寻求单文件加密实现,可以处理Delphi和C中的整个文件en / de-cryp

C已经在生产系统中使用了五年.

我添加了轻微测试的Delphi代码. Pascal是一个逐行端口,带有unsigned char到Byte.我只运行Pascal在Free Pascal与Delphi选项打开,而不是Delphi本身. C和Pascal都有简单的文件处理器.

加密密文给出了原来的明文.

迄今没有报告错误.希望这能解决你的问题.

rc4.h

#ifndef RC4_H
#define RC4_H

/*
 * rc4.h -- Declarations for a simple rc4 encryption/decryption implementation.
 * The code was inspired by libtomcrypt.  See www.libtomcrypt.org.
 */
typedef struct TRC4State_s {
  int x,y;
  unsigned char buf[256];
} TRC4State;

/* rc4.c */
void init_rc4(TRC4State *state);
void setup_rc4(TRC4State *state,char *key,int keylen);
unsigned endecrypt_rc4(unsigned char *buf,unsigned len,TRC4State *state);

#endif

rc4.c

void init_rc4(TRC4State *state)
{
  int x;
  state->x = state->y = 0;
  for (x = 0; x < 256; x++)
    state->buf[x] = x;
}

void setup_rc4(TRC4State *state,int keylen)
{
  unsigned tmp;
  int x,y;

  // use only first 256 characters of key 
  if (keylen > 256) 
    keylen = 256;

  for (x = y = 0; x < 256; x++) {
    y = (y + state->buf[x] + key[x % keylen]) & 255;
    tmp = state->buf[x]; 
    state->buf[x] = state->buf[y]; 
    state->buf[y] = tmp;
  }
  state->x = 255;
  state->y = y;
}

unsigned endecrypt_rc4(unsigned char *buf,TRC4State *state)
{
  int x,y; 
  unsigned char *s,tmp;
  unsigned n;

  x = state->x;
  y = state->y;
  s = state->buf;
  n = len;
  while (n--) {
    x = (x + 1) & 255;
    y = (y + s[x]) & 255;
    tmp = s[x]; s[x] = s[y]; s[y] = tmp;
    tmp = (s[x] + s[y]) & 255;
    *buf++ ^= s[tmp];
  }
  state->x = x;
  state->y = y;
  return len;
}

int endecrypt_file(FILE *f_in,FILE *f_out,char *key)
{
  TRC4State state[1];
  unsigned char buf[4096];
  size_t n_read,n_written;

  init_rc4(state);
  setup_rc4(state,key,strlen(key));
  do {
    n_read = fread(buf,1,sizeof buf,f_in);
    endecrypt_rc4(buf,n_read,state);
    n_written = fwrite(buf,f_out);
  } while (n_read == sizeof buf && n_written == n_read);
  return (n_written == n_read) ? 0 : 1;
}

int endecrypt_file_at(char *f_in_name,char *f_out_name,char *key)
{
  int rtn;

  FILE *f_in = fopen(f_in_name,"rb");
  if (!f_in) {
    return 1;
  }
  FILE *f_out = fopen(f_out_name,"wb");
  if (!f_out) {
    close(f_in);
    return 2;
  }
  rtn = endecrypt_file(f_in,f_out,key);
  fclose(f_in);
  fclose(f_out);
  return rtn;
}

#ifdef TEST

// Simple test.
int main(void)
{
  char *key = "This is the key!";

  endecrypt_file_at("rc4.pas","rc4-scrambled.c",key);
  endecrypt_file_at("rc4-scrambled.c","rc4-unscrambled.c",key);
  return 0;
}
#endif

这里是轻微测试的帕斯卡.我可以在C中加扰源代码,并用Pascal实现解密它.

type
  RC4State = record
    x,y : Integer;
    buf : array[0..255] of Byte;
  end;

  KeyString = String[255];

procedure initRC4(var state : RC4State);
var
  x : Integer;
begin
  state.x := 0;
  state.y := 0;
  for x := 0 to 255 do
    state.buf[x] := Byte(x);
end;

procedure setupRC4(var state : RC4State; var key : KeyString);
var
  tmp : Byte;
  x,y : Integer;
begin
  y := 0;
  for x := 0 to 255 do begin
    y := (y + state.buf[x] + Integer(key[1 + x mod Length(key)])) and 255;
    tmp := state.buf[x];
    state.buf[x] := state.buf[y];
    state.buf[y] := tmp;
  end;
  state.x := 255;
  state.y := y;
end;

procedure endecryptRC4(var buf : array of Byte; len : Integer; var state : RC4State);
var
  x,y,i : Integer;
  tmp : Byte;
begin
  x := state.x;
  y := state.y;
  for i := 0 to len - 1 do begin
    x := (x + 1) and 255;
    y := (y + state.buf[x]) and 255;
    tmp := state.buf[x];
    state.buf[x] := state.buf[y];
    state.buf[y] := tmp;
    tmp := (state.buf[x] + state.buf[y]) and 255;
    buf[i] := buf[i] xor state.buf[tmp]
  end;
  state.x := x;
  state.y := y;
end;

procedure endecryptFile(var fIn,fOut : File; key : KeyString);
var
  nRead,nWritten : Longword;
  buf : array[0..4095] of Byte;
  state : RC4State;
begin
  initRC4(state);
  setupRC4(state,key);
  repeat
    BlockRead(fIN,buf,sizeof(buf),nRead);
    endecryptRC4(buf,nRead,state);
    BlockWrite(fOut,nWritten);
  until (nRead <> sizeof(buf)) or (nRead <> nWritten);
end;

procedure endecryptFileAt(fInName,fOutName,key : String);
var
  fIn,fOut : File;
begin
  Assign(fIn,fInName);
  Assign(fOut,fOutName);
  Reset(fIn,1);
  Rewrite(fOut,1);
  endecryptFile(fIn,fOut,key);
  Close(fIn);
  Close(fOut);
end;

{$IFDEF TEST}
// Very small test.
const
  key = 'This is the key!';
begin
  endecryptFileAt('rc4.pas','rc4-scrambled.pas',key);
  endecryptFileAt('rc4-scrambled.pas','rc4-unscrambled.pas',key);
end.
{$ENDIF}