java.lang.Object | |
↳ | javax.crypto.Cipher |
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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:
(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.
See Also
Constants | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
int | DECRYPT_MODE | Constant used to initialize cipher to decryption mode. | |||||||||
int | ENCRYPT_MODE | Constant used to initialize cipher to encryption mode. | |||||||||
int | PRIVATE_KEY | Constant used to indicate the to-be-unwrapped key is a "private key". | |||||||||
int | PUBLIC_KEY | Constant used to indicate the to-be-unwrapped key is a "public key". | |||||||||
int | SECRET_KEY | Constant used to indicate the to-be-unwrapped key is a "secret key". | |||||||||
int | UNWRAP_MODE | Constant used to initialize cipher to key-unwrapping mode. | |||||||||
int | WRAP_MODE | Constant used to initialize cipher to key-wrapping mode. |
Protected Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Creates a Cipher object.
|
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
| |||||||||||
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
| |||||||||||
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
| |||||||||||
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
| |||||||||||
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
| |||||||||||
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
| |||||||||||
Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
| |||||||||||
Returns the algorithm name of this
Cipher object. | |||||||||||
Returns the block size (in bytes).
| |||||||||||
Returns the exemption mechanism object used with this cipher.
| |||||||||||
Returns the initialization vector (IV) in a new buffer.
| |||||||||||
Returns a
Cipher object that implements the specified
transformation. | |||||||||||
Returns a
Cipher object that implements the specified
transformation. | |||||||||||
Returns a
Cipher object that implements the specified
transformation. | |||||||||||
Returns the maximum key length for the specified transformation
according to the installed JCE jurisdiction policy files.
| |||||||||||
Returns an AlgorithmParameterSpec object which contains
the maximum cipher parameter value according to the
jurisdiction policy file.
| |||||||||||
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). | |||||||||||
Returns the parameters used with this cipher.
| |||||||||||
Returns the provider of this
Cipher object. | |||||||||||
Initializes this cipher with a key.
| |||||||||||
Initializes this cipher with a key and a source of randomness.
| |||||||||||
Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
| |||||||||||
Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
| |||||||||||
Initializes this cipher with a key and a set of algorithm
parameters.
| |||||||||||
Initializes this cipher with the public key from the given certificate
and
a source of randomness.
| |||||||||||
Initializes this cipher with the public key from the given certificate.
| |||||||||||
Initializes this cipher with a key and a set of algorithm
parameters.
| |||||||||||
Unwrap a previously wrapped key.
| |||||||||||
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
| |||||||||||
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
| |||||||||||
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
| |||||||||||
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
| |||||||||||
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
| |||||||||||
Wrap a key.
|
[Expand]
Inherited Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
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Constant used to initialize cipher to decryption mode.
Constant used to initialize cipher to encryption mode.
Constant used to indicate the to-be-unwrapped key is a "private key".
Constant used to indicate the to-be-unwrapped key is a "public key".
Constant used to indicate the to-be-unwrapped key is a "secret key".
Constant used to initialize cipher to key-unwrapping mode.
Constant used to initialize cipher to key-wrapping mode.
Creates a Cipher object.
cipherSpi | the delegate |
---|---|
provider | the provider |
transformation | the transformation |
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.
output | the buffer for the result |
---|---|
outputOffset | the offset in output where the result
is stored |
output
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 |
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.
input | the input buffer |
---|---|
inputOffset | the offset in input where the input
starts |
inputLen | the input length |
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 |
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.
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 |
output
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 |
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.
input | the input buffer |
---|---|
inputOffset | the offset in input where the input
starts |
inputLen | the input length |
output | the buffer for the result |
output
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 |
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.
input | the input buffer |
---|
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 |
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.
input | the input ByteBuffer |
---|---|
output | the output ByteBuffer |
output
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 |
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.
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 |
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..
Cipher
object.
Returns the block size (in bytes).
Returns the exemption mechanism object used with this cipher.
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 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.
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. |
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. |
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.
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. |
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. |
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.
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. |
---|
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. |
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.
transformation | the cipher transformation. |
---|
NullPointerException | if transformation is null. |
---|---|
NoSuchAlgorithmException | if transformation
is not a valid transformation, i.e. in the form of "algorithm" or
"algorithm/mode/padding". |
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.
transformation | the cipher transformation. |
---|
NullPointerException | if transformation
is null. |
---|---|
NoSuchAlgorithmException | if transformation
is not a valid transformation, i.e. in the form of "algorithm" or
"algorithm/mode/padding". |
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.
inputLen | the input length (in bytes) |
---|
IllegalStateException | if this cipher is in a wrong state (e.g., has not yet been initialized) |
---|
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 provider of this Cipher
object.
Cipher
object
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
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.)
SecureRandom
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.
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 |
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). |
---|
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.
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 |
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). |
---|
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.
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 |
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).
|
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.
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 |
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).
|
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
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.)
SecureRandom
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.
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 |
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).
|
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.
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 |
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). |
---|
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.
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 |
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). |
---|
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
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.)
SecureRandom
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.
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 |
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).
|
Unwrap a previously wrapped key.
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 . |
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 .
|
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.
input | the input ByteBuffer |
---|---|
output | the output ByteByffer |
output
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 |
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
.
input | the input buffer |
---|
IllegalStateException | if this cipher is in a wrong state (e.g., has not been initialized) |
---|
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.
input | the input buffer |
---|---|
inputOffset | the offset in input where the input
starts |
inputLen | the input length |
output | the buffer for the result |
output
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 |
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
.
input | the input buffer |
---|---|
inputOffset | the offset in input where the input
starts |
inputLen | the input length |
IllegalStateException | if this cipher is in a wrong state (e.g., has not been initialized) |
---|
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.
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 |
output
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 |
Wrap a key.
key | the key to be wrapped. |
---|
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). |