weakkey.cpp

伯克利做的SFTP安全文件传输协议

//  $Archive:: /STP/SafeTP/weakkey.cpp                                $
//     $Date: 1999/07/14 13:16:47 $
// $Revision: 1.6 $
// Description: Makekeys main
// copyright SafeTP Development Group, Inc., 2000  Terms of use are as specified in license.txt

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "weakkey.h"
#include "cryputil.h"    // various utilities
#include "globrand.h"    // global random pool
#include "keyutils.h"
#include "nonport.h"

//--------------------------------------------------------------
static string formKeyName(char* keydirname, char* valuename) {
  // careful about overruns..
  xassert(strlen(keydirname) + strlen(valuename) + 3 /*slop*/ < 1024);

  char buf[1024];
  strcpy(buf, keydirname);
  char *p = buf + strlen(buf) - 1;
  if (*p != '\\' && *p != '/') { *(p+1) = '/'; *(p+2) = '\0'; }
  strcat(buf, valuename);
  string name(buf);
  return name;
  }
//--------------------------------------------------------------
int SetKeyStrength(KeyStrength ks, char* keydirname, bool forceProtected) {
  DataBlock val(2);
  *(val.getData()) = (char)ks;
  val.setDataLen(1);
  string temp = formKeyName(keydirname, "KeyStrength");
  return SaveKey(temp, val, forceProtected);
  }
//--------------------------------------------------------------
KeyStrength GetKeyStrength(char* keydirname, bool forceProtected) {
  DataBlock val(2);
  string temp = formKeyName(keydirname, "KeyStrength");
  int result = LoadKey(temp, val, forceProtected);
  if (!result) return KS_UNKNOWN;
  if (*(val.getData()) == (char)KS_WEAK) return KS_WEAK;
  return KS_STRONG;
  }
//--------------------------------------------------------------
int GenerateWeakKey(char const * const * ElGamalParams, char* keydirname) {

  addEntropy();

  ElGamalParameters params(ElGamalParams);
  GlobalRandomPool grp;
  ElGamalPrivateKey elg(params, grp.pool());

  // save private key
  DataBlock prvkey;
  elg.encode(prvkey);
  string temp = formKeyName(keydirname, "private.key");
  if (!SaveKey(temp, prvkey)) return false;

  // save public key
  DataBlock pubkey;
  elg.ElGamalPublicKey::encode(pubkey);
  string temp2 = formKeyName(keydirname, "public.key");
  if (!SaveKey(temp2, pubkey)) return false;

  // set time stamp
  SetKeyTimeStamp();

  // mark it as weak
  return SetKeyStrength(KS_WEAK, keydirname);
  }
//--------------------------------------------------------------
int SetKeyTimeStamp(char* keydirname, bool forceProtected) {
    // retrieve date
  int m, d, y;
  getCurrentDate(m, d, y);

  char datestr[40];
  sprintf(datestr,"%i/%i/%i", m, d, y);

  DataBlock stamp(datestr);
  string temp = formKeyName(keydirname, "timestamp");
  return SaveKey(temp, stamp, forceProtected);
  }
//--------------------------------------------------------------