--- /dev/null
+package org.bouncycastle.crypto;
+
+import java.lang.IllegalStateException;
+
+/**
+ * Block cipher engines are expected to conform to this interface.
+ */
+public interface BlockCipher
+{
+ /**
+ * Initialise the cipher.
+ *
+ * @param forEncryption if true the cipher is initialised for
+ * encryption, if false for decryption.
+ * @param param the key and other data required by the cipher.
+ * @exception IllegalArgumentException if the params argument is
+ * inappropriate.
+ */
+ public void init(boolean forEncryption, CipherParameters params)
+ throws IllegalArgumentException;
+
+ /**
+ * Return the name of the algorithm the cipher implements.
+ *
+ * @return the name of the algorithm the cipher implements.
+ */
+ public String getAlgorithmName();
+
+ /**
+ * Return the block size for this cipher (in bytes).
+ *
+ * @return the block size for this cipher in bytes.
+ */
+ public int getBlockSize();
+
+ /**
+ * Process one block of input from the array in and write it to
+ * the out array.
+ *
+ * @param in the array containing the input data.
+ * @param inOff offset into the in array the data starts at.
+ * @param out the array the output data will be copied into.
+ * @param outOff the offset into the out array the output will start at.
+ * @exception DataLengthException if there isn't enough data in in, or
+ * space in out.
+ * @exception IllegalStateException if the cipher isn't initialised.
+ * @return the number of bytes processed and produced.
+ */
+ public int processBlock(byte[] in, int inOff, byte[] out, int outOff)
+ throws DataLengthException, IllegalStateException;
+
+ /**
+ * Reset the cipher. After resetting the cipher is in the same state
+ * as it was after the last init (if there was one).
+ */
+ public void reset();
+}