Package org.apache.sshd.common.kex

Class AbstractDH

java.lang.Object
org.apache.sshd.common.kex.AbstractDH
Direct Known Subclasses:
DHG, ECDH, XDH
public abstract class AbstractDH extends Object
Base class for the Diffie-Hellman key agreement.

  • Field Details

  • Constructor Details

    • AbstractDH

      protected AbstractDH()

  • Method Details

    • setF

      public abstract void setF(byte[] f)

    • isPublicDataAvailable

      public boolean isPublicDataAvailable()

    • calculateE

      protected abstract byte[] calculateE() throws Exception
      Lazy-called by getE() if the public key data has not been generated yet.
      Returns:
      The calculated public key data
      Throws:
      Exception - If failed to generate the relevant data

    • getE

      public byte[] getE() throws Exception
      Returns:
      The local public key data
      Throws:
      Exception - If failed to calculate it

    • putE

      public void putE(Buffer buffer, byte[] e)

    • putF

      public void putF(Buffer buffer, byte[] f)

    • isSharedSecretAvailable

      public boolean isSharedSecretAvailable()

    • calculateK

      protected abstract byte[] calculateK() throws Exception
      Lazy-called by getK() if the shared secret data has not been calculated yet
      Returns:
      The shared secret data
      Throws:
      Exception - If failed to calculate it

    • getK

      public byte[] getK() throws Exception
      Returns:
      The shared secret key
      Throws:
      Exception - If failed to calculate it

    • checkKeyAgreementNecessity

      protected void checkKeyAgreementNecessity()
      Called after either public or private parts have been calculated in order to check if the key-agreement mediator is still required. By default, if both public and private parts have been calculated then key-agreement mediator is null-ified to enable GC for it.
      See Also:

    • getHash

      public abstract Digest getHash() throws Exception
      Throws:
      Exception

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • stripLeadingZeroes

      public static byte[] stripLeadingZeroes(byte[] x)
      The shared secret returned by KeyAgreement.generateSecret() is a byte array, which can (by chance, roughly 1 out of 256 times) begin with zero byte (some JCE providers might strip this, though). In SSH, the shared secret is an integer, so we need to strip the leading zero(es).
      Parameters:
      x - The original array
      Returns:
      An (possibly) sub-array guaranteed to start with a non-zero byte
      Throws:
      IllegalArgumentException - If all zeroes array
      See Also: