Package net.i2p.router.transport.crypto

Class DHSessionKeyBuilder

java.lang.Object
net.i2p.router.transport.crypto.DHSessionKeyBuilder
public class DHSessionKeyBuilder extends Object
Generate a new session key through a diffie hellman exchange. This uses the constants defined in CryptoConstants, which causes the exchange to create a 256 bit session key. This class precalcs a set of values on its own thread. Whenever the pool has less than the minimum, it fills it up again to the max. There is a delay after each precalculation so that the CPU isn't hosed during startup. These three parameters are controlled by java environmental variables and can be adjusted via: -Dcrypto.dh.precalc.min=40 -Dcrypto.dh.precalc.max=100 -Dcrypto.dh.precalc.delay=60000 (delay is milliseconds) To disable precalculation, set min to 0
Since:
0.9 moved from net.i2p.crypto
Author:
jrandom

  • Constructor Details

    • DHSessionKeyBuilder

      DHSessionKeyBuilder()
      Create a new public/private value pair for the DH exchange. Only for internal use and unit tests. Others should get instances from PrecalcRunner.getBuilder()

    • DHSessionKeyBuilder

      DHSessionKeyBuilder(I2PAppContext ctx)
      Create a new public/private value pair for the DH exchange. Only for internal use and unit tests. Others should get instances from PrecalcRunner.getBuilder()

  • Method Details

    • getMyPublicValue

      public BigInteger getMyPublicValue()
      Retrieve the public value used by the local participant in the DH exchange,

    • getMyPublicValueBytes

      public byte[] getMyPublicValueBytes()
      Return a 256 byte representation of our public key, with leading 0s if necessary.

    • setPeerPublicValue

      public void setPeerPublicValue(BigInteger peerVal) throws DHSessionKeyBuilder.InvalidPublicParameterException
      Specify the value given by the peer for use in the session key negotiation
      Throws:
      IllegalStateException - if already set
      DHSessionKeyBuilder.InvalidPublicParameterException

    • setPeerPublicValue

      public void setPeerPublicValue(byte[] val) throws DHSessionKeyBuilder.InvalidPublicParameterException
      Parameters:
      val - 256 bytes
      Throws:
      DHSessionKeyBuilder.InvalidPublicParameterException

    • getPeerPublicValue

      public BigInteger getPeerPublicValue()

    • getPeerPublicValueBytes

      public byte[] getPeerPublicValueBytes()
      Return a 256 byte representation of his public key, with leading 0s if necessary.

    • getSessionKey

      public SessionKey getSessionKey()
      Retrieve the session key, calculating it if necessary (and if possible).
      Returns:
      session key exchanged, or null if the exchange is not complete

    • getExtraBytes

      public ByteArray getExtraBytes()
      Retrieve the extra bytes beyond the session key resulting from the DH exchange. If there aren't enough bytes (with all of them being consumed by the 32 byte key), the SHA256 of the key itself is used - but that won't ever happen. Used only by UDP. getData() will be non-null and have at least 32 bytes after call to getSessionKey()
      Returns:
      non-null (but rv.getData() may be null)