ctx_generic.c

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/****************************************************************************
*                                                                           *
*                   cryptlib Generic-Secret Object Routines                 *
*                       Copyright Peter Gutmann 1995-2009                   *
*                                                                           *
****************************************************************************/

#if defined( INC_ALL )
  #include "crypt.h"
  #include "context.h"
#else
  #include "crypt.h"
  #include "context/context.h"
#endif /* Compiler-specific includes */

/* This is a special-case context type that implements no actual 
   functionality but instead serves as a generic-secret container for use 
   with crypto mechanisms that employ intermediate cryptovariables, for 
   example ones that derive encryption keys, MAC keys, and IVs from a master
   secret value */

/****************************************************************************
*                                                                           *
*                               Self-test Routines                          *
*                                                                           *
****************************************************************************/

#ifndef CONFIG_NO_SELFTEST

static int selfTest( void )
    {
    return( CRYPT_OK );
    }
#else
    #define selfTest    NULL
#endif /* !CONFIG_NO_SELFTEST */

/****************************************************************************
*                                                                           *
*                               Key Management Routines                     *
*                                                                           *
****************************************************************************/

/* Since this is a pure data-storage object, this is the only routine that
   does anything */

static int initKey( CONTEXT_INFO *contextInfoPtr, const void *key, 
                    const int keyLength )
    {
    GENERIC_INFO *genericInfo = contextInfoPtr->ctxGeneric;

    /* Copy the key to internal storage */
    if( genericInfo->genericSecret != key )
        memcpy( genericInfo->genericSecret, key, keyLength );
    genericInfo->genericSecretLength = keyLength;

    return( CRYPT_OK );
    }

/****************************************************************************
*                                                                           *
*                       Capability Access Routines                          *
*                                                                           *
****************************************************************************/

static const CAPABILITY_INFO FAR_BSS capabilityInfo = {
    CRYPT_IALGO_GENERIC_SECRET, 0, "Generic Secret", 14,
    bitsToBytes( 128 ), bitsToBytes( 128 ), bitsToBytes( 256 ),
    selfTest, getDefaultInfo, NULL, initGenericParams, initKey, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
    };

const CAPABILITY_INFO *getGenericSecretCapability( void )
    {
    return( &capabilityInfo );
    }