CipherSpiExt (Bouncy Castle Library 1.54 API Specification)
Date: 2015-12-29

org.bouncycastle.pqc.jcajce.provider.util

## Class CipherSpiExt

- java.lang.Object
- - javax.crypto.CipherSpi
  - - org.bouncycastle.pqc.jcajce.provider.util.CipherSpiExt

- Direct Known Subclasses:
    AsymmetricBlockCipher, AsymmetricHybridCipher

      public abstract class CipherSpiExt
      extends javax.crypto.CipherSpi

  The CipherSpiExt class extends CipherSpi.

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `DECRYPT_MODE` Constant specifying decrypt mode.
    `static int` | `ENCRYPT_MODE` Constant specifying encrypt mode.
    `protected int` | `opMode` The operation mode for this cipher (`ENCRYPT_MODE` or `DECRYPT_MODE`).

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `CipherSpiExt()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `byte[]` | `doFinal()` Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
    `byte[]` | `doFinal(byte[] input)` Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
    `abstract byte[]` | `doFinal(byte[] input, int inOff, int inLen)` Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
    `abstract int` | `doFinal(byte[] input, int inOff, int inLen, byte[] output, int outOff)` Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
    `protected byte[]` | `engineDoFinal(byte[] input, int inOff, int inLen)` Return the result of the last step of a multi-step en-/decryption operation or the result of a single-step en-/decryption operation by processing the given input data and any remaining buffered data.
    `protected int` | `engineDoFinal(byte[] input, int inOff, int inLen, byte[] output, int outOff)` Perform the last step of a multi-step en-/decryption operation or a single-step en-/decryption operation by processing the given input data and any remaining buffered data.
    `protected int` | `engineGetBlockSize()`
    `protected byte[]` | `engineGetIV()` Return the initialization vector.
    `protected int` | `engineGetKeySize(java.security.Key key)` Return the key size of the given key object in bits.
    `protected int` | `engineGetOutputSize(int inLen)` Return 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 java.security.AlgorithmParameters` | `engineGetParameters()` Returns the parameters used with this cipher.
    `protected void` | `engineInit(int opMode, java.security.Key key, java.security.spec.AlgorithmParameterSpec params, java.security.SecureRandom javaRand)` Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness.
    `protected void` | `engineInit(int opMode, java.security.Key key, java.security.AlgorithmParameters algParams, java.security.SecureRandom random)` Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness.
    `protected void` | `engineInit(int opMode, java.security.Key key, java.security.SecureRandom random)` Initialize this cipher object with a proper key and some random seed.
    `protected void` | `engineSetMode(java.lang.String modeName)` Set the mode of this cipher.
    `protected void` | `engineSetPadding(java.lang.String paddingName)` Set the padding scheme of this cipher.
    `protected byte[]` | `engineUpdate(byte[] input, int inOff, int inLen)` Return the result of the next step of a multi-step en-/decryption operation.
    `protected int` | `engineUpdate(byte[] input, int inOff, int inLen, byte[] output, int outOff)` Perform the next step of a multi-step en-/decryption operation.
    `abstract int` | `getBlockSize()`
    `abstract byte[]` | `getIV()` Return the initialization vector.
    `abstract int` | `getKeySize(java.security.Key key)` Return the key size of the given key object in bits.
    `abstract java.lang.String` | `getName()`
    `abstract int` | `getOutputSize(int inputLen)` Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update or doFinal operation, given the input length inputLen (in bytes).
    `abstract java.security.spec.AlgorithmParameterSpec` | `getParameters()` Returns the parameters used with this cipher.
    `abstract void` | `initDecrypt(java.security.Key key, java.security.spec.AlgorithmParameterSpec cipherParams)` Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness for decryption.
    `abstract void` | `initEncrypt(java.security.Key key, java.security.spec.AlgorithmParameterSpec cipherParams, java.security.SecureRandom random)` Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness for encryption.
    `protected abstract void` | `setMode(java.lang.String mode)` Set the mode of this cipher.
    `protected abstract void` | `setPadding(java.lang.String padding)` Set the padding mechanism of this cipher.
    `byte[]` | `update(byte[] input)` Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
    `abstract byte[]` | `update(byte[] input, int inOff, int inLen)` Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
    `abstract int` | `update(byte[] input, int inOff, int inLen, byte[] output, int outOff)` Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

    - ### Methods inherited from class javax.crypto.CipherSpi

      `engineDoFinal, engineUnwrap, engineUpdate, engineUpdateAAD, engineUpdateAAD, engineWrap`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### ENCRYPT_MODE

          public static final int ENCRYPT_MODE

      Constant specifying encrypt mode.
      See Also:
        Constant Field Values

    - #### DECRYPT_MODE

          public static final int DECRYPT_MODE

      Constant specifying decrypt mode.
      See Also:
        Constant Field Values

    - #### opMode

          protected int opMode

      The operation mode for this cipher (`ENCRYPT_MODE` or `DECRYPT_MODE`).

  - ### Constructor Detail

    - #### CipherSpiExt

          public CipherSpiExt()

  - ### Method Detail

    - #### engineInit

          protected final void engineInit(int opMode,
                        java.security.Key key,
                        java.security.SecureRandom random)
                                   throws java.security.InvalidKeyException

      Initialize this cipher object with a proper key and some random seed. Before a cipher object is ready for data processing, it has to be initialized according to the desired cryptographic operation, which is specified by the `opMode` parameter.

      If this cipher (including its underlying mode or padding scheme) requires any random bytes, it will obtain them from `random`.

      Note: If the mode needs an initialization vector, a blank array is used in this case.

      Specified by:
        `engineInit` in class `javax.crypto.CipherSpi`
      Parameters:
        `opMode` - the operation mode (`ENCRYPT_MODE` or `DECRYPT_MODE`)
        `key` - the key
        `random` - the random seed
      Throws:
        `java.security.InvalidKeyException` - if the key is inappropriate for initializing this cipher.

    - #### engineInit

          protected final void engineInit(int opMode,
                        java.security.Key key,
                        java.security.AlgorithmParameters algParams,
                        java.security.SecureRandom random)
                                   throws java.security.InvalidKeyException,
                                          java.security.InvalidAlgorithmParameterException

      Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness. The cipher is initialized for encryption or decryption, depending on the value of `opMode`.

      If this cipher (including its underlying mode or padding scheme) requires any random bytes, it will obtain 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.

      Note: If the mode needs an initialization vector, a try to retrieve it from the AlgorithmParametersSpec is made.

      Specified by:
        `engineInit` in class `javax.crypto.CipherSpi`
      Parameters:
        `opMode` - the operation mode (`ENCRYPT_MODE` or `DECRYPT_MODE`)
        `key` - the key
        `algParams` - the algorithm parameters
        `random` - the random seed
      Throws:
        `java.security.InvalidKeyException` - if the key is inappropriate for initializing this block cipher.
        `java.security.InvalidAlgorithmParameterException` - if the parameters are inappropriate for initializing this block cipher.

    - #### engineInit

          protected void engineInit(int opMode,
                        java.security.Key key,
                        java.security.spec.AlgorithmParameterSpec params,
                        java.security.SecureRandom javaRand)
                             throws java.security.InvalidKeyException,
                                    java.security.InvalidAlgorithmParameterException

      Initialize 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 (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 `javax.crypto.CipherSpi`
      Parameters:
        `opMode` - the operation mode (`ENCRYPT_MODE` or `DECRYPT_MODE`)
        `key` - the encryption key
        `params` - the algorithm parameters
        `javaRand` - the source of randomness
      Throws:
        `java.security.InvalidKeyException` - if the given key is inappropriate for initializing this cipher
        `java.security.InvalidAlgorithmParameterException` - if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters and the parameters are null.

    - #### engineDoFinal

          protected final byte[] engineDoFinal(byte[] input,
                             int inOff,
                             int inLen)
                                        throws javax.crypto.IllegalBlockSizeException,
                                               javax.crypto.BadPaddingException

      Return the result of the last step of a multi-step en-/decryption operation or the result of a single-step en-/decryption operation by processing the given input data and any remaining buffered data. The data to be processed is given in an input byte array. Beginning at inputOffset, only the first inputLen bytes are en-/decrypted, including any buffered bytes of a previous update operation. If necessary, padding is performed. The result is returned as a output byte array.
      Specified by:
        `engineDoFinal` in class `javax.crypto.CipherSpi`
      Parameters:
        `input` - the byte array holding the data to be processed
        `inOff` - the offset indicating the start position within the input byte array
        `inLen` - the number of bytes to be processed
      Returns:
        the byte array containing the en-/decrypted data
      Throws:
        `javax.crypto.IllegalBlockSizeException` - if the ciphertext length is not a multiple of the blocklength.
        `javax.crypto.BadPaddingException` - if unpadding is not possible.

    - #### engineDoFinal

          protected final int engineDoFinal(byte[] input,
                          int inOff,
                          int inLen,
                          byte[] output,
                          int outOff)
                                     throws javax.crypto.ShortBufferException,
                                            javax.crypto.IllegalBlockSizeException,
                                            javax.crypto.BadPaddingException

      Perform the last step of a multi-step en-/decryption operation or a single-step en-/decryption operation by processing the given input data and any remaining buffered data. The data to be processed is given in an input byte array. Beginning at inputOffset, only the first inputLen bytes are en-/decrypted, including any buffered bytes of a previous update operation. If necessary, padding is performed. The result is stored in the given output byte array, beginning at outputOffset. The number of bytes stored in this byte array are returned.
      Specified by:
        `engineDoFinal` in class `javax.crypto.CipherSpi`
      Parameters:
        `input` - the byte array holding the data to be processed
        `inOff` - the offset indicating the start position within the input byte array
        `inLen` - the number of bytes to be processed
        `output` - the byte array for holding the result
        `outOff` - the offset indicating the start position within the output byte array to which the en/decrypted data is written
      Returns:
        the number of bytes stored in the output byte array
      Throws:
        `javax.crypto.ShortBufferException` - if the output buffer is too short to hold the output.
        `javax.crypto.IllegalBlockSizeException` - if the ciphertext length is not a multiple of the blocklength.
        `javax.crypto.BadPaddingException` - if unpadding is not possible.

    - #### engineGetBlockSize

          protected final int engineGetBlockSize()

      Specified by:
        `engineGetBlockSize` in class `javax.crypto.CipherSpi`
      Returns:
        the block size (in bytes), or 0 if the underlying algorithm is not a block cipher

    - #### engineGetKeySize

          protected final int engineGetKeySize(java.security.Key key)
                                        throws java.security.InvalidKeyException

      Return the key size of the given key object in bits.
      Overrides:
        `engineGetKeySize` in class `javax.crypto.CipherSpi`
      Parameters:
        `key` - the key object
      Returns:
        the key size in bits of the given key object
      Throws:
        `java.security.InvalidKeyException` - if key is invalid.

    - #### engineGetIV

          protected final byte[] engineGetIV()

      Return the initialization vector. This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase.
      Specified by:
        `engineGetIV` in class `javax.crypto.CipherSpi`
      Returns:
        the initialization vector in a new buffer, or `null` if the underlying algorithm does not use an IV, or if the IV has not yet been set.

    - #### engineGetOutputSize

          protected final int engineGetOutputSize(int inLen)

      Return 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, and padding.

      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 `javax.crypto.CipherSpi`
      Parameters:
        `inLen` - the input length (in bytes)
      Returns:
        the required output buffer size (in bytes)

    - #### engineGetParameters

          protected final java.security.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 the default set of parameters or a set of randomly generated parameters used by the underlying cipher implementation (provided that the underlying cipher implementation uses a default set of parameters or creates new parameters if it needs parameters but was not initialized with any).

      Specified by:
        `engineGetParameters` in class `javax.crypto.CipherSpi`
      Returns:
        the parameters used with this cipher, or null if this cipher does not use any parameters.

    - #### engineSetMode

          protected final void engineSetMode(java.lang.String modeName)
                                      throws java.security.NoSuchAlgorithmException

      Set the mode of this cipher.
      Specified by:
        `engineSetMode` in class `javax.crypto.CipherSpi`
      Parameters:
        `modeName` - the cipher mode
      Throws:
        `java.security.NoSuchAlgorithmException` - if neither the mode with the given name nor the default mode can be found

    - #### engineSetPadding

          protected final void engineSetPadding(java.lang.String paddingName)
                                         throws javax.crypto.NoSuchPaddingException

      Set the padding scheme of this cipher.
      Specified by:
        `engineSetPadding` in class `javax.crypto.CipherSpi`
      Parameters:
        `paddingName` - the padding scheme
      Throws:
        `javax.crypto.NoSuchPaddingException` - if the requested padding scheme cannot be found.

    - #### engineUpdate

          protected final byte[] engineUpdate(byte[] input,
                            int inOff,
                            int inLen)

      Return the result of the next step of a multi-step en-/decryption operation. The data to be processed is given in an input byte array. Beginning at inputOffset, only the first inputLen bytes are en-/decrypted. The result is returned as a byte array.
      Specified by:
        `engineUpdate` in class `javax.crypto.CipherSpi`
      Parameters:
        `input` - the byte array holding the data to be processed
        `inOff` - the offset indicating the start position within the input byte array
        `inLen` - the number of bytes to be processed
      Returns:
        the byte array containing the en-/decrypted data

    - #### engineUpdate

          protected final int engineUpdate(byte[] input,
                         int inOff,
                         int inLen,
                         byte[] output,
                         int outOff)
                                    throws javax.crypto.ShortBufferException

      Perform the next step of a multi-step en-/decryption operation. The data to be processed is given in an input byte array. Beginning at inputOffset, only the first inputLen bytes are en-/decrypted. The result is stored in the given output byte array, beginning at outputOffset. The number of bytes stored in this output byte array are returned.
      Specified by:
        `engineUpdate` in class `javax.crypto.CipherSpi`
      Parameters:
        `input` - the byte array holding the data to be processed
        `inOff` - the offset indicating the start position within the input byte array
        `inLen` - the number of bytes to be processed
        `output` - the byte array for holding the result
        `outOff` - the offset indicating the start position within the output byte array to which the en-/decrypted data is written
      Returns:
        the number of bytes that are stored in the output byte array
      Throws:
        `javax.crypto.ShortBufferException` - if the output buffer is too short to hold the output.

    - #### initEncrypt

          public abstract void initEncrypt(java.security.Key key,
                         java.security.spec.AlgorithmParameterSpec cipherParams,
                         java.security.SecureRandom random)
                                    throws java.security.InvalidKeyException,
                                           java.security.InvalidAlgorithmParameterException

      Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness for encryption.

      If this cipher requires any algorithm parameters and paramSpec 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, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption. The generated parameters can be retrieved using engineGetParameters or engineGetIV (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 initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

      Parameters:
        `key` - the encryption key
        `cipherParams` - the cipher parameters
        `random` - the source of randomness
      Throws:
        `java.security.InvalidKeyException` - if the given key is inappropriate for initializing this block cipher.
        `java.security.InvalidAlgorithmParameterException` - if the parameters are inappropriate for initializing this block cipher.

    - #### initDecrypt

          public abstract void initDecrypt(java.security.Key key,
                         java.security.spec.AlgorithmParameterSpec cipherParams)
                                    throws java.security.InvalidKeyException,
                                           java.security.InvalidAlgorithmParameterException

      Initialize this cipher with a key, a set of algorithm parameters, and a source of randomness for decryption.

      If this cipher requires any algorithm parameters and paramSpec 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, and throw an `InvalidAlgorithmParameterException` if it is being initialized for decryption. The generated parameters can be retrieved using engineGetParameters or engineGetIV (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 initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

      Parameters:
        `key` - the encryption key
        `cipherParams` - the cipher parameters
      Throws:
        `java.security.InvalidKeyException` - if the given key is inappropriate for initializing this block cipher.
        `java.security.InvalidAlgorithmParameterException` - if the parameters are inappropriate for initializing this block cipher.

    - #### getName

          public abstract java.lang.String getName()

      Returns:
        the name of this cipher

    - #### getBlockSize

          public abstract int getBlockSize()

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

    - #### getOutputSize

          public abstract int getOutputSize(int inputLen)

      Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update or doFinal operation, given the input length inputLen (in bytes).

      This call takes into account any unprocessed (buffered) data from a previous update call, and padding.

      The actual output length of the next update or doFinal call may be smaller than the length returned by this method.

      Parameters:
        `inputLen` - the input length (in bytes)
      Returns:
        the required output buffer size (in bytes)

    - #### getKeySize

          public abstract int getKeySize(java.security.Key key)
                                  throws java.security.InvalidKeyException

      Return the key size of the given key object in bits.
      Parameters:
        `key` - the key object
      Returns:
        the key size in bits of the given key object
      Throws:
        `java.security.InvalidKeyException` - if key is invalid.

    - #### getParameters

          public abstract java.security.spec.AlgorithmParameterSpec getParameters()

      Returns the parameters used with this cipher.

      The returned parameters may be the same that were used to initialize this cipher, or may contain the default set of parameters or a set of randomly generated parameters used by the underlying cipher implementation (provided that the underlying cipher implementation uses a default set of parameters or creates new parameters if it needs parameters but was not initialized with any).

      Returns:
        the parameters used with this cipher, or null if this cipher does not use any parameters.

    - #### getIV

          public abstract byte[] getIV()

      Return the initialization vector. This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase.
      Returns:
        the initialization vector in a new buffer, or `null` if the underlying algorithm does not use an IV, or if the IV has not yet been set.

    - #### setMode

          protected abstract void setMode(java.lang.String mode)
                                   throws java.security.NoSuchAlgorithmException

      Set the mode of this cipher.
      Parameters:
        `mode` - the cipher mode
      Throws:
        `java.security.NoSuchAlgorithmException` - if the requested mode cannot be found.

    - #### setPadding

          protected abstract void setPadding(java.lang.String padding)
                                      throws javax.crypto.NoSuchPaddingException

      Set the padding mechanism of this cipher.
      Parameters:
        `padding` - the padding mechanism
      Throws:
        `javax.crypto.NoSuchPaddingException` - if the requested padding scheme cannot be found.

    - #### update

          public final byte[] update(byte[] input)

      Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
      Parameters:
        `input` - the input buffer
      Returns:
        a new buffer with the result (maybe an empty byte array)

    - #### update

          public abstract byte[] update(byte[] input,
                      int inOff,
                      int inLen)

      Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
      Parameters:
        `input` - the input buffer
        `inOff` - the offset where the input starts
        `inLen` - the input length
      Returns:
        a new buffer with the result (maybe an empty byte array)

    - #### update

          public abstract int update(byte[] input,
                   int inOff,
                   int inLen,
                   byte[] output,
                   int outOff)
                              throws javax.crypto.ShortBufferException

      Continue a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
      Parameters:
        `input` - the input buffer
        `inOff` - the offset where the input starts
        `inLen` - the input length
        `output` - the output buffer
        `outOff` - the offset where the result is stored
      Returns:
        the length of the output
      Throws:
        `javax.crypto.ShortBufferException` - if the output buffer is too small to hold the result.

    - #### doFinal

          public final byte[] doFinal()
                               throws javax.crypto.IllegalBlockSizeException,
                                      javax.crypto.BadPaddingException

      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Returns:
        a new buffer with the result
      Throws:
        `javax.crypto.IllegalBlockSizeException` - if this cipher is a block cipher and the total input length is not a multiple of the block size (for encryption when no padding is used or for decryption).
        `javax.crypto.BadPaddingException` - if this cipher is a block cipher and unpadding fails.

    - #### doFinal

          public final byte[] doFinal(byte[] input)
                               throws javax.crypto.IllegalBlockSizeException,
                                      javax.crypto.BadPaddingException

      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Parameters:
        `input` - the input buffer
      Returns:
        a new buffer with the result
      Throws:
        `javax.crypto.IllegalBlockSizeException` - if this cipher is a block cipher and the total input length is not a multiple of the block size (for encryption when no padding is used or for decryption).
        `javax.crypto.BadPaddingException` - if this cipher is a block cipher and unpadding fails.

    - #### doFinal

          public abstract byte[] doFinal(byte[] input,
                       int inOff,
                       int inLen)
                                  throws javax.crypto.IllegalBlockSizeException,
                                         javax.crypto.BadPaddingException

      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Parameters:
        `input` - the input buffer
        `inOff` - the offset where the input starts
        `inLen` - the input length
      Returns:
        a new buffer with the result
      Throws:
        `javax.crypto.IllegalBlockSizeException` - if this cipher is a block cipher and the total input length is not a multiple of the block size (for encryption when no padding is used or for decryption).
        `javax.crypto.BadPaddingException` - if this cipher is a block cipher and unpadding fails.

    - #### doFinal

          public abstract int doFinal(byte[] input,
                    int inOff,
                    int inLen,
                    byte[] output,
                    int outOff)
                               throws javax.crypto.ShortBufferException,
                                      javax.crypto.IllegalBlockSizeException,
                                      javax.crypto.BadPaddingException

      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Parameters:
        `input` - the input buffer
        `inOff` - the offset where the input starts
        `inLen` - the input length
        `output` - the buffer for the result
        `outOff` - the offset where the result is stored
      Returns:
        the output length
      Throws:
        `javax.crypto.ShortBufferException` - if the output buffer is too small to hold the result.
        `javax.crypto.IllegalBlockSizeException` - if this cipher is a block cipher and the total input length is not a multiple of the block size (for encryption when no padding is used or for decryption).
        `javax.crypto.BadPaddingException` - if this cipher is a block cipher and unpadding fails.