公开(公告)号：US06324652B1

公开(公告)日：2001-11-27

申请号：US09232862

申请日：1999-01-15

申请人： Nathaniel Henderson ,  David Brown ,  Lai-Chin Lo ,  Ngo Ho

发明人： Nathaniel Henderson ,  David Brown ,  Lai-Chin Lo ,  Ngo Ho

IPC分类号： G06F104

CPC分类号： G06F1/08

摘要： An asynchronous switching circuit for multiple indeterminate bursting clocks. In one embodiment, the present invention recites a clock-switching circuit that provides a single unclipped and glitch-free clock signal at its output from among multiple clock inputs. The clock-switching circuit is comprised of a plurality of asynchronously-enabled clock circuits, a plurality of blocking circuits, a synchronizing clock, and a logic gate. Each of the plurality of blocking circuits has an input lead respectively coupled to one of the plurality of asynchronously-enabled clock circuits, each of the plurality of blocking circuits also has an output coupled to all of the plurality of asynchronously-enabled clock circuits except the one to which its input is coupled. The synchronizing clock is coupled to each of the plurality of blocking circuits while the logic gate is coupled to each of the plurality of asynchronously-enabled clock circuits.

摘要翻译： 用于多个不确定的突发时钟的异步切换电路。 在一个实施例中，本发明描述了一种时钟切换电路，其在多个时钟输入的输出端提供单个未切断和无毛刺的时钟信号。 时钟切换电路由多个异步使能时钟电路，多个阻塞电路，同步时钟和逻辑门组成。 多个阻塞电路中的每一个具有分别耦合到多个异步使能时钟电路中的一个的输入引线，多个阻塞电路中的每一个还具有耦合到所有多个异步使能的时钟电路的输出，除了 其输入耦合到其中。 同步时钟耦合到多个阻塞电路中的每一个，同时逻辑门耦合到多个异步使能的时钟电路中的每一个。

公开(公告)号：US20050201554A1

公开(公告)日：2005-09-15

申请号：US11078923

申请日：2005-03-10

申请人： Glen Kramer ,  Lawrence Davis ,  Edward Boyd ,  Ryan Hirth ,  Ngo Ho

发明人： Glen Kramer ,  Lawrence Davis ,  Edward Boyd ,  Ryan Hirth ,  Ngo Ho

IPC分类号： H04L9/00 ,  H04L9/12

CPC分类号： H04L9/12 ,  H04L9/0637

摘要： One embodiment of the present invention provides a system that decrypts downstream data in an Ethernet passive optical network (EPON). During operation, the system receives a data frame which is encrypted based on a remote input block and a session key, wherein the remote input block is constructed based on a remote cipher counter and a remote block counter. The system adjusts a local cipher counter based on a received checksum located in a preamble of the data frame, wherein the local cipher counter is substantially synchronized with the remote cipher counter. In addition, the system truncates the local cipher counter by discarding n least significant bits thereof. The system then constructs a local input block based on the truncated cipher counter and a local block counter for the received data frame. Next, the system decrypts the data frame based on the local input block and the session key.

摘要翻译： 本发明的一个实施例提供一种解密以太网无源光网络（EPON）中的下游数据的系统。 在操作期间，系统接收基于远程输入块和会话密钥加密的数据帧，其中基于远程密码计数器和远程块计数器构建远程输入块。 该系统基于位于数据帧的前导码中的接收到的校验和来调整本地密码计数器，其中本地密码计数器基本上与远程密码计数器同步。 此外，系统通过丢弃其最低有效位来截断本地密码计数器。 然后，系统基于截断的密码计数器和接收到的数据帧的本地块计数器构建本地输入块。 接下来，系统基于本地输入块和会话密钥来解密数据帧。