ExemptionMechanism (Java SE 15 & JDK 15) (original) (raw)

public class ExemptionMechanism extends Object

This class provides the functionality of an exemption mechanism, examples of which are key recovery, key weakening, and_key escrow_.

Applications or applets that use an exemption mechanism may be granted stronger encryption capabilities than those which don't.

Since:

1.4

• Constructor Summary

• Method Summary

Methods declared in class java.lang.Object

[clone](../../java/lang/Object.html#clone%28%29), [equals](../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../java/lang/Object.html#finalize%28%29), [getClass](../../java/lang/Object.html#getClass%28%29), [hashCode](../../java/lang/Object.html#hashCode%28%29), [notify](../../java/lang/Object.html#notify%28%29), [notifyAll](../../java/lang/Object.html#notifyAll%28%29), [toString](../../java/lang/Object.html#toString%28%29), [wait](../../java/lang/Object.html#wait%28%29), [wait](../../java/lang/Object.html#wait%28long%29), [wait](../../java/lang/Object.html#wait%28long,int%29)

• Constructor Details

  • ExemptionMechanism

  Creates a ExemptionMechanism object.
  Parameters:
  exmechSpi - the delegate
  provider - the provider
  mechanism - the exemption mechanism

• Method Details

  • getName

  public final String getName()
  Returns the exemption mechanism name of thisExemptionMechanism object.
  This is the same name that was specified in one of thegetInstance calls that created thisExemptionMechanism object.
  Returns:
  the exemption mechanism name of thisExemptionMechanism object.

  • getInstance

  Returns an ExemptionMechanism object that implements the specified exemption mechanism algorithm.
  This method traverses the list of registered security Providers, starting with the most preferred Provider. A new ExemptionMechanism object encapsulating the ExemptionMechanismSpi implementation from the first Provider that supports the specified algorithm is returned.
  Note that the list of registered providers may be retrieved via the Security.getProviders() method.
  Implementation Note:
  The JDK Reference Implementation additionally uses thejdk.security.provider.preferred Security property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned bySecurity.getProviders().
  Parameters:
  algorithm - the standard name of the requested exemption mechanism. See the ExemptionMechanism section in the Java Security Standard Algorithm Names Specification for information about standard exemption mechanism names.
  Returns:
  the new ExemptionMechanism object
  Throws:
  [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if no Provider supports anExemptionMechanismSpi implementation for the specified algorithm
  [NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if algorithm is null
  See Also:
  Provider

  • getInstance

  Returns an ExemptionMechanism object that implements the specified exemption mechanism algorithm.
  A new ExemptionMechanism object encapsulating the ExemptionMechanismSpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.
  Note that the list of registered providers may be retrieved via the Security.getProviders() method.
  Parameters:
  algorithm - the standard name of the requested exemption mechanism. See the ExemptionMechanism section in the Java Security Standard Algorithm Names Specification for information about standard exemption mechanism names.
  provider - the name of the provider.
  Returns:
  the new ExemptionMechanism object
  Throws:
  [IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the provider is null or empty
  [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if an ExemptionMechanismSpi implementation for the specified algorithm is not available from the specified provider
  [NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security") - if the specified provider is not registered in the security provider list
  [NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if algorithm is null
  See Also:
  Provider

  • getInstance

  Returns an ExemptionMechanism object that implements the specified exemption mechanism algorithm.
  A new ExemptionMechanism object encapsulating the ExemptionMechanismSpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.
  Parameters:
  algorithm - the standard name of the requested exemption mechanism. See the ExemptionMechanism section in the Java Security Standard Algorithm Names Specification for information about standard exemption mechanism names.
  provider - the provider.
  Returns:
  the new ExemptionMechanism object
  Throws:
  [IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the provider is null
  [NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if an ExemptionMechanismSpi implementation for the specified algorithm is not available from the specified Provider object
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if algorithm is null
  See Also:
  Provider

  • getProvider

  public final Provider getProvider()
  Returns the provider of this ExemptionMechanism object.
  Returns:
  the provider of this ExemptionMechanism object.

  • isCryptoAllowed

  Returns whether the result blob has been generated successfully by this exemption mechanism.
  The method also makes sure that the key passed in is the same as the one this exemption mechanism used in initializing and generating phases.
  Parameters:
  key - the key the crypto is going to use.
  Returns:
  whether the result blob of the same key has been generated successfully by this exemption mechanism; false if key is null.
  Throws:
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered while determining whether the result blob has been generated successfully by this exemption mechanism object.

  • getOutputSize

  Returns the length in bytes that an output buffer would need to be in order to hold the result of the nextgenExemptionBlob operation, given the input length inputLen (in bytes).
  The actual output length of the nextgenExemptionBlob call may be smaller than the length returned by this method.
  Parameters:
  inputLen - the input length (in bytes)
  Returns:
  the required output buffer size (in bytes)
  Throws:
  [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang") - if this exemption mechanism is in a wrong state (e.g., has not yet been initialized)

  • init

  Initializes this exemption mechanism with a key.
  If this exemption mechanism requires any algorithm parameters that cannot be derived from the given key, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidKeyException is raised.
  Parameters:
  key - the key for this exemption mechanism
  Throws:
  [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security") - if the given key is inappropriate for this exemption mechanism.
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of initializing.

  • init

  Initializes this exemption mechanism with a key and a set of algorithm parameters.
  If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, anInvalidAlgorithmParameterException is raised.
  Parameters:
  key - the key for this exemption mechanism
  params - the algorithm parameters
  Throws:
  [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security") - if the given key is inappropriate for this exemption mechanism.
  [InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security") - if the given algorithm parameters are inappropriate for this exemption mechanism.
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of initializing.

  • init

  Initializes this exemption mechanism with a key and a set of algorithm parameters.
  If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, anInvalidAlgorithmParameterException is raised.
  Parameters:
  key - the key for this exemption mechanism
  params - the algorithm parameters
  Throws:
  [InvalidKeyException](../../java/security/InvalidKeyException.html "class in java.security") - if the given key is inappropriate for this exemption mechanism.
  [InvalidAlgorithmParameterException](../../java/security/InvalidAlgorithmParameterException.html "class in java.security") - if the given algorithm parameters are inappropriate for this exemption mechanism.
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of initializing.

  • genExemptionBlob

  Generates the exemption mechanism key blob.
  Returns:
  the new buffer with the result key blob.
  Throws:
  [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang") - if this exemption mechanism is in a wrong state (e.g., has not been initialized).
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of generating.

  • genExemptionBlob

  Generates the exemption mechanism key blob, and stores the result in the output buffer.
  If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. UsegetOutputSize to determine how big the output buffer should be.
  Parameters:
  output - the buffer for the result
  Returns:
  the number of bytes stored in output
  Throws:
  [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang") - if this exemption mechanism is in a wrong state (e.g., has not been initialized).
  [ShortBufferException](ShortBufferException.html "class in javax.crypto") - if the given output buffer is too small to hold the result.
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of generating.

  • genExemptionBlob

  Generates the exemption mechanism key blob, and stores the result in the output buffer, starting at outputOffset inclusive.
  If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. UsegetOutputSize to determine how big the output buffer should be.
  Parameters:
  output - the buffer for the result
  outputOffset - the offset in output where the result is stored
  Returns:
  the number of bytes stored in output
  Throws:
  [IllegalStateException](../../java/lang/IllegalStateException.html "class in java.lang") - if this exemption mechanism is in a wrong state (e.g., has not been initialized).
  [ShortBufferException](ShortBufferException.html "class in javax.crypto") - if the given output buffer is too small to hold the result.
  [ExemptionMechanismException](ExemptionMechanismException.html "class in javax.crypto") - if problem(s) encountered in the process of generating.