Package org.bouncycastle.pqc.jcajce.provider.util

Class AsymmetricBlockCipher

java.lang.Object
javax.crypto.CipherSpi
org.bouncycastle.pqc.jcajce.provider.util.CipherSpiExt
org.bouncycastle.pqc.jcajce.provider.util.AsymmetricBlockCipher
Direct Known Subclasses:
McEliecePKCSCipherSpi
public abstract class AsymmetricBlockCipher extends CipherSpiExt
The AsymmetricBlockCipher class extends CipherSpiExt. NOTE: Some Ciphers are using Padding. OneAndZeroesPadding is used as default padding. However padding can still be specified, but mode is not supported; if you try to instantiate the cipher with something else than "NONE" as mode NoSuchAlgorithmException is thrown.

  • Field Details

    • paramSpec

      protected AlgorithmParameterSpec paramSpec
      ParameterSpec used with this cipher

    • buf

      protected ByteArrayOutputStream buf
      Internal buffer

    • maxPlainTextSize

      protected int maxPlainTextSize
      The maximum number of bytes the cipher can decrypt.

    • cipherTextSize

      protected int cipherTextSize
      The maximum number of bytes the cipher can encrypt.

  • Constructor Details

    • AsymmetricBlockCipher

      public AsymmetricBlockCipher()
      The AsymmetricBlockCipher() constructor

  • Method Details

    • getBlockSize

      public final int getBlockSize()
      Return the block size (in bytes). Note: although the ciphers extending this class are not block ciphers, the method was adopted to return the maximal plaintext and ciphertext sizes for non hybrid ciphers. If the cipher is hybrid, it returns 0.
      Specified by:
      getBlockSize in class CipherSpiExt
      Returns:
      if the cipher is not a hybrid one the max plain/cipher text size is returned, otherwise 0 is returned

    • getIV

      public final byte[] getIV()
      Description copied from class: CipherSpiExt
      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:
      getIV in class CipherSpiExt
      Returns:
      null since no initialization vector is used.

    • getOutputSize

      public final int getOutputSize(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 inLen (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.

      If the input length plus the length of the buffered data exceeds the maximum length, 0 is returned.

      Specified by:
      getOutputSize in class CipherSpiExt
      Parameters:
      inLen - the length of the input
      Returns:
      the length of the ciphertext or 0 if the input is too long.

    • getParameters

      public final 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).

      Specified by:
      getParameters in class CipherSpiExt
      Returns:
      the parameters used with this cipher, or null if this cipher does not use any parameters.

    • initEncrypt

      public final void initEncrypt(Key key) throws InvalidKeyException
      Initializes the cipher for encryption by forwarding it to initEncrypt(Key, FlexiSecureRandom).

      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, and raise an InvalidKeyException if it is being initialized for decryption. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

      Parameters:
      key - the encryption or decryption key.
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher.

    • initEncrypt

      public final void initEncrypt(Key key, SecureRandom random) throws InvalidKeyException
      Initialize this cipher for encryption by forwarding it to initEncrypt(Key, FlexiSecureRandom, AlgorithmParameterSpec).

      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, and raise an InvalidKeyException if it is being initialized for decryption. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

      Parameters:
      key - the encryption or decryption key.
      random - the source of randomness.
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher.

    • initEncrypt

      public final void initEncrypt(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
      Initializes the cipher for encryption by forwarding it to initEncrypt(Key, FlexiSecureRandom, AlgorithmParameterSpec).
      Parameters:
      key - the encryption or decryption key.
      params - the algorithm parameters.
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher.
      InvalidAlgorithmParameterException - if the given algortihm parameters are inappropriate for this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters and params is null.

    • initEncrypt

      public final void initEncrypt(Key key, AlgorithmParameterSpec params, SecureRandom secureRandom) throws InvalidKeyException, InvalidAlgorithmParameterException
      This method initializes the AsymmetricBlockCipher with a certain key for data encryption.

      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:
      initEncrypt in class CipherSpiExt
      Parameters:
      key - the key which has to be used to encrypt data.
      params - the algorithm parameters.
      secureRandom - 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 is being initialized for decryption and requires algorithm parameters and params is null.

    • initDecrypt

      public final void initDecrypt(Key key) throws InvalidKeyException
      Initialize the cipher for decryption by forwarding it to initDecrypt(Key, AlgorithmParameterSpec).

      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, and raise an InvalidKeyException if it is being initialized for decryption. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

      Parameters:
      key - the encryption or decryption key.
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher.

    • initDecrypt

      public final void initDecrypt(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
      This method initializes the AsymmetricBlockCipher with a certain key for data decryption.

      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:
      initDecrypt in class CipherSpiExt
      Parameters:
      key - the key which has to be used to decrypt data.
      params - the algorithm parameters.
      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 is being initialized for decryption and requires algorithm parameters and params is null.

    • update

      public final byte[] update(byte[] input, int inOff, int inLen)
      Continue a multiple-part encryption or decryption operation. This method just writes the input into an internal buffer.
      Specified by:
      update in class CipherSpiExt
      Parameters:
      input - byte array containing the next part of the input
      inOff - index in the array where the input starts
      inLen - length of the input
      Returns:
      a new buffer with the result (always empty)

    • update

      public final 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.
      Specified by:
      update in class CipherSpiExt
      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 (always 0)

    • doFinal

      public final byte[] doFinal(byte[] input, int inOff, int inLen) throws IllegalBlockSizeException, BadPaddingException
      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Specified by:
      doFinal in class CipherSpiExt
      Parameters:
      input - the input buffer
      inOff - the offset where the input starts
      inLen - the input length
      Returns:
      a new buffer with the result
      Throws:
      IllegalBlockSizeException - if the plaintext or ciphertext size is too large.
      BadPaddingException - if the ciphertext is invalid.

    • doFinal

      public final int doFinal(byte[] input, int inOff, int inLen, byte[] output, int outOff) throws ShortBufferException, IllegalBlockSizeException, BadPaddingException
      Finish a multiple-part encryption or decryption operation (depending on how this cipher was initialized).
      Specified by:
      doFinal in class CipherSpiExt
      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:
      ShortBufferException - if the output buffer is too small to hold the result.
      IllegalBlockSizeException - if the plaintext or ciphertext size is too large.
      BadPaddingException - if the ciphertext is invalid.

    • setMode

      protected final void setMode(String modeName)
      Since asymmetric block ciphers do not support modes, this method does nothing.
      Specified by:
      setMode in class CipherSpiExt
      Parameters:
      modeName - the cipher mode (unused)

    • setPadding

      protected final void setPadding(String paddingName)
      Since asymmetric block ciphers do not support padding, this method does nothing.
      Specified by:
      setPadding in class CipherSpiExt
      Parameters:
      paddingName - the name of the padding scheme (not used)

    • checkLength

      protected void checkLength(int inLen) throws IllegalBlockSizeException
      Check if the message length plus the length of the input length can be en/decrypted. This method uses the specific values maxPlainTextSize and cipherTextSize which are set by the implementations. If the input length plus the length of the internal buffer is greater than maxPlainTextSize for encryption or not equal to cipherTextSize for decryption, an IllegalBlockSizeException will be thrown.
      Parameters:
      inLen - length of the input to check
      Throws:
      IllegalBlockSizeException - if the input length is invalid.

    • initCipherEncrypt

      protected abstract void initCipherEncrypt(Key key, AlgorithmParameterSpec params, SecureRandom sr) throws InvalidKeyException, InvalidAlgorithmParameterException
      Initialize the AsymmetricBlockCipher with a certain key for data encryption.
      Parameters:
      key - the key which has to be used to encrypt data
      params - the algorithm parameters
      sr - the source of randomness
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher.
      InvalidAlgorithmParameterException - if the given parameters are inappropriate for initializing this cipher.

    • initCipherDecrypt

      protected abstract void initCipherDecrypt(Key key, AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
      Initialize the AsymmetricBlockCipher with a certain key for data encryption.
      Parameters:
      key - the key which has to be used to decrypt data
      params - the algorithm parameters
      Throws:
      InvalidKeyException - if the given key is inappropriate for initializing this cipher
      InvalidAlgorithmParameterException - if the given parameters are inappropriate for initializing this cipher.

    • messageEncrypt

      protected abstract byte[] messageEncrypt(byte[] input) throws IllegalBlockSizeException, BadPaddingException
      Encrypt the message stored in input. The method should also perform an additional length check.
      Parameters:
      input - the message to be encrypted (usually the message length is less than or equal to maxPlainTextSize)
      Returns:
      the encrypted message (it has length equal to maxCipherTextSize_)
      Throws:
      IllegalBlockSizeException - if the input is inappropriate for this cipher.
      BadPaddingException - if the input format is invalid.

    • messageDecrypt

      protected abstract byte[] messageDecrypt(byte[] input) throws IllegalBlockSizeException, BadPaddingException
      Decrypt the ciphertext stored in input. The method should also perform an additional length check.
      Parameters:
      input - the ciphertext to be decrypted (the ciphertext length is less than or equal to maxCipherTextSize)
      Returns:
      the decrypted message
      Throws:
      IllegalBlockSizeException - if the input is inappropriate for this cipher.
      BadPaddingException - if the input format is invalid.