Get key and IV values using Bouncy castle

user_19529591 0
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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??

bouncycastle java
1 Answers

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
user_90140970
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