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 Page 1 Plan 9 (printed 7/24/21) 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. Page 2 Plan 9 (printed 7/24/21)