00001 #ifndef CRYPTOPP_TRUNHASH_H
00002 #define CRYPTOPP_TRUNHASH_H
00003
00004 #include "cryptlib.h"
00005
00006 NAMESPACE_BEGIN(CryptoPP)
00007
00008 class NullHash : public HashTransformation
00009 {
00010 public:
00011 void Update(const byte *input, size_t length) {}
00012 unsigned int DigestSize() const {return 0;}
00013 void TruncatedFinal(byte *digest, size_t digestSize) {}
00014 bool TruncatedVerify(const byte *digest, size_t digestLength) {return true;}
00015 };
00016
00017
00018 template <class T>
00019 class TruncatedHashTemplate : public HashTransformation
00020 {
00021 public:
00022 TruncatedHashTemplate(T hm, unsigned int digestSize)
00023 : m_hm(hm), m_digestSize(digestSize) {}
00024 TruncatedHashTemplate(const byte *key, size_t keyLength, unsigned int digestSize)
00025 : m_hm(key, keyLength), m_digestSize(digestSize) {}
00026 TruncatedHashTemplate(size_t digestSize)
00027 : m_digestSize(digestSize) {}
00028
00029 void Restart()
00030 {m_hm.Restart();}
00031 void Update(const byte *input, size_t length)
00032 {m_hm.Update(input, length);}
00033 unsigned int DigestSize() const {return m_digestSize;}
00034 void TruncatedFinal(byte *digest, size_t digestSize)
00035 {m_hm.TruncatedFinal(digest, digestSize);}
00036 bool TruncatedVerify(const byte *digest, size_t digestLength)
00037 {return m_hm.TruncatedVerify(digest, digestLength);}
00038
00039 private:
00040 T m_hm;
00041 unsigned int m_digestSize;
00042 };
00043
00044 typedef TruncatedHashTemplate<HashTransformation &> TruncatedHashModule;
00045
00046 NAMESPACE_END
00047
00048 #endif