untcrypt.pas

1、通过串口连接手机或短信终端发送短信； 2、内置Access数据库

unit UntCrypt;

interface

uses StrUtils, SysUtils;

function CryptStr(const s:string; ntype: integer):string;
//第一种加解密方式，ntype为0表示加密，1表示解密
function CryptStr2(const s:string; ntype:integer):string;
//第二种加解密方式，且解密时能判断是否加过密
//本系统里已用该过程，过程内容需根据收发双方都了解的算法定制，不然最终接收者（手机用户）看不懂密文
function CryptStr3(const s:string; ntype:integer):string;
//第三种加解密方式

function StrTosAsc(const s:string; nUnitLen:integer):string;
//字符串转换成ASCII码，每个字符需要转换成nUnitLen位，不够的前面补0
function sAscToStr(const s:string; nUnitLen:integer):string;
//ASCII码串转换成源字符串，每个字符的ASCII码有nUnitLen位，

implementation

function StrTosAsc(const s:string; nUnitLen:integer):string;
var
  i,j,n:integer;
  sTmp:string;
begin
  Result := '';
  for i:=1 to Length(s) do
  begin
    sTmp := IntToStr(Ord(s[i]));
    n := Length(sTmp);
    if n>nUnitLen then sTmp := RightStr(sTmp,nUnitLen)
    else for j:=n+1 to nUnitLen do sTmp := '0' + sTmp;
    Result := Result + sTmp;
  end;
end;

function sAscToStr(const s:string; nUnitLen:integer):string;
var
  sTmp,TmpStr:string;
begin
  Result := '';
  TmpStr := s;
  sTmp := LeftStr(TmpStr, nUnitLen);
  TmpStr := RightStr(TmpStr,Length(TmpStr)-Length(sTmp));
  While Length(sTmp)>0 do
  begin
    Result := Result + Chr(byte(StrToInt(sTmp)));
    sTmp := LeftStr(TmpStr, nUnitLen);
    TmpStr := RightStr(TmpStr,Length(TmpStr)-Length(sTmp));
  end;
end;

function CryptStr(const s:string; ntype: integer):string;
var
  i: integer;
  fkey: integer;
begin
  result:='';
  if Length(s)=0 then exit;
  case ntype of
    0:         //setpass;
       begin
         randomize;
         fkey := 65 + random(26);
         for i:=1 to length(s) do
           result := result+chr( ord(s[i]) xor i xor fkey);
         result := result + char(fkey);
       end;
    else         //getpass
       begin
         fkey := ord(s[length(s)]);
         for i:=1 to length(s) - 1 do
           result := result+chr( ord(s[i]) xor i xor fkey);
       end;
  end;
end;

function CryptStr2(const s:string; ntype:integer):string;
var
  i: integer;
  fkey: integer;
begin
//  Result := s;
  result:='';
  if Length(s)=0 then exit;
  case ntype of
    0:         //setpass;
       begin
         randomize;
         fkey := 65 + random(26);
         Result := char($ff);
         for i:=1 to length(s) do
           result := result+chr( ord(s[i]) xor i xor fkey);
         result := result + char(fkey);
       end;
    else         //getpass
       begin
         if (s[1]=char($ff))and(s[length(s)]>='A')and(s[length(s)]<='Z') then
         begin
           fkey := ord(s[length(s)]);
           for i:=1 to length(s) - 2 do
             result := result+chr( ord(s[i+1]) xor i xor fkey);
         end else Result := s;
       end;
  end;
end;

function CryptStr3(const s:string; ntype:integer):string;
var
  TmpStr,sTmp:string;
  i,j,n:integer;
begin
  Result := '';
  case ntype of
    0:   begin  //加密
           for i:=1 to Length(s) do
           begin
             if (i mod 2 = 0) then sTmp := IntToStr(Ord(s[i])-2)
             else sTmp := IntToStr(Ord(s[i])-1);
             n := Length(sTmp);
             if n>3 then sTmp := RightStr(sTmp,3)
             else for j:=n+1 to 3 do sTmp := '0' + sTmp;
             Result := Result + sTmp;
           end;
         end;
    else begin  //解密
           TmpStr := s;
           sTmp := LeftStr(TmpStr, 3);
           TmpStr := RightStr(TmpStr,Length(TmpStr)-Length(sTmp));
           i := 1;
           While Length(sTmp)>0 do
           begin
             if (i mod 2 = 0) then Result := Result + Chr(byte(StrToInt(sTmp)+2))
             else Result := Result + Chr(byte(StrToInt(sTmp)+1));
             sTmp := LeftStr(TmpStr, 3);
             TmpStr := RightStr(TmpStr,Length(TmpStr)-Length(sTmp));
             Inc(i);
           end;
         end;
  end;//of "case ..."
end;

end.