Get key and IV values using Bouncy castle-CodePudding

With the below code i am using to do get the parameters required for AES encryption:

s_key is the file provided which contains the key that will be used to encrypt and decrypt

 File file = new File("/home/roxane/key");
        String passwordStr = FileUtils.readFileToString(file, "UTF-8");

        String outputPath = "/home/roxane/test1";
        String inputPath = "/home/roxane/test";

// Generate random 8 bytes salt
        SecureRandom random = new SecureRandom();
        byte salt[] = new byte[8];
        random.nextBytes(salt);

// Derive 32 bytes key (AES_256) and 16 bytes IV
        byte[] password = passwordStr.getBytes(StandardCharsets.UTF_8);
        OpenSSLPBEParametersGenerator pbeGenerator = new OpenSSLPBEParametersGenerator(new MD5Digest()); // SHA256 as of v1.1.0 (if in OpenSSL the default digest is applied)
        pbeGenerator.init(password, salt);
        ParametersWithIV parameters = (ParametersWithIV) pbeGenerator.generateDerivedParameters(256, 128);// keySize, ivSize in bits

How to segragate the Key and other parameters (IV and Salt) from ParametersWithIV and print to console??

CodePudding user response：

Passphrase and salt can be determined via the OpenSSLPBEParametersGenerator instance, key and IV via the ParametersWithIV instance. The following code:

import java.nio.charset.StandardCharsets;
import org.bouncycastle.crypto.digests.MD5Digest;
import org.bouncycastle.crypto.generators.OpenSSLPBEParametersGenerator;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.util.encoders.Hex;

...

byte[] passwordIn = "mypassword".getBytes(StandardCharsets.UTF_8);
byte[] saltIn = Hex.decode("1011121314151617");
OpenSSLPBEParametersGenerator pbeGenerator = new OpenSSLPBEParametersGenerator(new MD5Digest()); 
pbeGenerator.init(passwordIn, saltIn);
byte[] password = pbeGenerator.getPassword();
byte[] salt = pbeGenerator.getSalt();
int iterationCount = pbeGenerator.getIterationCount();

ParametersWithIV parameters = (ParametersWithIV) pbeGenerator.generateDerivedParameters(256, 128); 
byte[] iv = parameters.getIV();

KeyParameter keyParameter = (KeyParameter)parameters.getParameters();
byte[] key = keyParameter.getKey();

System.out.println("Password:   "   Hex.toHexString(password)); 
System.out.println("Salt:       "   Hex.toHexString(salt)); 
System.out.println("Iterations: "   iterationCount); 
System.out.println("IV:         "   Hex.toHexString(iv)); 
System.out.println("Key:        "   Hex.toHexString(key));

gives the output:

Password:   6d7970617373776f7264
Salt:       1011121314151617
Iterations: 1
IV:         3146b93c40ea036ca6a5fa6d28913e3b
Key:        9d75d2a0fd8625115ff0814a71a6f23ffb131e8afcd79dd90542956b8156a0ad

Key and IV can be easily verified with OpenSSL:

openssl enc -e -aes256 -md md5 -S 1011121314151617 -k mypassword -P

returns:

salt=1011121314151617
key=9D75D2A0FD8625115FF0814A71A6F23FFB131E8AFCD79DD90542956B8156A0AD
iv =3146B93C40EA036CA6A5FA6D28913E3B