aes.h File Reference

#include "crypto/axtls/crypto.h"

Go to the source code of this file.

Data Structures
struct	aes_context
	AES context. More...
Defines
#define	AES_BLOCKSIZE   16
	Basic AES blocksize.
#define	AES_CTX_SIZE   sizeof ( struct aes_context )
	AES context size.
Functions
	FILE_LICENCE (GPL2_OR_LATER)
int	aes_wrap (const void *kek, const void *src, void *dest, int nblk)
	Wrap a key or other data using AES Key Wrap (RFC 3394).
int	aes_unwrap (const void *kek, const void *src, void *dest, int nblk)
	Unwrap a key or other data using AES Key Wrap (RFC 3394).
Variables
struct cipher_algorithm	aes_algorithm
	Basic AES algorithm.
struct cipher_algorithm	aes_cbc_algorithm

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Define Documentation

#define AES_BLOCKSIZE   16

Basic AES blocksize.

Definition at line 9 of file aes.h.

Referenced by aes_decrypt(), and aes_encrypt().

#define AES_CTX_SIZE   sizeof ( struct aes_context )

AES context size.

Definition at line 22 of file aes.h.

Referenced by aes_unwrap(), and aes_wrap().

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Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

int aes_wrap	(	const void *	kek,
		const void *	src,
		void *	dest,
		int	nblk
	)

Wrap a key or other data using AES Key Wrap (RFC 3394).

Parameters:

	kek	Key Encryption Key, 16 bytes
	src	Data to encrypt
	nblk	Number of 8-byte blocks in data

Return values:

dest

Encrypted data (8 bytes longer than input)

The algorithm is implemented such that src and dest may point to the same buffer.

Definition at line 37 of file aes_wrap.c.

References aes_algorithm, AES_CTX_SIZE, cipher_encrypt, cipher_setkey(), free(), malloc(), memcpy, memmove(), memset(), and u8.

{
        u8 *A = dest;
        u8 B[16];
        u8 *R;
        int i, j;
        void *aes_ctx = malloc ( AES_CTX_SIZE );

        if ( ! aes_ctx )
                return -1;

        cipher_setkey ( &aes_algorithm, aes_ctx, kek, 16 );

        /* Set up */
        memset ( A, 0xA6, sizeof ( A ) );
        memmove ( dest + 8, src, nblk * 8 );

        /* Wrap */
        for ( j = 0; j < 6; j++ ) {
                R = dest + 8;
                for ( i = 1; i <= nblk; i++ ) {
                        memcpy ( B, A, 8 );
                        memcpy ( B + 8, R, 8 );
                        cipher_encrypt ( &aes_algorithm, aes_ctx, B, B, 16 );
                        memcpy ( A, B, 8 );
                        A[7] ^= ( nblk * j ) + i;
                        memcpy ( R, B + 8, 8 );
                        R += 8;
                }
        }

        free ( aes_ctx );
        return 0;
}

int aes_unwrap	(	const void *	kek,
		const void *	src,
		void *	dest,
		int	nblk
	)

Unwrap a key or other data using AES Key Wrap (RFC 3394).

Parameters:

	kek	Key Encryption Key, 16 bytes
	src	Data to decrypt
	nblk	Number of 8-byte blocks in plaintext key

Return values:

	dest	Decrypted data (8 bytes shorter than input)
	rc	Zero on success, nonzero on IV mismatch

The algorithm is implemented such that src and dest may point to the same buffer.

Definition at line 84 of file aes_wrap.c.

References aes_algorithm, AES_CTX_SIZE, cipher_decrypt, cipher_setkey(), free(), malloc(), memcpy, memmove(), and u8.

Referenced by ccmp_kie_decrypt().

{
        u8 A[8], B[16];
        u8 *R;
        int i, j;
        void *aes_ctx = malloc ( AES_CTX_SIZE );

        if ( ! aes_ctx )
                return -1;

        cipher_setkey ( &aes_algorithm, aes_ctx, kek, 16 );

        /* Set up */
        memcpy ( A, src, 8 );
        memmove ( dest, src + 8, nblk * 8 );

        /* Unwrap */
        for ( j = 5; j >= 0; j-- ) {
                R = dest + ( nblk - 1 ) * 8;
                for ( i = nblk; i >= 1; i-- ) {
                        memcpy ( B, A, 8 );
                        memcpy ( B + 8, R, 8 );
                        B[7] ^= ( nblk * j ) + i;
                        cipher_decrypt ( &aes_algorithm, aes_ctx, B, B, 16 );
                        memcpy ( A, B, 8 );
                        memcpy ( R, B + 8, 8 );
                        R -= 8;
                }
        }

        free ( aes_ctx );

        /* Check IV */
        for ( i = 0; i < 8; i++ ) {
                if ( A[i] != 0xA6 )
                        return -1;
        }

        return 0;
}

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Variable Documentation

struct cipher_algorithm aes_algorithm

Basic AES algorithm.

Definition at line 146 of file axtls_aes.c.

Referenced by aes_unwrap(), aes_wrap(), ccmp_cbc_mac(), ccmp_ctr_xor(), ccmp_feed_cbc_mac(), and ccmp_init().

struct cipher_algorithm aes_cbc_algorithm

Referenced by tls_select_cipher().