cbc.h File Reference

Cipher-block chaining. More...

#include <ipxe/crypto.h>

Go to the source code of this file.

Macros
#define	cbc_context_t(blocksize, ctxsize)
	A cipher-block chaining mode context.
#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_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
int	cbc_setkey (struct cipher_algorithm *cipher, void *ctx, const void *key, size_t keylen)
	Set key.
int	cbc_setiv (struct cipher_algorithm *cipher, void *ctx, const void *iv, size_t ivlen)
	Set initialisation vector.
void	cbc_encrypt (struct cipher_algorithm *cipher, void *ctx, const void *src, void *dst, size_t len)
	Encrypt data.
void	cbc_decrypt (struct cipher_algorithm *cipher, void *ctx, const void *src, void *dst, size_t len)
	Decrypt data.

Detailed Description

Cipher-block chaining.

Definition in file cbc.h.

Macro Definition Documentation

cbc_context_t

#define cbc_context_t	(		blocksize,
			ctxsize )

Value:

struct {                                                        \
        uint8_t cbc[ (blocksize) ];                             \
        uint8_t raw[ (ctxsize) - (blocksize) ];                 \
}

A cipher-block chaining mode context.

Definition at line 16 of file cbc.h.

#define cbc_context_t( blocksize, ctxsize )                             \
        struct {                                                        \
                uint8_t cbc[ (blocksize) ];                             \
                uint8_t raw[ (ctxsize) - (blocksize) ];                 \
        }

Referenced by cbc_decrypt(), cbc_encrypt(), cbc_setiv(), and cbc_setkey().

CBC_CIPHER

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

Value:

struct cipher_algorithm _cbc_cipher = {                                 \
        .name           = #_cbc_name,                                   \
        .ctxsize        = ( _blocksize + sizeof ( _raw_context ) ),     \
        .blocksize      = _blocksize,                                   \
        .alignsize      = _blocksize,                                   \
        .authsize       = 0,                                            \
        .confidential   = 1,                                            \
        .setkey         = cbc_setkey,                                   \
        .setiv          = cbc_setiv,                                    \
        .encrypt        = cbc_encrypt,                                  \
        .decrypt        = cbc_decrypt,                                  \
        .auth           = cipher_null_auth,                             \
        .priv           = &_raw_cipher,                                 \
};

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 40 of file cbc.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

cbc_setkey()

int cbc_setkey ( struct cipher_algorithm * cipher, void * ctx, const void * key, size_t keylen )

extern

Set key.

Parameters

cipher	Cipher algorithm
ctx	Context
key	Key
keylen	Key length

Return values

rc	Return status code

Definition at line 48 of file cbc.c.

                                                  {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        return cipher_setkey ( raw_cipher, context->raw, key, keylen );
}

References cipher_algorithm::blocksize, cbc_context_t, cipher_setkey(), ctx, cipher_algorithm::ctxsize, key, and cipher_algorithm::priv.

cbc_setiv()

int cbc_setiv ( struct cipher_algorithm * cipher, void * ctx, const void * iv, size_t ivlen )

extern

Set initialisation vector.

Parameters

cipher	Cipher algorithm
ctx	Context
iv	Initialisation vector
ivlen	Initialisation vector length

Return values

rc	Return status code

Definition at line 67 of file cbc.c.

                                               {
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        /* Check length */
        if ( ivlen != sizeof ( context->cbc ) )
                return -ENOTSUP;
 
        /* Record IV */
        memcpy ( context->cbc, iv, sizeof ( context->cbc ) );
 
        return 0;
}

References cipher_algorithm::blocksize, cbc_context_t, ctx, cipher_algorithm::ctxsize, ENOTSUP, iv, and memcpy().

cbc_encrypt()

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

extern

Encrypt data.

Parameters

cipher	Cipher algorithm
ctx	Context
src	Data to encrypt
dst	Buffer for encrypted data
len	Length of data

Definition at line 111 of file cbc.c.

                                                            {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
 
        assert ( ( len % blocksize ) == 0 );
 
        while ( len ) {
                cbc_xor ( src, context->cbc, blocksize );
                cipher_encrypt ( raw_cipher, context->raw, context->cbc, dst,
                                 blocksize );
                memcpy ( context->cbc, dst, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

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

cbc_decrypt()

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

extern

Decrypt data.

Parameters

cipher	Cipher algorithm
ctx	Context
src	Data to decrypt
dst	Buffer for decrypted data
len	Length of data

Definition at line 140 of file cbc.c.

                                                            {
        struct cipher_algorithm *raw_cipher = cipher->priv;
        size_t blocksize = cipher->blocksize;
        size_t ctxsize = cipher->ctxsize;
        cbc_context_t ( blocksize, ctxsize ) *context = ctx;
        uint8_t next_cbc_ctx[blocksize];
 
        assert ( ( len % blocksize ) == 0 );
 
        while ( len ) {
                memcpy ( next_cbc_ctx, src, blocksize );
                cipher_decrypt ( raw_cipher, context->raw, src, dst,
                                 blocksize );
                cbc_xor ( context->cbc, dst, blocksize );
                memcpy ( context->cbc, next_cbc_ctx, blocksize );
                dst += blocksize;
                src += blocksize;
                len -= blocksize;
        }
}

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