The KeyPairGenerator class is used to generate pairs of public and private keys. Key pair generators are constructed using the ![Rsa Rsa](/uploads/1/2/6/0/126043328/814508244.jpg)
- Below is the relevant information from the link which Zaki provided. Generate a 2048-bit RSA private key $ openssl genrsa -out privatekey.pem 2048. Convert private Key to PKCS#8 format (so Java can read it).
- This definitely was useful. In my case I was trying to use my openssh pubkey and had to run this magic first: ssh-keygen -f /.ssh/idrsa.pub -e -m pkcs8 key.pkcs8 - apparently openssh uses a proprietary format for the public key and and the standard pkcs8 format for the private.
- Keys can be used for Data Encryption and Digital Signing. They can be generated by OpenSSL which i have talked about in a previous article. OpenSSL – Generate a RSA Key and Keystore Actually, the Java JDK also provides API for creating key pair. Done =) Reference: RSA encryption in Java.
getInstance
Nov 01, 2018 A private key can be use to sign a document and the public key is use to verify that the signature of the document is valid. 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.
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.
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 InitializationAll 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 akeysize
argument, and uses theSecureRandom
implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation ofSecureRandom
, a system-provided source of randomness is used.)Since no other parameters are specified when you call the above algorithm-independentinitialize
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 thep
,q
, andg
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 InitializationFor 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 anAlgorithmParameterSpec
argument. One also has aSecureRandom
argument, while the the other uses theSecureRandom
implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation ofSecureRandom
, a system-provided source of randomness is used.)
![Rsa Rsa](/uploads/1/2/6/0/126043328/814508244.jpg)
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. Generate Rsa Public Key Java Login
Every implementation of the Java platform is required to support the following standard
KeyPairGenerator
algorithms and keysizes in parentheses: Create Rsa Public Private Key Pair
DiffieHellman
(1024)DSA
(1024)RSA
(1024, 2048)