求助把DELPHI加解密代码转换成C#的，可能类似BASE64

DELPHI代码如下：

const gamestr : array [0..127] of byte =
($4E, $3E, $54, $53, $56, $55, $4A, $6C, $77, $64, $63, $42, $4D, $46, $6A, $6E, $41, $4B, $62, $3F, $71, $78, $76, $79, $65, $47, $7A, $66, $4C, $50, $3D, $5F, $45, $52, $40, $5A, $5C, $61, $6D, $5D, $43, $68, $67, $6F, $57, $44, $3B, $51, $75, $58, $5B, $3C, $74, $6B, $70, $72, $5E, $60, $69, $49, $48, $4F, $59, $73, $2E, $33, $1E, $01, $13, $22, $10, $0B, $28, $2D, $20, $0D, $19, $3C, $3B, $06, $11, $1C, $0C, $00, $3D, $1D, $2F, $21, $03, $02, $05, $04, $2C, $31, $3E, $23, $32, $24, $27, $38, $1F, $39, $25, $12, $0A, $09, $18, $1B, $2A, $29, $3A, $0E, $35, $07, $26, $0F, $2B, $36, $14, $37, $3F, $34, $30, $16, $08, $15, $17, $1A); //密钥

function decode (inchar:pchar; len:integer ; outchar:pchar):integer; //解密
function encode (inchar:pchar; len:integer ; outchar:pchar):integer; //加密
function chartoascii(str:PChar;strlen:Integer):string;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function decode (inchar:pchar; len:integer ; outchar:pchar):integer; //解密
var
  a1, d1: byte;
  i, count, di, si :integer;
begin
  decode := len div 4 * 3 ; //返回长度。  
  i := 0;
  while i < len do
  begin
  d1 := byte (inchar[i] );
  if ( d1 = $3B ) or (d1 = $7A) then
  begin
  end;
  d1 := d1 and $0FF;
  d1 := gamestr [d1 + 05]; //d1 := byte ( gamestr [ 1 + d1 ] );
  byte (inchar [i] ) := d1; // 根据不同的gamestr数据定义选用不现的方法
  inc (i);
  end;
   
  di := 0 ;
  si := 0 ;   
  count := len div 4 ; //循环次数
  for i := 1 to count do
  begin
  a1 := ord ( inchar [di]); //解密数据 (取4个.转化3个)
  a1 := a1 shl 2 ;
  d1 := ord ( inchar [di + 1]);
  d1 := d1 shr 4 ;
  a1 := a1 or d1 ;
  outchar[si] := chr (a1);

  a1 := ord ( inchar [di + 1]);
  a1 := a1 shl 4 ;
  d1 := ord ( inchar [di + 2]);
  d1 := d1 shr 2 ;
  a1 := a1 or d1 ;
  outchar[si + 1] := chr (a1);
   
  a1 := ord ( inchar [di + 2]);
  a1 := a1 shl 6 ;
  d1 := ord ( inchar [di + 3]);
  a1 := a1 or d1 ;
  outchar[si + 2] := chr (a1);

  di := di + 4 ;
  si := si + 3 ;
  end;   
end;


function encode (inchar:pchar; len:integer ; outchar:pchar):integer; //加密
var
  a1, d1 :byte;
  i,count,di,si :integer;

begin
  encode := len div 3 * 4 ; //返回加密后数据长度
  di := 0 ;
  si := 0 ;
  count := len div 3; //定义循环次数
  for i := 1 to count do
  begin
  a1 := ord ( inchar [di]); //第一次转换 取3个 输出4个
  a1 := a1 shr 2 ;
  outchar [si] := chr (a1);

  a1 := ord (inchar[di]);
  a1 := a1 and 3 ;
  a1 := a1 shl 4 ;
  d1 := ord (inchar[di +1]);
  d1 := d1 shr 4 ;
  a1 := a1 or d1 ;
  outchar[si +1] := chr (a1) ;

  a1 := ord ( inchar[di + 1]) ;
  a1 := a1 and $0F ;
  a1 := a1 shl 2 ;
  d1 := ord ( inchar[di + 2]) ;
  d1 := d1 shr 6 ;
  a1 := a1 or d1 ;
  outchar[si + 2] := chr (a1);

  a1 := ord ( inchar[di + 2]) ;
  a1 := a1 and $3F;
  outchar[si + 3] := chr (a1) ;

  //第二次转换
  d1 := ord ( outchar [si]); //第 1 个
  d1 := gamestr [d1];
  outchar [si] := chr (d1);

  d1 := ord ( outchar [si + 1]); //第 2 个
  d1 := gamestr [d1];
  outchar [si + 1] := chr (d1);

  d1 := ord ( outchar [si + 2 ]); //第 3 个
  d1 := gamestr [d1];
  outchar [si + 2] := chr (d1);

  d1 := ord ( outchar [si + 3]); //第 4 个
  d1 := gamestr [d1];
  outchar [si + 3] := chr (d1);

  di := di + 3 ;
  si := si + 4 ;   
  end;
end;


下面是密码和明文
密文：UANNNNNNNNNBNNpNAEVN>A>XyNKe
密文16进制：05 10 00 00 00 00 00 00 00 00 00 0B 00 00 36 00 10 20 04 00 01 10 01 31 17 00 11 18

解密后16进制：15 00 00 00 00 00 00 00 0B 00 0D 80 42 01 00 05 00 71 5C 04 58

求大侠们赐教~

虽然学过pascal,但语句方面确实看不懂了

恩 有点代码要理解下~