Class KeyAgreementSpi

Constructor Detail

• KeyAgreementSpi

  public KeyAgreementSpi()

Method Detail

• engineInit

  protected abstract void engineInit(Key key,
                SecureRandom random)
                              throws InvalidKeyException

  Initializes this key agreement with the given key and source of randomness. The given key is required to contain all the algorithm parameters required for this key agreement.

  If the key agreement algorithm requires random bytes, it gets them from the given source of randomness, random. However, if the underlying algorithm implementation does not require any random bytes, random is ignored.

  Parameters:

  key - the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key.

  random - the source of randomness

  Throws:

  InvalidKeyException - if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.

• engineInit

  protected abstract void engineInit(Key key,
                AlgorithmParameterSpec params,
                SecureRandom random)
                              throws InvalidKeyException,
                                     InvalidAlgorithmParameterException

  Initializes this key agreement with the given key, set of algorithm parameters, and source of randomness.

  Parameters:

  key - the party's private information. For example, in the case of the Diffie-Hellman key agreement, this would be the party's own Diffie-Hellman private key.

  params - the key agreement parameters

  random - the source of randomness

  Throws:

  InvalidKeyException - if the given key is inappropriate for this key agreement, e.g., is of the wrong type or has an incompatible algorithm type.

  InvalidAlgorithmParameterException - if the given parameters are inappropriate for this key agreement.

• engineDoPhase

  protected abstract Key engineDoPhase(Key key,
                  boolean lastPhase)
                                throws InvalidKeyException,
                                       IllegalStateException

  Executes the next phase of this key agreement with the given key that was received from one of the other parties involved in this key agreement.

  Parameters:

  key - the key for this phase. For example, in the case of Diffie-Hellman between 2 parties, this would be the other party's Diffie-Hellman public key.

  lastPhase - flag which indicates whether or not this is the last phase of this key agreement.

  Returns:

  the (intermediate) key resulting from this phase, or null if this phase does not yield a key

  Throws:

  InvalidKeyException - if the given key is inappropriate for this phase.

  IllegalStateException - if this key agreement has not been initialized.

• engineGenerateSecret

  protected abstract byte[] engineGenerateSecret()
                                          throws IllegalStateException

  Generates the shared secret and returns it in a new buffer.

  This method resets this KeyAgreementSpi object, so that it can be reused for further key agreements. Unless this key agreement is reinitialized with one of the engineInit methods, the same private information and algorithm parameters will be used for subsequent key agreements.

  Returns:

  the new buffer with the shared secret

  Throws:

  IllegalStateException - if this key agreement has not been completed yet

• engineGenerateSecret

  protected abstract int engineGenerateSecret(byte[] sharedSecret,
                         int offset)
                                       throws IllegalStateException,
                                              ShortBufferException

  Generates the shared secret, and places it into the buffer sharedSecret, beginning at offset inclusive.

  If the sharedSecret buffer is too small to hold the result, a ShortBufferException is thrown. In this case, this call should be repeated with a larger output buffer.

  This method resets this KeyAgreementSpi object, so that it can be reused for further key agreements. Unless this key agreement is reinitialized with one of the engineInit methods, the same private information and algorithm parameters will be used for subsequent key agreements.

  Parameters:

  sharedSecret - the buffer for the shared secret

  offset - the offset in sharedSecret where the shared secret will be stored

  Returns:

  the number of bytes placed into sharedSecret

  Throws:

  IllegalStateException - if this key agreement has not been completed yet

  ShortBufferException - if the given output buffer is too small to hold the secret

• engineGenerateSecret

  protected abstract SecretKey engineGenerateSecret(String algorithm)
                                             throws IllegalStateException,
                                                    NoSuchAlgorithmException,
                                                    InvalidKeyException

  Creates the shared secret and returns it as a secret key object of the requested algorithm type.

  This method resets this KeyAgreementSpi object, so that it can be reused for further key agreements. Unless this key agreement is reinitialized with one of the engineInit methods, the same private information and algorithm parameters will be used for subsequent key agreements.

  Parameters:

  algorithm - the requested secret key algorithm

  Returns:

  the shared secret key

  Throws:

  IllegalStateException - if this key agreement has not been completed yet

  NoSuchAlgorithmException - if the requested secret key algorithm is not available

  InvalidKeyException - if the shared secret key material cannot be used to generate a secret key of the requested algorithm type (e.g., the key material is too short)