使用 DCPCrypt (3DES) 加密 Delphi 7 中的字符串

Question

我需要在 Delphi 7 中加密一个字符串。我设法获得的唯一加密库运行ning 是 DCPCrypt。

我研究了一个加密文件的例子，并尝试将其适配为字符串，但我恐怕失败得很惨......

这是我的功能：

function Encrypt3DES(psString, psKey: string): string;
var
    lCipher:TDCP_3des;
    CipherIV: array of byte;     // the initialisation vector (for chaining modes)
    lHash:TDCP_sha256;
    lHashDigest: array of byte;   // the result of hashing the passphrase with the salt
    Salt: array[0..7] of byte;   // a random salt to help prevent precomputated attacks
    i:integer;
begin
    lHash:=TDCP_sha256.Create(nil);
    SetLength(lHashDigest,lHash.HashSize div 8);
    for i := 0 to 7 do
      Salt[i] := Random(256);  // just fill the salt with random values (crypto secure PRNG would be better but not _really_ necessary)

    //strmOutput.WriteBuffer(Salt,Sizeof(Salt));  // write out the salt so we can decrypt! ***I don't know what to do with this***

    lHash.Init;
    lHash.Update(Salt[0],Sizeof(Salt));   // hash the salt
    lHash.UpdateStr(psKey);  // and the passphrase
    lHash.Final(lHashDigest[0]);           // store the output in HashDigest

    lCipher:=TDCP_3des.Create(nil);
    //3DES is a block cipher, we need an initialisation vector

    SetLength(CipherIV,TDCP_blockcipher(lCipher).BlockSize div 8);
    for i := 0 to (Length(CipherIV) - 1) do
      CipherIV[i] := Random(256);           // again just random values for the IV

    //strmOutput.WriteBuffer(CipherIV[0],Length(CipherIV));  // write out the IV so we can decrypt! ***I don't know what to do with this***

    lCipher.Init(lHashDigest[0],TNeo.Min(lCipher.MaxKeySize,lHash.HashSize),CipherIV);  // initialise the cipher with the hash as key
    TDCP_blockcipher(lCipher).CipherMode := cmCBC;   // use CBC chaining when encrypting

    //lCipher.EncryptStream(strmInput,strmOutput,strmInput.Size); // encrypt the entire file
    result:=lCipher.EncryptString(psString);
    lCipher.Burn;   // important! get rid of keying information
    //strmInput.Free;
    //strmOutput.Free;
end;

请记住，我完全不知道加密是如何工作的。我知道您不加密字符串，而是加密二进制文件，但我不知道如何将其转换为代码。每次我运行它，我都会得到不同的结果（我想如果你使用随机值是正常的），但我不知道它是否应该那样，因为我必须将它发送到另一个服务器所以他们可以在那里检查完整性。

Thay在API中给了我一个Java函数，但显然我不能使用它：

public byte [] encrypt_3DES(final String claveHex, final String datos) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException, IllegalBlockSizeException, BadPaddingException {
    byte [] ciphertext = null;
    // Crea la clave
    DESedeKeySpec desKeySpec = new DESedeKeySpec(toByteArray(claveHex));
    SecretKey desKey = new SecretKeySpec(desKeySpec.getKey(), "DESede");
    // Crea un cifrador
    Cipher desCipher = Cipher.getInstance("DESede/CBC/NoPadding");

    // Inicializa el cifrador para encriptar
    desCipher.init(Cipher.ENCRYPT_MODE, desKey, new IvParameterSpec(IV));

    // Se añaden los 0 en bytes necesarios para que sea un múltiplo de 8
    int numeroCerosNecesarios = 8 - (datos.length() % 8);
    if (numeroCerosNecesarios == 8) {
        numeroCerosNecesarios = 0;
    }
    ByteArrayOutputStream array = new ByteArrayOutputStream();
    array.write(datos.getBytes("UTF-8"), 0, datos.length());
    for (int i = 0; i < numeroCerosNecesarios; i++) {
        array.write(0);
    }
    byte [] cleartext = array.toByteArray();
    // Encripta el texto
    ciphertext = desCipher.doFinal(cleartext);
    return ciphertext;
}

任何好心人都可以帮助我解决这个问题，我将不胜感激。这几天我一直在苦苦思索。

提前致谢。

Answer 1

此示例使用开源 TLockBox 库 encrypt/decrypt 使用 3DES 的字符串 https://sourceforge.net/p/tplockbox/wiki/Home/

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,
  //lockbox units 
  LbCipher, LbClass, LbAsym, LbRSA, LbString;

type
  TForm1 = class(TForm)
    edPlainText: TEdit;
    edCipherText: TEdit;
    btnEncryptString: TButton;
    btnDescryptString: TButton;
    procedure btnEncryptStringClick(Sender: TObject);
    procedure btnDescryptStringClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

Function TripleDesEncrypt(const APlaintext, APassphrase: String): String;
Var
  Key128: TKey128;
begin
  GenerateLMDKey(Key128, SizeOf(Key128), APassphrase);
  result  := TripleDESEncryptStringEx(APlainText, Key128, True);
End;

Function TripleDesDecrypt(const ACipherText, APassphrase: String): String;
Var
  Key128: TKey128;
begin
  GenerateLMDKey(Key128, SizeOf(Key128), APassphrase);
  Try
    result := TripleDESEncryptStringEx(ACipherText, Key128, False);
  Except
    Result := '';
  End;
End;

procedure TForm1.btnEncryptStringClick(Sender: TObject);
begin
  edCipherText.text := TripleDesEncrypt(edPlainText.Text, 'SecretPassphrase');
end;

procedure TForm1.btnDescryptStringClick(Sender: TObject);
begin
  edPlainText.text := TripleDesDecrypt(edCipherText.text, 'SecretPassphrase');
end;

end.

Answer 2

后来我发现我使用了错误的 DCPCrypt 函数作为向导。我会 post 我找到的另一个，以防有人需要使用 DCPCrypt:

function Encrypt3DES(psData, psKey: string): string;
var
    Cipher: TDCP_3des;
begin
    Cipher:= TDCP_3des.Create(nil);
    Cipher.InitStr(psKey,TDCP_sha256);         // initialize the cipher with a hash of the passphrase
    result:=Cipher.EncryptString(psData);
    Cipher.Burn;
    Cipher.Free;
end;

使用 DCPCrypt (3DES) 加密 Delphi 7 中的字符串

Encrypt a string in Delphi 7 using DCPCrypt (3DES)

delphi

encryption

3des

delphi-7