我试图调整http://www.java2s.com/Code/Java/Security/Basicsymmetricencryptionexample.htm的示例代码，必须使用3个参数调用，模式（加密或解密），IV和密钥。它还可以读取和写入特定文件。
到目前为止，我忽略了给定的IV和键，直到我完成其余的操作。我的代码成功地从文件加密明文，并将密文写入文件，但解密不起作用。似乎解密模式读取的字节数多于加密写入的字节数，并且我得到块对齐错误。
我确定解密部分的某处存在一些基本错误，但我不知道它是什么。如果有人能够识别问题或者可以看到任何可能导致它的明显错误，请告诉我。
错误发生在
try{ ctLength += cipher.doFinal(cipherText, ctLength);}catch{IllegalBlockSizeException e)
代码行：
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.ShortBufferException;
import javax.crypto.spec.SecretKeySpec;
@SuppressWarnings("unused")
public class AESCTR {
static String inputFile = "plain-in.txt";
static String outputFile = "cipher-out.txt";
static String cInputFile = "cipher-in.txt";
static String cOutputFile = "plain-out.txt";
static String mode;
static String IV;
static String key;
public static void main(String[] args) {
if (Security.getProvider("BC") == null){
System.out.println("Bouncy Castle provider is NOT available");
System.exit(-1);
}
else{
System.out.println("Bouncy Castle provider is available");
}
Security.addProvider(Security.getProvider("BC"));
// TODO Auto-generated method stub
if (args.length != 3){
System.out.println("Invalid number of arguments\n");
System.exit(-1);
}
mode = args[0];
IV = args[1];
key = args[2];
if ((!mode.equals("enc")) && (!mode.equals("dec"))){
System.out.println("Invalid mode\n");
System.exit(-1);
}
byte[] keyBytes = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};
System.out.println(keyBytes.length);
SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");
System.out.println("Mode: " + mode + " IV: " + IV + " Key: " + key);
if(mode.equals("enc")){
int ctLength = 0;
byte[] data = null;
try {
Path path = Paths.get(inputFile);
data = Files.readAllBytes(path);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("Invalid Path\n");
System.exit(-1);
}
while((data.length % 16) != 0){ //Padding
byte[] dest = new byte[data.length + 1];
byte[] pad = new byte[] {0x00};
System.arraycopy(data, 0, dest, 0, data.length);
System.arraycopy(pad, 0, dest, data.length, pad.length);
data = dest;
}
System.out.println(data.length);
byte[] cipherText = new byte[data.length];
Cipher cipher = null;
try {
cipher = Cipher.getInstance("AES/ECB/NoPadding", "BC");
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchProviderException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchPaddingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("input text : " + new String(data));
try {
cipher.init(Cipher.ENCRYPT_MODE, key);
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ctLength = cipher.update(data, 0, data.length, cipherText, 0);
} catch (ShortBufferException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ctLength += cipher.doFinal(cipherText, ctLength);
} catch (IllegalBlockSizeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ShortBufferException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (BadPaddingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Writer writer = null;
try{ writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(cInputFile), "utf-8"));
writer.write(new String(cipherText));
} catch (IOException ex){
System.out.println("File Write Error\n");
System.exit(-1);
} finally{
try{writer.close();}catch (Exception ex){}
}
byte[] c = null;
try {
Path path = Paths.get(cInputFile);
c = Files.readAllBytes(path);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("Invalid Path\n");
System.exit(-1);
}
System.out.println("cipher text: " + new String(c) + " bytes: " + ctLength);
}
else if (mode.equals("dec")){
byte[] c = null;
try {
Path path = Paths.get(cInputFile);
c = Files.readAllBytes(path);
File f = new File(cInputFile);
System.out.println("In Bytes: " + c.length);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("Invalid Path\n");
System.exit(-1);
}
Cipher cipher = null;
try {
cipher = Cipher.getInstance("AES/ECB/NoPadding", "BC");
} catch (NoSuchAlgorithmException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (NoSuchProviderException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (NoSuchPaddingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
byte[] plainText = new byte[c.length];
try {
cipher.init(Cipher.DECRYPT_MODE, key);
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
int ptLength = 0;
try {
ptLength = cipher.update(c, 0, c.length, plainText, 0);
System.out.println(ptLength);
} catch (ShortBufferException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ptLength += cipher.doFinal(plainText, ptLength);
} catch (IllegalBlockSizeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ShortBufferException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (BadPaddingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("plain text : " + new String(plainText) + " bytes: " + ptLength);
}
}
}
答案 0 :(得分：2)
您正在尝试将大量随机字节解码为UTF-8编码文本。那不会奏效。您的密文文本已损坏，因为任何不能形成字符的有效UTF-8编码的字节序列都将替换为替换字符0 + FFFD（�）。
密文不是文本。不要使用与文本一起使用的Writer和Reader等API。使用OutputStream和InputStream等可与字节数组配合使用的API。
如果您需要将密文存储为文本，请使用二进制文本编码（如Base64）对其进行编码。
具体来说，您应该使用以下内容替换密文的写入：
try {
Files.write(Paths.get(cInputFile), cipherText);
} catch (IOException ex) {
System.out.println("File Write Error");
System.exit(-1);
}