org.cryptimeleon.craco.kem

Class SymmetricKeyKEM

java.lang.Object

org.cryptimeleon.craco.kem.SymmetricKeyKEM

All Implemented Interfaces:

KeyEncapsulationMechanism<SymmetricKey>, org.cryptimeleon.math.serialization.annotations.RepresentationRestorer, org.cryptimeleon.math.serialization.Representable, org.cryptimeleon.math.serialization.StandaloneRepresentable

public abstract class SymmetricKeyKEM
extends java.lang.Object
implements KeyEncapsulationMechanism<SymmetricKey>

A KEM that is implemented by the composition of a KeyEncapsulationMechanism providing KeyMaterial and a KeyDerivationFunction that derives a SymmetricKey from the KeyMaterial produced by the KEM.

This should be used in combination with an symmetric encryption scheme to implement the standard hybrid encryption technique.

Nested Class Summary

Nested classes/interfaces inherited from interface org.cryptimeleon.craco.kem.KeyEncapsulationMechanism

KeyEncapsulationMechanism.KeyAndCiphertext<T>

Field Summary

Fields

Modifier and Type	Field and Description
protected KeyDerivationFunction<? extends SymmetricKey>	kdf KDF that derives a symmetric key from the key material generated by kem
protected KeyEncapsulationMechanism<? extends KeyMaterial>	kem Underlying KEM that generates the key material of this KEM.

Constructor Summary

Constructors

Constructor and Description
SymmetricKeyKEM(KeyEncapsulationMechanism<? extends KeyMaterial> kem, KeyDerivationFunction<? extends SymmetricKey> kdf)
SymmetricKeyKEM(org.cryptimeleon.math.serialization.Representation repr)

Method Summary

Modifier and Type	Method and Description
SymmetricKey	decaps(CipherText encapsulatedKey, DecryptionKey sk) Takes an encapsulated key that was created by encaps() and decrypts it with sk.
KeyEncapsulationMechanism.KeyAndCiphertext<SymmetricKey>	encaps(EncryptionKey pk) Randomly chooses a key k and encrypts it using the given pk.
boolean	equals(java.lang.Object o)
KeyDerivationFunction<? extends SymmetricKey>	getKdf()
KeyEncapsulationMechanism<? extends KeyMaterial>	getKem()
org.cryptimeleon.math.serialization.Representation	getRepresentation()
int	hashCode()
DecryptionKey	restoreDecapsulationKey(org.cryptimeleon.math.serialization.Representation repr)
CipherText	restoreEncapsulatedKey(org.cryptimeleon.math.serialization.Representation repr)
EncryptionKey	restoreEncapsulationKey(org.cryptimeleon.math.serialization.Representation repr)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.craco.kem.KeyEncapsulationMechanism

restoreFromRepresentation

Field Detail

kem

protected KeyEncapsulationMechanism<? extends KeyMaterial> kem

Underlying KEM that generates the key material of this KEM.

kdf

protected KeyDerivationFunction<? extends SymmetricKey> kdf

KDF that derives a symmetric key from the key material generated by kem

Constructor Detail

SymmetricKeyKEM

public SymmetricKeyKEM(KeyEncapsulationMechanism<? extends KeyMaterial> kem,
                       KeyDerivationFunction<? extends SymmetricKey> kdf)

SymmetricKeyKEM

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

Method Detail

encaps

public KeyEncapsulationMechanism.KeyAndCiphertext<SymmetricKey> encaps(EncryptionKey pk)

Randomly chooses a key k and encrypts it using the given pk. The result is (key, encapsulatedKey).

It basically outputs the derived key from the key material given by the KEM's encaps and the corresponding encapsulation.

Specified by:

encaps in interface KeyEncapsulationMechanism<SymmetricKey>

Parameters:

pk - public key used for encrypting k

decaps

public SymmetricKey decaps(CipherText encapsulatedKey,
                           DecryptionKey sk)

Takes an encapsulated key that was created by encaps() and decrypts it with sk. That is, if (key, encapsulatedKey) = encaps(pk), then decrypt(encapsulatedKey, sk) == key.

It outputs the image of the kdf on the decapsulation of the given encapsulatedKey.

Specified by:

decaps in interface KeyEncapsulationMechanism<SymmetricKey>

restoreEncapsulatedKey

public CipherText restoreEncapsulatedKey(org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreEncapsulatedKey in interface KeyEncapsulationMechanism<SymmetricKey>

restoreEncapsulationKey

public EncryptionKey restoreEncapsulationKey(org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreEncapsulationKey in interface KeyEncapsulationMechanism<SymmetricKey>

restoreDecapsulationKey

public DecryptionKey restoreDecapsulationKey(org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreDecapsulationKey in interface KeyEncapsulationMechanism<SymmetricKey>

getKem

public KeyEncapsulationMechanism<? extends KeyMaterial> getKem()

getKdf

public KeyDerivationFunction<? extends SymmetricKey> getKdf()

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

getRepresentation

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

Specified by:

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