cbc.h File Reference

Cipher-block chaining. More...

#include <ipxe/crypto.h>

Go to the source code of this file.

Macros
#define	CBC_CIPHER(_cbc_name, _cbc_cipher, _raw_cipher, _raw_context, _blocksize)
	Create a cipher-block chaining mode of behaviour of an existing cipher. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static int	cbc_setkey (void *ctx, const void *key, size_t keylen, struct cipher_algorithm *raw_cipher, void *cbc_ctx __unused)
	Set key. More...
static void	cbc_setiv (void *ctx __unused, const void *iv, size_t ivlen, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Set initialisation vector. More...
void	cbc_encrypt (void *ctx, const void *src, void *dst, size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Encrypt data. More...
void	cbc_decrypt (void *ctx, const void *src, void *dst, size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Decrypt data. More...

Detailed Description

Cipher-block chaining.

Definition in file cbc.h.

Macro Definition Documentation

CBC_CIPHER

#define CBC_CIPHER	(		_cbc_name,
			_cbc_cipher,
			_raw_cipher,
			_raw_context,
			_blocksize
	)

Create a cipher-block chaining mode of behaviour of an existing cipher.

Parameters

_cbc_name	Name for the new CBC cipher
_cbc_cipher	New cipher algorithm
_raw_cipher	Underlying cipher algorithm
_raw_context	Context structure for the underlying cipher
_blocksize	Cipher block size

Definition at line 64 of file cbc.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

cbc_setkey()

static int cbc_setkey ( void *  ctx, const void *  key, size_t  keylen, struct cipher_algorithm *  raw_cipher, void *cbc_ctx  __unused  )

inlinestatic

Set key.

Parameters

ctx	Context
key	Key
keylen	Key length
raw_cipher	Underlying cipher algorithm
cbc_ctx	CBC context

Return values

rc	Return status code

Definition at line 24 of file cbc.h.

                                                        {

        return cipher_setkey ( raw_cipher, ctx, key, keylen );
}

References ctx, key, and keylen.

cbc_setiv()

static void cbc_setiv ( void *ctx  __unused, const void *  iv, size_t  ivlen, struct cipher_algorithm *  raw_cipher, void *  cbc_ctx  )

inlinestatic

Set initialisation vector.

Parameters

ctx	Context
iv	Initialisation vector
ivlen	Initialisation vector length
raw_cipher	Underlying cipher algorithm
cbc_ctx	CBC context

Definition at line 40 of file cbc.h.

                                               {
        assert ( ivlen == raw_cipher->blocksize );
        memcpy ( cbc_ctx, iv, raw_cipher->blocksize );
}

References assert(), cipher_algorithm::blocksize, iv, ivlen, and memcpy().

cbc_encrypt()

void cbc_encrypt	(	void *	ctx,
		const void *	src,
		void *	dst,
		size_t	len,
		struct cipher_algorithm *	raw_cipher,
		void *	cbc_ctx
	)

Encrypt data.

Parameters

ctx	Context
src	Data to encrypt
dst	Buffer for encrypted data
len	Length of data
raw_cipher	Underlying cipher algorithm
cbc_ctx	CBC context

Definition at line 66 of file cbc.c.

                                                                        {
        size_t blocksize = raw_cipher->blocksize;

        assert ( ( len % blocksize ) == 0 );

        while ( len ) {
                cbc_xor ( src, cbc_ctx, blocksize );
                cipher_encrypt ( raw_cipher, ctx, cbc_ctx, dst, blocksize );
                memcpy ( cbc_ctx, dst, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

References assert(), cipher_algorithm::blocksize, cbc_xor(), cipher_encrypt, ctx, dst, len, memcpy(), and src.

cbc_decrypt()

void cbc_decrypt	(	void *	ctx,
		const void *	src,
		void *	dst,
		size_t	len,
		struct cipher_algorithm *	raw_cipher,
		void *	cbc_ctx
	)

Decrypt data.

Parameters

ctx	Context
src	Data to decrypt
dst	Buffer for decrypted data
len	Length of data
raw_cipher	Underlying cipher algorithm
cbc_ctx	CBC context

Definition at line 92 of file cbc.c.

                                                                        {
        size_t blocksize = raw_cipher->blocksize;
        uint8_t next_cbc_ctx[blocksize];

        assert ( ( len % blocksize ) == 0 );

        while ( len ) {
                memcpy ( next_cbc_ctx, src, blocksize );
                cipher_decrypt ( raw_cipher, ctx, src, dst, blocksize );
                cbc_xor ( cbc_ctx, dst, blocksize );
                memcpy ( cbc_ctx, next_cbc_ctx, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

References assert(), cipher_algorithm::blocksize, cbc_xor(), cipher_decrypt, ctx, dst, len, memcpy(), and src.