hmac.c

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/*
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%           Wizard's Toolkit Keyed-Hashing for Message Authentication         %
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%                             Software Design                                 %
%                               John Cristy                                   %
%                               March 2003                                    %
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%  Copyright 1999-2010 ImageMagick Studio LLC, a non-profit organization      %
%  dedicated to making software imaging solutions freely available.           %
%                                                                             %
%  You may not use this file except in compliance with the License.  You may  %
%  obtain a copy of the License at                                            %
%                                                                             %
%    http://www.wizards-toolkit.org/script/license.php                        %
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%  Unless required by applicable law or agreed to in writing, software        %
%  distributed under the License is distributed on an "AS IS" BASIS,          %
%  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
%  See the License for the specific language governing permissions and        %
%  limitations under the License.                                             %
%                                                                             %
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%
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*/

/*
  Include declarations.
*/
#include "wizard/studio.h"
#include "wizard/exception.h"
#include "wizard/exception-private.h"
#include "wizard/hash.h"
#include "wizard/hmac.h"
#include "wizard/memory_.h"

/*
  Typedef declarations.
*/
struct _HMACInfo
{
  HashInfo
    *hash_info;

  StringInfo
    *digest,
    *final_nonce,
    *initial_nonce;

  time_t
    timestamp;

  size_t
    signature;
};

/*
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%  AcquireHMACInfo() allocate the HMACInfo structure.
%
%  The format of the AcquireHMACInfo method is:
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%      HMACInfo *AcquireHMACInfo(const HashType hash)
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%  A description of each parameter follows:
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%    o hash: The hash type.
%
*/
WizardExport HMACInfo *AcquireHMACInfo(const HashType hash)
{
  HMACInfo
    *hmac_info;

  hmac_info=(HMACInfo *) AcquireAlignedMemory(1,sizeof(*hmac_info));
  if (hmac_info == (HMACInfo *) NULL)
    ThrowWizardFatalError(MACDomain,MemoryError);
  (void) ResetWizardMemory(hmac_info,0,sizeof(*hmac_info));
  hmac_info->hash_info=AcquireHashInfo(hash);
  hmac_info->digest=AcquireStringInfo((size_t) GetHashDigestsize(
    hmac_info->hash_info));
  hmac_info->initial_nonce=AcquireStringInfo((size_t) GetHashBlocksize(
    hmac_info->hash_info));
  hmac_info->final_nonce=AcquireStringInfo((size_t) GetHashBlocksize(
    hmac_info->hash_info));
  hmac_info->timestamp=time((time_t *) NULL);
  hmac_info->signature=WizardSignature;
  return(hmac_info);
}

/*
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%  ConstructHMAC() constructs the HMAC digest.
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%  The format of the ConstructHMAC method is:
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%      ConstructHMAC(HMACInfo *hmac_info,const StringInfo *key,
%        const StringInfo *message)
%
%  A description of each parameter follows:
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%    o hmac_info: The address of a structure of type HMACInfo.
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%    o key: The key.
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%    o message: The message.
%
*/
WizardExport void ConstructHMAC(HMACInfo *hmac_info,const StringInfo *key,
  const StringInfo *message)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  assert(key != (StringInfo *) NULL);
  assert(message != (StringInfo *) NULL);
  InitializeHMAC(hmac_info,key);
  UpdateHMAC(hmac_info,message);
  FinalizeHMAC(hmac_info);
}

/*
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%  DestroyHMACInfo() zeros memory associated with the HMACInfo structure.
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%  The format of the DestroyHMACInfo method is:
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%      HMACInfo *DestroyHMACInfo(HMACInfo *hmac_info)
%
%  A description of each parameter follows:
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%    o hmac_info: The cipher hmac_info.
%
*/
WizardExport HMACInfo *DestroyHMACInfo(HMACInfo *hmac_info)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  if (hmac_info->final_nonce != (StringInfo *)  NULL)
    hmac_info->final_nonce=DestroyStringInfo(hmac_info->final_nonce);
  if (hmac_info->initial_nonce != (StringInfo *)  NULL)
    hmac_info->initial_nonce=DestroyStringInfo(hmac_info->initial_nonce);
  if (hmac_info->digest != (StringInfo *) NULL)
    hmac_info->digest=DestroyStringInfo(hmac_info->digest);
  if (hmac_info->hash_info != (HashInfo *) NULL)
    hmac_info->hash_info=DestroyHashInfo(hmac_info->hash_info);
  hmac_info->signature=(~WizardSignature);
  hmac_info=(HMACInfo *) RelinquishWizardMemory(hmac_info);
  return(hmac_info);
}

/*
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%  FinalizeHMAC() finalizes the HMAC message digest computation.
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%  The format of the FinalizeHMAC method is:
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%      FinalizeHMAC(HMACInfo *hmac_info)
%
%  A description of each parameter follows:
%
%    o hmac_info: The address of a structure of type HMACInfo.
%
*/
WizardExport void FinalizeHMAC(HMACInfo *hmac_info)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  FinalizeHash(hmac_info->hash_info);
  SetStringInfo(hmac_info->digest,GetHashDigest(hmac_info->hash_info));
  InitializeHash(hmac_info->hash_info);
  UpdateHash(hmac_info->hash_info,hmac_info->final_nonce);
  UpdateHash(hmac_info->hash_info,hmac_info->digest);
  FinalizeHash(hmac_info->hash_info);
  SetStringInfo(hmac_info->digest,GetHashDigest(hmac_info->hash_info));
}

/*
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%  GetHMACDigest() returns the hmac digest.
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%  The format of the GetHMACDigest method is:
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%      const StringInfo *GetHMACDigest(const hmacInfo *hmac_info)
%
%  A description of each parameter follows:
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%    o hmac_info: The hmac info.
%
*/
WizardExport const StringInfo *GetHMACDigest(const HMACInfo *hmac_info)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  WizardAssert(MACDomain,hmac_info != (HMACInfo *) NULL);
  WizardAssert(MACDomain,hmac_info->signature == WizardSignature);
  return(hmac_info->digest);
}

/*
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%  GetHMACDigestsize() returns the HMAC digest size.
%
%  The format of the GetHMACDigestsize method is:
%
%      unsigned int *GetHMACDigestsize(const HMACInfo *hmac_info)
%
%  A description of each parameter follows:
%
%    o hmac_info: The hmac info.
%
*/
WizardExport size_t GetHMACDigestsize(const HMACInfo *hmac_info)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  WizardAssert(CipherDomain,hmac_info != (HMACInfo *) NULL);
  WizardAssert(CipherDomain,hmac_info->signature == WizardSignature);
  return(GetHashDigestsize(hmac_info->hash_info));
}

/*
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%  IntializeHMAC() intializes the HMAC digest.
%
%  The format of the DestroyHMACInfo method is:
%
%      void InitializeHMACInfo(HMACInfo *hmac_info,const StringInfo *key)
%
%  A description of each parameter follows:
%
%    o hmac_info: The message authentication info.
%
%    o key: The key.
%
*/
WizardExport void InitializeHMAC(HMACInfo *hmac_info,const StringInfo *key)
{
  register size_t
    i;

  unsigned char
    *datum;

  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  (void) ResetStringInfo(hmac_info->initial_nonce);
  if (GetStringInfoLength(key) <= GetStringInfoLength(hmac_info->initial_nonce))
    SetStringInfo(hmac_info->initial_nonce,key);
  else
    {
      InitializeHash(hmac_info->hash_info);
      UpdateHash(hmac_info->hash_info,key);
      FinalizeHash(hmac_info->hash_info);
      SetStringInfo(hmac_info->initial_nonce,GetHashDigest(
        hmac_info->hash_info));
    }
  SetStringInfo(hmac_info->final_nonce,hmac_info->initial_nonce);
  datum=GetStringInfoDatum(hmac_info->initial_nonce);
  for (i=0; i < GetStringInfoLength(hmac_info->initial_nonce); i++)
    datum[i]^=0x36;
  datum=GetStringInfoDatum(hmac_info->final_nonce);
  for (i=0; i < GetStringInfoLength(hmac_info->final_nonce); i++)
    datum[i]^=0x5c;
  ResetHMAC(hmac_info);
}

/*
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%  ResetHMAC() resets the HMAC message digest computation.
%
%  The format of the ResetHMAC method is:
%
%      ResetHMAC(HMACInfo *hmac_info)
%
%  A description of each parameter follows:
%
%    o hmac_info: The address of a structure of type HMACInfo.
%
*/
WizardExport void ResetHMAC(HMACInfo *hmac_info)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  InitializeHash(hmac_info->hash_info);
  UpdateHash(hmac_info->hash_info,hmac_info->initial_nonce);
}

/*
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%  UpdateHMAC() updates the HMAC message digest.
%
%  The format of the UpdateHMAC method is:
%
%      UpdateHMAC(HMACInfo *hmac_info,const StringInfo *message)
%
%  A description of each parameter follows:
%
%    o hmac_info: The address of a structure of type HMACInfo.
%
%    o message: The message
%
*/
WizardExport void UpdateHMAC(HMACInfo *hmac_info,const StringInfo *message)
{
  (void) LogWizardEvent(TraceEvent,GetWizardModule(),"...");
  assert(hmac_info != (HMACInfo *) NULL);
  assert(hmac_info->signature == WizardSignature);
  UpdateHash(hmac_info->hash_info,message);
}