Package net.i2p.crypto

Class HMACGenerator

java.lang.Object

net.i2p.crypto.HMACGenerator

Direct Known Subclasses:

HMAC256Generator, SSUHMACGenerator

public abstract class HMACGenerator
extends Object

Calculate the HMAC of a key+message. As of 0.9.42, this is just a stub. See net.i2p.router.transport.udp.SSUHMACGenerator for the HMAC used in SSU (what was originally this class), and SHA256Generator for the HMAC used in Syndie.

Constructor Summary

Constructors

Constructor	Description
HMACGenerator()

Method Summary

Modifier and Type	Method	Description
protected byte[]	acquireTmp()	32 bytes from the byte array cache.
abstract void	calculate(SessionKey key, byte[] data, int offset, int length, byte[] target, int targetOffset)	Calculate the HMAC of the data with the given key
protected void	releaseTmp(byte[] tmp)
abstract boolean	verify(SessionKey key, byte[] curData, int curOffset, int curLength, byte[] origMAC, int origMACOffset, int origMACLength)	Verify the MAC inline, reducing some unnecessary memory churn.

Methods inherited from class java.lang.Object

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

Constructor Detail

HMACGenerator

public HMACGenerator()

Method Detail

calculate

public abstract void calculate(SessionKey key,
                               byte[] data,
                               int offset,
                               int length,
                               byte[] target,
                               int targetOffset)

Calculate the HMAC of the data with the given key

Parameters:

target - out parameter the first 16 bytes contain the HMAC, the last 16 bytes are zero

targetOffset - offset into target to put the hmac

Throws:

IllegalArgumentException - for bad key or target too small

verify

public abstract boolean verify(SessionKey key,
                               byte[] curData,
                               int curOffset,
                               int curLength,
                               byte[] origMAC,
                               int origMACOffset,
                               int origMACLength)

Verify the MAC inline, reducing some unnecessary memory churn.

Parameters:

key - session key to verify the MAC with

curData - MAC to verify

curOffset - index into curData to MAC

curLength - how much data in curData do we want to run the HMAC over

origMAC - what do we expect the MAC of curData to equal

origMACOffset - index into origMAC

origMACLength - how much of the MAC do we want to verify

Throws:

IllegalArgumentException - for bad key

acquireTmp

protected byte[] acquireTmp()

32 bytes from the byte array cache. Does NOT zero.

releaseTmp

protected void releaseTmp(byte[] tmp)