Sep 30, 2013 Hi guys!!! I'm learning RSA Encryption now and for this reason I'm programming a little sample in java in order to know how RSA works. But the problem here is that I can't know how programmers generate a Private Key or a Public Key(2048 bit Key) for making Encryption more secure. 2019-11-27 Generate RSA key pair and encode private as string. Ask Question Asked 10 years ago. Active 1 year, 1 month ago. Viewed 73k times 27. I want to generate 512 bit RSA keypair and then encode my public key as a string. How do I generate RSA key pair in JAVA (in openssl format) 0. How to generate unique api key and secret key in java. With every doubling of the RSA key length, decryption is 6-7 times times slower.Hence, when there are large messages for RSA encryption, the performance degrades.In such scenarios, we first do an AES encryption of the messages and the key used for AES encryption is RSA.
Java Generate Rsa 2048 Key Download
This procedure uses the Java keytool utility to generate a key and save it to a Java keystore.
NOTE:
- The CA you use might have specific options required for creating an HTTPS certificate. Review the instructions provided by the CA before creating your key pair.
- DSA keys used in Reflection Gateway server certificates must be either 2048 or 3072 bits. RSA keys must be between 2048 and 4096 bits.
To generate a new public/private key pair in a Java keystore
- Use the -genkeypair option to generate a key and save it to a Java keystore (newkeystore.jks in this example). The example shown here prompts you to enter values for items that make up the distinguished name (DN) in the certificate. See the example below to enter these values directly on the command line.
- The keytool prompts you to enter a password and values for the items that make up the distinguished name (DN) in the certificate (name = CN, organizational unit = OU, organization = O, city or locality = L, state or province = S, two letter country code = C). The generated DN will use the value 'Unknown' for any fields you don't specify.
- When you are prompted with “What is your first and last name?'You must enter the DNS name that is used to access the Reflection Gateway server (for example gateway.mycompany.com). This value is used as the CN (Common Name) in the certificate. If the CN in a certificate doesn't match the actual DNS name used to access the server, you will see a certificate warning when you connect to the server.
- When you are prompted with 'What is the two-letter country code for this unit?'You must enter a valid two-letter country code (for example US).
- When you are prompted for a password for the alias, press Enter to use the same password you used for the keystore.
An alternate option to responding to prompts is to specify the DN value on the command line using the -dname option. For example:
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.
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.)
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)