cbc.h File Reference

Cipher-block chaining. More...

#include <gpxe/crypto.h>

Go to the source code of this file.

Defines
#define	CBC_CIPHER(_cbc_name, _cbc_cipher, _raw_cipher, _raw_context, _blocksize)
	Create a cipher-block chaining mode of behaviour of an existing cipher.
Functions
	FILE_LICENCE (GPL2_OR_LATER)
static int	cbc_setkey (void *ctx, const void *key, size_t keylen, struct cipher_algorithm *raw_cipher, void *cbc_ctx __unused)
	Set key.
static void	cbc_setiv (void *ctx __unused, const void *iv, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Set initialisation vector.
void	cbc_encrypt (void *ctx, const void *src, void *dst, size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Encrypt data.
void	cbc_decrypt (void *ctx, const void *src, void *dst, size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx)
	Decrypt data.

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Detailed Description

Cipher-block chaining.

Definition in file cbc.h.

---

Define Documentation

#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 62 of file cbc.h.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

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

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.

References cipher_setkey().

                                                        {

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

static void cbc_setiv	(	void *ctx	__unused,
		const void *	iv,
		struct cipher_algorithm *	raw_cipher,
		void *	cbc_ctx
	)			[inline, static]

Set initialisation vector.

Parameters:

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

Definition at line 39 of file cbc.h.

References cipher_algorithm::blocksize, and memcpy.

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

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 61 of file cbc.c.

References assert, cipher_algorithm::blocksize, digest_algorithm::blocksize, cbc_xor(), cipher_encrypt, and memcpy.

                                                                        {
        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;
        }
}

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 87 of file cbc.c.

References assert, cipher_algorithm::blocksize, digest_algorithm::blocksize, cbc_xor(), cipher_decrypt, and memcpy.

                                                                        {
        size_t blocksize = raw_cipher->blocksize;

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

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