To Use keytool to Create a Server Certificate. Run keytool to generate a new key pair in the default development keystore file, keystore.jks.This example uses the alias server-alias to generate a new public/private key pair and wrap the public key into a self-signed certificate inside keystore.jks.The key pair is generated by using an algorithm of type RSA, with a default password of changeit. Nov 01, 2018  The API we use to generate the key pairs is in the java.security package. That’s mean we have to import this package into our code. The class for generating the key pairs is KeyPairGenerator. To get an instance of this class we have to call the getInstance methods by providing two parameters. The first parameter is algorithm and the second parameter is the provider. Create a Key Pair You must specify a key pair when you launch an EC2 instance and then specify the private key of the key pair when you connect to the instance. Create a Private/Public Key Pair with Keytool. Procedure 9.1. Create a Private/Public Key Pair with Keytool. Run the keytool -genkey -alias ALIAS -keyalg ALGORITHM -validity DAYS -keystore server.keystore -storetype TYPE command: keytool -genkey -alias teiid -keyalg RSA -validity 365 -keystore server.keystore -storetype JKS.

The KeyPairGenerator class is used to generate pairs of public and private keys. Key pair generators are constructed using the getInstance factory methods (static methods that return instances of a given class).

A Key pair generator for a particular algorithm creates a public/private key pair that can be used with this algorithm. It also associates algorithm-specific parameters with each of the generated keys.

Generate a pair of ssh keys. There are two ways to generate a key pair: in an algorithm-independent manner, and in an algorithm-specific manner. The only difference between the two is the initialization of the object:

• Algorithm-Independent Initialization

  All key pair generators share the concepts of a keysize and a source of randomness. The keysize is interpreted differently for different algorithms (e.g., in the case of the DSA algorithm, the keysize corresponds to the length of the modulus). There is an initialize method in this KeyPairGenerator class that takes these two universally shared types of arguments. There is also one that takes just a keysize argument, and uses the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)

  Since no other parameters are specified when you call the above algorithm-independent initialize methods, it is up to the provider what to do about the algorithm-specific parameters (if any) to be associated with each of the keys.

  If the algorithm is the DSA algorithm, and the keysize (modulus size) is 512, 768, or 1024, then the Sun provider uses a set of precomputed values for the p, q, and g parameters. If the modulus size is not one of the above values, the Sun provider creates a new set of parameters. Other providers might have precomputed parameter sets for more than just the three modulus sizes mentioned above. Still others might not have a list of precomputed parameters at all and instead always create new parameter sets.

• Algorithm-Specific Initialization

  For situations where a set of algorithm-specific parameters already exists (e.g., so-called community parameters in DSA), there are two initialize methods that have an AlgorithmParameterSpec argument. One also has a SecureRandom argument, while the the other uses the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)

In case the client does not explicitly initialize the KeyPairGenerator (via a call to an initialize method), each provider must supply (and document) a default initialization. For example, the Sun provider uses a default modulus size (keysize) of 1024 bits.

Note that this class is abstract and extends from KeyPairGeneratorSpi for historical reasons. Application developers should only take notice of the methods defined in this KeyPairGenerator class; all the methods in the superclass are intended for cryptographic service providers who wish to supply their own implementations of key pair generators.

Every implementation of the Java platform is required to support the following standard KeyPairGenerator algorithms and keysizes in parentheses:

• DiffieHellman (1024)
• DSA (1024)
• RSA (1024, 2048)

These algorithms are described in the KeyPairGenerator section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other algorithms are supported.

The Java KeyPairGenerator class (java.security.KeyPairGenerator) is used to generate asymmetric encryption / decryption key pairs. An asymmetric key pair consists of two keys. The first key is typically used to encrypt data. The second key which is used to decrypt data encrypted with the first key.

Public Key, Private Key Type Key Pairs

The most commonly known type of asymmetric key pair is the public key, private key type of key pair. The private key is used to encrypt data, and the public key can be used to decrypt the data again. Actually, you could also encrypt data using the public key and decrypt it using the private key.

List Pair Java

The private key is normally kept secret, and the public key can be made publicly available. Thus, if Jack encrypts some data with his private key, everyone in possession of Jack's public key can decrypt it.

Creating a KeyPairGenerator Instance

Ssh-keygen generate private key. To use the Java KeyPairGenerator you must first create a KeyPairGenerator instance. Creating a KeyPairGenerator instance is done by calling the method getInstance() method. Here is an example of creating a Java KeyPairGenerator instance:

The getInstance() method takes the name of the encryption algorithm to generate the key pair for. In this example we use the name RSA.

Initializing the KeyPairGenerator

Depending on the algorithm the key pair is generated for, you may have to initialize the KeyPairGenerator instance. Initializing the KeyPairGenerator is done by calling its initialize() method. Here is an example of initializing a Java KeyPairGenerator instance:

This example initializes the KeyPairGenerator to generate keys of 2048 bits in size.

Generating a Key Pair

To generate a KeyPair with a KeyPairGenerator you call the generateKeyPair() method. Here is an example of generating a KeyPair with the KeyPairGenerator:

Java Pair Type