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java.lang.Object | +----javax.crypto.Cipher
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:
Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");
When requesting a block cipher in stream cipher mode (e.g., DES in CFB or OFB mode), the user 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.)
DECRYPT_MODE
ENCRYPT_MODE
ident
Cipher(CipherSpi, Provider, String)
doFinal()
doFinal(byte[])
doFinal(byte[], int)
doFinal(byte[], int, int)
doFinal(byte[], int, int, byte[])
doFinal(byte[], int, int, byte[], int)
getAlgorithm()
getBlockSize()
getInstance(String)
getInstance(String, String)
getIV()
getOutputSize(int)
getParameters()
getProvider()
init(int, Key)
init(int, Key, AlgorithmParameters)
init(int, Key, AlgorithmParameters, SecureRandom)
init(int, Key, AlgorithmParameterSpec)
init(int, Key, AlgorithmParameterSpec, SecureRandom)
init(int, Key, SecureRandom)
update(byte[])
update(byte[], int, int)
update(byte[], int, int, byte[])
update(byte[], int, int, byte[], int)
ident
public static final String ident
ENCRYPT_MODE
public static final int ENCRYPT_MODE
DECRYPT_MODE
public static final int DECRYPT_MODE
Cipher
protected Cipher(CipherSpi cipherSpi,
Provider provider,
String transformation)
getInstance
public static final Cipher getInstance(String transformation) throws NoSuchAlgorithmException, NoSuchPaddingException
If the default provider package provides an implementation of the requested transformation, an instance of Cipher containing that implementation is returned. If the transformation is not available in the default provider package, other provider packages are searched.
getInstance
public static final Cipher getInstance(String transformation,
String provider) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException
getProvider
public final Provider getProvider()
getAlgorithm
public final String getAlgorithm()
This is the same name that was specified in one of the getInstance calls that created this Cipher object.
getBlockSize
public final int getBlockSize()
getOutputSize
public final int getOutputSize(int inputLen) throws IllegalStateException
This call takes into account any unprocessed (buffered) data from a previous update call, and padding.
The actual output length of the next update or doFinal call may be smaller than the length returned by this method.
getIV
public final byte[] getIV()
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.
getParameters
public final AlgorithmParameters getParameters()
The returned parameters may be the same that were used to initialise 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 initialised with any.
init
public final void init(int opmode,
Key key) throws InvalidKeyException
The cipher is initialised for encryption or decryption, depending on the value of opmode.
If this cipher requires any algorithm parameters that cannot be derived from the give key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider0specific default or random values) if it is being initialised for encryption, and raise and InvalidKeyException if it is being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system provided source of randomness will be used.)
Note that when a Cipher object is initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.
init
public final void init(int opmode,
Key key,
SecureRandom random) throws InvalidKeyException
The cipher is initialised for encryption or decryption, depending on the value of opmode.
If this cipher requires any algorithm parameters that cannot be derived from the give key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider0specific default or random values) if it is being initialised for encryption, and raise and InvalidKeyException if it is being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.
Note that when a Cipher object is initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.
init
public final void init(int opmode,
Key key,
AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system provided source of randomness will be used.)
Note that when a Cipher object is initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.
init
public final void init(int opmode,
Key key,
AlgorithmParameterSpec params,
SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException
The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.
Note that when a Cipher object is initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher, and initialising it.
init
public final void init(int opmode,
Key key,
AlgorithmParameters params) throws InvalidKeyException, InvalidAlgorithmParameterException
The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them using the SecureRandom implementation of the highest-priority installed provider as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system provided source of randomness will be used.)
Note that when a Cipher object is initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.
init
public final void init(int opmode,
Key key,
AlgorithmParameters params,
SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException
The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).
If this cipher (including its underlying feedback or padding scheme) requires any random bytes, it will get them from random.
Note that when a Cipher object is initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.
update
public final byte[] update(byte input[]) throws IllegalStateException
The bytes in the input buffer are processed, and the result is stored in a new buffer.
update
public final byte[] update(byte input[],
int inputOffset,
int inputLen) throws IllegalStateException
The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in a new buffer.
update
public final int update(byte input[],
int inputOffset,
int inputLen,
byte output[]) throws IllegalStateException, ShortBufferException
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.
update
public final int update(byte input[],
int inputOffset,
int inputLen,
byte output[],
int outputOffset) throws IllegalStateException, ShortBufferException
The first inputLen bytes in the input buffer, starting at inputOffset, are processed, and the result is stored in the output buffer, starting at outputOffset.
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.
doFinal
public final byte[] doFinal() throws IllegalStateException, IllegalBlockSizeException, BadPaddingException
Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. The result is stored in a new buffer.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
doFinal
public final int doFinal(byte output[],
int outputOffset) throws IllegalStateException, IllegalBlockSizeException, ShortBufferException, BadPaddingException
Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. The result is stored in the output buffer, starting at outputOffset.
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.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
doFinal
public final byte[] doFinal(byte input[]) throws IllegalStateException, 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. The result is stored in a new buffer.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
doFinal
public final byte[] doFinal(byte input[],
int inputOffset,
int inputLen) throws IllegalStateException, IllegalBlockSizeException, BadPaddingException
The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in a new buffer.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
doFinal
public final int doFinal(byte input[],
int inputOffset,
int inputLen,
byte output[]) throws IllegalStateException, ShortBufferException, IllegalBlockSizeException, BadPaddingException
The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in the output buffer.
If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use getOutputSize to determine how big the output buffer should be.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
doFinal
public final int doFinal(byte input[],
int inputOffset,
int inputLen,
byte output[],
int outputOffset) throws IllegalStateException, ShortBufferException, IllegalBlockSizeException, BadPaddingException
The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in the output buffer, starting at outputOffset.
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.
A call to this method resets this cipher object to the state it was in when previously initialised 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.
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