Package net.i2p.router.transport.udp

Class SSUHMACGenerator

java.lang.Object

net.i2p.crypto.HMACGenerator

net.i2p.router.transport.udp.SSUHMACGenerator

class SSUHMACGenerator
extends HMACGenerator

Calculate the HMAC-MD5-128 of a key+message. All the good stuff occurs in I2PHMac Keys are always 32 bytes. This is used only by UDP. Use deprecated outside the router, this may move to router.jar. NOTE THIS IS NOT COMPATIBLE with javax.crypto.Mac.getInstance("HmacMD5") as we tell I2PHMac that the digest length is 32 bytes, so it generates a different result. Quote jrandom: "The HMAC is hardcoded to use SHA256 digest size for backwards compatability. next time we have a backwards incompatible change, we should update this." Does this mean he intended it to be compatible with MD5? See also 2005-07-05 status notes.

Since:

0.9.42 moved from net.i2p.crypto.HMACGenerator

Constructor Summary

Constructors

Constructor	Description
SSUHMACGenerator()

Method Summary

Modifier and Type	Method	Description
void	calculate(SessionKey key, byte[] data, int offset, int length, byte[] target, int targetOffset)	Calculate the HMAC of the data with the given key
void	clearCache()
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 net.i2p.crypto.HMACGenerator

acquireTmp, releaseTmp

Methods inherited from class java.lang.Object

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

Constructor Details

SSUHMACGenerator

public SSUHMACGenerator()

Method Details

calculate

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

Calculate the HMAC of the data with the given key

Specified by:

calculate in class HMACGenerator

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 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.

Specified by:

verify in class HMACGenerator

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

clearCache

public void clearCache()

Since:

0.9.42