OpenJDK 27 · javax.crypto.CipherSpi · APIdia, the JavaDoc alternative

This class defines the Service Provider Interface (SPI) for the Cipher class. All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a particular cipher algorithm.

In order to create an instance of Cipher, which encapsulates an instance of this CipherSpi class, an application calls one of the getInstance factory methods of the Cipher engine class and specifies the requested transformation. Optionally, the application may also specify the name of a provider.

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:

"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("AES/CBC/PKCS5Padding");

A provider may supply a separate class for each combination of algorithm/mode/padding, or may decide to provide more generic classes representing sub-transformations corresponding to algorithm or algorithm/mode or algorithm//padding (note the double slashes), in which case the requested mode and/or padding are set automatically by the getInstance methods of Cipher, which invoke the engineSetMode and engineSetPadding methods of the provider's subclass of CipherSpi.

A Cipher property in a provider master class may have one of the following formats:

    // provider's subclass of "CipherSpi" implements "algName" with
    // pluggable mode and padding
    Cipher.algName

    // provider's subclass of "CipherSpi" implements "algName" in the
    // specified "mode", with pluggable padding
    Cipher.algName/mode

    // provider's subclass of "CipherSpi" implements "algName" with the
    // specified "padding", with pluggable mode
    Cipher.algName//padding

    // provider's subclass of "CipherSpi" implements "algName" with the
    // specified "mode" and "padding"
    Cipher.algName/mode/padding

For example, a provider may supply a subclass of CipherSpi that implements AES/ECB/PKCS5Padding, one that implements AES/CBC/PKCS5Padding, one that implements AES/CFB/PKCS5Padding, and yet another one that implements AES/OFB/PKCS5Padding. That provider would have the following Cipher properties in its master class:

```
    Cipher.AES/ECB/PKCS5Padding
```
```
    Cipher.AES/CBC/PKCS5Padding
```
```
    Cipher.AES/CFB/PKCS5Padding
```
```
    Cipher.AES/OFB/PKCS5Padding
```

Another provider may implement a class for each of the above modes (i.e., one class for ECB, one for CBC, one for CFB, and one for OFB), one class for PKCS5Padding, and a generic AES class that subclasses from CipherSpi. That provider would have the following Cipher properties in its master class:

```
    Cipher.AES
```

The getInstance factory method of the Cipher engine class follows these rules in order to instantiate a provider's implementation of CipherSpi for a transformation of the form "algorithm":

Check if the provider has registered a subclass of CipherSpi for the specified "algorithm".
If the answer is YES, instantiate this class, for whose mode and padding scheme default values (as supplied by the provider) are used.
If the answer is NO, throw a NoSuchAlgorithmException exception.

The getInstance factory method of the Cipher engine class follows these rules in order to instantiate a provider's implementation of CipherSpi for a transformation of the form "algorithm/mode/padding":

Check if the provider has registered a subclass of CipherSpi for the specified "algorithm/mode/padding" transformation.
If the answer is YES, instantiate it.
If the answer is NO, go to the next step.
Check if the provider has registered a subclass of CipherSpi for the sub-transformation "algorithm/mode".
If the answer is YES, instantiate it, and call engineSetPadding(padding) on the new instance.
If the answer is NO, go to the next step.
Check if the provider has registered a subclass of CipherSpi for the sub-transformation "algorithm//padding" (note the double slashes).
If the answer is YES, instantiate it, and call engineSetMode(mode) on the new instance.
If the answer is NO, go to the next step.
Check if the provider has registered a subclass of CipherSpi for the sub-transformation "algorithm".
If the answer is YES, instantiate it, and call engineSetMode(mode) and engineSetPadding(padding) on the new instance.
If the answer is NO, throw a NoSuchAlgorithmException exception.

Access	Constructor and Description
public	CipherSpi() Constructor for subclasses to call.

Method Summary

Modifier and Type	Method and Description
private int	bufferCrypt(ByteBuffer input, ByteBuffer output, boolean isUpdate) Implementation for encryption using ByteBuffers.
protected abstract byte[]	Returns: the new buffer with the result engineDoFinal(byte[] the input buffer input, int the offset in `input` where the input starts inputOffset, int the input length inputLen) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected abstract int	Returns: the number of bytes stored in `output` engineDoFinal(byte[] the input buffer input, int the offset in `input` where the input starts inputOffset, int the input length inputLen, byte[] the buffer for the result output, int the offset in `output` where the result is stored outputOffset) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected int	Returns: the number of bytes stored in `output` engineDoFinal(ByteBuffer the input ByteBuffer input, ByteBuffer the output ByteBuffer output) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected abstract int	Returns: the block size (in bytes), or 0 if the algorithm is not a block cipher engineGetBlockSize() Returns the block size (in bytes).
protected abstract byte[]	Returns: the initialization vector in a new buffer, or `null` if the algorithm does not use an IV, or if the IV has not yet been set engineGetIV() Returns the initialization vector (IV) in a new buffer.
protected int	Returns: the key size of the given key object engineGetKeySize(Key the key object key) Returns the key size of the given key object in bits.
protected abstract int	Returns: the required output buffer size (in bytes) engineGetOutputSize(int the input length (in bytes) 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).
protected abstract AlgorithmParameters	Returns: the parameters used with this cipher, or `null` engineGetParameters() Returns the parameters used with this cipher.
protected abstract void	engineInit(int the operation mode of this `CipherSpi` object (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`) opmode, Key the encryption key key, SecureRandom the source of randomness random) Initializes this `CipherSpi` object with a key and a source of randomness.
protected abstract void	engineInit(int the operation mode of this `CipherSpi` object (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE`, or `UNWRAP_MODE`) opmode, Key the encryption key key, AlgorithmParameterSpec the algorithm parameters params, SecureRandom the source of randomness random) Initializes this `CipherSpi` object with a key, a set of algorithm parameters, and a source of randomness.
protected abstract void	engineInit(int the operation mode of this `CipherSpi` object (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE`, or `UNWRAP_MODE`) opmode, Key the encryption key key, AlgorithmParameters the algorithm parameters params, SecureRandom the source of randomness random) Initializes this `CipherSpi` object with a key, a set of algorithm parameters, and a source of randomness.
protected abstract void	engineSetMode(String the cipher mode mode) Sets the mode of this cipher.
protected abstract void	engineSetPadding(String the padding mechanism padding) Sets the padding mechanism of this cipher.
protected Key	Returns: the unwrapped key engineUnwrap(byte[] the key to be unwrapped wrappedKey, String the algorithm associated with the wrapped key wrappedKeyAlgorithm, int the type of the wrapped key. This is one of `SECRET_KEY`, `PRIVATE_KEY`, or `PUBLIC_KEY`. wrappedKeyType) Unwrap a previously wrapped key.
protected abstract byte[]	Returns: the new buffer with the result, or `null` if the cipher is a block cipher and the input data is too short to result in a new block engineUpdate(byte[] the input buffer input, int the offset in `input` where the input starts inputOffset, int the input length inputLen) Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object was initialized), processing another data part.
protected abstract int	Returns: the number of bytes stored in `output` engineUpdate(byte[] the input buffer input, int the offset in `input` where the input starts inputOffset, int the input length inputLen, byte[] the buffer for the result output, int the offset in `output` where the result is stored outputOffset) Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object was initialized), processing another data part.
protected int	Returns: the number of bytes stored in `output` engineUpdate(ByteBuffer the input ByteBuffer input, ByteBuffer the output ByteBuffer output) Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object was initialized), processing another data part.
protected void	engineUpdateAAD(byte[] the buffer containing the AAD src, int the offset in `src` where the AAD input starts offset, int the number of AAD bytes len) Continues a multipart update of the Additional Authentication Data (AAD), using a subset of the provided buffer.
protected void	engineUpdateAAD(ByteBuffer the buffer containing the AAD src) Continues a multipart update of the Additional Authentication Data (AAD).
protected byte[]	Returns: the wrapped key engineWrap(Key the key to be wrapped key) Wrap a key.
pack-priv static int	getTempArraySize(int totalSize)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

CipherSpi	back to summary
public CipherSpi() Constructor for subclasses to call.

Method Detail

bufferCrypt	back to summary
private int bufferCrypt(ByteBuffer input, ByteBuffer output, boolean isUpdate) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException Implementation for encryption using ByteBuffers. Used for both engineUpdate() and engineDoFinal().

engineDoFinal back to summary

engineDoFinal	back to summary
protected abstract byte[] engineDoFinal(byte[] input, int inputOffset, int inputLen) throws IllegalBlockSizeException, BadPaddingException Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this `CipherSpi` object 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 or 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 `CipherSpi` object to the state it was in when previously initialized via a call to `engineInit`. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to `engineInit`) more data. Note if any exception is thrown, this `CipherSpi` 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 Exceptions 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 `CipherSpi` object 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 `CipherSpi` object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value

protected abstract byte[] engineDoFinal(byte[] input, int inputOffset, int inputLen) throws IllegalBlockSizeException, BadPaddingException

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this CipherSpi object 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 or 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 CipherSpi object to the state it was in when previously initialized via a call to engineInit. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to engineInit) more data.

Note

if any exception is thrown, this CipherSpi 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

Exceptions

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 CipherSpi object 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 CipherSpi object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value

engineDoFinal back to summary

engineDoFinal	back to summary
protected abstract int engineDoFinal(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this `CipherSpi` object 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 or 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. Upon finishing, this method resets this `CipherSpi` object to the state it was in when previously initialized via a call to `engineInit`. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to `engineInit`) more data. Note if any exception is thrown, this `CipherSpi` 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 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` Exceptions ShortBufferException: if the given output buffer is too small to hold the result 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 `CipherSpi` object 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 `CipherSpi` object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value

protected abstract int engineDoFinal(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException

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

Note

if any exception is thrown, this CipherSpi 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
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

Exceptions

ShortBufferException:: if the given output buffer is too small to hold the result
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 CipherSpi object 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 CipherSpi object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value

engineDoFinal back to summary

engineDoFinal	back to summary
protected int engineDoFinal(ByteBuffer input, ByteBuffer output) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this `CipherSpi` object was initialized. All `input.remaining()` bytes starting at `input.position()` are processed. If an AEAD mode such as GCM or 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. Upon finishing, this method resets this `CipherSpi` object to the state it was in when previously initialized via a call to `engineInit`. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to `engineInit` more data. Note if any exception is thrown, this `CipherSpi` object may need to be reset before it can be used again. Subclasses should consider overriding this method if they can process ByteBuffers more efficiently than byte arrays. Parameters input:ByteBuffer the input ByteBuffer output:ByteBuffer the output ByteBuffer Returns:int the number of bytes stored in `output` Exceptions ShortBufferException: if there is insufficient space in the output buffer 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 `CipherSpi` object 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 `CipherSpi` object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value NullPointerException: if either parameter is `null` Since 1.5

protected int engineDoFinal(ByteBuffer input, ByteBuffer output) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException

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

All input.remaining() bytes starting at input.position() are processed. If an AEAD mode such as GCM or 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.

Note

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

Subclasses should consider overriding this method if they can process ByteBuffers more efficiently than byte arrays.

Parameters

input:ByteBuffer: the input ByteBuffer
output:ByteBuffer: the output ByteBuffer

Returns:int

the number of bytes stored in output

Exceptions

ShortBufferException:: if there is insufficient space in the output buffer
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 CipherSpi object 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 CipherSpi object is decrypting in an AEAD mode (such as GCM or CCM), and the received authentication tag does not match the calculated value
NullPointerException:: if either parameter is null

Since

1.5

engineGetBlockSize	back to summary
protected abstract int engineGetBlockSize() Returns the block size (in bytes). Returns:int the block size (in bytes), or 0 if the algorithm is not a block cipher

engineGetBlockSize

back to summary

protected abstract int engineGetBlockSize()

Returns the block size (in bytes).

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

engineGetIV back to summary

engineGetIV	back to summary
protected abstract byte[] engineGetIV() Returns the initialization vector (IV) in a new buffer. This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase. Returns:byte[] the initialization vector in a new buffer, or `null` if the algorithm does not use an IV, or if the IV has not yet been set

protected abstract byte[] engineGetIV()

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

This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase.

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

engineGetKeySize back to summary

engineGetKeySize	back to summary
protected int engineGetKeySize(Key key) throws InvalidKeyException Returns the key size of the given key object in bits. This concrete method has been added to this previously-defined abstract class. It throws an `UnsupportedOperationException` if it is not overridden by the provider. Parameters key:Key the key object Returns:int the key size of the given key object Exceptions InvalidKeyException: if `key` is invalid

protected int engineGetKeySize(Key key) throws InvalidKeyException

Returns the key size of the given key object in bits.

This concrete method has been added to this previously-defined abstract class. It throws an UnsupportedOperationException if it is not overridden by the provider.

Parameters

key:Key: the key object

Returns:int

the key size of the given key object

Exceptions

InvalidKeyException:: if key is invalid

engineGetOutputSize back to summary

engineGetOutputSize	back to summary
protected abstract int engineGetOutputSize(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)

protected abstract int engineGetOutputSize(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)

engineGetParameters back to summary

engineGetParameters	back to summary
protected abstract AlgorithmParameters engineGetParameters() Returns the parameters used with this cipher. The returned parameters may be the same that were used to initialize this cipher, or may contain additional default or random parameter values used by the underlying cipher implementation. If the required parameters were not supplied and can be generated by the cipher, the generated parameters are returned. Otherwise, `null` is returned. Returns:AlgorithmParameters the parameters used with this cipher, or `null`

protected abstract AlgorithmParameters engineGetParameters()

Returns the parameters used with this cipher.

The returned parameters may be the same that were used to initialize this cipher, or may contain additional default or random parameter values used by the underlying cipher implementation. If the required parameters were not supplied and can be generated by the cipher, the generated parameters are returned. Otherwise, null is returned.

Returns:AlgorithmParameters: the parameters used with this cipher, or null

engineInit back to summary

engineInit	back to summary
protected abstract void engineInit(int opmode, Key key, SecureRandom random) throws InvalidKeyException Initializes this `CipherSpi` object with a key and a source of randomness. The `CipherSpi` object 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 `engineGetParameters` or `engineGetIV` (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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from `random`. Note that when a `CipherSpi` object is initialized, it loses all previously-acquired state. In other words, initializing a `CipherSpi` object is equivalent to creating a new instance of that `CipherSpi` object and initializing it. Parameters opmode:int the operation mode of this `CipherSpi` object (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 Exceptions InvalidKeyException: if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key UnsupportedOperationException: if `opmode` is `WRAP_MODE` or `UNWRAP_MODE` is not implemented by the cipher

protected abstract void engineInit(int opmode, Key key, SecureRandom random) throws InvalidKeyException

Initializes this CipherSpi object with a key and a source of randomness.

The CipherSpi object 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 engineGetParameters or engineGetIV (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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

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

Parameters

opmode:int: the operation mode of this CipherSpi object (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

Exceptions

InvalidKeyException:: if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key
UnsupportedOperationException:: if opmode is WRAP_MODE or UNWRAP_MODE is not implemented by the cipher

engineInit back to summary

engineInit	back to summary
protected abstract void engineInit(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException Initializes this `CipherSpi` object with a key, a set of algorithm parameters, and a source of randomness. The `CipherSpi` object 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 `engineGetParameters` or `engineGetIV` (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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from `random`. Note that when a `CipherSpi` object is initialized, it loses all previously-acquired state. In other words, initializing a `CipherSpi` object is equivalent to creating a new instance of that `CipherSpi` object and initializing it. Parameters opmode:int the operation mode of this `CipherSpi` object (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 Exceptions InvalidKeyException: if the given key is inappropriate for initializing this cipher InvalidAlgorithmParameterException: if the given algorithm parameters are inappropriate for this cipher, or if this cipher requires algorithm parameters and `params` is `null` UnsupportedOperationException: if `opmode` is `WRAP_MODE` or `UNWRAP_MODE` is not implemented by the cipher

protected abstract void engineInit(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException

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

The CipherSpi object 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 engineGetParameters or engineGetIV (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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Parameters

opmode:int: the operation mode of this CipherSpi object (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

Exceptions

InvalidKeyException:: if the given key is inappropriate for initializing this cipher
InvalidAlgorithmParameterException:: if the given algorithm parameters are inappropriate for this cipher, or if this cipher requires algorithm parameters and params is null
UnsupportedOperationException:: if opmode is WRAP_MODE or UNWRAP_MODE is not implemented by the cipher

engineInit back to summary

engineInit	back to summary
protected abstract void engineInit(int opmode, Key key, AlgorithmParameters params, SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException Initializes this `CipherSpi` object with a key, a set of algorithm parameters, and a source of randomness. The `CipherSpi` object 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 `engineGetParameters` or `engineGetIV` (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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from `random`. Note that when a `CipherSpi` object is initialized, it loses all previously-acquired state. In other words, initializing a `CipherSpi` object is equivalent to creating a new instance of that `CipherSpi` object and initializing it. Parameters opmode:int the operation mode of this `CipherSpi` object (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 Exceptions InvalidKeyException: if the given key is inappropriate for initializing this cipher InvalidAlgorithmParameterException: if the given algorithm parameters are inappropriate for this cipher, or if this cipher requires algorithm parameters and `params` is null UnsupportedOperationException: if `opmode` is `WRAP_MODE` or `UNWRAP_MODE` is not implemented by the cipher

protected abstract void engineInit(int opmode, Key key, AlgorithmParameters params, SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException

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

The CipherSpi object 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 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 feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Parameters

opmode:int: the operation mode of this CipherSpi object (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

Exceptions

InvalidKeyException:: if the given key is inappropriate for initializing this cipher
InvalidAlgorithmParameterException:: if the given algorithm parameters are inappropriate for this cipher, or if this cipher requires algorithm parameters and params is null
UnsupportedOperationException:: if opmode is WRAP_MODE or UNWRAP_MODE is not implemented by the cipher

engineSetMode	back to summary
protected abstract void engineSetMode(String mode) throws NoSuchAlgorithmException Sets the mode of this cipher. Parameters mode:String the cipher mode Exceptions NoSuchAlgorithmException: if the requested cipher mode does not exist

engineSetMode

back to summary

protected abstract void engineSetMode(String mode) throws NoSuchAlgorithmException

Sets the mode of this cipher.

Parameters

mode:String: the cipher mode

Exceptions

NoSuchAlgorithmException:: if the requested cipher mode does not exist

engineSetPadding	back to summary
protected abstract void engineSetPadding(String padding) throws NoSuchPaddingException Sets the padding mechanism of this cipher. Parameters padding:String the padding mechanism Exceptions NoSuchPaddingException: if the requested padding mechanism does not exist

engineSetPadding

back to summary

protected abstract void engineSetPadding(String padding) throws NoSuchPaddingException

Sets the padding mechanism of this cipher.

Parameters

padding:String: the padding mechanism

Exceptions

NoSuchPaddingException:: if the requested padding mechanism does not exist

engineUnwrap back to summary

engineUnwrap	back to summary
protected Key engineUnwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType) throws InvalidKeyException, NoSuchAlgorithmException Unwrap a previously wrapped key. This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) It may be overridden by a provider to unwrap a previously wrapped key. Such an override is expected to throw an `InvalidKeyException` if the given wrapped key cannot be unwrapped. If this method is not overridden, it always throws an `UnsupportedOperationException`. 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 is one of `SECRET_KEY`, `PRIVATE_KEY`, or `PUBLIC_KEY`. Returns:Key the unwrapped key Exceptions InvalidKeyException: if `wrappedKey` does not represent a wrapped key of type `wrappedKeyType` for the `wrappedKeyAlgorithm` NoSuchAlgorithmException: if no installed providers can create keys of type `wrappedKeyType` for the `wrappedKeyAlgorithm` UnsupportedOperationException: if this method is not supported

protected Key engineUnwrap(byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType) throws InvalidKeyException, NoSuchAlgorithmException

Unwrap a previously wrapped key.

This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) It may be overridden by a provider to unwrap a previously wrapped key. Such an override is expected to throw an InvalidKeyException if the given wrapped key cannot be unwrapped. If this method is not overridden, it always throws an UnsupportedOperationException.

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 is one of SECRET_KEY, PRIVATE_KEY, or PUBLIC_KEY.

Returns:Key

the unwrapped key

Exceptions

InvalidKeyException:: if wrappedKey does not represent a wrapped key of type wrappedKeyType for the wrappedKeyAlgorithm
NoSuchAlgorithmException:: if no installed providers can create keys of type wrappedKeyType for the wrappedKeyAlgorithm
UnsupportedOperationException:: if this method is not supported

engineUpdate back to summary

engineUpdate	back to summary
protected abstract byte[] engineUpdate(byte[] input, int inputOffset, int inputLen) Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object 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. 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 cipher is a block cipher and the input data is too short to result in a new block

protected abstract byte[] engineUpdate(byte[] input, int inputOffset, int inputLen)

Continues a multiple-part encryption or decryption operation (depending on how this CipherSpi object 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.

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 cipher is a block cipher and the input data is too short to result in a new block

engineUpdate back to summary

engineUpdate	back to summary
protected abstract int engineUpdate(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) throws ShortBufferException Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object 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. 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` Exceptions ShortBufferException: if the given output buffer is too small to hold the result

protected abstract int engineUpdate(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) throws ShortBufferException

Continues a multiple-part encryption or decryption operation (depending on how this CipherSpi object 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.

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

Exceptions

ShortBufferException:: if the given output buffer is too small to hold the result

engineUpdate back to summary

engineUpdate	back to summary
protected int engineUpdate(ByteBuffer input, ByteBuffer output) throws ShortBufferException Continues a multiple-part encryption or decryption operation (depending on how this `CipherSpi` object 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. Subclasses should consider overriding this method if they can process ByteBuffers more efficiently than byte arrays. Parameters input:ByteBuffer the input ByteBuffer output:ByteBuffer the output ByteBuffer Returns:int the number of bytes stored in `output` Exceptions ShortBufferException: if there is insufficient space in the output buffer NullPointerException: if either parameter is `null` Since 1.5

protected int engineUpdate(ByteBuffer input, ByteBuffer output) throws ShortBufferException

Continues a multiple-part encryption or decryption operation (depending on how this CipherSpi object 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.

Subclasses should consider overriding this method if they can process ByteBuffers more efficiently than byte arrays.

Parameters

input:ByteBuffer: the input ByteBuffer
output:ByteBuffer: the output ByteBuffer

Returns:int

the number of bytes stored in output

Exceptions

ShortBufferException:: if there is insufficient space in the output buffer
NullPointerException:: if either parameter is null

Since

1.5

engineUpdateAAD back to summary

engineUpdateAAD	back to summary
protected void engineUpdateAAD(byte[] src, int offset, int len) Continues a multipart 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 or 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 Exceptions IllegalStateException: if this `CipherSpi` object 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 this method has not been overridden by an implementation Since 1.7

protected void engineUpdateAAD(byte[] src, int offset, int len)

Continues a multipart 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 or 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

Exceptions

IllegalStateException:: if this CipherSpi object 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 this method has not been overridden by an implementation

Since

1.7

engineUpdateAAD back to summary

engineUpdateAAD	back to summary
protected void engineUpdateAAD(ByteBuffer src) Continues a multipart update of the Additional Authentication Data (AAD). Calls to this method provide AAD to the cipher when operating in modes such as AEAD (GCM or 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 Exceptions IllegalStateException: if this `CipherSpi` object 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 this method has not been overridden by an implementation Since 1.7

protected void engineUpdateAAD(ByteBuffer src)

Continues a multipart update of the Additional Authentication Data (AAD).

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

Exceptions

IllegalStateException:: if this CipherSpi object 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 this method has not been overridden by an implementation

Since

1.7

engineWrap back to summary

engineWrap	back to summary
protected byte[] engineWrap(Key key) throws IllegalBlockSizeException, InvalidKeyException Wrap a key. This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) It may be overridden by a provider to wrap a key. Such an override is expected to throw an `IllegalBlockSizeException` or `InvalidKeyException` (under the specified circumstances), if the given key cannot be wrapped. If this method is not overridden, it always throws an `UnsupportedOperationException`. Parameters key:Key the key to be wrapped Returns:byte[] the wrapped key Exceptions 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 this method is not supported

protected byte[] engineWrap(Key key) throws IllegalBlockSizeException, InvalidKeyException

Wrap a key.

This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.) It may be overridden by a provider to wrap a key. Such an override is expected to throw an IllegalBlockSizeException or InvalidKeyException (under the specified circumstances), if the given key cannot be wrapped. If this method is not overridden, it always throws an UnsupportedOperationException.

Parameters

key:Key: the key to be wrapped

Returns:byte[]

the wrapped key

Exceptions

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 this method is not supported

getTempArraySize	back to summary
pack-priv static int getTempArraySize(int totalSize)

public abstract Class CipherSpi

Constructor Summary

Method Summary

Constructor Detail

Method Detail