Class CipherInputStream

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    public class CipherInputStream
    extends FilterInputStream
    A CipherInputStream is composed of an InputStream and a cipher so that read() methods return data that are read in from the underlying InputStream but have been additionally processed by the Cipher. The cipher must be fully initialized before being used by a CipherInputStream.

    For example, if the Cipher is initialized for decryption, the CipherInputStream will attempt to read in data and decrypt them, before returning the decrypted data.

    This is a reimplementation of CipherInputStream that is safe for use with AEAD block ciphers, and does not silently catch BadPaddingException and IllegalBlockSizeException errors. Any errors that occur during finalisation are rethrown wrapped in an InvalidCipherTextIOException.

    • Constructor Detail

      • CipherInputStream

        public CipherInputStream​(InputStream input,
                                 Cipher cipher)
        Constructs a CipherInputStream from an InputStream and an initialised Cipher.
    • Method Detail

      • read

        public int read()
                 throws IOException
        Reads data from the underlying stream and processes it with the cipher until the cipher outputs data, and returns the next available byte.

        If the underlying stream is exhausted by this call, the cipher will be finalised.

        Overrides:
        read in class FilterInputStream
        Throws:
        IOException - if there was an error closing the input stream.
        InvalidCipherTextIOException - if the data read from the stream was invalid ciphertext (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails).
      • read

        public int read​(byte[] b,
                        int off,
                        int len)
                 throws IOException
        Reads data from the underlying stream and processes it with the cipher until the cipher outputs data, and then returns up to len bytes in the provided array.

        If the underlying stream is exhausted by this call, the cipher will be finalised.

        Overrides:
        read in class FilterInputStream
        Parameters:
        b - the buffer into which the data is read.
        off - the start offset in the destination array b
        len - the maximum number of bytes read.
        Returns:
        the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
        Throws:
        IOException - if there was an error closing the input stream.
        InvalidCipherTextIOException - if the data read from the stream was invalid ciphertext (e.g. the cipher is an AEAD cipher and the ciphertext tag check fails).