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-rw-r--r--CryptoPP/trunhash.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/CryptoPP/trunhash.h b/CryptoPP/trunhash.h
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+++ b/CryptoPP/trunhash.h
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+#ifndef CRYPTOPP_TRUNHASH_H
+#define CRYPTOPP_TRUNHASH_H
+
+#include "cryptlib.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+class NullHash : public HashTransformation
+{
+public:
+ void Update(const byte *input, size_t length) {}
+ unsigned int DigestSize() const {return 0;}
+ void TruncatedFinal(byte *digest, size_t digestSize) {}
+ bool TruncatedVerify(const byte *digest, size_t digestLength) {return true;}
+};
+
+//! construct new HashModule with smaller DigestSize() from existing one
+template <class T>
+class TruncatedHashTemplate : public HashTransformation
+{
+public:
+ TruncatedHashTemplate(T hm, unsigned int digestSize)
+ : m_hm(hm), m_digestSize(digestSize) {}
+ TruncatedHashTemplate(const byte *key, size_t keyLength, unsigned int digestSize)
+ : m_hm(key, keyLength), m_digestSize(digestSize) {}
+ TruncatedHashTemplate(size_t digestSize)
+ : m_digestSize(digestSize) {}
+
+ void Restart()
+ {m_hm.Restart();}
+ void Update(const byte *input, size_t length)
+ {m_hm.Update(input, length);}
+ unsigned int DigestSize() const {return m_digestSize;}
+ void TruncatedFinal(byte *digest, size_t digestSize)
+ {m_hm.TruncatedFinal(digest, digestSize);}
+ bool TruncatedVerify(const byte *digest, size_t digestLength)
+ {return m_hm.TruncatedVerify(digest, digestLength);}
+
+private:
+ T m_hm;
+ unsigned int m_digestSize;
+};
+
+typedef TruncatedHashTemplate<HashTransformation &> TruncatedHashModule;
+
+NAMESPACE_END
+
+#endif