Unable to perform Encryption using Fernet-Java in Android Studio

Question

Fernet encryption is my client requirement.

I have Fernet key and want to achieve encryption in Java(Android Studio) by follow https://github.com/l0s/fernet-java8 this link. Working on this from last one week but didn't achieve till now anyone can help me out on this.?

There is no any method introduced to perform encryption

final Key key = new Key("3t55GSk5qDRUif_v4MNQGLrkzaWv-TFOSJpqQWj9KKg=");
final Token token = Token.generate(key, "This is my message");

I have added dependency in build.gradle as mentioned in Fernet documentation

implementation 'com.macasaet.fernet:fernet-java8:1.4.2'

score 1 · Accepted Answer · answered Jul 16 '20 at 18:25

The following code is a minimal example for string encryption with Fernet Java 8 and has no propper error handling, as well I didn't check what encryption algorithm, mode or key length is in use.

To encrypt more complex data structures please refer to https://github.com/l0s/fernet-java8.

In the first encryption/decryption part a fresh new key is generated and a new token is produced. This token has a (default) duration of 60 seconds that can be changed. The decryption is done immediately so it is not expired.

The second decryption takes an old token (from GitHub readme.md) and when trying to decrypt you receive a "TokenExpiredException".

Console:

key: j2v_wwTtEanOKF4-OqXtJ8ECi9UGOD72uGuJLJqZUuE=
token: gAAAAABfEJkmA7qy6voW6-xZMz4wYqcies156jEBXbqkk585aerDwKRlQAuFOkSv94Ac503WSk222ayQMvPmweDp9IRakq3mBMrBY7zyRt9ou5luqpTXs8HDWvCjpJ0y66-hboULhyut
token timestamp: 2020-07-16T18:15:02.456832100Z
decryptedtext: this is my data that needs encryption
token2 timestamp: 1985-10-26T08:20:00Z
Exception in thread "main" com.macasaet.fernet.TokenExpiredException: Token is expired
    at com.macasaet.fernet.Token.validateAndDecrypt(Token.java:250)
    at com.macasaet.fernet.Validator.validateAndDecrypt(Validator.java:104)
    at com.macasaet.fernet.Token.validateAndDecrypt(Token.java:228)
    at Unable_to_perform_Encryption_using_Fernet_Java.Main.main(Main.java:27)

Code:

import com.macasaet.fernet.Key;
import com.macasaet.fernet.StringValidator;
import com.macasaet.fernet.Token;
import com.macasaet.fernet.Validator;
// get Fernet_Java here: https://mvnrepository.com/artifact/com.macasaet.fernet/fernet-java8
// version used: 1.42
public class Main {
    static final Validator<String> validator = new StringValidator() {
    };
    public static void main(String[] args) {
        System.out.println("https://stackoverflow.com/questions/62939044/unable-to-perform-encryption-using-fernet-java-in-android-studio\n");
        // generate a key
        Key key = Key.generateKey();
        System.out.println("key: " + key.serialise());
        // encrypt
        String plaintext = "this is my data that needs encryption";
        Token token = Token.generate(key, plaintext);
        System.out.println("token: " + token.serialise());
        // decrypt
        System.out.println("token timestamp: " + token.getTimestamp());
        String decryptedtext = token.validateAndDecrypt(key, validator);
        System.out.println("decryptedtext: " + decryptedtext);
        // old token
        Token token2 = Token.fromString("gAAAAAAdwJ6wAAECAwQFBgcICQoLDA0ODy021cpGVWKZ_eEwCGM4BLLF_5CV9dOPmrhuVUPgJobwOz7JcbmrR64jVmpU4IwqDA==");
        System.out.println("token2 timestamp: " + token2.getTimestamp());
        String decryptedtext2 = token2.validateAndDecrypt(key, validator);
        System.out.println("decryptedtext2: " + decryptedtext2);
    }
}

Yes, but the token additionally holds a timestamp so this token is valid only for 60 seconds. Think about the login to a webservice - the token will be saved in your browser history but when you're trying to login later then 60seconds the login will fail. If you found my answer helpful please mark it as accepted, thank you. — Michael Fehr, Jul 17 '20 at 09:10
@Rohit TP: The question was about **encryption**, not **decryption**. If you stuck on this kindly ask your own question, add the code your'e struggling with and add a sample dataset (plaintext, key, ciphertext), thanks. — Michael Fehr, Dec 21 '20 at 21:55

Unable to perform Encryption using Fernet-Java in Android Studio

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