The ten
Why the shape is worth knowing
The single most common way people lose money in this subject is by using an address somebody handed them. Not a broken address, a working one, pointing at a copy of the market that keeps whatever you type into it. No amount of staring at the string will tell you which one you have.
Knowing the shape does not solve that. It does something smaller and still useful: it tells you which parts of the string are worth comparing and which are theatre. The first eight characters of a mars market address are the cheapest part to fake. The middle is the expensive part. Most people compare exactly the wrong end.
The other reason to know the shape is that it kills a whole class of false alarm. An address that is 55 characters long is not a shortened address, it is a broken one. A mars market onion address that contains a zero or a nine is not a new format, it is a typo or a fabrication. These are cheap checks and they take seconds.
Reading the list
| Chip | What it means |
|---|---|
| Counted | The value drops out of the specification or the definition. Anybody who checks gets the same answer. |
| Judged | Somebody had to pick an assumption before the number exists. The page names the assumption in its first paragraph. |
Six of the ten address numbers are counted. The three prefix costs are judgements, because a search rate depends entirely on the hardware doing the searching, and the tenth sits in between. Where a judgement is involved the arithmetic is printed so you can substitute your own assumption.
The order to read them in
If you have never looked at the format before, start with fifty six and thirty five. Those two explain what the string is, and almost everything else follows from them. The alphabet page after that turns the theory into a check you can run in a second.
If you already know the format and came here to work out how much a comparison is worth, skip to the three prefix pages. They are the only part of this section with an argument rather than a definition, and the argument is about cost. Matching the opening of an address is cheap. Matching the middle is not. Almost every habit people have around checking addresses is built on the wrong half of that sentence.
And if you arrived because something stopped working, the one character page is the right starting point. Broken transcription accounts for more failures than anything else, and it looks identical from the outside to a service that has gone away.
What this section deliberately leaves out
There is no page here on how to find a new address, because this site has no method for that which it would be willing to recommend. Every route people use, whether a forum post, a directory, a search result or a message from somebody helpful, has the same weakness: the address arrives with no proof of who sent it.
There is also no page here that ranks or grades the published addresses, because grading would require testing and testing is not something this site does. The three strings at the top of this page are printed in the order they were supplied and nothing about their order means anything.
The gap left by both of those omissions is real, and it is filled by exactly one thing. A signature over the list, checked against a fingerprint you got somewhere else. That is not an address number, which is why it lives in its own section rather than this one.
Questions people ask
Do all three published addresses have the same shape?
Yes. All three are 56 characters, all three use the same 32 symbol alphabet, and all three carry the same 2 byte checksum. That is true of every v3 onion address on the network, not a property of this market.
Can I shorten an onion address?
No. There is no short form. Anything shorter than 56 characters before the suffix will not resolve, because the missing bits are part of the key itself.