The KeyFactory class is an engine class that is designed to provide opaque cryptographic keys (of type Key) and key specifications (transparent representations of the underlying key material). The keys generated by this provider are similar to the keys that are available in a software provider. However, the keys have more methods that relate to the PKCS#11 standard attributes. There are two external representations by which a key may be transmitted—by its encoded format, or by the parameters that were used to generate the key. Either of these representations may be encapsulated in a key specification, which is used to interact with the KeyFactory class (java.security.KeyFactory) that actually imports and exports keys.
gistfile1.java
importjava.security.KeyPairGenerator; |
importjava.security.KeyPair; |
importjava.security.PrivateKey; |
importjava.security.PublicKey; |
importjava.security.KeyFactory; |
importjava.security.spec.EncodedKeySpec; |
importjava.security.spec.PKCS8EncodedKeySpec; |
importjava.security.spec.X509EncodedKeySpec; |
importjava.security.spec.InvalidKeySpecException; |
importjava.security.NoSuchAlgorithmException; |
importcom.sun.jersey.core.util.Base64; |
publicclassGeneratePublicPrivateKeys { |
privatestaticvoidgenerateKeys(StringkeyAlgorithm, intnumBits) { |
try { |
// Get the public/private key pair |
KeyPairGenerator keyGen =KeyPairGenerator.getInstance(keyAlgorithm); |
keyGen.initialize(numBits); |
KeyPair keyPair = keyGen.genKeyPair(); |
PrivateKey privateKey = keyPair.getPrivate(); |
PublicKey publicKey = keyPair.getPublic(); |
System.out.println('n'+'Generating key/value pair using '+ privateKey.getAlgorithm() +' algorithm'); |
// Get the bytes of the public and private keys |
byte[] privateKeyBytes = privateKey.getEncoded(); |
byte[] publicKeyBytes = publicKey.getEncoded(); |
// Get the formats of the encoded bytes |
String formatPrivate = privateKey.getFormat(); // PKCS#8 |
String formatPublic = publicKey.getFormat(); // X.509 |
System.out.println('Private Key : '+Base64.encode(String.valueOf(privateKeyBytes))); |
System.out.println('Public Key : '+Base64.encode(String.valueOf(publicKeyBytes))); |
// The bytes can be converted back to public and private key objects |
KeyFactory keyFactory =KeyFactory.getInstance(keyAlgorithm); |
EncodedKeySpec privateKeySpec =newPKCS8EncodedKeySpec(privateKeyBytes); |
PrivateKey privateKey2 = keyFactory.generatePrivate(privateKeySpec); |
EncodedKeySpec publicKeySpec =newX509EncodedKeySpec(publicKeyBytes); |
PublicKey publicKey2 = keyFactory.generatePublic(publicKeySpec); |
// The original and new keys are the same |
System.out.println(' Are both private keys equal? '+ privateKey.equals(privateKey2)); |
System.out.println(' Are both public keys equal? '+ publicKey.equals(publicKey2)); |
} catch (InvalidKeySpecException specException) { |
System.out.println('Exception'); |
System.out.println('Invalid Key Spec Exception'); |
} catch (NoSuchAlgorithmException e) { |
System.out.println('Exception'); |
System.out.println('No such algorithm: '+ keyAlgorithm); |
} |
} |
publicstaticvoidmain(String[] args) { |
// Generate a 1024-bit Digital Signature Algorithm (DSA) key pair |
generateKeys('DSA', 1024); |
// Generate a 576-bit DH key pair |
generateKeys('DH', 576); |
// Generate a 1024-bit RSA key pair |
generateKeys('RSA', 1024); |
} |
} |
Java Keyfactory To Generate Public Keys In Excel
![Java keyfactory to generate public keys 2016 Java keyfactory to generate public keys 2016](/uploads/1/2/6/3/126360397/888998609.jpg)
commented Mar 14, 2018
Hi You post is interestnig , is there away I can create a privatre key instance via a signature given stiring? I have pub/private keys generated already KeyPairGenerator keyPairGenerator is going to createa key pair, but in my case I alrady have it and then further want to use them for signign. Avg pc tuneup registration key. e.g //ecdsaSign.initSign(keyPair.getPrivate()); byte[] pkInfo = '51114cac71a9575bc1b39104d176a39d81bd1a705b9a1ad32efd2222f13e59ad'.getBytes(); // PrivateKey pvtKey = DSAPrivateKey <<<<< create a private key here via above string. instead of keyPair created above. ecdsaSign.initSign(pvtKey); //byte[] publicKeyBytes = keyPair.getPublic().getEncoded(); byte[] publicKeyBytes = '025fe2d166a5a8ff005eb0c799a474174f5d061de266438c69d36c2032c6bff51a'.getBytes(); |
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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.)
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:
Create a Key Pair Generator
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.
![Java keyfactory to generate public keys free Java keyfactory to generate public keys free](/uploads/1/2/6/3/126360397/807649569.png)
Put the following statement after the
Java Keyfactory To Generate Public Keys 2017
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.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. https://ixpowerup473.weebly.com/windows-7-ultimate-x64-activation-key-generator.html.