98 lines
3.9 KiB
C
98 lines
3.9 KiB
C
// I retain copyright in this code but I encourage its free use provided
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// that I don't carry any responsibility for the results. I am especially
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// happy to see it used in free and open source software. If you do use
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// it I would appreciate an acknowledgement of its origin in the code or
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// the product that results and I would also appreciate knowing a little
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// about the use to which it is being put. I am grateful to Frank Yellin
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// for some ideas that are used in this implementation.
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//
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// Dr B. R. Gladman <brg@gladman.uk.net> 6th April 2001.
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//
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// This is an implementation of the AES encryption algorithm (Rijndael)
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// designed by Joan Daemen and Vincent Rijmen. This version is designed
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// to provide both fixed and dynamic block and key lengths and can also
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// run with either big or little endian internal byte order (see aes.h).
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// It inputs block and key lengths in bytes with the legal values being
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// 16, 24 and 32.
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/*
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* Modified by Jari Ruusu, May 1 2001
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* - Fixed some compile warnings, code was ok but gcc warned anyway.
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* - Changed basic types: byte -> unsigned char, word -> u_int32_t
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* - Major name space cleanup: Names visible to outside now begin
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* with "aes_" or "AES_". A lot of stuff moved from aes.h to aes.c
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* - Removed C++ and DLL support as part of name space cleanup.
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* - Eliminated unnecessary recomputation of tables. (actual bug fix)
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* - Merged precomputed constant tables to aes.c file.
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* - Removed data alignment restrictions for portability reasons.
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* - Made block and key lengths accept bit count (128/192/256)
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* as well byte count (16/24/32).
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* - Removed all error checks. This change also eliminated the need
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* to preinitialize the context struct to zero.
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* - Removed some totally unused constants.
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*/
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#ifndef _AES_H
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#define _AES_H
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#if defined(__linux__) && defined(__KERNEL__)
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# include <linux/types.h>
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#else
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# include <sys/types.h>
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#endif
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// CONFIGURATION OPTIONS (see also aes.c)
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//
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// Define AES_BLOCK_SIZE to set the cipher block size (16, 24 or 32) or
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// leave this undefined for dynamically variable block size (this will
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// result in much slower code).
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// IMPORTANT NOTE: AES_BLOCK_SIZE is in BYTES (16, 24, 32 or undefined). If
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// left undefined a slower version providing variable block length is compiled
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#define AES_BLOCK_SIZE 16
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// The number of key schedule words for different block and key lengths
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// allowing for method of computation which requires the length to be a
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// multiple of the key length
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//
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// Nk = 4 6 8
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// -------------
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// Nb = 4 | 60 60 64
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// 6 | 96 90 96
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// 8 | 120 120 120
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#if !defined(AES_BLOCK_SIZE) || (AES_BLOCK_SIZE == 32)
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#define AES_KS_LENGTH 120
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#define AES_RC_LENGTH 29
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#else
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#define AES_KS_LENGTH 4 * AES_BLOCK_SIZE
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#define AES_RC_LENGTH (9 * AES_BLOCK_SIZE) / 8 - 8
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#endif
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typedef struct
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{
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u_int32_t aes_Nkey; // the number of words in the key input block
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u_int32_t aes_Nrnd; // the number of cipher rounds
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u_int32_t aes_e_key[AES_KS_LENGTH]; // the encryption key schedule
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u_int32_t aes_d_key[AES_KS_LENGTH]; // the decryption key schedule
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#if !defined(AES_BLOCK_SIZE)
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u_int32_t aes_Ncol; // the number of columns in the cipher state
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#endif
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} aes_context;
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// THE CIPHER INTERFACE
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#if !defined(AES_BLOCK_SIZE)
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extern void aes_set_blk(aes_context *, const int);
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#endif
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extern void aes_set_key(aes_context *, const unsigned char [], const int, const int);
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extern void aes_encrypt(const aes_context *, const unsigned char [], unsigned char []);
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extern void aes_decrypt(const aes_context *, const unsigned char [], unsigned char []);
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// The block length inputs to aes_set_block and aes_set_key are in numbers
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// of bytes or bits. The calls to subroutines must be made in the above
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// order but multiple calls can be made without repeating earlier calls
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// if their parameters have not changed.
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#endif // _AES_H
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