org.bouncycastle.crypto.agreement

## Class XDHBasicAgreement

- java.lang.Object
- - org.bouncycastle.crypto.agreement.XDHBasicAgreement

- All Implemented Interfaces:
    BasicAgreement

      public class XDHBasicAgreement
      extends java.lang.Object
      implements BasicAgreement

  Key agreement using X25519 or X448. Same as Weierstrauss curve based ECDH, except this uses the U-coordinate while ECDH uses the X-coordinate.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `XDHBasicAgreement()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.math.BigInteger` | `calculateAgreement(CipherParameters pubKey)` given a public key from a given party calculate the next message in the agreement sequence.
    `int` | `getFieldSize()` return the field size for the agreement algorithm in bytes.
    `void` | `init(CipherParameters key)` initialise the agreement engine.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### XDHBasicAgreement

          public XDHBasicAgreement()

  - ### Method Detail

    - #### init

          public void init(CipherParameters key)

      Description copied from interface: `BasicAgreement`
      initialise the agreement engine.
      Specified by:
        `init` in interface `BasicAgreement`

    - #### getFieldSize

          public int getFieldSize()

      Description copied from interface: `BasicAgreement`
      return the field size for the agreement algorithm in bytes.
      Specified by:
        `getFieldSize` in interface `BasicAgreement`

    - #### calculateAgreement

          public java.math.BigInteger calculateAgreement(CipherParameters pubKey)

      Description copied from interface: `BasicAgreement`
      given a public key from a given party calculate the next message in the agreement sequence.
      Specified by:
        `calculateAgreement` in interface `BasicAgreement`