Import java.security.Key; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import. About RandomKeygen. Our free mobile-friendly tool offers a variety of randomly generated keys and passwords you can use to secure any application, service or device. Simply click to copy a password or press the 'Generate' button for an entirely new set. Password Recommendations.

In order to be able to create a digital signature, you need a private key. (Its corresponding public key will be needed in order to verify the authenticity of the signature.)

Generate Random Secret Key Java Code

In some cases the key pair (private key and corresponding public key) are already available in files. In that case the program can import and use the private key for signing, as shown in Weaknesses and Alternatives.

In other cases the program needs to generate the key pair. A key pair is generated by using the KeyPairGenerator class.

In this example you will generate a public/private key pair for the Digital Signature Algorithm (DSA). You will generate keys with a 1024-bit length.

Generating a key pair requires several steps:

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The first step is to get a key-pair generator object for generating keys for the DSA signature algorithm.

As with all engine classes, the way to get a KeyPairGenerator object for a particular type of algorithm is to call the getInstance static factory method on the KeyPairGenerator class. This method has two forms, both of which hava a String algorithm first argument; one form also has a String provider second argument.

A caller may thus optionally specify the name of a provider, which will guarantee that the implementation of the algorithm requested is from the named provider. The sample code of this lesson always specifies the default SUN provider built into the JDK.

Put the following statement after the

line in the file created in the previous step, Prepare Initial Program Structure:

Initialize the Key Pair Generator

The next step is to initialize the key pair generator. All key pair generators share the concepts of a keysize and a source of randomness. The KeyPairGenerator class has an initialize method that takes these two types of arguments.

The keysize for a DSA key generator is the key length (in bits), which you will set to 1024.

The source of randomness must be an instance of the SecureRandom class that provides a cryptographically strong random number generator (RNG). For more information about SecureRandom, see the SecureRandom API Specification and the Java Cryptography Architecture Reference Guide .

The following example requests an instance of SecureRandom that uses the SHA1PRNG algorithm, as provided by the built-in SUN provider. The example then passes this SecureRandom instance to the key-pair generator initialization method.

Generate Random Secret Key Java Code

Some situations require strong random values, such as when creating high-value and long-lived secrets like RSA public and private keys. To help guide applications in selecting a suitable strong SecureRandom implementation, starting from JDK 8 Java distributions include a list of known strong SecureRandom implementations in the securerandom.strongAlgorithms property of the java.security.Security class. When you are creating such data, you should consider using SecureRandom.getInstanceStrong(), as it obtains an instance of the known strong algorithms.

Generate the Pair of Keys

The final step is to generate the key pair and to store the keys in PrivateKey and PublicKey objects.

java-otp is a Java library for generating HOTP (RFC 4226) or TOTP (RFC 6238) one-time passwords.

Getting java-otp

You can download java-otp as a jar file (it has no dependencies) from the GitHub releases page and add it to your project's classpath. If you're using Maven (or something that understands Maven dependencies) to build your project, you can add java-otp as a dependency:

java-otp works with Java 8 or newer. If you need support for versions of Java older than Java 8, you may try using java-otp v0.1 (although it is no longer supported).

Usage

To demonstrate generating one-time passwords, we'll focus on the TOTP algorithm. To create a TOTP generator with a default password length (6 digits), time step (30 seconds), and HMAC algorithm (HMAC-SHA1):

To actually generate time-based one-time passwords, you'll need a key and a timestamp. Secure key management is beyond the scope of this document; for the purposes of an example, though, we'll generate a random key:

Armed with a key, we can deterministically generate one-time passwords for any timestamp:

…which produces (for one randomly-generated key):

License and copyright

java-otp is published under the MIT License.