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public class Cipher extends Object
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., AES ), 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("
AES/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 "
AES/CFB8/NoPadding
" and
"
AES/OFB32/PKCS5Padding
" transformations. If no such
number is specified, a provider-specific default is used.
Thus, block ciphers can be turned into byte-oriented stream ciphers by
using an 8 bit mode such as CFB8 or OFB8.
Modes such as Authenticated Encryption with Associated Data (AEAD)
provide authenticity assurances for both confidential data and
Additional Associated Data (AAD) that is not encrypted. (Please see
RFC 5116
for more
information on AEAD and AEAD algorithms such as GCM/CCM.) Both
confidential and AAD data can be used when calculating the
authentication tag (similar to a
Mac
). This tag is appended
to the ciphertext during encryption, and is verified on decryption.
AEAD modes such as GCM/CCM perform all AAD authenticity calculations
before starting the ciphertext authenticity calculations. To avoid
implementations having to internally buffer ciphertext, all AAD data
must be supplied to GCM/CCM implementations (via the
updateAAD
methods)
before
the ciphertext is processed (via
the
update
and
doFinal
methods).
Note that GCM mode has a uniqueness requirement on IVs used in
encryption with a given key. When IVs are repeated for GCM
encryption, such usages are subject to forgery attacks. Thus, after
each encryption operation using GCM mode, callers should re-initialize
the cipher objects with GCM parameters which has a different IV value.
GCMParameterSpec s = ...;
cipher.init(..., s);
// If the GCM parameters were generated by the provider, it can
// be retrieved by:
// cipher.getParameters().getParameterSpec(GCMParameterSpec.class);
cipher.updateAAD(...); // AAD
cipher.update(...); // Multi-part update
cipher.doFinal(...); // conclusion of operation
// Use a different IV value for every encryption
byte[] newIv = ...;
s = new GCMParameterSpec(s.getTLen(), newIv);
cipher.init(..., s);
Every implementation of the Java platform is required to support
the following standard
Cipher
transformations with the keysizes
in parentheses:
KeyGenerator
,
SecretKey
byte[]
doFinal
(byte[] input)
doFinal
(byte[] output,
int outputOffset)
byte[]
doFinal
(byte[] input,
int inputOffset,
int inputLen)
doFinal
(byte[] input,
int inputOffset,
int inputLen,
byte[] output)
doFinal
(byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
doFinal
(
ByteBuffer
input,
ByteBuffer
output)
String
getAlgorithm
()
Cipher
object.
getBlockSize
()
ExemptionMechanism
getExemptionMechanism
()
static
Cipher
getInstance
(
String
transformation)
Cipher
object that implements the specified
transformation.
static
Cipher
getInstance
(
String
transformation,
Provider
provider)
Cipher
object that implements the specified
transformation.
static
Cipher
getInstance
(
String
transformation,
String
provider)
Cipher
object that implements the specified
transformation.
byte[]
getIV
()
static int
getMaxAllowedKeyLength
(
String
transformation)
static
AlgorithmParameterSpec
getMaxAllowedParameterSpec
(
String
transformation)
getOutputSize
(int inputLen)
update
or
doFinal
operation, given the input length
inputLen
(in bytes).
AlgorithmParameters
getParameters
()
Provider
getProvider
()
Cipher
object.
init
(int opmode,
Certificate
certificate)
init
(int opmode,
Certificate
certificate,
SecureRandom
random)
init
(int opmode,
Key
key)
init
(int opmode,
Key
key,
AlgorithmParameters
params)
init
(int opmode,
Key
key,
AlgorithmParameterSpec
params)
init
(int opmode,
Key
key,
AlgorithmParameterSpec
params,
SecureRandom
random)
init
(int opmode,
Key
key,
AlgorithmParameters
params,
SecureRandom
random)
init
(int opmode,
Key
key,
SecureRandom
random)
unwrap
(byte[] wrappedKey,
String
wrappedKeyAlgorithm,
int wrappedKeyType)
byte[]
update
(byte[] input)
byte[]
update
(byte[] input,
int inputOffset,
int inputLen)
update
(byte[] input,
int inputOffset,
int inputLen,
byte[] output)
update
(byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
update
(
ByteBuffer
input,
ByteBuffer
output)
updateAAD
(byte[] src)
updateAAD
(byte[] src,
int offset,
int len)
updateAAD
(
ByteBuffer
src)
byte[]
wrap
(
Key
key)
public static final int ENCRYPT_MODE
public static final int DECRYPT_MODE
public static final int WRAP_MODE
public static final int UNWRAP_MODE
public static final int PUBLIC_KEY
public static final int PRIVATE_KEY
public static final int SECRET_KEY
public static final Cipher getInstance(String transformation) throws NoSuchAlgorithmException, NoSuchPaddingException
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.,
AES/CBC/PKCS5Padding
.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
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.
Provider
public static final Cipher getInstance(String transformation, String provider) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException
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.,
AES/CBC/PKCS5Padding
.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
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.
Provider
public static final Cipher getInstance(String transformation, Provider provider) throws NoSuchAlgorithmException, NoSuchPaddingException
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.,
AES/CBC/PKCS5Padding
.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
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.
Provider
public final Provider getProvider()
Cipher
object.
Cipher
object
public final String getAlgorithm()
Cipher
object.
This is the same name that was specified in one of the
getInstance
calls that created this
Cipher
object..
Cipher
object.
public final int getBlockSize()
public final int getOutputSize(int inputLen)
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, padding, and AEAD tagging.
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)
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.
public final AlgorithmParameters getParameters()
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.
public final ExemptionMechanism getExemptionMechanism()
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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 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).
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 requires algorithm parameters that cannot be derived from the input parameters, and there are no reasonable provider-specific default values, initialization will necessarily fail.
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
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
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).
public final byte[] update(byte[] input)
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)
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)
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
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
public final int update(ByteBuffer input, ByteBuffer output) throws ShortBufferException
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
Input data that may have been buffered during a previous
update
operation is processed, with padding (if requested)
being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
public final int doFinal(byte[] output,
int outputOffset)
throws IllegalBlockSizeException,
ShortBufferException,
BadPaddingException
Input data that may have been buffered during a previous
update
operation is processed, with padding (if requested)
being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
public final byte[] doFinal(byte[] input)
throws IllegalBlockSizeException,
BadPaddingException
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.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
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.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
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.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
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.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
public final int doFinal(ByteBuffer input, ByteBuffer output) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException
All
input.remaining()
bytes starting at
input.position()
are processed.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
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
AEADBadTagException
- if this cipher is decrypting in an
AEAD mode (such as GCM/CCM), and the received authentication tag
does not match the calculated value
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).
public final Key unwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType) throws InvalidKeyException, NoSuchAlgorithmException
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
.
public static final int getMaxAllowedKeyLength(String transformation) throws NoSuchAlgorithmException
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".
public static final AlgorithmParameterSpec getMaxAllowedParameterSpec(String transformation) throws NoSuchAlgorithmException
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".
public final void updateAAD(byte[] src)
update
and
doFinal
methods).
src
- the buffer containing the Additional Authentication Data
IllegalArgumentException
- if the
src
byte array is null
IllegalStateException
- if this cipher is in a wrong state
(e.g., has not been initialized), does not accept AAD, or if
operating in either GCM or CCM mode and one of the
update
methods has already been called for the active
encryption/decryption operation
UnsupportedOperationException
- if the corresponding method
in the
CipherSpi
has not been overridden by an
implementation
update
and
doFinal
methods).
src
- the buffer containing the AAD
offset
- the offset in
src
where the AAD input starts
len
- the number of AAD bytes
IllegalArgumentException
- if the
src
byte array is null, or the
offset
or
length
is less than 0, or the sum of the
offset
and
len
is greater than the length of the
src
byte array
IllegalStateException
- if this cipher is in a wrong state
(e.g., has not been initialized), does not accept AAD, or if
operating in either GCM or CCM mode and one of the
update
methods has already been called for the active
encryption/decryption operation
UnsupportedOperationException
- if the corresponding method
in the
CipherSpi
has not been overridden by an
implementation
public final void updateAAD(ByteBuffer src)
update
and
doFinal
methods).
All
src.remaining()
bytes starting at
src.position()
are processed.
Upon return, the input buffer's position will be equal
to its limit; its limit will not have changed.
src
- the buffer containing the AAD
IllegalArgumentException
- if the
src ByteBuffer
is null
IllegalStateException
- if this cipher is in a wrong state
(e.g., has not been initialized), does not accept AAD, or if
operating in either GCM or CCM mode and one of the
update
methods has already been called for the active
encryption/decryption operation
UnsupportedOperationException
- if the corresponding method
in the
CipherSpi
has not been overridden by an
implementation
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彷徨的山楂 · 斗破、武动、大主宰、元尊 - 知乎 2 年前 |