package org.bouncycastle.crypto;
/**
* Ciphers producing a key stream which can be reset to particular points in the stream implement this.
*/
public interface SkippingCipher
{
/**
* Skip numberOfBytes forwards, or backwards.
*
* @param numberOfBytes the number of bytes to skip (positive forward, negative backwards).
* @return the number of bytes actually skipped.
* @throws java.lang.IllegalArgumentException if numberOfBytes is an invalid value.
*/
long skip(long numberOfBytes);
/**
* Reset the cipher and then skip forward to a given position.
*
* @param position the number of bytes in to set the cipher state to.
* @return the byte position moved to.
*/
long seekTo(long position);
/**
* Return the current "position" of the cipher
*
* @return the current byte position.
*/
long getPosition();
}