How to Encrypt or Decrypt a File in Java?
I want to encrypt and decrypt a file in java, i had read this url http://www-users.york.ac.uk/~mal503/lore/pkencryption.htm and i got two files namely public Security certificate and private security certificate file and private.pem file, i copied these files and pasted in the current directory and worte java code as follows, when i run this no encryption or decryption is performed, pls see this and tell me where i went wrong
Encrypt Code
File ecryptfile=new File("encrypt data");
File publickeydata=new File("/publickey");
File encryptmyfile=new File("/sys_data.db");
File copycontent =new File("Copy Data");
secure.makeKey();
secure.saveKey(ecryptfile, publickeydata);
secure.encrypt(encryptmyfile, copycontent);
Decrypt code
File ecryptfile=new File("encrypt data");
File privateKeyFile=new File("/privatekey");
File encryptmyfile=new File("/sys_data.db");
File unencryptedFile =new File("unencryptedFile");
try {
secure.loadKey(encryptmyfile, privateKeyFile);
secure.decrypt(encryptmyfile, unencryptedFile);
} catch (GeneralSecurityException e) {
// TODO Auto-generated catch block
e.pri开发者_C百科ntStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
You simply have muddled your files. This code works using the DER files generated from openssl as described in the article you linked:
FileEncryption secure = new FileEncryption();
// Encrypt code
{
File encryptFile = new File("encrypt.data");
File publicKeyData = new File("public.der");
File originalFile = new File("sys_data.db");
File secureFile = new File("secure.data");
// create AES key
secure.makeKey();
// save AES key using public key
secure.saveKey(encryptFile, publicKeyData);
// save original file securely
secure.encrypt(originalFile, secureFile);
}
// Decrypt code
{
File encryptFile = new File("encrypt.data");
File privateKeyFile = new File("private.der");
File secureFile = new File("secure.data");
File unencryptedFile = new File("unencryptedFile");
// load AES key
secure.loadKey(encryptFile, privateKeyFile);
// decrypt file
secure.decrypt(secureFile, unencryptedFile);
}
Here is the Simplest Piece of Code for encrypting a document with any Key(Here Random Key)
randomKey = randomKey.substring(0, 16);
keyBytes = randomKey.getBytes();
key = new SecretKeySpec(keyBytes, "AES");
paramSpec = new IvParameterSpec(iv);
ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
in = new FileInputStream(srcFile);
out = new FileOutputStream(encryptedFile);
out = new CipherOutputStream(out, ecipher);
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
in.close();
out.flush();
out.close();
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