SM4加密 Delphi 源码

以下是 SM4 加密的 Delphi 源码：

unit SM4;

interface

uses
  System.SysUtils, System.Classes;

type
  TSM4 = class
  private
    const
      SBox: array[0..255] of Byte = (
        $2, $3, $1, $1,
        $4, $6, $6, $5,
        $5, $7, $7, $7,
        $1, $F, $E, $D,
        $D, $F, $C, $C,
        $E, $B, $B, $B,
        $F, $A, $A, $9,
        $9, $A, $D, $8,
        $8, $D, $E, $9,
        $0, $0, $0, $0,
        $1, $2, $3, $4,
        $5, $6, $7, $8,
        $9, $A, $B, $C,
        $D, $E, $F, $0,
        $0, $F, $E, $D,
        $C, $B, $A, $9,
        $8, $7, $6, $5,
        $4, $3, $2, $1
      );
    var
      FKey: array[0..15] of UInt32;
      function L(T: UInt32): UInt32;
      function L_(T: UInt32): UInt32;
      function F(X0, X1, X2, X3, rk: UInt32): UInt32;
      procedure SetKey(const Key: TBytes);
  public
    procedure Encrypt(const Input: TBytes; var Output: TBytes);
    procedure Decrypt(const Input: TBytes; var Output: TBytes);
  end;

implementation

procedure TSM4.SetKey(const Key: TBytes);
var
  K: array[0..3] of UInt32;
  i: Integer;
begin
  if Length(Key) <> 16 then
    raise Exception.Create('Invalid key length');

  for i := 0 to 3 do
    K[i] := PUInt32(@Key[i * 4])^;

  FKey[0] := K[0] xor $A3B1BAC6;
  FKey[1] := K[1] xor $56AA3350;
  FKey[2] := K[2] xor $677D9197;
  FKey[3] := K[3] xor $B27022DC;

  for i := 0 to 31 do
    FKey[i + 4] := FKey[i] xor L(FKey[i + 1] xor FKey[i + 2] xor FKey[i + 3] xor PUInt32(@SBox[i * 4])^);
end;

function TSM4.L(T: UInt32): UInt32;
var
  t1, t2, t3, t4: UInt32;
begin
  t1 := T shr 24;
  t2 := (T shr 16) and $FF;
  t3 := (T shr 8) and $FF;
  t4 := T and $FF;

  Result := (L_[t1] xor L_[t2 + 256] xor L_[t3 + 512] xor L_[t4 + 768]);
end;

function TSM4.L_(T: UInt32): UInt32;
begin
  Result := (T xor (T shl 2) xor (T shl 10) xor (T shl 18) xor (T shl 24));
end;

function TSM4.F(X0, X1, X2, X3, rk: UInt32): UInt32;
begin
  Result := X0 xor L(X1 xor X2 xor X3 xor rk);
end;

procedure TSM4.Encrypt(const Input: TBytes; var Output: TBytes);
var
  X: array[0..3] of UInt32;
  i, j: Integer;
begin
  if Length(Input) <> 16 then
    raise Exception.Create('Invalid input length');

  SetKey(TBytes.Create($01, $23, $45, $67, $89, $AB, $CD, $EF, $FE, $DC, $BA, $98, $76, $54, $32, $10));

  for i := 0 to 3 do
    X[i] := PUInt32(@Input[i * 4])^;

  for i := 0 to 31 do
  begin
    X[4] := F(X[0], X[1], X[2], X[3], FKey[i]);
    X[0] := X[1];
    X[1] := X[2];
    X[2] := X[3];
    X[3] := X[4];
  end;

  for i := 0 to 3 do
    for j := 0 to 3 do
      Output[i * 4 + j] := (X[i] shr (j * 8)) and $FF;
end;

procedure TSM4.Decrypt(const Input: TBytes; var Output: TBytes);
var
  X: array[0..3] of UInt32;
  i, j: Integer;
begin
  if Length(Input) <> 16 then
    raise Exception.Create('Invalid input length');

  SetKey(TBytes.Create($01, $23, $45, $67, $89, $AB, $CD, $EF, $FE, $DC, $BA, $98, $76, $54, $32, $10));

  for i := 0 to 3 do
    X[i] := PUInt32(@Input[i * 4])^;

  for i := 31 downto 0 do
  begin
    X[4] := F(X[0], X[1], X[2], X[3], FKey[i]);
    X[0] := X[1];
    X[1] := X[2];
    X[2] := X[3];
    X[3] := X[4];
  end;

  for i := 0 to 3 do
    for j := 0 to 3 do
      Output[i * 4 + j] := (X[i] shr (j * 8)) and $FF;
end;

end.

使用示例：

var
  SM4: TSM4;
  Input, Output: TBytes;
begin
  SM4 := TSM4.Create;
  try
    Input := TEncoding.UTF8.GetBytes('Hello, world!');
    SetLength(Output, 16);

    SM4.Encrypt(Input, Output);
    // Output contains the encrypted data

    SM4.Decrypt(Output, Input);
    // Input contains the decrypted data
  finally
    SM4.Free;
  end;