String algorithm; KeyGenerator.getInstance(algorithm) String algorithm;String provider; KeyGenerator.getInstance(algorithm, provider) String algorithm; KeyGenerator.getInstance(algorithm, 'AndroidKeyStore') Smart code suggestions by Codota. Key generators are constructed using one of the getInstance class methods of this class. KeyGenerator objects are reusable, i.e., after a key has been generated, the same KeyGenerator object can be re-used to generate further keys. There are two ways to generate a key: in an algorithm-independent manner, and in an algorithm-specific manner. The following are Jave code examples for showing how to use generateKey of the javax.crypto.KeyGenerator class. You can vote up the examples you like. Your votes will be used in our system to get more good examples.

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Contents

• Conclusion

1. Introduction

A Message Authentication Code or a MAC provides a way to guarantee that a message (a byte array) has not been modified in transit. It is similar to a message digest to calculate a hash, but uses a secret key so that only a person with the secret key can verify the authenticity of the message.

Using a MAC to ensure safe transmission of messages requires that the two parties share a secret key to be able to generate and verify the MAC. There are two approaches available here – the two parties can share a secret key directly. Or the secret key can be generated using a password. We investigate both approaches below.

2. Java Imports

The following java imports are required.

3. Generating a Key

Let us now look into generating a secret key that the parties exchanging messages can share. Either party can generate the key as shown here and send it to the other party via a secure channel.

The following KeyGenerator algorithms are supported in my version of java. Of these, ones starting with HMAC are useful as a secret key for a MAC.

4. Saving and Restoring a Key

You will need to send the key to the receiver to enable verification. So you need to be able to save and restore the key. Here is how you can save it to a file.

And restoring the key is also quite simple.

5. Generating the Message Authentication Code (MAC)

Once you generate the key, you can proceed with generating the MAC for a message.

Use one of the following values for the algorithm (algo):

The static method processFile() is defined as follows:

Once the MAC is obtained, you can send it to the other party along with the file for verification.

6. Using a Password for Key Generation

While one way of generating a secret key is to directly use a KeyGenerator as shown above, sometimes it is more convenient to use a password to generate the key. This can be accomplished using a SecretKeyFactory.

One aspect of using a password for key generation is that it requires the use of a salt. This salt can be generated using the SecureRandom class while generating the key, but the same salt must be used again for verification. This means the salt also must be communicated to the message receiver, but it need not be kept secret – it can be transmitted as plain-text.

The following code generates and prints the salt for transmission.

And now for the generation of the secret key.

Use one of the following values for the algorithm (algo):

Once you have the SecretKey, the procedure for computing the MAC is the same as above. However, you will need to use one of the following algorithms:

Conclusion

In this article, we learned how to compute a MAC (Message Authentication Code) for a message. A MAC requires a secret key which needs to be shared among the parties in the exchange. A password can be used for generating the secret key too.

• Java Cryptography Tutorial

• Message Digest and MAC

Keygenerator.getinstance Algorithm Generate Key Code

• Keys and Key Store

• Generating Keys

• Digital Signature

• Cipher Text

• Java Cryptography Resources

• Selected Reading

Java provides KeyGenerator class this class is used to generate secret keys and objects of this class are reusable.

To generate keys using the KeyGenerator class follow the steps given below.

Step 1: Create a KeyGenerator object

The KeyGenerator class provides getInstance() method which accepts a String variable representing the required key-generating algorithm and returns a KeyGenerator object that generates secret keys.

Create KeyGenerator object using the getInstance() method as shown below.

Generate Key Code

Step 2: Create SecureRandom object

The SecureRandom class of the java.Security package provides a strong random number generator which is used to generate random numbers in Java. Instantiate this class as shown below.

Step 3: Initialize the KeyGenerator

The KeyGenerator class provides a method named init() this method accepts the SecureRandom object and initializes the current KeyGenerator.

Keygenerator.getinstance Algorithm Generate Key Download

Initialize the KeyGenerator object created in the previous step using the init() method. Cisco 3560 generate rsa key.

Example

Following example demonstrates the key generation of the secret key using the KeyGenerator class of the javax.crypto package.

Keygenerator.getinstance Algorithm Generate Key Generator

Output

Keygenerator.getinstance Algorithm Generate Key Code

The above program generates the following output −