com.microej.crypto.internal.cipher

Class AbstractCipherSpi

java.lang.Object

javax.crypto.CipherSpi

com.microej.crypto.internal.cipher.AbstractCipherSpi

Direct Known Subclasses:

NativeCipherSpi

public abstract class AbstractCipherSpi
extends CipherSpi

Implementation forked from com.sun.crypto.provider.CipherCore.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCipherSpi(int blockSize)
protected	AbstractCipherSpi(int blockSize, int unitBytes, int cipherMode)

Method Summary

Modifier and Type	Method and Description
static int	addExact(int x, int y) Returns the sum of its arguments, throwing an exception if the result overflows an int.
protected abstract int	decrypt(byte[] cipher, int cipherOffset, int cipherLen, byte[] plain, int plainOffset, boolean doFinal) Performs decryption operation.
protected abstract int	encrypt(byte[] plain, int plainOffset, int plainLen, byte[] cipher, int cipherOffset, boolean doFinal) Performs encryption operation.
protected byte[]	engineDoFinal(byte[] input, int inputOffset, int inputLen) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected int	engineDoFinal(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.
protected int	engineGetBlockSize() Returns the block size (in bytes).
protected 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).
protected abstract void	engineInit(boolean decrypting, String algorithm, SecretKey key, byte[] iv, int tagLen) Initializes the cipher in the specified mode with the given key and iv.
protected void	engineInit(int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random) Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
protected void	engineInit(int opmode, Key key, SecureRandom random) Initializes this cipher with a key and a source of randomness.
protected abstract void	engineSetIV(byte[] iv) Sets the initial vector.
protected byte[]	engineUpdate(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.
protected int	engineUpdate(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.
protected void	engineUpdateAAD(byte[] src, int offset, int len) Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer.
protected abstract int	getBufferedLength() TODO
protected abstract 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.

Methods inherited from class javax.crypto.CipherSpi

engineGetIV, engineUnwrap, engineWrap

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractCipherSpi

protected AbstractCipherSpi(int blockSize)

AbstractCipherSpi

protected AbstractCipherSpi(int blockSize,
                            int unitBytes,
                            int cipherMode)

Method Detail

addExact

public static int addExact(int x,
                           int y)

Returns the sum of its arguments, throwing an exception if the result overflows an int.

Parameters:

x - the first value

y - the second value

Returns:

the result

Throws:

ArithmeticException - if the result overflows an int

Since:

1.8

decrypt

protected abstract int decrypt(byte[] cipher,
                               int cipherOffset,
                               int cipherLen,
                               byte[] plain,
                               int plainOffset,
                               boolean doFinal)

Performs decryption operation.

The input cipher, starting at cipherOffset and ending at (cipherOffset+cipherLen-1), is decrypted. The result is stored in plain, starting at plainOffset.

The subclass that implements Cipher should ensure that init has been called before this method is called.

Parameters:

cipher - the input buffer with the data to be decrypted

cipherOffset - the offset in cipher

cipherLen - the length of the input data

plain - the buffer for the decryption result

plainOffset - the offset in plain

Returns:

the number of bytes placed into plain

encrypt

protected abstract int encrypt(byte[] plain,
                               int plainOffset,
                               int plainLen,
                               byte[] cipher,
                               int cipherOffset,
                               boolean doFinal)

Performs encryption operation.

The input plain, starting at plainOffset and ending at (plainOffset+plainLen-1), is encrypted. The result is stored in cipher, starting at cipherOffset.

The subclass that implements Cipher should ensure that init has been called before this method is called.

Parameters:

plain - the input buffer with the data to be encrypted

plainOffset - the offset in plain

plainLen - the length of the input data

cipher - the buffer for the encryption result

cipherOffset - the offset in cipher

Returns:

the number of bytes placed into cipher

engineDoFinal

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

Description copied from class: CipherSpi

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 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 cipher object may need to be reset before it can be used again.

Specified by:

engineDoFinal in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

the new buffer with the result

Throws:

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

engineDoFinal

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

Description copied from class: CipherSpi

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.

Upon finishing, this method resets this cipher 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 cipher object may need to be reset before it can be used again.

Specified by:

engineDoFinal in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

outputOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

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 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

engineGetBlockSize

protected int engineGetBlockSize()

Description copied from class: CipherSpi

Returns the block size (in bytes).

Specified by:

engineGetBlockSize in class CipherSpi

Returns:

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

engineGetOutputSize

protected int engineGetOutputSize(int inputLen)

Description copied from class: CipherSpi

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.

Specified by:

engineGetOutputSize in class CipherSpi

Parameters:

inputLen - the input length (in bytes)

Returns:

the required output buffer size (in bytes)

engineInit

protected abstract void engineInit(boolean decrypting,
                                   String algorithm,
                                   SecretKey key,
                                   byte[] iv,
                                   int tagLen)
                            throws InvalidKeyException,
                                   InvalidAlgorithmParameterException

Initializes the cipher in the specified mode with the given key and iv.

Parameters:

decrypting - flag indicating encryption or decryption mode

algorithm - the algorithm name (never null)

key - the key (never null)

iv - the iv (either null or blockSize bytes long)

tagLen - the tag Length (only for GCM)

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher

InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher.

engineInit

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

Description copied from class: CipherSpi

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 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 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.

Specified by:

engineInit in class CipherSpi

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

params - the algorithm parameters

random - the source of randomness

Throws:

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.

engineInit

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

Description copied from class: CipherSpi

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 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 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.

Specified by:

engineInit in class CipherSpi

Parameters:

opmode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

random - the source of randomness

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key.

engineSetIV

protected abstract void engineSetIV(byte[] iv)

Sets the initial vector.

Parameters:

iv - the iv (either null or blockSize bytes long)

engineUpdate

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

Description copied from class: CipherSpi

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.

Specified by:

engineUpdate in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

Returns:

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.

engineUpdate

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

Description copied from class: CipherSpi

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.

Specified by:

engineUpdate in class CipherSpi

Parameters:

input - the input buffer

inputOffset - the offset in input where the input starts

inputLen - the input length

output - the buffer for the result

outputOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

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

engineUpdateAAD

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

Description copied from class: CipherSpi

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).

Overrides:

engineUpdateAAD in class CipherSpi

Parameters:

src - the buffer containing the AAD

offset - the offset in src where the AAD input starts

len - the number of AAD bytes

getBufferedLength

protected abstract int getBufferedLength()

TODO

Returns:

natively buffered length

updateAAD

protected abstract 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 - the buffer containing the AAD

offset - the offset in src where the AAD input starts

len - the number of AAD bytes

Throws:

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 this method has not been overridden by an implementation

Since:

1.8