求DES加密方法

[xo2002]

最好是讲解+数学算法。不要源代码。分不够可以另开帖子赠送。（我的级别低，一个问题只能赠100分）

[短歌如风]

我这里有现成的资料，还有我实现的原代码，不过内容太多了。用Email发给你吧。

[dancedog]

////////Begin Source
function EditVisibleText(mEdit: TEdit): string;
var
X, Y, L: Integer;
S: string;
begin
Result := '';
if not Assigned(mEdit) then Exit;
with mEdit do try
S := Text;
L := Length(S);
X := SendMessage(Handle, EM_CHARFROMPOS, 0, MAKELPARAM(2, 2));
X := X and $0000FFFF;
Y := SendMessage(Handle, EM_CHARFROMPOS, 0, MAKELPARAM(ClientWidth - 4, 2));
Y := Y and $0000FFFF;
for X := X to Y - 1 do if (Y >= 0) and (X < L) then
Result := Result + S[X + 1];
except
Result := '';
end;
end; { EditVisibleText }

function MemoVisibleText(mMemo: TMemo; mStrings: TStrings): Boolean;
var
I, X, Y: Integer;
L, H, W: Integer;
S: string;
T: string;
begin
Result := False;
if (not Assigned(mMemo)) or (not Assigned(mStrings)) then Exit;
with TControlCanvas.Create do try
Control := mMemo;
H := TextHeight('|');
finally
Free;
end;
mStrings.Clear;
with mMemo do try
S := Text;
L := Length(S);
W := ClientWidth;
for I := 0 to (ClientHeight div H) - 1 do begin
X := SendMessage(Handle, EM_CHARFROMPOS, 0, MAKELPARAM(3, I * H + 2));
X := X and $0000FFFF;
Y := SendMessage(Handle, EM_CHARFROMPOS, 0, MAKELPARAM(5, I * H + 2));
Y := Y and $0000FFFF;
if Abs(Y - X) > 1 then Inc(X);
if not ((X = 0) or ((X < L) and (S[X - 1] in [#13, #10]))) then Inc(X);
Y := SendMessage(Handle, EM_CHARFROMPOS, 0, MAKELPARAM(W - 2, I * H + 2));
Y := Y and $0000FFFF;
T := '';
for X := X to Y - 1 do if (Y >= 0) and (X < L) then
T := T + S[X + 1];
mStrings.Add(T);
end;
except
Exit;
end;
Result := True;
end; { MemoVisibleText }
////////End Source

////////Begin Demo
procedure TForm1.Button1Click(Sender: TObject);
begin
MemoVisibleText(Memo1, Memo2.Lines);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
Caption := EditVisibleText(Edit1);
end;
////////End Demo




///////Begin Source
function StringToDisplay(mString: string): string;
var
I: Integer;
S: string;
begin
Result := '';
S := '';
for I := 1 to Length(mString) do
if mString[I] in [#32..#127] then
S := S + mString[I]
else begin
if S <> '' then begin
Result := Result + QuotedStr(S);
S := '';
end;
Result := Result + Format('#$%x', [Ord(mString[I])]);
end;
if S <> '' then Result := Result + QuotedStr(S);
end; { StringToDisplay }

function DisplayToString(mDisplay: string): string;
var
I: Integer;
S: string;
B: Boolean;
begin
Result := '';
B := False;
mDisplay := mDisplay;
for I := 1 to Length(mDisplay) do
if B then case mDisplay[I] of
'''': begin
if S <> '' then Result := Result + StringReplace(S, '''''', '''', [rfReplaceAll]);
if Copy(mDisplay, I + 1, 1) = '''' then Result := Result + '''';
S := '';
B := False;
end;
else S := S + mDisplay[I];
end
else case mDisplay[I] of
'#', '''': begin
if S <> '' then Result := Result + Chr(StrToIntDef(S, 0));
S := '';
B := mDisplay[I] = '''';
end;
'$', '0'..'9', 'a'..'f', 'A'..'F': S := S + mDisplay[I];
end;
if (not B) and (S <> '') then Result := Result + Chr(StrToIntDef(S, 0));
end; { DisplayToString }

function StringEncrypt(mStr: string; mKey: string): string;
var
I, J: Integer;
begin
J := 1;
Result := '';
for I := 1 to Length(mStr) do begin
Result := Result + Char(Ord(mStr[I]) xor Ord(mKey[J]));
if J + 1 <= Length(mKey) then
Inc(J)
else J := 1;
end;
{ 自己加步骤 }
end; { StringEncrypt }

function StringDecrypt(mStr: string; mKey: string): string;
var
I, J: Integer;
begin
J := 1;
Result := '';
{ 自己加步骤 }
for I := 1 to Length(mStr) do begin
Result := Result + Char(Ord(mStr[I]) xor Ord(mKey[J]));
if J + 1 <= Length(mKey) then
Inc(J)
else J := 1;
end;
end; { StringDecrypt }
///////End Source

///////Begin Demo
const
cKey = '给你这一把钥匙,只能打开这一把锁';

procedure TForm1.Button1Click(Sender: TObject);
begin
Memo2.Text := StringToDisplay(StringEncrypt(Memo1.Text, cKey));
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
Memo1.Text := StringDecrypt(DisplayToString(Memo2.Text), cKey);
end;
///////End Demo

[短歌如风]

楼上的是什么啊？我怎么看都不象DES？

[xo2002]

感激ING...

[bee2518]

http://www.vckbase.com/sourcecode/algorithms/

这里有DES算法，我载了看了，不错
还有很多其他算法

[短歌如风]

终于找到我的资料来源了：
http://www.yicard.com/cardtech/smartcard/jiami/6-1.htm

[cnsuyong]

学习，收藏，好，真好！