我目前正在开发一个使用密钥加密/解密特定文件的函数。我写了三个类，一个生成一个密钥，一个用密钥加密文件，另一个用密钥解密。
生成密钥并加密文件可以正常工作，但是当我尝试解密文件时，会抛出一个异常：c.init(Cipher.DECRYPT_MODE, keySpec);：
java.security.InvalidKeyException：缺少参数
我认为我在将密钥流式传输到byte[]时出错了，或者在解密文件时出错了。
快速解释这三个类：KeyHandler创建一个AES密钥并将其存储在硬盘上。密钥/明文/加密/解密文件的名称目前是硬编码的，用于测试目的。
EncryptionHandler将磁盘上的.txt文件转换为字节，使用密钥加密文件，然后使用CipherOutputStream将加密的字节写入磁盘。
DecryptionHandler当然与EncryptionHandler相反。
以下是代码：
public class KeyHandler {
Scanner scan = new Scanner(System.in);
public KeyHandler(){
try {
startMenu();
} catch (Exception e) {
System.out.println("fel någonstanns :)");
}
}
public void startMenu() throws Exception{
System.out.println("Hej. Med detta program kan du generera en hemlig nyckel"+"\n"+"Vill du:"+"\n"+ "1. Generera en nyckel"+"\n"+"2. Avsluta");
int val=Integer.parseInt(scan.nextLine());
do{
switch (val){
case 1: generateKey(); break;
case 2: System.exit(1);
default: System.out.println("Du måste välja val 1 eller 2");
}
}
while (val!=3);
}
public void generateKey() throws Exception{
try {
KeyGenerator gen = KeyGenerator.getInstance("AES");
gen.init(128);
SecretKey key=gen.generateKey();
byte[] keyBytes = key.getEncoded();
System.out.print("Ge nyckeln ett filnamn: ");
String filename = scan.next();
System.out.println("Genererar nyckeln...");
FileOutputStream fileOut = new FileOutputStream(filename);
fileOut.write(keyBytes);
fileOut.close();
System.out.println("Nyckeln är genererad med filnamnet: "+filename+"...");
System.exit(1);
} catch (NoSuchAlgorithmException e) {
}
}
public static void main(String[] args){
new KeyHandler();
}
}
public class EncryptHandler {
private String encryptedDataString;
private Cipher ecipher;
AlgorithmParameterSpec paramSpec;
byte[] iv;
public EncryptHandler(String dataString, String secretKey, String encryptedDataString){
this.encryptedDataString=encryptedDataString;
try {
encryptFile(dataString, secretKey);
} catch (Exception e) {
}
}
public void encryptFile(String dataString, String secretKey) throws Exception{
FileInputStream fis = new FileInputStream(secretKey);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int theByte = 0;
while ((theByte = fis.read()) != -1)
{
baos.write(theByte);
}
fis.close();
byte[] keyBytes = baos.toByteArray();
baos.close();
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
try
{
ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
ecipher.init(Cipher.ENCRYPT_MODE, keySpec);
}
catch (Exception e)
{
e.printStackTrace();
}
System.out.println("Encrypting file...");
try
{
encryptStream(new FileInputStream(dataString),new FileOutputStream(encryptedDataString));
}
catch(Exception e){
e.printStackTrace();
}
}
public void encryptStream(InputStream in, OutputStream out){
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
try {
out = new CipherOutputStream(out, ecipher);
// read the cleartext and write it to out
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
bOut.writeTo(out);
out.close();
bOut.reset();
}
catch (java.io.IOException e)
{
}
}
public static void main(String[] args){
String data = "test.txt";
String keyFileName="a";
String encryptedFile="krypterad.txt";
//String encryptedFile =args[2];
new EncryptHandler(data, keyFileName, encryptedFile);
}
}
public class DecryptHandler {
public DecryptHandler(){
try {
decryptFile();
} catch (Exception e) {
System.out.println("något gick fel :) ");
}
}
public void decryptFile()throws Exception{
byte[] buf = new byte[1024];
String keyFilename = "hemlig";
FileInputStream fis = new FileInputStream(keyFilename);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int theByte = 0;
while ((theByte = fis.read()) != -1)
{
baos.write(theByte);
}
fis.close();
byte[] keyBytes = baos.toByteArray();
baos.close();
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
System.out.println("här");
c.init(Cipher.DECRYPT_MODE, keySpec);
System.out.println("Decrypting file...");
try{
decryptStream(new FileInputStream("krypterad.txt"),new FileOutputStream("Dekryperad.txt"), c, buf);
}
catch (java.io.IOException e){
}
System.out.println("File decrypted!");
}
public void decryptStream(InputStream in, OutputStream out, Cipher dcipher, byte[] buf){
try
{
in = new CipherInputStream(in, dcipher);
// Read in the decrypted bytes and write the cleartext to out
int numRead = 0;
while ((numRead = in.read(buf)) >= 0)
{
out.write(buf, 0, numRead);
}
out.close();
}
catch (java.io.IOException e){
}
}
public static void main(String[]args){
new DecryptHandler();
}
}
答案 0 :(得分：50)
如果您使用像CBC这样的块链接模式，您还需要为Cipher提供IvParameterSpec。
所以你可以像这样初始化IvParameterSpec：
// build the initialization vector. This example is all zeros, but it
// could be any value or generated using a random number generator.
byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
然后进行加密，将启动密码的代码更改为：
ecipher.init(Cipher.ENCRYPT_MODE, keySpec, ivspec);
你解密的地方：
c.init(Cipher.DECRYPT_MODE, keySpec, ivspec);
所以你的完整代码应该是这样的（它对我有用）：
public class KeyHandler {
Scanner scan = new Scanner(System.in);
public KeyHandler() {
try {
startMenu();
} catch (Exception e) {
System.out.println("fel någonstanns :)");
}
}
public void startMenu() throws Exception {
System.out.println("Hej. Med detta program kan du generera en hemlig nyckel" + "\n" + "Vill du:" + "\n" + "1. Generera en nyckel" + "\n" + "2. Avsluta");
int val = Integer.parseInt(scan.nextLine());
do {
switch (val) {
case 1:
generateKey();
break;
case 2:
System.exit(1);
default:
System.out.println("Du måste välja val 1 eller 2");
}
} while (val != 3);
}
public void generateKey() throws Exception {
try {
KeyGenerator gen = KeyGenerator.getInstance("AES");
gen.init(128);
SecretKey key = gen.generateKey();
byte[] keyBytes = key.getEncoded();
System.out.print("Ge nyckeln ett filnamn: ");
String filename = scan.next();
System.out.println("Genererar nyckeln...");
FileOutputStream fileOut = new FileOutputStream(filename);
fileOut.write(keyBytes);
fileOut.close();
System.out.println("Nyckeln är genererad med filnamnet: " + filename + "...");
System.exit(1);
} catch (NoSuchAlgorithmException e) {
}
}
public static void main(String[] args) {
new KeyHandler();
}
}
public class EncryptHandler {
private String encryptedDataString;
private Cipher ecipher;
AlgorithmParameterSpec paramSpec;
byte[] iv;
public EncryptHandler(String dataString, String secretKey, String encryptedDataString) {
this.encryptedDataString = encryptedDataString;
try {
encryptFile(dataString, secretKey);
} catch (Exception e) {
}
}
public void encryptFile(String dataString, String secretKey) throws Exception {
FileInputStream fis = new FileInputStream(secretKey);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int theByte = 0;
while ((theByte = fis.read()) != -1) {
baos.write(theByte);
}
fis.close();
byte[] keyBytes = baos.toByteArray();
baos.close();
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
// build the initialization vector. This example is all zeros, but it
// could be any value or generated using a random number generator.
byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
try {
ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
ecipher.init(Cipher.ENCRYPT_MODE, keySpec, ivspec);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Encrypting file...");
try {
encryptStream(new FileInputStream(dataString), new FileOutputStream(encryptedDataString));
} catch (Exception e) {
e.printStackTrace();
}
}
public void encryptStream(InputStream in, OutputStream out) {
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
try {
out = new CipherOutputStream(out, ecipher);
// read the cleartext and write it to out
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
bOut.writeTo(out);
out.close();
bOut.reset();
} catch (java.io.IOException e) {
}
}
public static void main(String[] args) {
String data = "test.txt";
String keyFileName = "a";
String encryptedFile = "krypterad.txt";
//String encryptedFile =args[2];
new EncryptHandler(data, keyFileName, encryptedFile);
}
}
public class DecryptHandler {
public DecryptHandler() {
try {
decryptFile();
} catch (Exception e) {
e.printStackTrace();
System.out.println("något gick fel :) ");
}
}
public void decryptFile() throws Exception {
byte[] buf = new byte[1024];
String keyFilename = "hemlig";
FileInputStream fis = new FileInputStream(keyFilename);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int theByte = 0;
while ((theByte = fis.read()) != -1) {
baos.write(theByte);
}
fis.close();
byte[] keyBytes = baos.toByteArray();
baos.close();
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
// build the initialization vector. This example is all zeros, but it
// could be any value or generated using a random number generator.
byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
System.out.println("här");
c.init(Cipher.DECRYPT_MODE, keySpec, ivspec);
System.out.println("Decrypting file...");
try {
decryptStream(new FileInputStream("krypterad.txt"), new FileOutputStream("Dekryperad.txt"), c, buf);
} catch (java.io.IOException e) {
}
System.out.println("File decrypted!");
}
public void decryptStream(InputStream in, OutputStream out, Cipher dcipher, byte[] buf) {
try {
in = new CipherInputStream(in, dcipher);
// Read in the decrypted bytes and write the cleartext to out
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
out.close();
} catch (java.io.IOException e) {
}
}
public static void main(String[] args) {
new DecryptHandler();
}
}