1 package org.bouncycastle.crypto; 2 3 /** 4 * Ciphers producing a key stream which can be reset to particular points in the stream implement this. 5 */ 6 public interface SkippingCipher 7 { 8 /** 9 * Skip numberOfBytes forwards, or backwards. 10 * 11 * @param numberOfBytes the number of bytes to skip (positive forward, negative backwards). 12 * @return the number of bytes actually skipped. 13 * @throws java.lang.IllegalArgumentException if numberOfBytes is an invalid value. 14 */ 15 long skip(long numberOfBytes); 16 17 /** 18 * Reset the cipher and then skip forward to a given position. 19 * 20 * @param position the number of bytes in to set the cipher state to. 21 * @return the byte position moved to. 22 */ 23 long seekTo(long position); 24 25 /** 26 * Return the current "position" of the cipher 27 * 28 * @return the current byte position. 29 */ 30 long getPosition(); 31 } 32
