iaik.security.kdf

Class KDF3

java.lang.Object

javax.crypto.KeyGeneratorSpi

iaik.security.kdf.KDF1

iaik.security.kdf.KDF2

iaik.security.kdf.KDF3

public class KDF3
extends KDF2

This class implements the Key Derivation Function (KDF) 3, defined in ANSI X9.44. A KDF is a function which derives keying material of desired length from a shared secret and additional, optional information. The KDF itself is further parameterized with, e.g., a cryptographic hash function.

An application which wants to use KDF3 has to obtain it via the KeyGenerator engine class.

     KeyGenerator kdf3 = KeyGenerator.getInstance("KDF3", "IAIK")
 

A caller has to configure the KDF3 with a cryptographic hash function, like SHA2-256, SHA3-256,.... For that use KDF3ParameterSpec. An example usage may look like this:

     AlgorithmID hashAlg = ...;
     int keyLength = ...;
     byte[] secretValue = ...
     KDF3ParameterSpec spec = new KDF3ParameterSpec(hashAlg, keyLength);
     spec.setSecretValue(secretValue);
     kg.init(spec);
     SecretKey key = (SecretKey) kg.generateKey();
 

If an implementation tries to use the KDF3 without a call to KDF1.engineInit(AlgorithmParameterSpec, SecureRandom), the class will throw an exception.

This class extends KDF2, because of the similarity of their workflow.

See Also:

KDF3ParameterSpec

Field Summary

Fields

Modifier and Type	Field and Description
static ObjectID	OID The ASN.1 object identifier (1.3.133.16.840.9.44.1.2) for the KDF3 key derivation function.

Constructor Summary

Constructors

Constructor and Description
KDF3()

Method Summary

Methods

Modifier and Type	Method and Description
protected javax.crypto.SecretKey	engineGenerateKey() Generates a key according to the specification of KDF3 with the provided information.
protected HashBasedGenerationFunction	generateHBGF(KDF1ParameterSpec spec) Intern helper function to create an instance of HashBasedGenerationFunction.
protected java.lang.String	name() Outputs the algorithm name.

Methods inherited from class iaik.security.kdf.KDF1

engineInit, engineInit, engineInit

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

OID

public static final ObjectID OID

The ASN.1 object identifier (1.3.133.16.840.9.44.1.2) for the KDF3 key derivation function.

Constructor Detail

KDF3

public KDF3()

Method Detail

name

protected java.lang.String name()

Outputs the algorithm name. Will always return "KDF3".

Overrides:

name in class KDF2

Returns:

"KDF3"

generateHBGF

protected HashBasedGenerationFunction generateHBGF(KDF1ParameterSpec spec)

Intern helper function to create an instance of HashBasedGenerationFunction. Note: Do not call this on your own.

Overrides:

generateHBGF in class KDF2

engineGenerateKey

protected javax.crypto.SecretKey engineGenerateKey()

Generates a key according to the specification of KDF3 with the provided information. This method returns an instance of SecretKey. To obtain the secret, call SecretKey.getEncoded().

Overrides:

engineGenerateKey in class KDF2

Returns:

an instance of SecretKey holding the derived secret.

Throws:

InternalErrorException - if the caller did not initialize the object accordingly.