字符串加密解密

type
TDynByteArray = array of byte;
const
SeedA = 5678; /// 常量，你可以修改
SeedB = 5432; /// 常量，你可以修改
/// 对数组加密
function Crypt(const s: TDynByteArray; Key: Word; const bEncrypt: boolean = true): TDynByteArray; overload;
var
i : integer;
begin
SetLength(Result, Length(s));
for i := Low(s) to High(s) do
begin
Result := s xor (key shr 8);
if bEncrypt then
Key := (Result + key) * SeedA + SeedB
else
Key := (s + Key) * SeedA + SeedB;
end;
end;
/// 字符串
function Crypt(const s: string; Key: Word; const bEncrypt: boolean = True): string; overload;
var
i : integer;
ps, pr : ^byte;
begin
SetLength(Result, Length(s));
ps := @s[1];
pr := @Result[1];
for i := 1 to length(s) do
begin
pr^ := ps^ xor (Key shr 8);
if bEncrypt then
Key := (pr^ + Key) * SeedA + SeedB
else
Key := (ps^ + Key) * SeedA + SeedB;
pr := pointer(integer(pr) + 1);
ps := pointer(integer(ps) + 1);
end
end;
/// 也可以对记录进行加密，只要把TResultData改成你的记录类型即可！！！！！！
function Crypt(const s: TResultData; Key: Word; const bEncrypt: boolean = True): TResultData; overload;
var
i : integer;
ps, pr : ^byte;
begin
ps := @s;
pr := @Result;
for i := 1 to SizeOf(s) do
begin
pr^ := ps^ xor (Key shr 8);
if bEncrypt then
Key := (pr^ + Key) * SeedA + SeedB
else
Key := (ps^ + Key) * SeedA + SeedB;
pr := pointer(integer(pr) + 1);
ps := pointer(integer(ps) + 1);
end;
end;
***************************
function cryptstr(const s:string; stype: dword):string;
var
i: integer;
fkey: integer;
begin
result:='';
case stype of
0:
begin
randomize;
fkey := random($ff);
for i:=1 to length(s) do
result := result+chr( ord(s) xor i xor fkey);
result := result + char(fkey);
end;
1:
begin
fkey := ord(s[length(s)]);
for i:=1 to length(s) - 1 do
result := result+chr( ord(s) xor i xor fkey);
end;
end;