The longest way to represent a date

2026-03-14T00:00:00Z

The other day, someone on IRC posed this question: “What is the longest way to represent a date using any means possible that isn’t just repeated filler?”

Some people jumped for writing the date out in languages that had longer translations. My immediate reaction was instead to suggest an obnoxious string-based representation of a unix timestamp: “one second after one second after one second after … midnight on January 1st 1970”. It’s very repetitive, but it’s not filler: taking out any of the repetitions would change the value. Effectively it’s a successor function for unix timestamps, writ long. Some quick napkin maths suggests the full string representation would be around 30GiB¹.

An obvious approach to make it bigger is to make it more precise. If we do the same sort of successor function for milliseconds it’d be a bit over 1000x longer². It actually ends up being just over 35TiB³.

There’s no reason to stop there, though. You can step down to microseconds, nanoseconds, and so on… or… we can just skip right to the end. How about: “one oscillation of the caesium-133 hyperfine transition frequency after one oscillation of the caesium-133 hyperfine transition frequency after … midnight on January 1st 1970”? There are over 9 billion of those every second, and the phrasing is wordy. That comes out to almost 1ZiB⁴. If we pooled all the data storage on the planet together we could save a couple hundred of these timestamps.

One final step, then: why use the unix epoch when we could use the universe’s own⁵? We’re something around 4×10^17 seconds past the big bang, so… hold on, I need to look up some units… that’d be over 200,000 yobibytes⁶. There’s not actually a standard prefix for that order of magnitude, according to Wikipedia. I think it should be 200 robibytes. Does anyone have a contact at the IEC?

That is a big number. Is it impossibly big? If we wanted to track our current time, we’d need to write around 600GiB/s⁷ to disk. That’s a bit more than we can manage at the minute, but isn’t completely outrageous. What about storage? Apparently hard drives require around a million atoms to store a bit of data. There’s some research showing it’s possible to use as few as 12, but I don’t think it’s anything that can be used at scale anytime soon⁸. So just for the direct data storage, not counting all the other infrastructure you need for a disk drive to work we’d need around 10^36 atoms. If we sourced our atoms for our local paperclip maximiser we’d need around 200 trillion paperclips. For just one timestamp.

On the plus side, this timestamp format would compress wonderfully.

17 bytes of repetition * 1773528583 seconds ~= 3×10^10. ↩︎
There’d be a thousand times more repetitions, and each one would have the extra five bytes from the “milli” prefix. ↩︎
22 bytes of repetition * 1773528583000 milliseconds ~= 3×10^13. ↩︎
72 bytes of repetition * 1773528583 seconds * 9192631770 oscillations per second ~= 1×10^21. ↩︎
Other than it being impractical, not known to a decent accuracy, and the myriad other problems, of course. ↩︎
72 bytes of repetition * 4×10^17 seconds * 9192631770 oscillations per second ~= 3×10^29. ↩︎
72 bytes of repetition * 9192631770 oscillations per second ~= 6×10^11. ↩︎
Not that we could scale conventional drives up this much, either. ↩︎

Why you should be using HTTPS

2016-06-17T00:00:00Z

The EFF’s HTTPS Everywhere logo

One of my favourite hobbyhorses recently has been the use of HTTPS, or lack thereof. HTTPS is the thing that makes the little padlock appear in your browser, and has existed for over 20 years. In the past, that little padlock was the exclusive preserve of banks and other ‘high security’ establishments; over time its use has gradually expanded to most (but not all) websites that handle user information, and the time is now right for it to become ubiquitous.

Why use HTTPS?

There are numerous advantages to using HTTPS, both for the users of a website and for the operator:

Privacy

The most obvious advantage is that HTTPS gives your users additional privacy. An insecure (HTTP) request can potentially be read by anyone on the same network, or the network operators, or anyone who happens to operate a network along the path between the user and the server.

Users on shared WiFi networks (such as those in coffee shops, hotels, or offices) are particularly vulnerable to passive sniffing by anyone else on that network. If the network is open (as is frequently the case) then anyone in radio range can see exactly what the user is up to.

Integrity

HTTPS also helps to maintain the integrity of your site. With a plain HTTP request, there’s nothing to stop anyone in between the server and the user from modifying the content of the request or the response. This is a frequent tactic used by annoying WiFi gateways (such as the ones you’d find in a hotel), dubious ISPs who want to serve you extra adverts, or just plain old nefarious attackers.

If you’re trying to convey some kind of information to users (and if you aren’t, why exactly are you running a website again?) it seems beneficial to both you and them if the information arrives as you intended, rather than in a modified form due to someone or something tampering with it.

Security

If your website has any kind of authentication, or session identifiers, it becomes extremely vulnerable to an attacker monitoring the traffic and stealing the credentials. This was starkly demonstrated in 2010 when Firesheep was released. This tool allowed anyone to quickly and automatically hijack social media accounts of anyone on the same network who was using HTTP to access them.

Even if your login pages are served over HTTPS, if you send a single session ID cookie over HTTP (such as a page you decided wasn’t particularly ‘important’) then an attacker can probably spoof the user’s session and gain full access to their account. Again, in the case of open WiFi networks that could be anyone in radio range.

Search engine rankings

Some search engines use HTTPS as a signal in their ranking algorithms. Google announced in 2004 that it was using the presence of HTTPS as a small positive signal, but that it may strengthen that signal over time as more and more websites switch to using a secure transport. It’s not unthinkable that at some point in the future there will be HTTPS-only search engines.

But… But… But…

There are lots of excuses for not implementing HTTPS. Most of them are either misguided or outdated.

It’s too expensive and/or complicated

In the past, getting HTTPS certificates was a pain. A number of free suppliers have existed for a while but the process for getting their certificates wasn’t particularly straight forward, and many imposed arbitrary restrictions on the certificate parameters. Even once you had the certificate, you had to fiddle about with your HTTP server configuration to make it work, remember to manually get a new certificate when the old one expired, and lots of other annoying busywork.

With the arrival of Let’s Encrypt, all that changed. You can retrieve and deploy a free HTTPS certificate with two or three commands. Renewal can be handled completely automatically with a single command executed by cron.

There’s no point; nothing on my site is sensitive

You might not think your content warrants privacy, but can you speak for everyone who accesses it? Even content that seems mundane to you — such as travel advice, or technical writing — could be used to build up a profile of a user. If an attacker is monitoring traffic in a coffee shop and sees a user looking at travel advice and weather forecasts for a foreign country, he could use that information to plan a burglary knowing that the user will be away. Similarly, some content which is perfectly mundane to you may actually be very sensitive in other countries with repressive governments. HTTPS makes it much harder for these people to snoop on traffic.

From another angle, if you’re offering any kind of information, instructions, or especially file downloads, there’s a severe risk to users if the content is modified on its way to them. An evil sysadmin could rewrite your travel advice to suggest visiting the local drug dealer’s hangout, or replace your download with a malware-infested version.

HTTPS is slower, uses more resources, etc

Back in 1995 this might have been a valid argument. Enabling HTTPS on a modern server will make an almost negligible difference to performance. If you also enable HTTP/2 (which most implementations only support over HTTPS), it’s likely to actually use fewer resources, and result in a faster, smoother experience for your users. HTTP/2 was designed to work with HTTPS, and designed with modern requirements and networking techniques in mind.

CloudFlare have an excellent demonstration of the benefits of HTTP/2, and it can show speed improvements of 2-3x in a typical environment. On top of being faster, HTTP/2 uses fewer connections which results in less resource overhead on both the server and the client.

So what are you waiting for?

If you run a website and aren’t using HTTPS, give it a try.

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