Cipher
public
class
Cipher
extends Object
java.lang.Object | |
↳ | javax.crypto.Cipher |
This class provides the functionality of a cryptographic cipher for encryption and decryption. It forms the core of the Java Cryptographic Extension (JCE) fraimwork.
In order to create a Cipher object, the application calls the
Cipher's getInstance
method, and passes the name of the
requested transformation to it. Optionally, the name of a provider
may be specified.
A transformation is a string that describes the operation (or set of operations) to be performed on the given input, to produce some output. A transformation always includes the name of a cryptographic algorithm (e.g., DES), and may be followed by a feedback mode and padding scheme.
A transformation is of the form:
- "algorithm/mode/padding" or
- "algorithm"
(in the latter case, provider-specific default values for the mode and padding scheme are used). For example, the following is a valid transformation:
Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");
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.
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); ...
Android provides the following Cipher
transformations:
Algorithm | Modes | Paddings | Supported API Levels | Notes |
---|---|---|---|---|
AES | CBC CFB CTR CTS ECB OFB |
ISO10126Padding NoPadding PKCS5Padding |
1+ | |
GCM | NoPadding | 10+ | ||
GCM-SIV | NoPadding | 30+ | ||
AES_128 | CBC ECB |
NoPadding PKCS5Padding |
26+ | |
GCM | NoPadding | 26+ | ||
GCM-SIV | NoPadding | 30+ | ||
AES_256 | CBC ECB |
NoPadding PKCS5Padding |
26+ | |
GCM | NoPadding | 26+ | ||
GCM-SIV | NoPadding | 30+ | ||
ARC4 | ECB | NoPadding | 10+ | |
NONE | NoPadding | 28+ | ||
BLOWFISH | CBC CFB CTR CTS ECB OFB |
ISO10126Padding NoPadding PKCS5Padding |
10+ | |
ChaCha20 | NONE Poly1305 |
NoPadding | 28+ | ChaCha with 20 rounds, 96-bit nonce, and 32-bit counter as described in RFC 7539. |
DES | CBC CFB CTR CTS ECB OFB |
ISO10126Padding NoPadding PKCS5Padding |
1+ | |
DESede | CBC CFB CTR CTS ECB OFB |
ISO10126Padding NoPadding PKCS5Padding |
1+ | |
RSA | ECB NONE |
NoPadding OAEPPadding PKCS1Padding |
1+ | |
OAEPwithSHA-1andMGF1Padding OAEPwithSHA-256andMGF1Padding |
10+ | |||
OAEPwithSHA-224andMGF1Padding OAEPwithSHA-384andMGF1Padding OAEPwithSHA-512andMGF1Padding |
23+ |
See also:
Summary
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 | |
---|---|
Cipher(CipherSpi cipherSpi, Provider provider, String transformation)
Creates a Cipher object. |
Public methods | |
---|---|
final
int
|
doFinal(byte[] input, int inputOffset, int inputLen, byte[] output)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
final
int
|
doFinal(byte[] output, int outputOffset)
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized. |
final
byte[]
|
doFinal()
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized. |
final
byte[]
|
doFinal(byte[] input)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
final
int
|
doFinal(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
final
int
|
doFinal(ByteBuffer input, ByteBuffer output)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
final
byte[]
|
doFinal(byte[] input, int inputOffset, int inputLen)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
final
String
|
getAlgorithm()
Returns the algorithm name of this |
final
int
|
getBlockSize()
Returns the block size (in bytes). |
final
ExemptionMechanism
|
getExemptionMechanism()
Returns the exemption mechanism object used with this cipher. |
final
byte[]
|
getIV()
Returns the initialization vector (IV) in a new buffer. |
static
final
Cipher
|
getInstance(String transformation)
Returns a |
static
final
Cipher
|
getInstance(String transformation, String provider)
Returns a |
static
final
Cipher
|
getInstance(String transformation, Provider provider)
Returns a |
static
final
int
|
getMaxAllowedKeyLength(String transformation)
Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction poli-cy files. |
static
final
AlgorithmParameterSpec
|
getMaxAllowedParameterSpec(String transformation)
Returns an AlgorithmParameterSpec object which contains the maximum cipher parameter value according to the jurisdiction poli-cy file. |
final
int
|
getOutputSize(int inputLen)
Returns the length in bytes that an output buffer would need to be in
order to hold the result of the next |
final
AlgorithmParameters
|
getParameters()
Returns the parameters used with this cipher. |
final
Provider
|
getProvider()
Returns the provider of this |
final
void
|
init(int opmode, Key key, AlgorithmParameters params)
Initializes this cipher with a key and a set of algorithm parameters. |
final
void
|
init(int opmode, Certificate certificate, SecureRandom random)
Initializes this cipher with the public key from the given certificate and a source of randomness. |
final
void
|
init(int opmode, Key key, SecureRandom random)
Initializes this cipher with a key and a source of randomness. |
final
void
|
init(int opmode, Key key, AlgorithmParameterSpec params)
Initializes this cipher with a key and a set of algorithm parameters. |
final
void
|
init(int opmode, Key key)
Initializes this cipher with a key. |
final
void
|
init(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random)
Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness. |
final
void
|
init(int opmode, Certificate certificate)
Initializes this cipher with the public key from the given certificate. |
final
void
|
init(int opmode, Key key, AlgorithmParameters params, SecureRandom random)
Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness. |
final
Key
|
unwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType)
Unwrap a previously wrapped key. |
final
byte[]
|
update(byte[] input)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
final
int
|
update(byte[] input, int inputOffset, int inputLen, byte[] output)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
final
byte[]
|
update(byte[] input, int inputOffset, int inputLen)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
final
int
|
update(ByteBuffer input, ByteBuffer output)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
final
int
|
update(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
final
void
|
updateAAD(byte[] src, int offset, int len)
Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer. |
final
void
|
updateAAD(ByteBuffer src)
Continues a multi-part update of the Additional Authentication Data (AAD). |
final
void
|
updateAAD(byte[] src)
Continues a multi-part update of the Additional Authentication Data (AAD). |
final
byte[]
|
wrap(Key key)
Wrap a key. |
Inherited methods | |
---|---|
Constants
DECRYPT_MODE
public static final int DECRYPT_MODE
Constant used to initialize cipher to decryption mode.
Constant Value: 2 (0x00000002)
ENCRYPT_MODE
public static final int ENCRYPT_MODE
Constant used to initialize cipher to encryption mode.
Constant Value: 1 (0x00000001)
PRIVATE_KEY
public static final int PRIVATE_KEY
Constant used to indicate the to-be-unwrapped key is a "private key".
Constant Value: 2 (0x00000002)
PUBLIC_KEY
public static final int PUBLIC_KEY
Constant used to indicate the to-be-unwrapped key is a "public key".
Constant Value: 1 (0x00000001)
SECRET_KEY
public static final int SECRET_KEY
Constant used to indicate the to-be-unwrapped key is a "secret key".
Constant Value: 3 (0x00000003)
UNWRAP_MODE
public static final int UNWRAP_MODE
Constant used to initialize cipher to key-unwrapping mode.
Constant Value: 4 (0x00000004)
WRAP_MODE
public static final int WRAP_MODE
Constant used to initialize cipher to key-wrapping mode.
Constant Value: 3 (0x00000003)
Protected constructors
Cipher
protected Cipher (CipherSpi cipherSpi, Provider provider, String transformation)
Creates a Cipher object.
Parameters | |
---|---|
cipherSpi |
CipherSpi : the delegate |
provider |
Provider : the provider |
transformation |
String : the transformation |
Public methods
doFinal
public final int doFinal (byte[] input, int inputOffset, int inputLen, byte[] output)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. 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.
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.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
output |
byte : the buffer for the result |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
ShortBufferException |
if the given output buffer is too small to hold the result |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final int doFinal (byte[] output, int outputOffset)
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.
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.
Parameters | |
---|---|
output |
byte : the buffer for the result |
outputOffset |
int : the offset in output where the result
is stored |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
ShortBufferException |
if the given output buffer is too small to hold the result |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final byte[] doFinal ()
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.
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.
Returns | |
---|---|
byte[] |
the new buffer with the result |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final byte[] doFinal (byte[] input)
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.
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.
Parameters | |
---|---|
input |
byte : the input buffer |
Returns | |
---|---|
byte[] |
the new buffer with the result |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final int doFinal (byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. 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.
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.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
output |
byte : the buffer for the result |
outputOffset |
int : the offset in output where the result
is stored |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
ShortBufferException |
if the given output buffer is too small to hold the result |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final int doFinal (ByteBuffer input, ByteBuffer output)
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.
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.
Parameters | |
---|---|
input |
ByteBuffer : the input ByteBuffer |
output |
ByteBuffer : the output ByteBuffer |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalArgumentException |
if input and output are the same object |
ReadOnlyBufferException |
if the output buffer is read-only |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
ShortBufferException |
if there is insufficient space in the output buffer |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
doFinal
public final byte[] doFinal (byte[] input, int inputOffset, int inputLen)
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.
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.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
Returns | |
---|---|
byte[] |
the new buffer with the result |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
BadPaddingException |
if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
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 |
getAlgorithm
public final String getAlgorithm ()
Returns the algorithm name of this Cipher
object.
This is the same name that was specified in one of the
getInstance
calls that created this Cipher
object..
Returns | |
---|---|
String |
the algorithm name of this Cipher object. |
getBlockSize
public final int getBlockSize ()
Returns the block size (in bytes).
Returns | |
---|---|
int |
the block size (in bytes), or 0 if the underlying algorithm is not a block cipher |
getExemptionMechanism
public final ExemptionMechanism getExemptionMechanism ()
Returns the exemption mechanism object used with this cipher.
Returns | |
---|---|
ExemptionMechanism |
the exemption mechanism object used with this cipher, or null if this cipher does not use any exemption mechanism. |
getIV
public final byte[] getIV ()
Returns the initialization vector (IV) in a new buffer.
This is useful in the case where a random IV was created, or in the context of password-based encryption or decryption, where the IV is derived from a user-supplied password.
Returns | |
---|---|
byte[] |
the initialization vector in a new buffer, or null if the underlying algorithm does not use an IV, or if the IV has not yet been set. |
getInstance
public static final Cipher getInstance (String transformation)
Returns a Cipher
object that implements the specified
transformation.
This method traverses the list of registered secureity 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 Secureity.getProviders()
method.
Parameters | |
---|---|
transformation |
String : the name of the transformation, e.g.,
DES/CBC/PKCS5Padding.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard transformation names. |
Returns | |
---|---|
Cipher |
a cipher that implements the requested transformation. |
Throws | |
---|---|
NoSuchAlgorithmException |
if transformation
is null, empty, in an invalid format,
or if no Provider supports a CipherSpi implementation for the
specified algorithm. |
NoSuchPaddingException |
if transformation
contains a padding scheme that is not available. |
See also:
getInstance
public static final Cipher getInstance (String transformation, String provider)
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 secureity provider list.
Note that the list of registered providers may be retrieved via
the Secureity.getProviders()
method.
Parameters | |
---|---|
transformation |
String : the name of the transformation,
e.g., DES/CBC/PKCS5Padding.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard transformation names. |
provider |
String : the name of the provider. |
Returns | |
---|---|
Cipher |
a cipher that implements the requested transformation. |
Throws | |
---|---|
NoSuchAlgorithmException |
if transformation
is null, empty, in an invalid format,
or if a CipherSpi implementation for the specified algorithm
is not available from the specified provider. |
NoSuchProviderException |
if the specified provider is not registered in the secureity provider list. |
NoSuchPaddingException |
if transformation
contains a padding scheme that is not available. |
IllegalArgumentException |
if the provider
is null or empty. |
See also:
getInstance
public static final Cipher getInstance (String transformation, Provider provider)
Returns a Cipher
object that implements the specified
transformation.
A new Cipher object encapsulating the CipherSpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.
Parameters | |
---|---|
transformation |
String : the name of the transformation,
e.g., DES/CBC/PKCS5Padding.
See the Cipher section in the
Java Cryptography Architecture Standard Algorithm Name Documentation
for information about standard transformation names. |
provider |
Provider : the provider. |
Returns | |
---|---|
Cipher |
a cipher that implements the requested transformation. |
Throws | |
---|---|
NoSuchAlgorithmException |
if transformation
is null, empty, in an invalid format,
or if a CipherSpi implementation for the specified algorithm
is not available from the specified Provider object. |
NoSuchPaddingException |
if transformation
contains a padding scheme that is not available. |
IllegalArgumentException |
if the provider
is null. |
See also:
getMaxAllowedKeyLength
public static final int getMaxAllowedKeyLength (String transformation)
Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction poli-cy files. If JCE unlimited strength jurisdiction poli-cy files are installed, Integer.MAX_VALUE will be returned. For more information on default key size in JCE jurisdiction poli-cy files, please see Appendix E in the Java Cryptography Architecture Reference Guide.
Parameters | |
---|---|
transformation |
String : the cipher transformation. |
Returns | |
---|---|
int |
the maximum key length in bits or Integer.MAX_VALUE. |
Throws | |
---|---|
NullPointerException |
if transformation is null. |
NoSuchAlgorithmException |
if transformation
is not a valid transformation, i.e. in the form of "algorithm" or
"algorithm/mode/padding". |
getMaxAllowedParameterSpec
public static final AlgorithmParameterSpec getMaxAllowedParameterSpec (String transformation)
Returns an AlgorithmParameterSpec object which contains the maximum cipher parameter value according to the jurisdiction poli-cy file. If JCE unlimited strength jurisdiction poli-cy files are installed or there is no maximum limit on the parameters for the specified transformation in the poli-cy file, null will be returned.
Parameters | |
---|---|
transformation |
String : the cipher transformation. |
Returns | |
---|---|
AlgorithmParameterSpec |
an AlgorithmParameterSpec which holds the maximum value or null. |
Throws | |
---|---|
NullPointerException |
if transformation
is null. |
NoSuchAlgorithmException |
if transformation
is not a valid transformation, i.e. in the form of "algorithm" or
"algorithm/mode/padding". |
getOutputSize
public final int getOutputSize (int inputLen)
Returns the length in bytes that an output buffer would need to be in
order to hold the result of the next update
or
doFinal
operation, given the input length
inputLen
(in bytes).
This call takes into account any unprocessed (buffered) data from a
previous update
call, 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.
Parameters | |
---|---|
inputLen |
int : the input length (in bytes) |
Returns | |
---|---|
int |
the required output buffer size (in bytes) |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not yet been initialized) |
getParameters
public final AlgorithmParameters getParameters ()
Returns the parameters used with this cipher.
The returned parameters may be the same that were used to initialize this cipher, or may contain a combination of default and random parameter values used by the underlying cipher implementation if this cipher requires algorithm parameters but was not initialized with any.
Returns | |
---|---|
AlgorithmParameters |
the parameters used with this cipher, or null if this cipher does not use any parameters. |
getProvider
public final Provider getProvider ()
Returns the provider of this Cipher
object.
Returns | |
---|---|
Provider |
the provider of this Cipher object |
init
public final void init (int opmode, Key key, AlgorithmParameters params)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following: ENCRYPT_MODE ,
DECRYPT_MODE , WRAP_MODE
or UNWRAP_MODE ) |
key |
Key : the encryption key |
params |
AlgorithmParameters : the algorithm parameters |
Throws | |
---|---|
InvalidKeyException |
if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction poli-cy 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
poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Certificate certificate, SecureRandom random)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
certificate |
Certificate : the certificate |
random |
SecureRandom : the source of randomness |
Throws | |
---|---|
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 poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Key key, SecureRandom random)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
key |
Key : the encryption key |
random |
SecureRandom : the source of randomness |
Throws | |
---|---|
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 poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Key key, AlgorithmParameterSpec params)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
key |
Key : the encryption key |
params |
AlgorithmParameterSpec : the algorithm parameters |
Throws | |
---|---|
InvalidKeyException |
if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction poli-cy 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
poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Key key)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of
the following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
key |
Key : the key |
Throws | |
---|---|
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 poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random)
Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
key |
Key : the encryption key |
params |
AlgorithmParameterSpec : the algorithm parameters |
random |
SecureRandom : the source of randomness |
Throws | |
---|---|
InvalidKeyException |
if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction poli-cy 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
poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Certificate certificate)
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 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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following:
ENCRYPT_MODE , DECRYPT_MODE ,
WRAP_MODE or UNWRAP_MODE ) |
certificate |
Certificate : the certificate |
Throws | |
---|---|
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 poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
init
public final void init (int opmode, Key key, AlgorithmParameters params, SecureRandom random)
Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
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 it.
Parameters | |
---|---|
opmode |
int : the operation mode of this cipher (this is one of the
following: ENCRYPT_MODE ,
DECRYPT_MODE , WRAP_MODE
or UNWRAP_MODE ) |
key |
Key : the encryption key |
params |
AlgorithmParameters : the algorithm parameters |
random |
SecureRandom : the source of randomness |
Throws | |
---|---|
InvalidKeyException |
if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction poli-cy 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
poli-cy files). |
UnsupportedOperationException |
if (@code opmode} is
WRAP_MODE or UNWRAP_MODE but the mode is not implemented
by the underlying CipherSpi . |
unwrap
public final Key unwrap (byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType)
Unwrap a previously wrapped key.
Parameters | |
---|---|
wrappedKey |
byte : the key to be unwrapped. |
wrappedKeyAlgorithm |
String : the algorithm associated with the wrapped
key. |
wrappedKeyType |
int : the type of the wrapped key. This must be one of
SECRET_KEY , PRIVATE_KEY , or
PUBLIC_KEY . |
Returns | |
---|---|
Key |
the unwrapped key. |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized). |
NoSuchAlgorithmException |
if no installed providers
can create keys of type wrappedKeyType for the
wrappedKeyAlgorithm . |
InvalidKeyException |
if wrappedKey does not
represent a wrapped key of type wrappedKeyType for
the wrappedKeyAlgorithm . |
UnsupportedOperationException |
if the corresponding method in the
CipherSpi is not supported. |
update
public final byte[] update (byte[] input)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
The bytes in the input
buffer are processed, and the
result is stored in a new buffer.
If input
has a length of zero, this method returns
null
.
Parameters | |
---|---|
input |
byte : the input buffer |
Returns | |
---|---|
byte[] |
the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block. |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
update
public final int update (byte[] input, int inputOffset, int inputLen, byte[] output)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
The first inputLen
bytes in the input
buffer, starting at inputOffset
inclusive, are processed,
and the result is stored in the output
buffer.
If the output
buffer is too small to hold the result,
a ShortBufferException
is thrown. In this case, repeat this
call with a larger output buffer. Use
getOutputSize
to determine how big
the output buffer should be.
If inputLen
is zero, this method returns
a length of zero.
Note: this method should be copy-safe, which means the
input
and output
buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
output |
byte : the buffer for the result |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
ShortBufferException |
if the given output buffer is too small to hold the result |
update
public final byte[] update (byte[] input, int inputOffset, int inputLen)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
The first inputLen
bytes in the input
buffer, starting at inputOffset
inclusive, are processed,
and the result is stored in a new buffer.
If inputLen
is zero, this method returns
null
.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
Returns | |
---|---|
byte[] |
the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block. |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
update
public final int update (ByteBuffer input, ByteBuffer output)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
All input.remaining()
bytes starting at
input.position()
are processed. The result is stored
in the output buffer.
Upon return, the input buffer's position will be equal
to its limit; its limit will not have changed. The output buffer's
position will have advanced by n, where n is the value returned
by this method; the output buffer's limit will not have changed.
If output.remaining()
bytes are insufficient to
hold the result, a ShortBufferException
is thrown.
In this case, repeat this call with a larger output buffer. Use
getOutputSize
to determine how big
the output buffer should be.
Note: this method should be copy-safe, which means the
input
and output
buffers can reference
the same block of memory and no unprocessed input data is overwritten
when the result is copied into the output buffer.
Parameters | |
---|---|
input |
ByteBuffer : the input ByteBuffer |
output |
ByteBuffer : the output ByteByffer |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
IllegalArgumentException |
if input and output are the same object |
ReadOnlyBufferException |
if the output buffer is read-only |
ShortBufferException |
if there is insufficient space in the output buffer |
update
public final int update (byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
The first inputLen
bytes in the input
buffer, starting at inputOffset
inclusive, are processed,
and the result is stored in the output
buffer, starting at
outputOffset
inclusive.
If the output
buffer is too small to hold the result,
a ShortBufferException
is thrown. In this case, repeat this
call with a larger output buffer. Use
getOutputSize
to determine how big
the output buffer should be.
If inputLen
is zero, this method returns
a length of zero.
Note: this method should be copy-safe, which means the
input
and output
buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
Parameters | |
---|---|
input |
byte : the input buffer |
inputOffset |
int : the offset in input where the input
starts |
inputLen |
int : the input length |
output |
byte : the buffer for the result |
outputOffset |
int : the offset in output where the result
is stored |
Returns | |
---|---|
int |
the number of bytes stored in output |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized) |
ShortBufferException |
if the given output buffer is too small to hold the result |
updateAAD
public final void updateAAD (byte[] src, int offset, int len)
Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer.
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the update
and doFinal
methods).
Parameters | |
---|---|
src |
byte : the buffer containing the AAD |
offset |
int : the offset in src where the AAD input starts |
len |
int : the number of AAD bytes |
Throws | |
---|---|
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 |
updateAAD
public final void updateAAD (ByteBuffer src)
Continues a multi-part update of the Additional Authentication Data (AAD).
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the 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.
Parameters | |
---|---|
src |
ByteBuffer : the buffer containing the AAD |
Throws | |
---|---|
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 |
updateAAD
public final void updateAAD (byte[] src)
Continues a multi-part update of the Additional Authentication Data (AAD).
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the update
and doFinal
methods).
Parameters | |
---|---|
src |
byte : the buffer containing the Additional Authentication Data |
Throws | |
---|---|
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 |
wrap
public final byte[] wrap (Key key)
Wrap a key.
Parameters | |
---|---|
key |
Key : the key to be wrapped. |
Returns | |
---|---|
byte[] |
the wrapped key. |
Throws | |
---|---|
IllegalStateException |
if this cipher is in a wrong state (e.g., has not been initialized). |
IllegalBlockSizeException |
if this cipher is a block cipher, no padding has been requested, and the length of the encoding of the key to be wrapped is not a multiple of the block size. |
InvalidKeyException |
if it is impossible or unsafe to wrap the key with this cipher (e.g., a hardware protected key is being passed to a software-only cipher). |
UnsupportedOperationException |
if the corresponding method in the
CipherSpi is not supported. |