Cipher (Java Platform SE 6)

This class provides the functionality of a cryptographic cipher for encryption and decryption. It forms the core of the Java Cryptographic Extension (JCE) framework.

In order to create a Cipher object, the application calls the Cipher's getInstance method, and passes the name of the requested transformation to it. Optionally, the name of a provider may be specified.

A transformation is a string that describes the operation (or set of operations) to be performed on the given input, to produce some output. A transformation always includes the name of a cryptographic algorithm (e.g., DES), and may be followed by a feedback mode and padding scheme.

A transformation is of the form:

"algorithm/mode/padding" or
"algorithm"

(in the latter case, provider-specific default values for the mode and padding scheme are used). For example, the following is a valid transformation:

     Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");

Using modes such as CFB and

OFB, block
 ciphers can encrypt data in units smaller than the cipher's actual
 block size.  When requesting such a mode, you may optionally specify
 the number of bits to be processed at a time by appending this number
 to the mode name as shown in the "DES/CFB8/NoPadding" and
 "DES/OFB32/PKCS5Padding" transformations. If no such
 number is specified, a provider-specific default is used. (For
 example, the SunJCE provider uses a default of 64 bits for DES.)
 Thus, block ciphers can be turned into byte-oriented stream ciphers by
 using an 8 bit mode such as CFB8 or OFB8.




Since:
  1.4
See Also:
KeyGenerator, 
SecretKey









Field Summary



static int
DECRYPT_MODE



          Constant used to initialize cipher to decryption mode.



static int
ENCRYPT_MODE



          Constant used to initialize cipher to encryption mode.



static int
PRIVATE_KEY



          Constant used to indicate the to-be-unwrapped key is a "private key".



static int
PUBLIC_KEY



          Constant used to indicate the to-be-unwrapped key is a "public key".



static int
SECRET_KEY



          Constant used to indicate the to-be-unwrapped key is a "secret key".



static int
UNWRAP_MODE



          Constant used to initialize cipher to key-unwrapping mode.



static int
WRAP_MODE



          Constant used to initialize cipher to key-wrapping mode.


 






Constructor Summary



protected 
Cipher(CipherSpi cipherSpi,
       Provider provider,
       String transformation)



          Creates a Cipher object.


 






Method Summary



 byte[]
doFinal()



          Finishes a multiple-part encryption or decryption operation, depending
 on how this cipher was initialized.



 byte[]
doFinal(byte[] input)



          Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation.



 int
doFinal(byte[] output,
        int outputOffset)



          Finishes a multiple-part encryption or decryption operation, depending
 on how this cipher was initialized.



 byte[]
doFinal(byte[] input,
        int inputOffset,
        int inputLen)



          Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation.



 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.



 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.



 int
doFinal(ByteBuffer input,
        ByteBuffer output)



          Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation.



 String
getAlgorithm()



          Returns the algorithm name of this Cipher object.



 int
getBlockSize()



          Returns the block size (in bytes).



 ExemptionMechanism
getExemptionMechanism()



          Returns the exemption mechanism object used with this cipher.



static Cipher
getInstance(String transformation)



          Returns a Cipher object that implements the specified
 transformation.



static Cipher
getInstance(String transformation,
            Provider provider)



          Returns a Cipher object that implements the specified
 transformation.



static Cipher
getInstance(String transformation,
            String provider)



          Returns a Cipher object that implements the specified
 transformation.



 byte[]
getIV()



          Returns the initialization vector (IV) in a new buffer.



static int
getMaxAllowedKeyLength(String transformation)



          Returns the maximum key length for the specified transformation
 according to the installed JCE jurisdiction policy files.



static AlgorithmParameterSpec
getMaxAllowedParameterSpec(String transformation)



          Returns an AlgorithmParameterSpec object which contains
 the maximum cipher parameter value according to the
 jurisdiction policy file.



 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).



 AlgorithmParameters
getParameters()



          Returns the parameters used with this cipher.



 Provider
getProvider()



          Returns the provider of this Cipher object.



 void
init(int opmode,
     Certificate certificate)



          Initializes this cipher with the public key from the given certificate.



 void
init(int opmode,
     Certificate certificate,
     SecureRandom random)



          Initializes this cipher with the public key from the given certificate
 and
 a source of randomness.



 void
init(int opmode,
     Key key)



          Initializes this cipher with a key.



 void
init(int opmode,
     Key key,
     AlgorithmParameters params)



          Initializes this cipher with a key and a set of algorithm
 parameters.



 void
init(int opmode,
     Key key,
     AlgorithmParameterSpec params)



          Initializes this cipher with a key and a set of algorithm
 parameters.



 void
init(int opmode,
     Key key,
     AlgorithmParameterSpec params,
     SecureRandom random)



          Initializes this cipher with a key, a set of algorithm
 parameters, and a source of randomness.



 void
init(int opmode,
     Key key,
     AlgorithmParameters params,
     SecureRandom random)



          Initializes this cipher with a key, a set of algorithm
 parameters, and a source of randomness.



 void
init(int opmode,
     Key key,
     SecureRandom random)



          Initializes this cipher with a key and a source of randomness.



 Key
unwrap(byte[] wrappedKey,
       String wrappedKeyAlgorithm,
       int wrappedKeyType)



          Unwrap a previously wrapped key.



 byte[]
update(byte[] input)



          Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.



 byte[]
update(byte[] input,
       int inputOffset,
       int inputLen)



          Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.



 int
update(byte[] input,
       int inputOffset,
       int inputLen,
       byte[] output)



          Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.



 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 was initialized), processing another data
 part.



 int
update(ByteBuffer input,
       ByteBuffer output)



          Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.



 byte[]
wrap(Key key)



          Wrap a key.


 


Methods inherited from class java.lang.Object


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


 








Field Detail




ENCRYPT_MODE
public static final int ENCRYPT_MODE

Constant used to initialize cipher to encryption mode.


See Also:
Constant Field Values




DECRYPT_MODE
public static final int DECRYPT_MODE

Constant used to initialize cipher to decryption mode.


See Also:
Constant Field Values




WRAP_MODE
public static final int WRAP_MODE

Constant used to initialize cipher to key-wrapping mode.


See Also:
Constant Field Values




UNWRAP_MODE
public static final int UNWRAP_MODE

Constant used to initialize cipher to key-unwrapping mode.


See Also:
Constant Field Values




PUBLIC_KEY
public static final int PUBLIC_KEY

Constant used to indicate the to-be-unwrapped key is a "public key".


See Also:
Constant Field Values




PRIVATE_KEY
public static final int PRIVATE_KEY

Constant used to indicate the to-be-unwrapped key is a "private key".


See Also:
Constant Field Values




SECRET_KEY
public static final int SECRET_KEY

Constant used to indicate the to-be-unwrapped key is a "secret key".


See Also:
Constant Field Values








Constructor Detail




Cipher
protected Cipher(CipherSpi cipherSpi,
                 Provider provider,
                 String transformation)

Creates a Cipher object.


Parameters:
cipherSpi - the delegate
provider - the provider
transformation - the transformation








Method Detail




getInstance
public static final Cipher getInstance(String transformation)
                                throws NoSuchAlgorithmException,
                                       NoSuchPaddingException

Returns a Cipher object that implements the specified
 transformation.

  This method traverses the list of registered security Providers,
 starting with the most preferred Provider.
 A new Cipher object encapsulating the
 CipherSpi 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.


Parameters:
transformation - the name of the transformation, e.g.,
 DES/CBC/PKCS5Padding.
 See Appendix A in the
 
 Java Cryptography Architecture Reference Guide
 for information about standard transformation names.
Returns:
a cipher that implements the requested transformation.
Throws:
NoSuchAlgorithmException - if transformation
                is null, empty, in an invalid format,
                or if no Provider supports a CipherSpi implementation for the
                specified algorithm.
NoSuchPaddingException - if transformation
                contains a padding scheme that is not available.
See Also:
Provider





getInstance
public static final Cipher getInstance(String transformation,
                                       String provider)
                                throws NoSuchAlgorithmException,
                                       NoSuchProviderException,
                                       NoSuchPaddingException

Returns a Cipher object that implements the specified
 transformation.

  A new Cipher object encapsulating the
 CipherSpi 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:
transformation - the name of the transformation,
 e.g., DES/CBC/PKCS5Padding.
 See Appendix A in the
 
 Java Cryptography Architecture Reference Guide
 for information about standard transformation names.
provider - the name of the provider.
Returns:
a cipher that implements the requested transformation.
Throws:
NoSuchAlgorithmException - if transformation
                is null, empty, in an invalid format,
                or if a CipherSpi implementation for the specified algorithm
                is not available from the specified provider.
NoSuchProviderException - if the specified provider is not
                registered in the security provider list.
NoSuchPaddingException - if transformation
                contains a padding scheme that is not available.
IllegalArgumentException - if the provider
                is null or empty.
See Also:
Provider





getInstance
public static final Cipher getInstance(String transformation,
                                       Provider provider)
                                throws NoSuchAlgorithmException,
                                       NoSuchPaddingException

Returns a Cipher object that implements the specified
 transformation.

  A new Cipher object encapsulating the
 CipherSpi 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:
transformation - the name of the transformation,
 e.g., DES/CBC/PKCS5Padding.
 See Appendix A in the
 
 Java Cryptography Architecture Reference Guide
 for information about standard transformation names.
provider - the provider.
Returns:
a cipher that implements the requested transformation.
Throws:
NoSuchAlgorithmException - if transformation
                is null, empty, in an invalid format,
                or if a CipherSpi implementation for the specified algorithm
                is not available from the specified Provider object.
NoSuchPaddingException - if transformation
                contains a padding scheme that is not available.
IllegalArgumentException - if the provider
                is null.
See Also:
Provider





getProvider
public final Provider getProvider()

Returns the provider of this Cipher object.



Returns:
the provider of this Cipher object





getAlgorithm
public final String getAlgorithm()

Returns the algorithm name of this Cipher object.

 This is the same name that was specified in one of the
 getInstance calls that created this Cipher
 object..



Returns:
the algorithm name of this Cipher object.





getBlockSize
public final int getBlockSize()

Returns the block size (in bytes).



Returns:
the block size (in bytes), or 0 if the underlying algorithm is
 not a block cipher





getOutputSize
public 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).

 This call takes into account any unprocessed (buffered) data from a
 previous update call, and padding.

 
The actual output length of the next update or
 doFinal 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 - if this cipher is in a wrong state
 (e.g., has not yet been initialized)





getIV
public final byte[] getIV()

Returns the initialization vector (IV) in a new buffer.

 This is useful in the case where a random IV was created,
 or in the context of password-based encryption or
 decryption, where the IV is derived from a user-supplied password.



Returns:
the initialization vector in a new buffer, or null if the
 underlying algorithm does not use an IV, or if the IV has not yet
 been set.





getParameters
public final AlgorithmParameters getParameters()

Returns the parameters used with this cipher.

 The returned parameters may be the same that were used to initialize
 this cipher, or may contain a combination of default and random
 parameter values used by the underlying cipher implementation if this
 cipher requires algorithm parameters but was not initialized with any.



Returns:
the parameters used with this cipher, or null if this cipher
 does not use any parameters.





getExemptionMechanism
public final ExemptionMechanism getExemptionMechanism()

Returns the exemption mechanism object used with this cipher.



Returns:
the exemption mechanism object used with this cipher, or
 null if this cipher does not use any exemption mechanism.





init
public final void init(int opmode,
                       Key key)
                throws InvalidKeyException

Initializes this cipher with a key.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters that cannot be
 derived from the given key, the underlying cipher
 implementation is supposed to generate the required parameters itself
 (using provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidKeyException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them using the SecureRandom
 implementation of the highest-priority
 installed provider as the source of randomness.
 (If none of the installed providers supply an implementation of
 SecureRandom, a system-provided source of randomness will be used.)

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of
 the following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
key - the key
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or if this cipher is being initialized for
 decryption and requires algorithm parameters that cannot be
 determined from the given key, or if the given key has a keysize that
 exceeds the maximum allowable keysize (as determined from the
 configured jurisdiction policy files).





init
public final void init(int opmode,
                       Key key,
                       SecureRandom random)
                throws InvalidKeyException

Initializes this cipher with a key and a source of randomness.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters that cannot be
 derived from the given key, the underlying cipher
 implementation is supposed to generate the required parameters itself
 (using provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidKeyException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them from random.

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
key - the encryption key
random - the source of randomness
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or if this cipher is being initialized for
 decryption and requires algorithm parameters that cannot be
 determined from the given key, or if the given key has a keysize that
 exceeds the maximum allowable keysize (as determined from the
 configured jurisdiction policy files).





init
public final void init(int opmode,
                       Key key,
                       AlgorithmParameterSpec params)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

Initializes this cipher with a key and a set of algorithm
 parameters.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters and
 params is null, the underlying cipher implementation is
 supposed to generate the required parameters itself (using
 provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidAlgorithmParameterException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them using the SecureRandom
 implementation of the highest-priority
 installed provider as the source of randomness.
 (If none of the installed providers supply an implementation of
 SecureRandom, a system-provided source of randomness will be used.)

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
key - the encryption key
params - the algorithm parameters
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or its keysize exceeds the maximum allowable
 keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException - if the given algorithm
 parameters are inappropriate for this cipher,
 or this cipher is being initialized for decryption and requires
 algorithm parameters and params is null, or the given
 algorithm parameters imply a cryptographic strength that would exceed
 the legal limits (as determined from the configured jurisdiction
 policy files).





init
public final void init(int opmode,
                       Key key,
                       AlgorithmParameterSpec params,
                       SecureRandom random)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

Initializes this cipher with a key, a set of algorithm
 parameters, and a source of randomness.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters and
 params is null, the underlying cipher implementation is
 supposed to generate the required parameters itself (using
 provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidAlgorithmParameterException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them from random.

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
key - the encryption key
params - the algorithm parameters
random - the source of randomness
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or its keysize exceeds the maximum allowable
 keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException - if the given algorithm
 parameters are inappropriate for this cipher,
 or this cipher is being initialized for decryption and requires
 algorithm parameters and params is null, or the given
 algorithm parameters imply a cryptographic strength that would exceed
 the legal limits (as determined from the configured jurisdiction
 policy files).





init
public final void init(int opmode,
                       Key key,
                       AlgorithmParameters params)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

Initializes this cipher with a key and a set of algorithm
 parameters.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters and
 params is null, the underlying cipher implementation is
 supposed to generate the required parameters itself (using
 provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidAlgorithmParameterException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them using the SecureRandom
 implementation of the highest-priority
 installed provider as the source of randomness.
 (If none of the installed providers supply an implementation of
 SecureRandom, a system-provided source of randomness will be used.)

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following: ENCRYPT_MODE,
 DECRYPT_MODE, WRAP_MODE
 or UNWRAP_MODE)
key - the encryption key
params - the algorithm parameters
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or its keysize exceeds the maximum allowable
 keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException - if the given algorithm
 parameters are inappropriate for this cipher,
 or this cipher is being initialized for decryption and requires
 algorithm parameters and params is null, or the given
 algorithm parameters imply a cryptographic strength that would exceed
 the legal limits (as determined from the configured jurisdiction
 policy files).





init
public final void init(int opmode,
                       Key key,
                       AlgorithmParameters params,
                       SecureRandom random)
                throws InvalidKeyException,
                       InvalidAlgorithmParameterException

Initializes this cipher with a key, a set of algorithm
 parameters, and a source of randomness.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If this cipher requires any algorithm parameters and
 params is null, the underlying cipher implementation is
 supposed to generate the required parameters itself (using
 provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidAlgorithmParameterException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them from random.

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following: ENCRYPT_MODE,
 DECRYPT_MODE, WRAP_MODE
 or UNWRAP_MODE)
key - the encryption key
params - the algorithm parameters
random - the source of randomness
Throws:
InvalidKeyException - if the given key is inappropriate for
 initializing this cipher, or its keysize exceeds the maximum allowable
 keysize (as determined from the configured jurisdiction policy files).
InvalidAlgorithmParameterException - if the given algorithm
 parameters are inappropriate for this cipher,
 or this cipher is being initialized for decryption and requires
 algorithm parameters and params is null, or the given
 algorithm parameters imply a cryptographic strength that would exceed
 the legal limits (as determined from the configured jurisdiction
 policy files).





init
public final void init(int opmode,
                       Certificate certificate)
                throws InvalidKeyException

Initializes this cipher with the public key from the given certificate.
  The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping or  key unwrapping, depending
 on the value of opmode.

 
If the certificate is of type X.509 and has a key usage
 extension field marked as critical, and the value of the key usage
 extension field implies that the public key in
 the certificate and its corresponding private key are not
 supposed to be used for the operation represented by the value
 of opmode,
 an InvalidKeyException
 is thrown.

 
 If this cipher requires any algorithm parameters that cannot be
 derived from the public key in the given certificate, the underlying
 cipher
 implementation is supposed to generate the required parameters itself
 (using provider-specific default or ramdom values) if it is being
 initialized for encryption or key wrapping, and raise an 
 InvalidKeyException if it is being initialized for decryption or
 key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them using the
 SecureRandom
 implementation of the highest-priority
 installed provider as the source of randomness.
 (If none of the installed providers supply an implementation of
 SecureRandom, a system-provided source of randomness will be used.)

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
certificate - the certificate
Throws:
InvalidKeyException - if the public key in the given
 certificate is inappropriate for initializing this cipher, or this
 cipher is being initialized for decryption or unwrapping keys and
 requires algorithm parameters that cannot be determined from the
 public key in the given certificate, or the keysize of the public key
 in the given certificate has a keysize that exceeds the maximum
 allowable keysize (as determined by the configured jurisdiction policy
 files).





init
public final void init(int opmode,
                       Certificate certificate,
                       SecureRandom random)
                throws InvalidKeyException

Initializes this cipher with the public key from the given certificate
 and
 a source of randomness.

 The cipher is initialized for one of the following four operations:
 encryption, decryption, key wrapping
 or key unwrapping, depending on
 the value of opmode.

 
If the certificate is of type X.509 and has a key usage
 extension field marked as critical, and the value of the key usage
 extension field implies that the public key in
 the certificate and its corresponding private key are not
 supposed to be used for the operation represented by the value of
 opmode,
 an InvalidKeyException
 is thrown.

 
If this cipher requires any algorithm parameters that cannot be
 derived from the public key in the given certificate,
 the underlying cipher
 implementation is supposed to generate the required parameters itself
 (using provider-specific default or random values) if it is being
 initialized for encryption or key wrapping, and raise an
 InvalidKeyException if it is being
 initialized for decryption or key unwrapping.
 The generated parameters can be retrieved using
 getParameters or
 getIV (if the parameter is an IV).

 
If this cipher (including its underlying feedback or padding scheme)
 requires any random bytes (e.g., for parameter generation), it will get
 them from random.

 
Note that when a Cipher object is initialized, it loses all
 previously-acquired state. In other words, initializing a Cipher is
 equivalent to creating a new instance of that Cipher and initializing
 it.


Parameters:
opmode - the operation mode of this cipher (this is one of the
 following:
 ENCRYPT_MODE, DECRYPT_MODE,
 WRAP_MODE or UNWRAP_MODE)
certificate - the certificate
random - the source of randomness
Throws:
InvalidKeyException - if the public key in the given
 certificate is inappropriate for initializing this cipher, or this
 cipher is being initialized for decryption or unwrapping keys and
 requires algorithm parameters that cannot be determined from the
 public key in the given certificate, or the keysize of the public key
 in the given certificate has a keysize that exceeds the maximum
 allowable keysize (as determined by the configured jurisdiction policy
 files).





update
public final byte[] update(byte[] input)

Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.

 The bytes in the input buffer are processed, and the
 result is stored in a new buffer.

 
If input has a length of zero, this method returns
 null.


Parameters:
input - the input buffer
Returns:
the new buffer with the result, or null if the underlying
 cipher is a block cipher and the input data is too short to result in a
 new block.
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)





update
public final byte[] update(byte[] input,
                           int inputOffset,
                           int inputLen)

Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, are processed,
 and the result is stored in a new buffer.

 
If inputLen is zero, this method returns
 null.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
Returns:
the new buffer with the result, or null if the underlying
 cipher is a block cipher and the input data is too short to result in a
 new block.
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)





update
public final int update(byte[] input,
                        int inputOffset,
                        int inputLen,
                        byte[] output)
                 throws ShortBufferException

Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, are processed,
 and the result is stored 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. Use
 getOutputSize to determine how big
 the output buffer should be.

 
If inputLen is zero, this method returns
 a length of zero.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same byte array and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
output - the buffer for the result
Returns:
the number of bytes stored in output
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
ShortBufferException - if the given output buffer is too small
 to hold the result





update
public final int update(byte[] input,
                        int inputOffset,
                        int inputLen,
                        byte[] output,
                        int outputOffset)
                 throws ShortBufferException

Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, are processed,
 and the result is stored 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. Use
 getOutputSize to determine how big
 the output buffer should be.

 
If inputLen is zero, this method returns
 a length of zero.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same byte array and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
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 - if this cipher is in a wrong state
 (e.g., has not been initialized)
ShortBufferException - if the given output buffer is too small
 to hold the result





update
public final int update(ByteBuffer input,
                        ByteBuffer output)
                 throws ShortBufferException

Continues a multiple-part encryption or decryption operation
 (depending on how this cipher was initialized), processing another data
 part.

 All input.remaining() bytes starting at
 input.position() are processed. The result is stored
 in the output buffer.
 Upon return, the input buffer's position will be equal
 to its limit; its limit will not have changed. The output buffer's
 position will have advanced by n, where n is the value returned
 by this method; the output buffer's limit will not have changed.

 
If output.remaining() bytes are insufficient to
 hold the result, a ShortBufferException is thrown.
 In this case, repeat this call with a larger output buffer. Use
 getOutputSize to determine how big
 the output buffer should be.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same block of memory and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input ByteBuffer
output - the output ByteByffer
Returns:
the number of bytes stored in output
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalArgumentException - if input and output are the
   same object
ReadOnlyBufferException - if the output buffer is read-only
ShortBufferException - if there is insufficient space in the
 output buffer
Since:
  1.5






doFinal
public final byte[] doFinal()
                     throws IllegalBlockSizeException,
                            BadPaddingException

Finishes a multiple-part encryption or decryption operation, depending
 on how this cipher was initialized.

 Input data that may have been buffered during a previous
 update operation is processed, with padding (if requested)
 being applied.
 The result is stored in a new buffer.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.



Returns:
the new buffer with the result
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final int doFinal(byte[] output,
                         int outputOffset)
                  throws IllegalBlockSizeException,
                         ShortBufferException,
                         BadPaddingException

Finishes a multiple-part encryption or decryption operation, depending
 on how this cipher was initialized.

 Input data that may have been buffered during a previous
 update operation is processed, with padding (if requested)
 being applied.
 The result is stored 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. Use
 getOutputSize to determine how big
 the output buffer should be.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.


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 - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
ShortBufferException - if the given output buffer is too small
 to hold the result
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final byte[] doFinal(byte[] input)
                     throws IllegalBlockSizeException,
                            BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation. The data is encrypted or decrypted,
 depending on how this cipher was initialized.

 The bytes in the input buffer, and any input bytes that
 may have been buffered during a previous update operation,
 are processed, with padding (if requested) being applied.
 The result is stored in a new buffer.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.


Parameters:
input - the input buffer
Returns:
the new buffer with the result
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final byte[] doFinal(byte[] input,
                            int inputOffset,
                            int inputLen)
                     throws IllegalBlockSizeException,
                            BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation. The data is encrypted or decrypted,
 depending on how this cipher was initialized.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, and any input
 bytes that may have been buffered during a previous update
 operation, are processed, with padding (if requested) being applied.
 The result is stored in a new buffer.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
Returns:
the new buffer with the result
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final int doFinal(byte[] input,
                         int inputOffset,
                         int inputLen,
                         byte[] output)
                  throws ShortBufferException,
                         IllegalBlockSizeException,
                         BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation. The data is encrypted or decrypted,
 depending on how this cipher was initialized.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, and any input
 bytes that may have been buffered during a previous update
 operation, are processed, with padding (if requested) being applied.
 The result is stored 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. Use
 getOutputSize to determine how big
 the output buffer should be.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same byte array and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
output - the buffer for the result
Returns:
the number of bytes stored in output
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
ShortBufferException - if the given output buffer is too small
 to hold the result
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final int doFinal(byte[] input,
                         int inputOffset,
                         int inputLen,
                         byte[] output,
                         int outputOffset)
                  throws ShortBufferException,
                         IllegalBlockSizeException,
                         BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation. The data is encrypted or decrypted,
 depending on how this cipher was initialized.

 The first inputLen bytes in the input
 buffer, starting at inputOffset inclusive, and any input
 bytes that may have been buffered during a previous
 update operation, are processed, with padding
 (if requested) being applied.
 The result is stored 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. Use
 getOutputSize to determine how big
 the output buffer should be.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same byte array and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input buffer
inputOffset - the offset in input where the input
 starts
inputLen - the input length
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 - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
ShortBufferException - if the given output buffer is too small
 to hold the result
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes





doFinal
public final int doFinal(ByteBuffer input,
                         ByteBuffer output)
                  throws ShortBufferException,
                         IllegalBlockSizeException,
                         BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a
 multiple-part operation. The data is encrypted or decrypted,
 depending on how this cipher was initialized.

 All input.remaining() bytes starting at
 input.position() are processed. The result is stored
 in the output buffer.
 Upon return, the input buffer's position will be equal
 to its limit; its limit will not have changed. The output buffer's
 position will have advanced by n, where n is the value returned
 by this method; the output buffer's limit will not have changed.

 
If output.remaining() bytes are insufficient to
 hold the result, a ShortBufferException is thrown.
 In this case, repeat this call with a larger output buffer. Use
 getOutputSize to determine how big
 the output buffer should be.

 
Upon finishing, this method resets this cipher object to the state
 it was in when previously initialized via a call to init.
 That is, the object is reset and available to encrypt or decrypt
 (depending on the operation mode that was specified in the call to
 init) more data.

 
Note: if any exception is thrown, this cipher object may need to
 be reset before it can be used again.

 
Note: this method should be copy-safe, which means the
 input and output buffers can reference
 the same byte array and no unprocessed input data is overwritten
 when the result is copied into the output buffer.


Parameters:
input - the input ByteBuffer
output - the output ByteBuffer
Returns:
the number of bytes stored in output
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized)
IllegalArgumentException - if input and output are the
   same object
ReadOnlyBufferException - if the output buffer is read-only
IllegalBlockSizeException - if this cipher is a block cipher,
 no padding has been requested (only in encryption mode), and the total
 input length of the data processed by this cipher is not a multiple of
 block size; or if this encryption algorithm is unable to
 process the input data provided.
ShortBufferException - if there is insufficient space in the
 output buffer
BadPaddingException - if this cipher is in decryption mode,
 and (un)padding has been requested, but the decrypted data is not
 bounded by the appropriate padding bytes
Since:
  1.5






wrap
public final byte[] wrap(Key key)
                  throws IllegalBlockSizeException,
                         InvalidKeyException

Wrap a key.


Parameters:
key - the key to be wrapped.
Returns:
the wrapped key.
Throws:
IllegalStateException - if this cipher is in a wrong
 state (e.g., has not been initialized).
IllegalBlockSizeException - if this cipher is a block
 cipher, no padding has been requested, and the length of the
 encoding of the key to be wrapped is not a
 multiple of the block size.
InvalidKeyException - if it is impossible or unsafe to
 wrap the key with this cipher (e.g., a hardware protected key is
 being passed to a software-only cipher).





unwrap
public final Key unwrap(byte[] wrappedKey,
                        String wrappedKeyAlgorithm,
                        int wrappedKeyType)
                 throws InvalidKeyException,
                        NoSuchAlgorithmException

Unwrap a previously wrapped key.


Parameters:
wrappedKey - the key to be unwrapped.
wrappedKeyAlgorithm - the algorithm associated with the wrapped
 key.
wrappedKeyType - the type of the wrapped key. This must be one of
 SECRET_KEY, PRIVATE_KEY, or
 PUBLIC_KEY.
Returns:
the unwrapped key.
Throws:
IllegalStateException - if this cipher is in a wrong state
 (e.g., has not been initialized).
NoSuchAlgorithmException - if no installed providers
 can create keys of type wrappedKeyType for the
 wrappedKeyAlgorithm.
InvalidKeyException - if wrappedKey does not
 represent a wrapped key of type wrappedKeyType for
 the wrappedKeyAlgorithm.





getMaxAllowedKeyLength
public static final int getMaxAllowedKeyLength(String transformation)
                                        throws NoSuchAlgorithmException

Returns the maximum key length for the specified transformation
 according to the installed JCE jurisdiction policy files. If
 JCE unlimited strength jurisdiction policy files are installed,
 Integer.MAX_VALUE will be returned.
 For more information on default key size in JCE jurisdiction
 policy files, please see Appendix E in the
 
 Java Cryptography Architecture Reference Guide.


Parameters:
transformation - the cipher transformation.
Returns:
the maximum key length in bits or Integer.MAX_VALUE.
Throws:
NullPointerException - if transformation is null.
NoSuchAlgorithmException - if transformation
 is not a valid transformation, i.e. in the form of "algorithm" or
 "algorithm/mode/padding".
Since:
  1.5






getMaxAllowedParameterSpec
public static final AlgorithmParameterSpec getMaxAllowedParameterSpec(String transformation)
                                                               throws NoSuchAlgorithmException

Returns an AlgorithmParameterSpec object which contains
 the maximum cipher parameter value according to the
 jurisdiction policy file. If JCE unlimited strength jurisdiction
 policy files are installed or there is no maximum limit on the
 parameters for the specified transformation in the policy file,
 null will be returned.


Parameters:
transformation - the cipher transformation.
Returns:
an AlgorithmParameterSpec which holds the maximum
 value or null.
Throws:
NullPointerException - if transformation
 is null.
NoSuchAlgorithmException - if transformation
 is not a valid transformation, i.e. in the form of "algorithm" or
 "algorithm/mode/padding".
Since:
  1.5















  
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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

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

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

javax.crypto Class Cipher

ENCRYPT_MODE

DECRYPT_MODE

WRAP_MODE

UNWRAP_MODE

PUBLIC_KEY

PRIVATE_KEY

SECRET_KEY

Cipher

getInstance

getInstance

getInstance

getProvider

getAlgorithm

getBlockSize

getOutputSize

getIV

getParameters

getExemptionMechanism

init

init

init

init

init

init

init

init

update

update

update

update

update

doFinal

doFinal

doFinal

doFinal

doFinal

doFinal

doFinal

wrap

unwrap

getMaxAllowedKeyLength

getMaxAllowedParameterSpec

javax.crypto
Class Cipher