javax.crypto
abstract public class: KeyAgreementSpi [javadoc |
source]
java.lang.Object
javax.crypto.KeyAgreementSpi
This class defines the
Service Provider Interface (
SPI)
for the
KeyAgreement class.
All the abstract methods in this class must be implemented by each
cryptographic service provider who wishes to supply the implementation
of a particular key agreement algorithm.
The keys involved in establishing a shared secret are created by one
of the
key generators (KeyPairGenerator or
KeyGenerator), a KeyFactory, or as a result from
an intermediate phase of the key agreement protocol
( engineDoPhase ).
For each of the correspondents in the key exchange,
engineDoPhase
needs to be called. For example, if the key exchange is with one other
party, engineDoPhase needs to be called once, with the
lastPhase flag set to true.
If the key exchange is
with two other parties, engineDoPhase needs to be called twice,
the first time setting the lastPhase flag to
false, and the second time setting it to true.
There may be any number of parties involved in a key exchange.
| Methods from java.lang.Object: |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Method from javax.crypto.KeyAgreementSpi Detail: |
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 abstract protected 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. |
abstract protected 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. |
abstract protected 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. |
abstract protected 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. |
abstract protected 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. |
abstract protected 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. |