Postcards and encryption

While I was down the Charles Babbage and the Crimean War rabbit hole, I came across a couple of coding cribs designed to allow people using postcards to encode the message written on the cards.

You see, when postcards were first introduced in Britain in 1870, it was thought that people might be reluctant to use them because anyone in the postal system, or even, gasp, one’s servants could read the message on the back of them.


It’s important to remember that when they were introduced, postcards were different from the picture postcard that anyone over forty remembers sending.

The first postcards, like this rather impressive Russian example, were prepaid cards where one wrote the address on one side and the message on the other. If you can read pre revolutionary Russian text, you’ll see that while the French reads Carte Postale – post card – the Russian reads Открытое Писъмо – open letter, which basically is what a postcard was

Picture postcards as we knew them, didn’t really appear to some time around 1900 when the various postal administrations agreed to accept divided back cards with a picture on one side and with the address and message written on the back, with the address in the right-hand half and the message on the left.


When first introduced in Britain in 1870 at a cost of ½d – half an old penny and half the price of the penny post for a letter they proved amazingly successful with thirty seven million being sent in the first year they were on sale, more than one for everyone living in Britain at the time.

It can be hard to get a handle on the cost in real terms due to inflation and the change in incomes and living standards but using the Bank of England’s inflation calculator you end up with the cost being roughly 20p ($A0.37), which compares quite well with the current UK price of 75p ($A1.40) for an economy (second class) letter


(The Bank of England’s inflation calculator assumes you convert your price to British post 1971 decimal currency. As there were 240 pre decimal pennies to the pound, there were 480 half pennies, making the half penny worth around £0.002 in post 1971 currency).

Mostly, postcard seem to have been used in much the same way we use text an whatsapp messages today – as a way of sending short simple messages or confirming meetings or travel arrangements. I did a very rough scan of vintage postcards for sale on ebay and etsy, and while some had longer messages on the back, most have pretty short messages.

I thought we might see some examples with messages written in code or in Ancient Greek or Latin, to stop the servants reading the message, but no.

In fact one postcard collector who had come across an example in code says that it’s the only example he’s come across in twenty years of collecting. There are a few examples out there, as well as ones in which the text has been obfuscated, such as by using mirror writing.

Basically, it looks like people mostly wrote postcards in clear text. That’s not to say that the messages were not sometimes used to confirm assignations and the like, but that they looked innocuous.

To explain consider the following made up example

Dearest Dottie,

Are you able to meet for tea on Sunday? I’ll be coming on the Norwich train


Seemingly innocent, except for the word Norwich – which was used by British squaddies during World War II, and possibly earlier, as an acronym for ‘knickers off ready when I come home’ and was commonly used in telegrams to let wives and girlfriends know that they had some unexpected leave. Telegrams cost a shilling (5p) for the first few words so brevity and acronyms were required.

So, returning to our nineteenth century courting couple, they may well have used some private words to communicate something more private given that postcards were open media.

But did they? Possibly they did, or as always in such matters probably some did, some didn’t, and one should always be careful not to read too much into a message, after all Albert might have genuinely caught the Norwich train …


About dgm

Former IT professional, previously a digital archiving and repository person, ex research psychologist, blogger, twitterer, and amateur classical medieval and nineteenth century historian ...
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