Class NullCipher

java.lang.Object

javax.crypto.Cipher

javax.crypto.NullCipher

public class NullCipher extends Cipher

The NullCipher class is a class that provides an "identity cipher" -- one that does not transform the plain text. As a consequence, the ciphertext is identical to the plaintext. All initialization methods do nothing, while the blocksize is set to 1 byte. Unlike other ciphers, the NullCipher has no state, and will never throw an IllegalStateException when Cipher methods are called.

Since:: 1.4

Field Summary

Fields declared in class Cipher

DECRYPT_MODE, ENCRYPT_MODE, PRIVATE_KEY, PUBLIC_KEY, SECRET_KEY, UNWRAP_MODE, WRAP_MODE

Modifier and Type	Field	Description
`static final int`	`DECRYPT_MODE`	Constant used to initialize cipher to decryption mode.
`static final int`	`ENCRYPT_MODE`	Constant used to initialize cipher to encryption mode.
`static final int`	`PRIVATE_KEY`	Constant used to indicate the to-be-unwrapped key is a "private key".
`static final int`	`PUBLIC_KEY`	Constant used to indicate the to-be-unwrapped key is a "public key".
`static final int`	`SECRET_KEY`	Constant used to indicate the to-be-unwrapped key is a "secret key".
`static final int`	`UNWRAP_MODE`	Constant used to initialize cipher to key-unwrapping mode.
`static final int`	`WRAP_MODE`	Constant used to initialize cipher to key-wrapping mode.

Constructor Summary

Constructor	Description
`NullCipher()`	Creates a `NullCipher` object.

Method Summary

Methods declared in class Cipher

doFinal, doFinal, doFinal, doFinal, doFinal, doFinal, doFinal, getAlgorithm, getBlockSize, getExemptionMechanism, getInstance, getInstance, getInstance, getIV, getMaxAllowedKeyLength, getMaxAllowedParameterSpec, getOutputSize, getParameters, getProvider, init, init, init, init, init, init, init, init, toString, unwrap, update, update, update, update, update, updateAAD, updateAAD, updateAAD, wrap

Modifier and Type	Method	Description
`final byte[]`	`doFinal()`	Finishes a multiple-part encryption or decryption operation, depending on how this `Cipher` object was initialized.
`final byte[]`	`doFinal(byte[] input)`	Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
`final int`	`doFinal(byte[] output, int outputOffset)`	Finishes a multiple-part encryption or decryption operation, depending on how this `Cipher` object was initialized.
`final byte[]`	`doFinal(byte[] input, int inputOffset, int inputLen)`	Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
`final int`	`doFinal(byte[] input, int inputOffset, int inputLen, byte[] output)`	Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
`final int`	`doFinal(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)`	Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
`final int`	`doFinal(ByteBuffer input, ByteBuffer output)`	Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
`final String`	`getAlgorithm()`	Returns the algorithm name of this `Cipher` object.
`final int`	`getBlockSize()`	Returns the block size (in bytes).
`final ExemptionMechanism`	`getExemptionMechanism()`	Returns the exemption mechanism object used with this `Cipher` object.
`static final Cipher`	`getInstance(String transformation)`	Returns a `Cipher` object that implements the specified transformation.
`static final Cipher`	`getInstance(String transformation, String provider)`	Returns a `Cipher` object that implements the specified transformation.
`static final Cipher`	`getInstance(String transformation, Provider provider)`	Returns a `Cipher` object that implements the specified transformation.
`final byte[]`	`getIV()`	Returns the initialization vector (IV) in a new buffer.
`static final int`	`getMaxAllowedKeyLength(String transformation)`	Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction policy files.
`static final AlgorithmParameterSpec`	`getMaxAllowedParameterSpec(String transformation)`	Returns an `AlgorithmParameterSpec` object which contains the maximum `Cipher` parameter value according to the jurisdiction policy file.
`final int`	`getOutputSize(int inputLen)`	Returns the length in bytes that an output buffer would need to be in order to hold the result of the next `update` or `doFinal` operation, given the input length `inputLen` (in bytes).
`final AlgorithmParameters`	`getParameters()`	Returns the parameters used with this `Cipher` object.
`final Provider`	`getProvider()`	Returns the provider of this `Cipher` object.
`final void`	`init(int opmode, Certificate certificate)`	Initializes this `Cipher` object with the public key from the given certificate.
`final void`	`init(int opmode, Certificate certificate, SecureRandom random)`	Initializes this `Cipher` object with the public key from the given certificate and a source of randomness.
`final void`	`init(int opmode, Key key)`	Initializes this `Cipher` object with a key.
`final void`	`init(int opmode, Key key, AlgorithmParameters params)`	Initializes this `Cipher` object with a key and a set of algorithm parameters.
`final void`	`init(int opmode, Key key, AlgorithmParameters params, SecureRandom random)`	Initializes this `Cipher` object with a key, a set of algorithm parameters, and a source of randomness.
`final void`	`init(int opmode, Key key, SecureRandom random)`	Initializes this `Cipher` object with a key and a source of randomness.
`final void`	`init(int opmode, Key key, AlgorithmParameterSpec params)`	Initializes this `Cipher` object with a key and a set of algorithm parameters.
`final void`	`init(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random)`	Initializes this `Cipher` object with a key, a set of algorithm parameters, and a source of randomness.
`String`	`toString()`	Returns a `String` representation of this `Cipher` object.
`final Key`	`unwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType)`	Unwrap a previously wrapped key.
`final byte[]`	`update(byte[] input)`	Continues a multiple-part encryption or decryption operation (depending on how this `Cipher` object was initialized), processing another data part.
`final byte[]`	`update(byte[] input, int inputOffset, int inputLen)`	Continues a multiple-part encryption or decryption operation (depending on how this `Cipher` object was initialized), processing another data part.
`final int`	`update(byte[] input, int inputOffset, int inputLen, byte[] output)`	Continues a multiple-part encryption or decryption operation (depending on how this `Cipher` object was initialized), processing another data part.
`final int`	`update(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)`	Continues a multiple-part encryption or decryption operation (depending on how this `Cipher` object was initialized), processing another data part.
`final int`	`update(ByteBuffer input, ByteBuffer output)`	Continues a multiple-part encryption or decryption operation (depending on how this `Cipher` object was initialized), processing another data part.
`final void`	`updateAAD(byte[] src)`	Continues a multi-part update of the Additional Authentication Data (AAD).
`final void`	`updateAAD(byte[] src, int offset, int len)`	Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer.
`final void`	`updateAAD(ByteBuffer src)`	Continues a multi-part update of the Additional Authentication Data (AAD).
`final byte[]`	`wrap(Key key)`	Wrap a key.

Methods declared in class Object

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

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

NullCipher

public NullCipher()

Creates a NullCipher object.

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.