underlying algorithm in the same manner as the AD.
nonceSz	Length of nonce buffer in bytes.
in	Ciphertext buffer to decrypt.
inSz	Length of ciphertext buffer.
siv	The SIV that accompanies the ciphertext (see RFC 5297 2.4).
out	Buffer to hold the decrypted plaintext. Should be the same length as the ciphertext buffer.

Example

byte key[] = { some 32, 48, or 64 byte key };
byte assoc[] = {0x01, 0x2, 0x3};
byte nonce[] = {0x04, 0x5, 0x6};
byte cipherText[] = {0xDE, 0xAD, 0xBE, 0xEF};
byte siv[AES_BLOCK_SIZE] = { the SIV that came with the ciphertext };
byte plainText[sizeof(cipherText)];
if (wc_AesSivDecrypt(key, sizeof(key), assoc, sizeof(assoc), nonce,
    sizeof(nonce), cipherText, sizeof(cipherText), siv, plainText) != 0) {
    // failed to decrypt
}

See also

wc_AesSivEncrypt

wc_AesSivEncrypt()

int wc_AesSivEncrypt	(	const byte *	key,
		word32	keySz,
		const byte *	assoc,
		word32	assocSz,
		const byte *	nonce,
		word32	nonceSz,
		const byte *	in,
		word32	inSz,
		byte *	siv,
		byte *	out
	)

This function performs SIV (synthetic initialization vector) encryption as described in RFC 5297.

Returns

0 On successful encryption.

BAD_FUNC_ARG If key, SIV, or output buffer are NULL. Also returned if the key size isn't 32, 48, or 64 bytes.

Other Other negative error values returned if AES or CMAC operations fail.

Parameters

key	Byte buffer containing the key to use.
keySz	Length of the key buffer in bytes.
assoc	Additional, authenticated associated data (AD).
assocSz	Length of AD buffer in bytes.
nonce	A number used once. Used by the algorithm in the same manner as the AD.
nonceSz	Length of nonce buffer in bytes.
in	Plaintext buffer to encrypt.
inSz	Length of plaintext buffer.
siv	The SIV output by S2V (see RFC 5297 2.4).
out	Buffer to hold the ciphertext. Should be the same length as the plaintext buffer.

Example

byte key[] = { some 32, 48, or 64 byte key };
byte assoc[] = {0x01, 0x2, 0x3};
byte nonce[] = {0x04, 0x5, 0x6};
byte plainText[] = {0xDE, 0xAD, 0xBE, 0xEF};
byte siv[AES_BLOCK_SIZE];
byte cipherText[sizeof(plainText)];
if (wc_AesSivEncrypt(key, sizeof(key), assoc, sizeof(assoc), nonce,
    sizeof(nonce), plainText, sizeof(plainText), siv, cipherText) != 0) {
    // failed to encrypt
}

See also

wc_AesSivDecrypt

wc_AesXtsDecrypt()

int wc_AesXtsDecrypt	(	XtsAes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		const byte *	i,
		word32	iSz
	)

Same process as encryption but Aes key is AES_DECRYPTION type.

Returns

0 Success

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold plain text
in	input cipher text buffer to decrypt
sz	size of both out and in buffers
i	value to use for tweak
iSz	size of i buffer, should always be AES_BLOCK_SIZE but having this input adds a sanity check on how the user calls the function.

Example

XtsAes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
unsigned char i[AES_BLOCK_SIZE];
 
//set up key with AES_DECRYPTION as dir and tweak with AES_ENCRYPTION
 
if(wc_AesXtsDecrypt(&aes, plain, cipher, SIZE, i, sizeof(i)) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsEncrypt

wc_AesXtsSetKey

wc_AesXtsFree

wc_AesXtsDecryptSector()

int wc_AesXtsDecryptSector	(	XtsAes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		word64	sector
	)

Same process as wc_AesXtsDecrypt but uses a word64 type as the tweak value instead of a byte array. This just converts the word64 to a byte array.

Returns

0 Success

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold plain text
in	input cipher text buffer to decrypt
sz	size of both out and in buffers
sector	value to use for tweak

Example

XtsAes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
word64 s = VALUE;
 
//set up aes key with AES_DECRYPTION as dir and tweak with AES_ENCRYPTION
 
if(wc_AesXtsDecryptSector(&aes, plain, cipher, SIZE, s) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsEncrypt

wc_AesXtsDecrypt

wc_AesXtsSetKey

wc_AesXtsFree

wc_AesXtsEncrypt()

int wc_AesXtsEncrypt	(	XtsAes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		const byte *	i,
		word32	iSz
	)

AES with XTS mode. (XTS) XEX encryption with Tweak and cipher text Stealing.

Returns

0 Success

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold cipher text
in	input plain text buffer to encrypt
sz	size of both out and in buffers
i	value to use for tweak
iSz	size of i buffer, should always be AES_BLOCK_SIZE but having this input adds a sanity check on how the user calls the function.

Example

XtsAes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
unsigned char i[AES_BLOCK_SIZE];
 
//set up key with AES_ENCRYPTION as dir
 
if(wc_AesXtsEncrypt(&aes, cipher, plain, SIZE, i, sizeof(i)) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsDecrypt

wc_AesXtsSetKey

wc_AesXtsFree

wc_AesXtsEncryptSector()

int wc_AesXtsEncryptSector	(	XtsAes *	aes,
		byte *	out,
		const byte *	in,
		word32	sz,
		word64	sector
	)

Same process as wc_AesXtsEncrypt but uses a word64 type as the tweak value instead of a byte array. This just converts the word64 to a byte array and calls wc_AesXtsEncrypt.

Returns

0 Success

Parameters

aes	AES keys to use for block encrypt/decrypt
out	output buffer to hold cipher text
in	input plain text buffer to encrypt
sz	size of both out and in buffers
sector	value to use for tweak

Example

XtsAes aes;
unsigned char plain[SIZE];
unsigned char cipher[SIZE];
word64 s = VALUE;
 
//set up keys with AES_ENCRYPTION as dir
 
if(wc_AesXtsEncryptSector(&aes, cipher, plain, SIZE, s) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsEncrypt

wc_AesXtsDecrypt

wc_AesXtsSetKey

wc_AesXtsFree

wc_AesXtsFree()

int wc_AesXtsFree

(

XtsAes *

aes

)

This is to free up any resources used by the XtsAes structure.

Returns

0 Success

Parameters

aes	AES keys to free

Example

XtsAes aes;
 
if(wc_AesXtsSetKey(&aes, key, sizeof(key), AES_ENCRYPTION, NULL, 0) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsEncrypt

wc_AesXtsDecrypt

wc_AesXtsSetKey

wc_AesXtsSetKey()

int wc_AesXtsSetKey	(	XtsAes *	aes,
		const byte *	key,
		word32	len,
		int	dir,
		void *	heap,
		int	devId
	)

This is to help with setting keys to correct encrypt or decrypt type. It is up to user to call wc_AesXtsFree on aes key when done.

Returns

0 Success

Parameters

aes	AES keys for encrypt/decrypt process
key	buffer holding aes key | tweak key
len	length of key buffer in bytes. Should be twice that of key size. i.e. 32 for a 16 byte key.
dir	direction, either AES_ENCRYPTION or AES_DECRYPTION
heap	heap hint to use for memory. Can be NULL
devId	id to use with async crypto. Can be 0

Example

XtsAes aes;
 
if(wc_AesXtsSetKey(&aes, key, sizeof(key), AES_ENCRYPTION, NULL, 0) != 0)
{
    // Handle error
}
wc_AesXtsFree(&aes);

See also

wc_AesXtsEncrypt

wc_AesXtsDecrypt

wc_AesXtsFree

wc_GmacSetKey()

int wc_GmacSetKey	(	Gmac *	gmac,
		const byte *	key,
		word32	len
	)

This function initializes and sets the key for a GMAC object to be used for Galois Message Authentication.

Returns

0 On successfully setting the key

BAD_FUNC_ARG Returned if key length is invalid.

Parameters

gmac	pointer to the gmac object used for authentication
key	16, 24, or 32 byte secret key for authentication
len	length of the key

Example

Gmac gmac;
key[] = { some 16, 24, or 32 byte length key };
wc_AesInit(gmac.aes, HEAP_HINT, INVALID_DEVID); // Make sure devId updated
wc_GmacSetKey(&gmac, key, sizeof(key));

See also

wc_GmacUpdate

wc_AesInit

wc_GmacUpdate()

int wc_GmacUpdate	(	Gmac *	gmac,
		const byte *	iv,
		word32	ivSz,
		const byte *	authIn,
		word32	authInSz,
		byte *	authTag,
		word32	authTagSz
	)

This function generates the Gmac hash of the authIn input and stores the result in the authTag buffer. After running wc_GmacUpdate, one should compare the generated authTag to a known authentication tag to verify the authenticity of a message.

Returns

0 On successfully computing the Gmac hash.

Parameters

gmac	pointer to the gmac object used for authentication
iv	initialization vector used for the hash
ivSz	size of the initialization vector used
authIn	pointer to the buffer containing the authentication vector to verify
authInSz	size of the authentication vector
authTag	pointer to the output buffer in which to store the Gmac hash
authTagSz	the size of the output buffer used to store the Gmac hash

Example

Gmac gmac;
key[] = { some 16, 24, or 32 byte length key };
iv[] = { some 16 byte length iv };
 
wc_AesInit(gmac.aes, HEAP_HINT, INVALID_DEVID); // Make sure devId updated
wc_GmacSetKey(&gmac, key, sizeof(key));
authIn[] = { some 16 byte authentication input };
tag[AES_BLOCK_SIZE]; // will store authentication code
 
wc_GmacUpdate(&gmac, iv, sizeof(iv), authIn, sizeof(authIn), tag,
sizeof(tag));

See also

wc_GmacSetKey

wc_AesInit