我创建了加密文件，结合了AES加密，intilizatio矢量和原始数据。所以我的加密文件包含加密形式的3个以上元素。现在在解密期间，我再次将所有这3个元素分开，而且我必须在加密期间生成的解密期间使用硬编码的AES密钥长度。
public static void encrypt() throws Exception {
// RSA with ECB mode
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, generatePublicKey(readKeysFromFile("My_public.pub")));
// AES key generator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128, srandom);
SecretKey skey = kgen.generateKey();
// Initialization vector 16 byte
byte[] iv = new byte[128/8];
srandom.nextBytes(iv);
IvParameterSpec ivspec = new IvParameterSpec(iv);
try (FileOutputStream out = new FileOutputStream("dataFile" + ".enc")) {
{
byte[] b = cipher.doFinal(skey.getEncoded());
out.write(b);
System.err.println("AES Key Length: " + b.length);
}
out.write(iv);
System.err.println("IV Length: " + iv.length);
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.ENCRYPT_MODE, skey, ivspec);
File inputDataFile = new File("dataFile.xml");
try (DataInputStream in = new DataInputStream(new FileInputStream(inputDataFile))) {
byte[] buffer = new byte[(int)inputDataFile.length()];
in.readFully(buffer);
in.close();
byte[] encryptedData = ci.doFinal(buffer);
out.write(encryptedData);
out.close();
}
}
}
public static void decryptRSAAES() throws Exception {
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.DECRYPT_MODE, generatePrivateKey(readKeysFromFile("My_private.key")));
File file2 = new File("dataFile.enc");
RandomAccessFile raf = new RandomAccessFile(file2, "r");
// length of AES key
byte[] c = new byte[384];
// read the AES key from file
raf.read(c, 0 , 384);
byte[] fileContent = Files.readAllBytes(file2.toPath());
byte[] keyb = cipher.doFinal(c);
SecretKeySpec skey = new SecretKeySpec(keyb, "AES");
// read the initializatoin vector
byte[] iv = new byte[128/8];
raf.seek(384);
raf.read(iv);
IvParameterSpec ivspec = new IvParameterSpec(iv);
raf.seek(400);
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.DECRYPT_MODE, skey, ivspec);
try (FileOutputStream out = new FileOutputStream("decryptedFileTest"+".xml")){
byte[] decryptedData = ci.doFinal(fileContent);
out.write(decryptedData);
out.close();
//processDecryptFile(ci, in, out);
}
}
实际结果：使用AES密钥和原始纯文本数据创建解密文件
预期结果：在输出中仅写入原始明文数据，删除AES和初始化向量。
让我们简化一下，使用Java qazxsw poi类中新增的函数：
InputStream正如您所看到的，代码现在更像是镜像。我只是复制了加密代码，然后对其进行了更改。正如您所看到的，现在依靠public static void encrypt(RSAPublicKey publicKey) throws Exception {
try (FileOutputStream out = new FileOutputStream("dataFile" + ".enc")) {
// --- RSA using PKCS#1 v1.5 padding
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
// --- AES key generator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128);
SecretKey skey = kgen.generateKey();
// --- write encrypted AES key
byte[] encryptedSKey = cipher.doFinal(skey.getEncoded());
out.write(encryptedSKey);
// --- Initialization vector 16 byte
SecureRandom srandom = new SecureRandom();
byte[] iv = new byte[128/8];
srandom.nextBytes(iv);
IvParameterSpec ivspec = new IvParameterSpec(iv);
// --- write IV
out.write(iv);
// --- initialize AES cipher
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.ENCRYPT_MODE, skey, ivspec);
// --- convert file by copying to memory
try (FileInputStream in = new FileInputStream("dataFile.xml")) {
byte[] buffer = in.readAllBytes();
byte[] encryptedData = ci.doFinal(buffer);
out.write(encryptedData);
}
}
}
public static void decrypt(RSAPrivateKey privateKey) throws Exception {
try (FileInputStream in = new FileInputStream("dataFile" + ".enc")) {
// --- RSA using PKCS#1 v1.5 padding
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
// --- read encrypted AES key
byte[] encryptedSKey = in.readNBytes(determineEncryptionSizeInBytes(privateKey));
byte[] decryptedSKey = cipher.doFinal(encryptedSKey);
SecretKey skey = new SecretKeySpec(decryptedSKey, "AES");
// --- Initialization vector 16 byte
byte[] iv = in.readNBytes(128 / Byte.SIZE);
IvParameterSpec ivspec = new IvParameterSpec(iv);
// --- initialize AES cipher
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.DECRYPT_MODE, skey, ivspec);
// --- convert file by copying to memory
File outputDataFile = new File("dataFile.xml2");
try (FileOutputStream out = new FileOutputStream(outputDataFile)) {
byte[] buffer = in.readAllBytes();
byte[] decryptedData = ci.doFinal(buffer);
out.write(decryptedData);
}
}
}
private static int determineEncryptionSizeInBytes(RSAPrivateKey privateKey) {
return (privateKey.getModulus().bitLength() + Byte.SIZE - 1) / Byte.SIZE;
}
public static void main(String[] args) throws Exception {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(384 * Byte.SIZE);
KeyPair pair = kpg.generateKeyPair();
encrypt((RSAPublicKey) pair.getPublic());
decrypt((RSAPrivateKey) pair.getPrivate());
}
（自Java 9起）和InputStream#readAllBytes()（自Java 11起）使用更少的类。
请注意，您通常希望使用较小的缓冲区来流式传输文件。由于整个明文和密文当前都是缓冲的，因此您的应用程序使用的内存比所需的多得多。要使用流加密数据，您可以依赖InputStream#readNBytes()和CipherInputStream。
不用说异常处理需要改进，我只是简单地看一下解决当前问题的最佳方法。当你的工作正常工作（让事情正常，做好事情，优化事情）时，请再看看它。