ztest_hash.txt

当前常用的500多种加密解密算法

How do I use a hash function? 
Moderator: weidai (inherited from parent)  
(excerpt from a message posted to the Crypto++ mailing list)

SHA (or any other hash module) is used like this:

   #include "sha.h"    // or "md5.h" for MD5, etc
   .
   .
   .
   SHA().CalculateDigest(pbOutputBuffer, pbData, nDataLen);
     // pbOutputBuffer must be SHA::DIGESTSIZE bytes in length
 
or, if you have data that's made up of multiple pieces:
 
   #include "sha.h"
   .
   .
   .
   SHA hash;
   hash.Update(pbData1, nData1Len);
   hash.Update(pbData2, nData2Len);
   hash.Update(pbData3, nData3Len);
   hash.Final(pbOutputBuffer);

See also the definition of HashModule::CalculateDigest() in
cryptlib.h.
2001-Jan-15 3:04pm faq-o-matic 
Here is an example of hashing using filters.  Note that I encode the output as hex and that is why the output buffer must be 2x the size of the MD5 digest.
==============================================
#include <cryptopp/md5.h>
#include <cryptopp/filters.h>
#include <cryptopp/files.h>
#include <cryptopp/hex.h>

#include <iostream>

using namespace CryptoPP;
using namespace std;

int main( int argc, char** argv )
{
  MD5 hash;
  byte buffer[2 * MD5::DIGESTSIZE]; //output size of the buffer
 
  FileSource f(argv[1], true,
                new HashFilter(hash,
                new HexEncoder(new ArraySink(buffer,2 * MD5::DIGESTSIZE))));
  cout << string((const char*)buffer,2 * MD5::DIGESTSIZE)  << endl;
  return 0;
}
2002-Mar-07 1:08am boykin 
[Append to This Answer] 
2002-Mar-07 1:08am  
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