Java in a Nutshell, 5th Edition [Electronic resources] نسخه متنی

Some countries place legal restrictions on the
use of cryptographic algorithms. In some cases, a program may be
exempt from these restrictions if it implements an
"exemption mechanism" such as key
recovery, key escrow, or key weakening. This class defines a very
general API to such mechanism. This class is rarely used, and is not
supported in the default implementation provided by Sun. Using this
class successfully is quite complex, and is beyond the scope of this
reference. For details, see the discussion "How to
Make Applications `Exempt' from
Cryptographic Restrictions" in the

JCE
Reference Guide which is part of the standard bundle of
documentation shipped by Sun with the JDK.

public class

ExemptionMechanism {
// Protected Constructors
protected

ExemptionMechanism (ExemptionMechanismSpi

exmechSpi ,
java.security.Provider

provider , String

mechanism );
// Public Class Methods
public static final ExemptionMechanism

getInstance (String

algorithm )
throws java.security.NoSuchAlgorithmException;
public static final ExemptionMechanism

getInstance (String

algorithm ,
String

provider ) throws java.security.NoSuchAlgorithmException,
java.security.NoSuchProviderException;
public static final ExemptionMechanism

getInstance (String

algorithm ,
java.security.Provider

provider )
throws java.security.NoSuchAlgorithmException;
// Public Instance Methods
public final byte[ ]

genExemptionBlob ( ) throws IllegalStateException,
ExemptionMechanismException;
public final int

genExemptionBlob (byte[ ]

output )
throws IllegalStateException, ShortBufferException,
ExemptionMechanismException;
public final int

genExemptionBlob (byte[ ]

output , int

outputOffset )
throws IllegalStateException, ShortBufferException,
ExemptionMechanismException;
public final String

getName ( );
public final int

getOutputSize (int

inputLen ) throws IllegalStateException;
public final java.security.Provider

getProvider ( );
public final void

init (java.security.Key

key )
throws java.security.InvalidKeyException,
ExemptionMechanismException;
public final void

init (java.security.Key

key ,
java.security.spec.AlgorithmParameterSpec

params )
throws java.security.InvalidKeyException,
java.security.InvalidAlgorithmParameterException,
ExemptionMechanismException;
public final void

init (java.security.Key

key ,
java.security.AlgorithmParameters

params )
throws java.security.InvalidKeyException,
java.security.InvalidAlgorithmParameterException,
ExemptionMechanismException;
public final boolean

isCryptoAllowed (java.security.Key

key )
throws ExemptionMechanismException;
// Protected Methods Overriding Object
protected void

finalize ( );
}

Returned By

Cipher.getExemptionMechanism( )