- What it is
- A short message containing your delivery details, composed calmly in advance and encrypted to the recipient, held ready to paste.
- How you get one
- Type the details out in a plain text editor, check them line by line, then encrypt the result to the key you already stored.
- Where to keep it
- The ciphertext in a file you can reach quickly, the readable original kept separately and treated as the more sensitive half.
- How it goes wrong
- Details change and the encrypted copy does not, so a stale block gets pasted that describes where you used to be.
- What fails without it
- You compose under pressure, mistype a line, and discover the error at the point where correcting it is awkward.
- Time to acquire
- One unhurried sitting, most of which goes on proofreading rather than typing, plus a minute for the encryption itself.
What goes inside the block
Whatever the recipient needs in order to send something to the right place, written out fully rather than abbreviated. Full lines, no clever shorthand, no assumptions about what the reader can infer. This page is not going to tell you what to put in it, because that varies by country and by situation and it is your message.
What this page can say is that blocks fail on formatting far more often than on content. A line break in the wrong place, an abbreviation that means one thing locally and another elsewhere, a postal code typed in the format of the wrong country. Reading the block aloud once catches most of that.
Composing away from the hurry
Prepare it in a plain text editor with no autocorrect, no smart quotes, and no help from anything trying to be clever about capitalisation. Editors that reformat as you type introduce characters you did not intend, and those characters survive encryption perfectly well and turn up at the other end looking odd.
Then leave it for an hour and read it again. Errors in your own address are the hardest kind to see, because you know what it is supposed to say and your eye supplies the missing line. A gap between writing and checking is worth more than a careful first pass. Whatever you send ends up in the copies you keep of your own messages, so a block worth pasting is a block worth proofreading twice.
Two copies, one of them readable
You end up holding both halves. The ciphertext is the thing you paste, and it is not sensitive in the ordinary sense because it cannot be read without the matching private key. The plaintext is the thing you proofread against, and it is exactly as sensitive as the details it contains.
Treat them differently. The ciphertext can sit in a working folder. The plaintext belongs wherever you keep material you would not want read, which for many people means paper rather than a file. Where things live works through that split for the rest of the inventory.
Why this item ages faster than most
It ages twice over. The details inside can change, and the key it was encrypted to can be replaced. Either makes the stored ciphertext worthless without any visible sign, since an encrypted file looks the same whether it is current or three months out of date.
The habit that fixes it is a date on the file and a note of which key it was encrypted to. When you next check the stored vendor key and find it has changed, the note tells you immediately that the block needs regenerating. Without the note you would have to remember, and you would not.
Mistakes that surface at the far end
- A block encrypted to a key that has since been replaced, which simply does not open.
- Smart quotes or a stray non ASCII character introduced by a word processor.
- A line that reads unambiguously to you and ambiguously to somebody unfamiliar with your country's conventions.
- An old block pasted from habit because it was the top file in the folder.
- A missing line that you have read past so many times it has become invisible.
Questions that come up
Should I keep the readable version at all?
You need something to check against, and reconstructing it from memory each time defeats the purpose. Keep it, but keep it deliberately: on paper, or in a place you treat as sensitive rather than in the same folder as everything else. The point is that the readable half and the pasteable half should not share a hiding place.
How often should I regenerate the block?
When the details change, when the key it was encrypted to changes, or when you cannot remember which of those two happened last. A block with a date and a key note attached answers that question in seconds. A block without them means regenerating on suspicion, which is not the end of the world but is a few minutes you could have saved.
Is preparing this in advance not just leaving evidence lying around?
The encrypted half reveals little on its own. The readable half is the part that matters, and that is true whether you prepared in advance or typed it fresh each time, since typing it fresh means it existed on the machine anyway. Preparing in advance changes where it lives, not whether it exists, which is why the storage split above is the part worth getting right.