info.pppc.base.plugin.security.dh

Class DHExchange

java.lang.Object

info.pppc.base.plugin.security.dh.AbstractExchange

info.pppc.base.plugin.security.dh.DHExchange

public final class DHExchange
extends AbstractExchange

Creates a shared secret between two parties. Both parties need to first call the create method, then to send the created integer to the corresponding communication partner. After receiving this message, they call the get secret method and obtain a shared secret (a SHA256 hash) that can be directly used for key creation.

Author:

Wolfgang Apolinarski

Field Summary

Fields inherited from class info.pppc.base.plugin.security.dh.AbstractExchange

PERFORM_ECDH, PERFORM_FAST_ECDH, PERFORM_NORMAL_DH

Method Summary

Methods

Modifier and Type	Method and Description
static DHExchange	createInstance()
byte[]	createLocalSecret() Creates the the BigInteger of this communication end-point.
byte[]	getSharedSecret(byte[] remoteParameter) Creates the shared secret out of the public BigInteger from the communication partner.

Methods inherited from class info.pppc.base.plugin.security.dh.AbstractExchange

createInstance, registerInstance

Methods inherited from class java.lang.Object

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

Method Detail

createInstance

public static DHExchange createInstance()

createLocalSecret

public byte[] createLocalSecret()

Creates the the BigInteger of this communication end-point. This integer should be transferred to the communication partner.

Specified by:

createLocalSecret in class AbstractExchange

Returns:

A BigInteger (g^a). This message can be read by anybody without revealing the shared secret.

getSharedSecret

public byte[] getSharedSecret(byte[] remoteParameter)

Creates the shared secret out of the public BigInteger from the communication partner. The returned bytes can directly be transformed into a shared secret key.

Specified by:

getSharedSecret in class AbstractExchange

Parameters:

remoteParameter - The BigInteger that was obtained from the communication partner

cert - The certificate of the remote device is not used and can be null

Returns:

32 bytes that can directly be used to create a shared symmetric key.