OSX/libsecurity_apple_csp/lib/castContext.h

   1 /*
   2  * Copyright (c) 2000-2001,2011,2013-2014 Apple Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /*
  20  * castContext.h - glue between BlockCrytpor and ssleay CAST-128 (CAST5)
  21  *                               implementation
  22  *
  23  *
  24  * Here's what RFC 2144 has to say about CAST128 and CAST5 nomenclature:
  25  *
  26  *    In order to avoid confusion when variable keysize operation is
  27  *    used, the name CAST-128 is to be considered synonymous with the
  28  *    name CAST5; this allows a keysize to be appended without ambiguity.
  29  *    Thus, for example, CAST-128 with a 40-bit key is to be referred to
  30  *    as CAST5-40; where a 128-bit key is explicitly intended, the
  31  *    name CAST5-128 should be used.
  32  *
  33  * This module implements a variable key length, from 40 bits to 128 bits,
  34  * and can thus be said to implement both CAST-128 and CAST5.
  35  */
  36
  37 #ifndef _CAST_CONTEXT_H_
  38 #define _CAST_CONTEXT_H_
  39
  40 #include "AppleCSPContext.h"
  41 #include "BlockCryptor.h"
  42 #include <CommonCrypto/CommonCryptor.h>
  43 #include <CommonCrypto/CommonCryptorSPI.h>
  44
  45 class CastContext : public BlockCryptor {
  46 public:
  47         CastContext(AppleCSPSession &session);
  48         virtual ~CastContext();
  49
  50         // called by CSPFullPluginSession
  51         void init(const Context &context, bool encoding = true);
  52
  53         // As an optimization, we allow reuse of a modified context.
  54         // The main thing we avoid is a redundant key scheduling. We
  55         // save the current raw keys bits in mRawKey and compare on
  56         // re-init.
  57         bool changed(const Context &context)     { return true; }
  58
  59         // called by BlockCryptor
  60         void encryptBlock(
  61                 const void              *plainText,             // length implied (one block)
  62                 size_t                  plainTextLen,
  63                 void                    *cipherText,
  64                 size_t                  &cipherTextLen, // in/out, throws on overflow
  65                 bool                    final);
  66         void decryptBlock(
  67                 const void              *cipherText,    // length implied (one cipher block)
  68                 size_t                  cipherTextLen,
  69                 void                    *plainText,
  70                 size_t                  &plainTextLen,  // in/out, throws on overflow
  71                 bool                    final);
  72
  73 private:
  74         void deleteKey();
  75
  76         /* scheduled key */
  77     CCCryptorRef        mCastKey;
  78
  79         bool                            mInitFlag;                      // for easy reuse
  80
  81         /*
  82          * Raw key bits saved here and checked on re-init to avoid
  83          * extra key schedule
  84          */
  85         uint8                           mRawKey[kCCKeySizeMaxCAST];
  86         uint32                          mRawKeySize;
  87
  88
  89 };      /* CastContext */
  90
  91 #endif //_CAST_CONTEXT_H_