/// <summary>Gets a random initialization vector.</summary>
/// <param name="len">the length of the initialization vector</param>
/// <returns>a random initialization vector</returns>
public static byte[] GetIV(int len)
{
byte[] b = new byte[len];
lock (arcfour) {
arcfour.EncryptARCFOUR(b);
}
return(b);
}
/// <summary>
/// Writes
/// <paramref name="len"/>
/// bytes from the specified byte array
/// starting at offset
/// <paramref name="off"/>
/// to this output stream.
/// The general contract for
/// <c>write(b, off, len)</c>
/// is that
/// some of the bytes in the array
/// <paramref name="b"/>
/// are written to the
/// output stream in order; element
/// <c>b[off]</c>
/// is the first
/// byte written and
/// <c>b[off+len-1]</c>
/// is the last byte written
/// by this operation.
/// <p>
/// The
/// <c>write</c>
/// method of
/// <c>OutputStream</c>
/// calls
/// the write method of one argument on each of the bytes to be
/// written out. Subclasses are encouraged to override this method and
/// provide a more efficient implementation.
/// <p>
/// If
/// <paramref name="b"/>
/// is
/// <see langword="null"/>
/// , a
/// <c>NullPointerException</c>
/// is thrown.
/// <p>
/// If
/// <paramref name="off"/>
/// is negative, or
/// <paramref name="len"/>
/// is negative, or
/// <c>off+len</c>
/// is greater than the length of the array
/// <paramref name="b"/>
/// , then an <tt>IndexOutOfBoundsException</tt> is thrown.
/// </summary>
/// <param name="b">the data.</param>
/// <param name="off">the start offset in the data.</param>
/// <param name="len">the number of bytes to write.</param>
/// <exception cref="System.IO.IOException">
/// if an I/O error occurs. In particular,
/// an
/// <c>IOException</c>
/// is thrown if the output
/// stream is closed.
/// </exception>
public override void Write(byte[] b, int off, int len)
{
byte[] b2 = new byte[Math.Min(len, 4192)];
while (len > 0)
{
int sz = Math.Min(len, b2.Length);
arcfour.EncryptARCFOUR(b, off, sz, b2, 0);
@out.Write(b2, 0, sz);
len -= sz;
off += sz;
}
}