所以基本上我的程序从用户选择的文本文件中加密/解密字符串。 他可以选择五种算法中的一种。问题是当我用例如创建密文时。 AES 然后将此密文保存到文本文件，并希望解密它以获取它不起作用的原始字符串。有人可以指出问题出在哪里吗？
例如：如果我使用AES加密String：“Hello World !!”我得到这个密文：“1za7slAXv2KZvDlVZlzu / A ==”然后我将它保存到.txt并使用第二种方式进行解密以获得“Hello World !!”背部。但结果很糟糕。
我的方法好吗？还有更好的方法吗？
忘记添加导入： 抱歉以前的格式化。
import java.io.*;
import java.util.Scanner;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.KeyGenerator;
import java.security.spec.KeySpec;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.BadPaddingException;
import java.io.IOException;
import java.security.InvalidAlgorithmParameterException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidKeyException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.IllegalBlockSizeException;
import java.io.UnsupportedEncodingException;
public class sifrovaniRaw {
Cipher sifr, desifr;
sifrovaniRaw(SecretKey klic, String algoritmus)
{
try {
sifr = Cipher.getInstance(algoritmus);
desifr = Cipher.getInstance(algoritmus);
sifr.init(Cipher.ENCRYPT_MODE, klic);
desifr.init(Cipher.DECRYPT_MODE, klic);
}
catch (NoSuchPaddingException e) {
System.out.println(" NoSuchPaddingException");
}
catch (NoSuchAlgorithmException e) {
System.out.println(" NoSuchAlgorithmException");
}
catch (InvalidKeyException e) {
System.out.println(" InvalidKeyException");
}
}
sifrovaniRaw(String passph) {
byte[] sul =
{
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
};
int iterace = 20;
try {
KeySpec klicSpecifikace = new PBEKeySpec(passph.toCharArray(), sul, iterace);
SecretKey klic = SecretKeyFactory.getInstance("PBEWithMD5AndTripleDES").generateSecret(klicSpecifikace);
sifr = Cipher.getInstance(klic.getAlgorithm());
desifr = Cipher.getInstance(klic.getAlgorithm());
AlgorithmParameterSpec parametry = new PBEParameterSpec(sul, iterace);
sifr.init(Cipher.ENCRYPT_MODE, klic, parametry);
desifr.init(Cipher.DECRYPT_MODE, klic, parametry);
}
catch (InvalidAlgorithmParameterException e) {
System.out.println(" InvalidAlgorithmParameterException");
}
catch (InvalidKeySpecException e) {
System.out.println(" InvalidKeySpecException");
}
catch (NoSuchPaddingException e) {
System.out.println(" NoSuchPaddingException");
}
catch (NoSuchAlgorithmException e) {
System.out.println(" NoSuchAlgorithmException");
}
catch (InvalidKeyException e) {
System.out.println(" InvalidKeyException");
}
}
public String encryption(String str) {
try {
byte[] utf8 = str.getBytes("UTF8");
byte[] enco = sifr.doFinal(utf8);
return new sun.misc.BASE64Encoder().encode(enco);
} catch (BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (IOException e) {
}
return null;
}
public String decryption(String str) {
try {
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
byte[] utf8 = desifr.doFinal(dec);
return new String(utf8, "UTF8");
} catch (BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (IOException e) {
}
return null;
}
public static void testsecklic()
{
System.out.println("Testing method using secret key");
System.out.println("");
try {
System.out.println("Give a path:");
System.out.println("-----");
System.out.println("for UNIX eg: \"/home/user/text_to_encrypt/decrypt.txt\"");
System.out.println("for NT Windows eg: \"C://FileIO//text.txt\"");
System.out.println("------");
Scanner scan = new Scanner(System.in);
String filepath = scan.next();
File file = new File(filepath);
BufferedInputStream bin = null;
FileInputStream fin = new FileInputStream(file);
bin = new BufferedInputStream(fin);
byte[] contents = new byte[1024];
int bytesRead=0;
String StringCont;
while( (bytesRead = bin.read(contents)) != -1)
{
StringCont = new String(contents, 0, bytesRead);
System.out.print(StringCont);
SecretKey aesKlic = KeyGenerator.getInstance("AES").generateKey();
SecretKey desKlic = KeyGenerator.getInstance("DES").generateKey();
SecretKey desedeKlic = KeyGenerator.getInstance("DESede").generateKey();
SecretKey rc2Klic = KeyGenerator.getInstance("RC2").generateKey();
SecretKey blowfishKlic = KeyGenerator.getInstance("Blowfish").generateKey();
StringEncrypter aesEncrypt = new StringEncrypter(aesKlic, aesKlic.getAlgorithm());
StringEncrypter desEncrypt = new StringEncrypter(desKlic, desKlic.getAlgorithm());
StringEncrypter desedeEncrypt = new StringEncrypter(desedeKlic, desedeKlic.getAlgorithm());
StringEncrypter rc2Encrypt = new StringEncrypter(rc2Klic, rc2Klic.getAlgorithm());
StringEncrypter blowfishEncrypt = new StringEncrypter(blowfishKlic, blowfishKlic.getAlgorithm());
String aesEncrypted = aesEncrypt.encrypt(StringCont);
String desEncrypted = desEncrypt.encrypt(StringCont);
String rc2Encrypted = desedeEncrypt.encrypt(StringCont);
String desedeEncrypted = rc2Encrypt.encrypt(StringCont);
String blowfishEncrypted = blowfishEncrypt.encrypt(StringCont);
String aesDecrypt = aesEncrypt.decrypt(aesEncrypted);
String desDecrypt = desEncrypt.decrypt(desEncrypted);
String rc2Decrypt = rc2Encrypt.decrypt(desedeEncrypted);
String desedeDecrypt = desedeEncrypt.decrypt(rc2Encrypted);
String blowfishDecrypt = blowfishEncrypt.decrypt(blowfishEncrypted);
//FIRST NON-WORKING WAY of decrypting.
System.out.println("Do you want to encrypt[1] or decrypt[2] text ?");
int sifDesif = scan.nextInt();
if(sifDesif == 1)
{
System.out.println("What cypher do you want to choose?");
System.out.println("AES[1], DES[2], rc2[3], blowfish[4], desede[5]");
int vyber = scan.nextInt();
switch(vyber)
{
case 1: System.out.println("encrypted : " + aesEncrypted); break;
case 2: System.out.println("encrypted : " + desEncrypted); break;
case 3: System.out.println("encrypted : " + rc2Encrypted); break;
case 4: System.out.println("encrypted : " + blowfishEncrypted); break;
case 5: System.out.println("encrypted : " + desedeEncrypted); break;
}
}
else if(sifDesif == 2)
{
System.out.println("What cypher do you want to choose?");
System.out.println("AES[1], DES[2], rc2[3], blowfish[4], desede[5]");
int vyber = scan.nextInt();
switch(vyber)
{
case 1:System.out.println("decrypted : " + aesDecrypt); break;
case 2:System.out.println("decrypted : " + desDecrypt); break;
case 3:System.out.println("decrypted : " + rc2Decrypt); break;
case 4:System.out.println("decrypted : " + blowfishDecrypt); break;
case 5:System.out.println("decrypted : " + desedeDecrypt); break;
}
}
//SECOND WORKING WAY of decrypting.
System.out.println("Algorith used:" + aesKlic.getAlgorithm());
System.out.println("text : " + StringCont);
System.out.println("encryption : " + aesEncrypted);
System.out.println("decryption text : " + aesDecrypt);
System.out.println();
}
}
catch (NoSuchAlgorithmException e)
{
System.out.println(" No such Algo");
}
catch(FileNotFoundException e)
{
System.out.println("File not found" + e);
}
catch(IOException ioe)
{
System.out.println("Exception while reading the file "+ ioe);
}
}
public static void main(String[] args)
{
testsecklic();
}
}
答案 0 :(得分：2)
由于您每次都生成加密密钥，因此程序将无法解密使用其他加密密钥创建的密文。如果要在程序运行之间重复使用加密密钥，则需要找到一种方法来保留加密密钥。
以下程序是原始示例的较小版本，除了它使用每个密码加密和解密明文。我无法访问StringEncrypter类，所以我写了一个简单的版本：
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
public class EncTest {
public static void main(String[] args) throws Exception {
System.out.println("Testing method using secret key");
String plaintext = "hello world";
SecretKey aesKlic = KeyGenerator.getInstance("AES").generateKey();
SecretKey desKlic = KeyGenerator.getInstance("DES").generateKey();
SecretKey desedeKlic = KeyGenerator.getInstance("DESede").generateKey();
SecretKey rc2Klic = KeyGenerator.getInstance("RC2").generateKey();
SecretKey blowfishKlic = KeyGenerator.getInstance("Blowfish").generateKey();
StringEncrypter[] ciphers = new StringEncrypter[] {
new StringEncrypter(aesKlic, aesKlic.getAlgorithm()),
new StringEncrypter(desKlic, desKlic.getAlgorithm()),
new StringEncrypter(desedeKlic, desedeKlic.getAlgorithm()),
new StringEncrypter(rc2Klic, rc2Klic.getAlgorithm()),
new StringEncrypter(blowfishKlic, blowfishKlic.getAlgorithm())
};
byte[][] ciphertexts = new byte[ciphers.length][];
int i = 0;
for (StringEncrypter cipher : ciphers) {
ciphertexts[i] = cipher.encrypt(plaintext);
System.out.println(cipher.getAlgorithm() + " encrypted: " + hexEncode(ciphertexts[i]));
i++;
}
System.out.println();
i = 0;
for (StringEncrypter cipher : ciphers) {
System.out.println(cipher.getAlgorithm() + " decrypted: " + cipher.decrypt(ciphertexts[i]));
i++;
}
}
// Hex encoding lifted from commons-codec
private static String hexEncode(byte [] input) {
return new String(encodeHex(input));
}
private static char[] encodeHex(byte[] data) {
int l = data.length;
char[] out = new char[l << 1];
// two characters form the hex value.
for (int i = 0, j = 0; i < l; i++) {
out[j++] = DIGITS[(0xF0 & data[i]) >>> 4 ];
out[j++] = DIGITS[ 0x0F & data[i] ];
}
return out;
}
private static final char[] DIGITS = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
};
private static class StringEncrypter {
private final SecretKey key;
private final String algorithm;
public StringEncrypter(SecretKey key, String algorithm) {
this.key = key;
this.algorithm = algorithm;
}
public String getAlgorithm() {
return algorithm;
}
public byte[] encrypt(String input) throws Exception {
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, key);
return cipher.doFinal(input.getBytes("UTF-8"));
}
public String decrypt(byte[] input) throws Exception {
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.DECRYPT_MODE, key);
return new String(cipher.doFinal(input));
}
}
}