aes.h File Reference

Go to the source code of this file.

Data Structures
struct	aes_context

Macros
#define	AES_ENC_PREKEYED   /* AES encryption with a precomputed key schedule */
#define	AES_DEC_PREKEYED   /* AES decryption with a precomputed key schedule */
#define	N_ROW   4
#define	N_COL   4
#define	N_BLOCK   (N_ROW * N_COL)
#define	N_MAX_ROUNDS   14

Typedefs
typedef unsigned char	uint_8t
typedef uint_8t	return_type
typedef uint_8t	length_type

Functions
return_type	aes_set_key (const unsigned char key[], length_type keylen, aes_context ctx[1])
return_type	aes_encrypt (const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK], const aes_context ctx[1])
return_type	aes_cbc_encrypt (const unsigned char *in, unsigned char *out, int n_block, unsigned char iv[N_BLOCK], const aes_context ctx[1])
return_type	aes_decrypt (const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK], const aes_context ctx[1])
return_type	aes_cbc_decrypt (const unsigned char *in, unsigned char *out, int n_block, unsigned char iv[N_BLOCK], const aes_context ctx[1])

Macro Definition Documentation

#define AES_DEC_PREKEYED   /* AES decryption with a precomputed key schedule */

Definition at line 43 of file aes.h.

#define AES_ENC_PREKEYED   /* AES encryption with a precomputed key schedule */

Definition at line 40 of file aes.h.

#define N_BLOCK   (N_ROW * N_COL)

Definition at line 60 of file aes.h.

Referenced by aes_cbc_decrypt(), aes_cbc_encrypt(), aes_decrypt(), aes_encrypt(), inv_mix_sub_columns(), and mix_sub_columns().

#define N_COL   4

Definition at line 59 of file aes.h.

#define N_MAX_ROUNDS   14

Definition at line 61 of file aes.h.

#define N_ROW   4

Definition at line 58 of file aes.h.

Typedef Documentation

typedef uint_8t length_type

Definition at line 71 of file aes.h.

typedef uint_8t return_type

Definition at line 65 of file aes.h.

typedef unsigned char uint_8t

Definition at line 63 of file aes.h.

Function Documentation

return_type aes_cbc_decrypt	(	const unsigned char *	in,
		unsigned char *	out,
		int	n_block,
		unsigned char	iv[N_BLOCK],
		const aes_context	ctx[1]
	)

Definition at line 586 of file aes.c.

References aes_decrypt(), N_BLOCK, and xor_block().

{
    while (n_block--) {
        uint_8t tmp[N_BLOCK];

        memcpy(tmp, in, N_BLOCK);
        if (aes_decrypt(in, out, ctx) != EXIT_SUCCESS) {
            return EXIT_FAILURE;
        }
        xor_block(out, iv);
        memcpy(iv, tmp, N_BLOCK);
        in += N_BLOCK;
        out += N_BLOCK;
    }
    return EXIT_SUCCESS;
}

return_type aes_cbc_encrypt	(	const unsigned char *	in,
		unsigned char *	out,
		int	n_block,
		unsigned char	iv[N_BLOCK],
		const aes_context	ctx[1]
	)

Definition at line 537 of file aes.c.

References aes_encrypt(), N_BLOCK, and xor_block().

{
    while (n_block--) {
        xor_block(iv, in);
        if (aes_encrypt(iv, iv, ctx) != EXIT_SUCCESS) {
            return EXIT_FAILURE;
        }
        memcpy(out, iv, N_BLOCK);
        in += N_BLOCK;
        out += N_BLOCK;
    }
    return EXIT_SUCCESS;
}

return_type aes_decrypt	(	const unsigned char	in[N_BLOCK],
		unsigned char	out[N_BLOCK],
		const aes_context	ctx[1]
	)

Definition at line 557 of file aes.c.

References add_round_key(), copy_and_key(), inv_mix_sub_columns(), inv_shift_sub_rows(), aes_context::ksch, N_BLOCK, and aes_context::rnd.

Referenced by aes_cbc_decrypt().

{
    if (ctx->rnd) {
        uint_8t s1[N_BLOCK], r;
        copy_and_key(s1, in, ctx->ksch + ctx->rnd * N_BLOCK);
        inv_shift_sub_rows(s1);

        for (r = ctx->rnd; --r;)
#if defined(VERSION_1)
        {
            add_round_key(s1, ctx->ksch + r * N_BLOCK);
            inv_mix_sub_columns(s1);
        }
#else
        {
            uint_8t s2[N_BLOCK];
            copy_and_key(s2, s1, ctx->ksch + r * N_BLOCK);
            inv_mix_sub_columns(s1, s2);
        }
#endif
        copy_and_key(out, s1, ctx->ksch);
    } else {
        return -1;
    }
    return 0;
}

return_type aes_encrypt	(	const unsigned char	in[N_BLOCK],
		unsigned char	out[N_BLOCK],
		const aes_context	ctx[1]
	)

Definition at line 508 of file aes.c.

References add_round_key(), copy_and_key(), aes_context::ksch, mix_sub_columns(), N_BLOCK, aes_context::rnd, shift_sub_rows(), and VERSION_1.

Referenced by aes_cbc_encrypt().

{
    if (ctx->rnd) {
        uint_8t s1[N_BLOCK], r;
        copy_and_key(s1, in, ctx->ksch);

        for (r = 1; r < ctx->rnd; ++r)
#if defined(VERSION_1)
        {
            mix_sub_columns(s1);
            add_round_key(s1, ctx->ksch + r * N_BLOCK);
        }
#else
        {
            uint_8t s2[N_BLOCK];
            mix_sub_columns(s2, s1);
            copy_and_key(s1, s2, ctx->ksch + r * N_BLOCK);
        }
#endif
        shift_sub_rows(s1);
        copy_and_key(out, s1, ctx->ksch + r * N_BLOCK);
    } else {
        return -1;
    }
    return 0;
}

return_type aes_set_key	(	const unsigned char	key[],
		length_type	keylen,
		aes_context	ctx[1]
	)

Definition at line 449 of file aes.c.

References block_copy_nn, f2, aes_context::ksch, aes_context::rnd, and s_box.

{
    uint_8t cc, rc, hi;

    switch (keylen) {
    case 16:
    case 128:
        keylen = 16;
        break;
    case 24:
    case 192:
        keylen = 24;
        break;
    case 32:
        //case 256:
        keylen = 32;
        break;
    default:
        ctx->rnd = 0;
        return -1;
    }
    block_copy_nn(ctx->ksch, key, keylen);
    hi = (keylen + 28) << 2;
    ctx->rnd = (hi >> 4) - 1;
    for (cc = keylen, rc = 1; cc < hi; cc += 4) {
        uint_8t tt, t0, t1, t2, t3;

        t0 = ctx->ksch[cc - 4];
        t1 = ctx->ksch[cc - 3];
        t2 = ctx->ksch[cc - 2];
        t3 = ctx->ksch[cc - 1];
        if (cc % keylen == 0) {
            tt = t0;
            t0 = s_box(t1) ^ rc;
            t1 = s_box(t2);
            t2 = s_box(t3);
            t3 = s_box(tt);
            rc = f2(rc);
        } else if (keylen > 24 && cc % keylen == 16) {
            t0 = s_box(t0);
            t1 = s_box(t1);
            t2 = s_box(t2);
            t3 = s_box(t3);
        }
        tt = cc - keylen;
        ctx->ksch[cc + 0] = ctx->ksch[tt + 0] ^ t0;
        ctx->ksch[cc + 1] = ctx->ksch[tt + 1] ^ t1;
        ctx->ksch[cc + 2] = ctx->ksch[tt + 2] ^ t2;
        ctx->ksch[cc + 3] = ctx->ksch[tt + 3] ^ t3;
    }
    return 0;
}