问题
how to modify this AES encryption code so that it can encrypt and decrypt any type of file (pdf, docx....), because when I decrypt a pdf file or other I don't get the original file.
public EncryptData(File originalFile, File encrypted, SecretKeySpec secretKey, String cipherAlgorithm) throws IOException, GeneralSecurityException{
this.cipher = Cipher.getInstance(cipherAlgorithm);
encryptFile(getFileInBytes(originalFile), encrypted, secretKey);
}
public void encryptFile(byte[] input, File output, SecretKeySpec key) throws IOException, GeneralSecurityException {
this.cipher.init(Cipher.ENCRYPT_MODE, key);
writeToFile(output, this.cipher.doFinal(input));
}
public SecretKeySpec getSecretKey(String filename, String algorithm) throws IOException{
byte[] keyBytes = Files.readAllBytes(new File(filename).toPath());
return new SecretKeySpec(keyBytes, algorithm);
}
public static void main(String[] args) throws IOException, GeneralSecurityException, Exception{
StartEncryption startEnc = new StartEncryption();
File originalFile = new File("file.docx");
File encryptedFile = new File("EncryptedFiles/encryptedFile");
new EncryptData(originalFile, encryptedFile, startEnc.getSecretKey("OneKey/secretKey", "AES"), "AES");
}
public DecryptData(File encryptedFileReceived, File decryptedFile, SecretKeySpec secretKey, String algorithm) throws IOException, GeneralSecurityException {
this.cipher = Cipher.getInstance(algorithm);
decryptFile(getFileInBytes(encryptedFileReceived), decryptedFile, secretKey);
}
public void decryptFile(byte[] input, File output, SecretKeySpec key) throws IOException, GeneralSecurityException {
this.cipher.init(Cipher.DECRYPT_MODE, key);
writeToFile(output, this.cipher.doFinal(input));
}
public SecretKeySpec getSecretKey(String filename, String algorithm) throws IOException{
byte[] keyBytes = Files.readAllBytes(new File(filename).toPath());
return new SecretKeySpec(keyBytes, algorithm);
}
public static void main(String[] args) throws IOException, GeneralSecurityException, Exception{
StartDecryption startEnc = new StartDecryption();
File encryptedFileReceived = new File("EncryptedFiles/encryptedFile");
File decryptedFile = new File("DecryptedFiles/decryptedFile");
new DecryptData(encryptedFileReceived, decryptedFile, startEnc.getSecretKey("DecryptedFiles/SecretKey", "AES"), "AES");
}
回答1:
As some important information regarding your source code is missing (method writeToFile, no information about the cipherAlgorithm, no information about the used key) your code is not executable.
Therefore I'm providing a sample program to encrypt and decrypt any kind of files using the AES mode ECB.
Security warning: do NOT use AES ECB Mode in production because it is UNSECURE ! It's better to use a mode like AES GCM.
Provide the filenames for the original file (plaintextfile), the encrypted file (ciphertextfile) and the decrypted file (decryptedfile) and run the program - the decrypted file is equal to the original file.
I'm using a static key (32 byte/256 bit key length) for this example - to run this program you need the unlimited crypto policies enabled on your Java system.
That's the result:
https://stackoverflow.com/questions/62883618/encryption-decryption-aes-for-all-type-of-file-in-java
AES ECB Stream Encryption
* * * WARNING Do NOT use AES ECB mode in production as it is UNSECURE ! * * *
file used for encryption: plaintext.pdf
created encrypted file : plaintext.enc
created decrypted file : plaintext_decrypted.pdf
AES ECB Stream Encryption ended
The code:
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
public class AES_ECB_Stream {
public static void main(String[] args) throws IOException, NoSuchPaddingException, NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException, InvalidKeyException {
System.out.println("https://stackoverflow.com/questions/62883618/encryption-decryption-aes-for-all-type-of-file-in-java");
System.out.println("AES ECB Stream Encryption");
System.out.println("* * * WARNING Do NOT use AES ECB mode in production as it is UNSECURE ! * * *");
String plaintextFilename = "plaintext.pdf";
String ciphertextFilename = "plaintext.enc";
String decryptedtextFilename = "plaintext_decrypted.pdf";
byte[] key = "12345678901234561234567890123456".getBytes("UTF-8"); // 32 byte = 256 bit key length
encryptWitEcb(plaintextFilename, ciphertextFilename, key);
decryptWithEcb(ciphertextFilename, decryptedtextFilename, key);
System.out.println("file used for encryption: " + plaintextFilename);
System.out.println("created encrypted file : " + ciphertextFilename);
System.out.println("created decrypted file : " + decryptedtextFilename);
System.out.println("AES ECB Stream Encryption ended");
}
public static void encryptWitEcb(String filenamePlain, String filenameEnc, byte[] key) throws IOException,
NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
IllegalBlockSizeException, BadPaddingException {
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
try (FileInputStream fis = new FileInputStream(filenamePlain);
BufferedInputStream in = new BufferedInputStream(fis);
FileOutputStream out = new FileOutputStream(filenameEnc);
BufferedOutputStream bos = new BufferedOutputStream(out)) {
byte[] ibuf = new byte[1024];
int len;
while ((len = in.read(ibuf)) != -1) {
byte[] obuf = cipher.update(ibuf, 0, len);
if (obuf != null)
bos.write(obuf);
}
byte[] obuf = cipher.doFinal();
if (obuf != null)
bos.write(obuf);
}
}
public static void decryptWithEcb(String filenameEnc, String filenameDec, byte[] key) throws IOException,
NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
IllegalBlockSizeException, BadPaddingException {
try (FileInputStream in = new FileInputStream(filenameEnc);
FileOutputStream out = new FileOutputStream(filenameDec)) {
byte[] ibuf = new byte[1024];
int len;
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
while ((len = in.read(ibuf)) != -1) {
byte[] obuf = cipher.update(ibuf, 0, len);
if (obuf != null)
out.write(obuf);
}
byte[] obuf = cipher.doFinal();
if (obuf != null)
out.write(obuf);
}
}
}
来源：https://stackoverflow.com/questions/62883618/encryption-decryption-aes-for-all-type-of-file-in-java