AES(2) AES(2)
NAME
setupAESstate, aesCBCencrypt, aesCBCdecrypt, aesCFBencrypt,
aesCFBdecrypt, aesOFBencrypt, aes_xts_encrypt,
aes_xts_decrypt, setupAESGCMstate, aesgcm_setiv,
aesgcm_encrypt, aesgcm_decrypt - advanced encryption
standard (rijndael)
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
void aes_encrypt(ulong rk[], int Nr, uchar pt[16], uchar
ct[16])
void aes_decrypt(ulong rk[], int Nr, uchar ct[16], uchar
pt[16])
void setupAESstate(AESstate *s, uchar key[], int nkey, uchar
*ivec)
void aesCBCencrypt(uchar *p, int len, AESstate *s)
void aesCBCdecrypt(uchar *p, int len, AESstate *s)
void aesCFBencrypt(uchar *p, int len, AESstate *s)
void aesCFBdecrypt(uchar *p, int len, AESstate *s)
void aesOFBencrypt(uchar *p, int len, AESstate *s)
void aes_xts_encrypt(AESstate *tweak, AESstate *ecb, uvlong
sectorNumber, uchar *input, uchar *output, ulong len)
void aes_xts_decrypt(AESstate *tweak, AESstate *ecb, uvlong
sectorNumber, uchar *input, uchar *output, ulong len)
void setupAESGCMstate(AESGCMstate *s, uchar *key, int
keylen, uchar *iv, int ivlen)
void aesgcm_setiv(AESGCMstate *s, uchar *iv, int ivlen)
void aesgcm_encrypt(uchar *dat, ulong ndat, uchar *aad,
ulong naad, uchar tag[16], AESGCMstate *s)
int aesgcm_decrypt(uchar *dat, ulong ndat, uchar *aad,
ulong naad, uchar tag[16], AESGCMstate *s)
DESCRIPTION
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AES(2) AES(2)
AES (a.k.a. Rijndael) has replaced DES as the preferred
block cipher. Aes_encrypt and aes_decrypt are the block
ciphers, corresponding to des(2)'s block_cipher.
AesCBCencrypt and aesCBCdecrypt implement cipher-block-
chaining encryption. AesCFBencrypt, aesCFBdecrypt and
aesOFBencrypt implement cipher-feedback- and output-
feedback-mode stream cipher encryption. Aes_xts_encrypt and
aes_xts_decrypt implement the XTS-AES tweakable block
cipher, per IEEE 1619-2017 (see bugs below). SetupAESstate
is used to initialize the state of the above encryption
modes. The expanded roundkey parameters rk and Nr of
aes_encrypt and aes_decrypt are returned in AESstate.ekey
and AESstate.dkey with the corresponding number of rounds in
AESstate.rounds. SetupAESGCMstate, aesgcm_setiv,
aesgcm_encrypt and aesgcm_decrypt implement Galois/Counter
Mode (GCM) authenticated encryption with associated data
(AEAD). Before encryption or decryption, a new initializa-
tion vector (nonce) has to be set with aesgcm_setiv or by
calling setupAESGCMstate with non-zero iv and ivlen argu-
ments. Aesgcm_decrypt returns zero when authentication and
decryption where successfull and non-zero otherwise. All
ciphering is performed in place. The byte keysize nkey
should be 16, 24, or 32. The initialization vector ivec of
AESbsize bytes should be random enough to be unlikely to be
reused but does not need to be cryptographically strongly
unpredictable.
SOURCE
/sys/src/libsec
SEE ALSO
aescbc in secstore(1), mp(2), blowfish(2), des(2), dsa(2),
elgamal(2), rc4(2), rsa(2), sechash(2), prime(2), rand(2)
http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
BUGS
Because of the way that non-multiple-of-16 buffers are han-
dled, aesCBCdecrypt must be fed buffers of the same size as
the aesCBCencrypt calls that encrypted it.
The functions aes_xts_encrypt an aes_xts_decrypt abort on a
non-multiple-of-16 length as ciphertext stealing is not
implemented.
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