include/wvdigest.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Tunnel Vision Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * MD5, SHA-1 and HMAC digest abstractions.
   6  */
   7 #ifndef __WVDIGEST_H
   8 #define __WVDIGEST_H
   9
  10 #include "wvencoder.h"
  11
  12 struct env_md_st;
  13 struct env_md_ctx_st;
  14 struct hmac_ctx_st;
  15
  16 /**
  17  * Superclass for all message digests.
  18  *
  19  * All message digest encoders have the following semantics:
  20  *
  21  *  - On encode() or flush(), data from the input buffer is
  22  *     consumed and a message digest function is applied to
  23  *     incrementally update the internal digest state.
  24  *     No output is ever generated.
  25  *  - On finish(), the message digest is finalized and its value
  26  *     is written to the output buffer.  Afterwards, no new data
  27  *     can be processed unless reset() is called.
  28  *  - On reset(), the current digest state is discarded allowing
  29  *     a new stream of data to be processed.
  30  *
  31  */
  32 class WvDigest : public WvEncoder
  33 {
  34 public:
  35     /** Returns the number of bytes in the message digest. */
  36     virtual size_t digestsize() const = 0;
  37 };
  38
  39
  40 /**
  41  * @internal
  42  * Base class for all digests constructed using the OpenSSL EVP API.
  43  */
  44 class WvEVPMDDigest : public WvDigest
  45 {
  46     friend class WvHMACDigest;
  47     const env_md_st *evpmd;
  48     env_md_ctx_st *evpctx;
  49     bool active;
  50
  51 public:
  52     virtual ~WvEVPMDDigest();
  53     virtual size_t digestsize() const;
  54
  55 protected:
  56     WvEVPMDDigest(const env_md_st *_evpmd);
  57     virtual bool _encode(WvBuf &inbuf, WvBuf &outbuf,
  58         bool flush); // consumes input
  59     virtual bool _finish(WvBuf &outbuf); // outputs digest
  60     virtual bool _reset(); // supported: resets digest value
  61
  62     const env_md_st *getevpmd()
  63         { return evpmd; }
  64
  65 private:
  66     void cleanup();
  67 };
  68
  69
  70 /**
  71  * MD5 Digest.
  72  * Has a digest length of 128 bits.
  73  */
  74 class WvMD5Digest : public WvEVPMDDigest
  75 {
  76 public:
  77     /** Creates an MD5 digest encoder. */
  78     WvMD5Digest();
  79     virtual ~WvMD5Digest() { }
  80 };
  81
  82
  83 /**
  84  * SHA-1 Digest.
  85  * Has a digest length of 160 bits.
  86  */
  87 class WvSHA1Digest : public WvEVPMDDigest
  88 {
  89 public:
  90     /** Creates an SHA1 digest encoder. */
  91     WvSHA1Digest();
  92     virtual ~WvSHA1Digest() { }
  93 };
  94
  95
  96 /**
  97  * HMAC Message Authentication Code.
  98  * Has a digest length that equals that of its underlying
  99  * message digest encoder.
 100  */
 101 class WvHMACDigest : public WvDigest
 102 {
 103     WvEVPMDDigest *digest;
 104     unsigned char *key;
 105     size_t keysize;
 106     hmac_ctx_st *hmacctx;
 107     bool active;
 108
 109 public:
 110     /**
 111      * Creates an HMAC digest encoder.
 112      *
 113      * "digest" is the message digest encoder to use as a
 114      *        hash function
 115      * "key" is the authentication key
 116      * "keysize" is the key size in bytes
 117      */
 118     WvHMACDigest(WvEVPMDDigest *_digest, const void *_key,
 119                  size_t _keysize);
 120     virtual ~WvHMACDigest();
 121     virtual size_t digestsize() const;
 122
 123 protected:
 124     virtual bool _encode(WvBuf &inbuf, WvBuf &outbuf,
 125         bool flush); // consumes input
 126     virtual bool _finish(WvBuf &outbuf); // outputs digest
 127     virtual bool _reset(); // supported: resets digest value
 128
 129 private:
 130     void cleanup();
 131 };
 132
 133
 134 /**
 135  * CRC32 checksum
 136  * Digest length of 4 bytes.
 137  */
 138 class WvCrc32Digest : public WvDigest
 139 {
 140     uint32_t crc;
 141
 142 public:
 143     WvCrc32Digest();
 144     virtual ~WvCrc32Digest() { }
 145
 146     virtual size_t digestsize() const;
 147     virtual bool _encode(WvBuf &inbuf, WvBuf &outbuf,
 148                          bool flush); // consumes input
 149     virtual bool _finish(WvBuf &outbuf); // outputs digest
 150     virtual bool _reset(); // supported: resets digest value
 151 };
 152
 153
 154 /**
 155  * Adler32 checksum
 156  * Digest length of 4 bytes.
 157  */
 158 class WvAdler32Digest : public WvDigest
 159 {
 160     uint32_t crc;
 161
 162 public:
 163     WvAdler32Digest();
 164     virtual ~WvAdler32Digest() { }
 165
 166     virtual size_t digestsize() const;
 167     virtual bool _encode(WvBuf &inbuf, WvBuf &outbuf,
 168                          bool flush); // consumes input
 169     virtual bool _finish(WvBuf &outbuf); // outputs digest
 170     virtual bool _reset(); // supported: resets digest value
 171 };
 172
 173 #endif // __WVDIGEST_H