Using Java to decrypt openssl aes-256-cbc using provided key and iv
I have been searching for a Java code example to do the following but have been unsuccessful. I'm looking for a solution for my particular situation.
A key and IV have been generated using "testtest" for a password:
openssl enc -aes-256-cbc -P
salt=2855243412E30BD7
key=E4A38479A2349177EAE6038A018483318350E7F5430BDC8F82F1974715CB54E5
iv=629E2E1500B6BA687A385D410D5B08E3
A file(named text) has been encrypted on Linux using openssl command:
openssl enc -aes-256-cbc -K
E4A38479A2349177EAE6038A018483318350E7F5430BDC8F82F1974715CB54E5 -iv
629E2E1500B6BA687A385D410D5B08E3 -e -in text -out text_ENCRYPTED
It can be decrypted successfully using:
openssl enc -aes-256-cbc -K
E4A38479A2349177EAE6038A018483318350E7F5430BDC8F82F1974715CB54E5 -iv
629E2E1500B6BA687A385D410D5B08E3 -d -in text_ENCRYPTED -out text_DECRYPTED
I have access to the encrypted file, the salt, the key and the iv. I do not believe I'm going to receive the password. Also, i have installed the unlimited strength JCE policy. So far I have only found examples where another java program does the encryption and generates these parameters. For my case I must use the salt, key and iv values given to me to decrypt a file. Is this possible with Java? Please remember I'm bound by this configuration, thank you very much for your time and help.
Solution 1:
You should use something like this:
InputStream cipherInputStream = null;
try {
final StringBuilder output = new StringBuilder();
final byte[] secretKey = javax.xml.bind.DatatypeConverter.parseHexBinary("E4A38479A2349177EAE6038A018483318350E7F5430BDC8F82F1974715CB54E5");
final byte[] initVector = javax.xml.bind.DatatypeConverter.parseHexBinary("629E2E1500B6BA687A385D410D5B08E3");
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(secretKey, "AES"), new IvParameterSpec(initVector, 0, cipher.getBlockSize()));
cipherInputStream = new CipherInputStream(new FileInputStream("text_ENCRYPTED"), cipher);
final String charsetName = "UTF-8";
final byte[] buffer = new byte[8192];
int read = cipherInputStream.read(buffer);
while (read > -1) {
output.append(new String(buffer, 0, read, charsetName));
read = cipherInputStream.read(buffer);
}
System.out.println(output);
} finally {
if (cipherInputStream != null) {
cipherInputStream.close();
}
}