Archive for August, 2011

What Governs our Clocks

Tuesday, August 23rd, 2011

Most of us recognise how long an hour, a minute, or a second is, and we are used to seeing our clocks tick past these increments, but have you ever thought what governs clocks, watches and the time on our computers to ensure that a second is a second and an hour an hour?

Early clocks had a very visible form of clock precision, the pendulum. Galileo Galilei was the first to discover the effects of weight suspended from a pivot. On observing a swinging chandelier, Galileo realised that a pendulum oscillated continuously above its equilibrium and didn’t falter in the time between swings (although the effect weakens, with the pendulum swinging less far, and eventually stops) and that a pendulum could provide a method of keeping time.

Early mechanical clocks that had pendulums fitted proved highly accurate compared to other methods tried, with a second able to be calibrated by the length of a pendulum.

Of course, minute inaccuracies in measurement and effects of temperature and humidity meant that pendulums were not wholly precise and pendulum clocks would drift by as much as half an hour a day.

The next big step in keeping track of time was the electronic clock. These devices used a crystal, commonly quartz, which when introduced to electricity, will resonate. This resonance is highly precise which made electric clocks far more accurate than their mechanical predecessors were.

True accuracy, however, wasn’t reached until the development of the atomic clock. Rather than using a mechanical form, as with a pendulum, or an electrical resonance as with quartz, atomic clocks use the resonance of atoms themselves, a resonance that doesn’t change, alter, slow or become affected by the environment.

In fact, the International System of Units that define world measurements, now define a second as the 9,192,631,770 oscillations of a caesium atom.

Because of the accuracy and precision of atomic clocks, they provide the source of time for many technologies, including computer networks. While atomic clocks only exist in laboratories and satellites, using devices like Galleon’s NTS 6001 NTP time server.

A time server such as the NTS 6001 receives a source of atomic clock time from either GPS satellites (which use them to provide our sat navs with a way to calculate position) or from radio signals broadcast by physics laboratories such as NIST (National Institute of Standards and Time) or NPL (National Physical Laboratory).


Receiving Time Signals with GPS

Wednesday, August 17th, 2011

Accurate time is one of the most important aspects to keeping a computer network secure and safe. Places such as stock exchanges, banks and air traffic control rely on secure and accurate time. As computers rely on time as their only reference for when events happen, a slight error in a time code could lead to all sorts of errors, from millions being wiped off share prices to aeroplane flight paths being incorrect.

And time doesn’t just need to be accurate for these organizations, but secure too. A malicious user who interferes with a timestamp could cause all sorts of trouble, so ensuring time sources are both secure and accurate is vital.

Security is increasingly important for all sorts of organisations. With so much trade and communication conducted over the internet, using a source of accurate and secure time is as important a part of network security as anti-virus and firewall protection.

Despite the need for accuracy and security, many computer networks still rely on online time servers. Internet sources of time are not only unreliable, with inaccuracies commonplace, and distance and latency affecting the precision, but an Internet time server is also unsecure and able to be hijacked by malicious users.

But an accurate, reliable and completely secure source of time is available everywhere, 365 days a year—GPS.

While commonly thought of as a means of navigation, GPS actually provides an atomic clock time code, direct from the satellite signals. It is this time code that navigation systems use for calculating position but it is just as effective to provide a secure time stamp for a computer network.

Organizations that rely on accurate time for safety and security all use GPS, as it is a continuous signal, that never goes down, is always accurate and can’t be interfered with by third parties.

To utilise GPS as a source of time, all that is required is a GPS time server. Using an antenna, the time server receives the GPS signal, while NTP (Network Time Protocol) distributes it around the network.

With a GPS time server, a computer network is able to maintain accuracy to within a few milliseconds of the atomic clock time signal, which is translated into UTC time (Coordinated Universal Time) thanks to NTP, ensuring the network is running the same accurate time as other networks also synchronised to a UTC time source.

Precise Time on the Markets

Wednesday, August 10th, 2011

The stock market has been in the news a lot lately. As global uncertainty about national debts rise, the markets are in flux, with prices changing incredibly quickly. On a trading floor, every second counts and precise time is essential for global buying and selling of commodities, bonds and shares.

NTS 6001 from Galleon Systems

The international stock exchanges such as the NASDAQ and London Stock Exchange all require accurate and precise time. With traders buying and selling shares for customers across the globe, a few seconds of inaccuracy could cost millions as share prices fluctuate.

NTP servers linked to atomic clock timing signals ensure that the stock exchange keeps an accurate and precise time. As computers across the globe all receive the stock prices, as and when they change, these two use NTP server systems to maintain time.

The global timescale UTC (Coordinated Universal Time) is used as the basis for atomic clock timing, so no matter where a trader is on the globe, the same timescale prevents confusion and errors when dealing with stocks and shares.

Because of the billions of pounds worth of stocks and shares that are bought and sold on trading floors every day, security is essential. NTP servers work externally to networks, getting their time from sources such as GPS (Global Positioning System) or radio signals put out by organisations like the National Physical Laboratory (NPL) or the National Institute for Standards and Time (NIST).

The stock exchanges can’t use a source of internet because of the risk this could pose. Hackers and malicious users could tamper with the time source, leading to mayhem and cost millions and perhaps billions if the wrong time was spread around the exchanges.

The precision of internet time is limited too. Latency over distance can create delays, which could lead to errors, and if the time source ever went down, the stock markets could hit trouble.

It is not only stock markets that need precise and accurate time, computer networks across the globe concerned about security use dedicated NTP servers like Galleon Systems’ NTS 6001. Providing accurate time from both GPS and radio signals from NPL and NIST, the NTS 6001 ensure accurate, precise and secure time every day of the year.

Hackers and Time Servers

Wednesday, August 3rd, 2011

Computer hacking is a common subject in the news. Some of the biggest companies have fallen victim to hackers, and for a myriad of reasons. Protecting computer networks from invasion from malicious users is an expensive and sophisticated industry as hackers use many methods to invade a system.

Various forms of security exist to defend against unauthorised access to computer networks such as antivirus software and firewalls.

One area often overlooked, however, is where a computer network gets it source of time from, which can often be a vulnerable aspect to a network and a way in for hackers.

Most computer networks use NTP (Network Time Protocol) as a method of keeping synchronised. NTP is excellent at keeping computers at the same time, often to within a few milliseconds, but is dependent on a single source of time.

Because computer networks from different organisations need to communicate together, having the same source of time makes sense, which is the reason most computer networks synchronise to a source of UTC (Coordinated Universal Time).

UTC, the world’s global timescale, is kept true by atomic clocks and various methods of utilising UTC are available.

Quite often, computer networks use an internet time source to obtain UTC but this is often when they run into security issues.

Using internet time sources leave a computer network open to several vulnerabilities. Firstly, to allow access to the internet time source, a port needs keeping open in the system firewall (UDP 123). As with any open port, unauthorised users could take advantage of this, using the open port as a way into the network.

Secondly, if the internet time source itself if tampered with, such as by BGP injection (Border Gateway Protocol) this could lead to all sorts of problems. By telling internet time servers it was a different time or date, major havoc could ensue with data getting lost, system crashes—a type of Y2K effect!

Finally, internet time servers can’t be authenticated by NTP and can also be inaccurate. Vulnerable to latency and affected to distance, errors can also occur; earlier this year some reputable time servers lost several minutes, leading to thousands of computer networks receiving the wrong time.

To ensure complete protection, dedicated and external time servers, such as Galleon’s NTS 6001 are the only secure method of receiving UTC. Using GPS (or a radio transmission) an external NTP time server can’t be manipulated by malicious users, is accurate to a few milliseconds, can’t drift and is not susceptible to timing errors.