shmac.h

伯克利做的SFTP安全文件传输协议

// shmac.h
// Scott McPeak's transmogrify of Wei Dai's HMAC, which is itself an
//   implementation of RFC 2104 HMAC; validation vectors for MD5-HMAC
//   and SHA-HMAC can be found in RFC 2202
// hmac.h - written and placed in the public domain by Wei Dai

#ifndef HMAC_H
#define HMAC_H

#include "cryptlib.h"
#include "misc.h"

// HMAC(K, text) = H(K XOR opad, H(K XOR ipad, text))

class HMAC : public MessageAuthenticationCode
{
public:
        // SM: g++ 2.7.2 needs to see KEYLENGTH before it is used
	enum {KEYLENGTH=16,
              // SM: we don't need these, and they are problematic
              // MAX_KEYLENGTH=T::DATASIZE, DIGESTSIZE=T::DIGESTSIZE, DATASIZE=T::DATASIZE
              };

	HMAC(HashModule &hash,
             const byte *userKey, unsigned int keylength=KEYLENGTH);
	void Update(const byte *input, unsigned int length);
	void Final(byte *mac);
	unsigned int DigestSize() const;
        unsigned int DataSize() const;

private:
	enum {IPAD=0x36, OPAD=0x5c};

	void Init();

	SecByteBlock k_ipad, k_opad;
	HashModule &hash;
};

#endif