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