unit Base64Unit;

unit Base64Unit;

unit Base64Unit;
//Download by http://www.codefans.net interface

uses
Classes, SysUtils;

function Base64Encryption(const Input:String):String;
function Base64Decryption(const Input:String):String;

implementation

const
BASE64Table : array[0..63] of Char = ( #65,  #66,  #67,  #68,  #69,
#70,  #71,  #72,  #73,  #74,  #75,  #76,  #77,  #78,  #79,
#80,  #81,  #82,  #83,  #84,  #85,  #86,  #87,  #88,  #89,
#90,  #97,  #98,  #99, #100, #101, #102, #103, #104, #105,
#106, #107, #108, #109, #110, #111, #112, #113, #114, #115,
#116, #117, #118, #119, #120, #121, #122,  #48,  #49,  #50,
#51,  #52,  #53,  #54,  #55,  #56,  #57,  #43,  #47);

const
BASE64DeTable : array[43..122] of Byte = ($3E, $7F, $7F, $7F, $3F, $34,
$35, $36, $37, $38, $39, $3A, $3B, $3C, $3D, $7F, $7F, $7F, $7F,
$7F, $7F, $7F, $00, $01, $02, $03, $04, $05, $06, $07, $08, $09,
$0A, $0B, $0C, $0D, $0E, $0F, $10, $11, $12, $13, $14, $15, $16,
$17, $18, $19, $7F, $7F, $7F, $7F, $7F, $7F, $1A, $1B, $1C, $1D,
$1E, $1F, $20, $21, $22, $23, $24, $25, $26, $27, $28, $29, $2A,
$2B, $2C, $2D, $2E, $2F, $30, $31, $32, $33);

//BASE64算法流加密
procedure EncodeStream(InStream, OutStream : TStream);
var
I, O, Count : Integer;
InBuf  : array[1..45] of Byte;
OutBuf : array[0..62] of Char;
Temp : Byte;
begin
FillChar(OutBuf, Sizeof(OutBuf), #0);

repeat
Count := InStream.Read(InBuf, SizeOf(InBuf));
if Count = 0 then Break;
I := 1;
O := 0;
while I <= (Count-2) do begin
{ 编码第一个字节 }
Temp := (InBuf[I] shr 2);
OutBuf[O] := Char(BASE64Table[Temp and $3F]);

{ 编码第二个字节 }
Temp := (InBuf[I] shl 4) or (InBuf[I+1] shr 4);
OutBuf[O+1] := Char(BASE64Table[Temp and $3F]);

{ 编码第三个字节 }
Temp := (InBuf[I+1] shl 2) or (InBuf[I+2] shr 6);
OutBuf[O+2] := Char(BASE64Table[Temp and $3F]);

{ 编码第四个字节 }
Temp := (InBuf[I+2] and $3F);
OutBuf[O+3] := Char(BASE64Table[Temp]);

Inc(I, 3);
Inc(O, 4);
end;

if (I <= Count) then begin
Temp := (InBuf[I] shr 2);
OutBuf[O] := Char(BASE64Table[Temp and $3F]);

{ 一个奇数字节 }
if I = Count then begin
Temp := (InBuf[I] shl 4) and $30;
OutBuf[O+1] := Char(BASE64Table[Temp and $3F]);
OutBuf[O+2] := '=';
{ 两个基数字节 }
end else begin
Temp := ((InBuf[I] shl 4) and $30) or ((InBuf[I+1] shr 4) and $0F);
OutBuf[O+1] := Char(BASE64Table[Temp and $3F]);
Temp := (InBuf[I+1] shl 2) and $3C;
OutBuf[O+2] := Char(BASE64Table[Temp and $3F]);
end;
{ 增加= }
OutBuf[O+3] := '=';
Inc(O, 4);
end;

{ 把编码好的块写到流中 }
OutStream.Write(OutBuf, O);
until Count < SizeOf(InBuf);
end;

//BASE64算法流解密
procedure DecodeStream(InStream, OutStream : TStream);
var
I, O, Count, c1, c2, c3 : Byte;
InBuf  : array[0..87] of Byte;
OutBuf : array[0..65] of Byte;
begin
repeat
O := 0;
I := 0;

Count := InStream.Read(InBuf, SizeOf(InBuf));
if (Count = 0) then
Break;

{ 解密的数据输入到流中 }
while I < Count do begin
if (InBuf[I] < 43) or (InBuf[I] > 122) or
(InBuf[I+1] < 43) or (InBuf[I+1] > 122) or
(InBuf[I+2] < 43) or (InBuf[I+2] > 122) or
(InBuf[I+3] < 43) or (InBuf[I+3] > 122) then
raise Exception.Create('Invalid Base64 Character');

c1 := BASE64DeTable[InBuf[I]];
c2 := BASE64DeTable[InBuf[I+1]];
c3 := BASE64DeTable[InBuf[I+2]];
OutBuf[O] := ((c1 shl 2) or (c2 shr 4));
Inc(O);
if Char(InBuf[I+2]) <> '=' then begin
OutBuf[O] := ((c2 shl 4) or (c3 shr 2));
Inc(O);
if Char(InBuf[I+3]) <> '=' then begin
OutBuf[O] := ((c3 shl 6) or BASE64DeTable[InBuf[I+3]]);
Inc(O);
end;
end;
Inc(I, 4);
end;
OutStream.Write(OutBuf, O);
until Count < SizeOf(InBuf);
end;

//BASE64算法字符串加密
function Base64Encryption(const Input:String):String;
var
InStream  : TMemoryStream;
OutStream : TMemoryStream;
begin
InStream := TMemoryStream.Create;
OutStream := TMemoryStream.Create;

InStream.Write(Input[1], Length(Input));
InStream.Position := 0;
EncodeStream(InStream, OutStream);
OutStream.Position := 0;
SetLength(Result, OutStream.Size);
OutStream.Read(Result[1], OutStream.Size);

InStream.Free;
OutStream.Free;
end;

//BASE64算法字符串解密
function Base64Decryption(const Input:String):String;
var
InStream  : TMemoryStream;
OutStream : TMemoryStream;
begin
InStream := TMemoryStream.Create;
OutStream := TMemoryStream.Create;

InStream.Write(Input[1], Length(Input));
InStream.Position := 0;
DecodeStream(InStream, OutStream);
OutStream.Position := 0;
SetLength(Result, OutStream.Size);
OutStream.Read(Result[1], OutStream.Size);

InStream.Free;
OutStream.Free;
end;

end.

　　

procedure TForm1.Button1Click(Sender: TObject);
begin
Edit2.Text:=BASE64Encryption(Edit1.Text);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
Edit4.Text:=BASE64Decryption(Edit3.Text);
end;