org.cryptimeleon.craco.kem

Class HashBasedKeyDerivationFunction

java.lang.Object

org.cryptimeleon.craco.kem.HashBasedKeyDerivationFunction

All Implemented Interfaces:

KeyDerivationFunction<SymmetricKey>, org.cryptimeleon.math.serialization.Representable, org.cryptimeleon.math.serialization.StandaloneRepresentable

public class HashBasedKeyDerivationFunction
extends java.lang.Object
implements KeyDerivationFunction<SymmetricKey>

A basic implementation of a KeyDerivationFunction using a hash function. This class can be used to generate key derivation functions that are not provably secure (e.g. using SHA256HashFunction as a hash function), or it can be used to generate provably secure key derivation functions.

Constructor Summary

Constructors

Constructor and Description
HashBasedKeyDerivationFunction() Initializes this key derivation function based on the SHA256 hash function.
HashBasedKeyDerivationFunction(org.cryptimeleon.math.hash.HashFunction hashFunction)
HashBasedKeyDerivationFunction(org.cryptimeleon.math.serialization.Representation repr)

Method Summary

Modifier and Type	Method and Description
int	bitSize() Returns the output length in number of bytes
SymmetricKey	deriveKey(KeyMaterial material)
boolean	equals(java.lang.Object obj)
org.cryptimeleon.math.serialization.Representation	getRepresentation()
int	hashCode()

Methods inherited from class java.lang.Object

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

Constructor Detail

HashBasedKeyDerivationFunction

public HashBasedKeyDerivationFunction(org.cryptimeleon.math.hash.HashFunction hashFunction)

HashBasedKeyDerivationFunction

public HashBasedKeyDerivationFunction()

Initializes this key derivation function based on the SHA256 hash function. Does not yield a provably secure key derivation function.

HashBasedKeyDerivationFunction

public HashBasedKeyDerivationFunction(org.cryptimeleon.math.serialization.Representation repr)

Method Detail

getRepresentation

public org.cryptimeleon.math.serialization.Representation getRepresentation()

Specified by:

getRepresentation in interface org.cryptimeleon.math.serialization.Representable

deriveKey

public SymmetricKey deriveKey(KeyMaterial material)

Specified by:

deriveKey in interface KeyDerivationFunction<SymmetricKey>

bitSize

public int bitSize()

Returns the output length in number of bytes

Returns:

the output length in number of bytes

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object