Nexus market links copied off a directory page

A nexus market link copied off a directory page walks through three carriers before the address bar. Each one is quiet, and each one can shape the run in ways the reader will not see happen.

What it is

Copying nexus market links off a directory page is the most common path on the site. The reader opens a page that lists onion strings for a set of markets, finds the row for the market they want, selects the address and pastes it into the tor browser. Three carriers sit between the row and the address bar: the directory itself, the clipboard on the operating system and the paste behaviour of the browser. All three can change the string without warning.

The directory is the biggest of the three carriers. Whoever runs the directory chose which string to publish, chose when to update it, chose whether to wrap it in anything, and chose the order the mirrors appear in. Every one of these choices is invisible to the reader unless they knew where to look before they arrived. The path is only as clean as the directory that fed it.

The directory as a carrier

Selection

The directory picked which of the many onion strings for this market to publish. It might publish one, three or the row of everything anyone has ever supplied.

Order

The directory picked the order the rows appear in. A reader who copies the top line without reading the note under it inherits that order as a decision.

Wrapping

Some directories wrap onion strings in a proxy prefix, a copy widget or an html anchor with a slightly different href. What the reader sees and what the clipboard picks up can differ.

Freshness

The directory picked when to update the row. A page that has not been touched in a long while can still list a string that is no longer answering. The path cannot tell the difference from a reading of the page alone.

What the clipboard adds and removes

The clipboard is a quieter carrier than the directory, but it is not neutral. Some copy widgets add a trailing newline to the paste. Some drag selections pick up a leading space or a hidden zero width character from the page markup. Some browsers keep both an html fragment and a plain text version on the clipboard, and paste behaviour depends on where the reader pastes it. Pasting into the tor browser address bar strips most of this, but not always all of it. A hidden character in the paste is not a common trap, but it is a real one.

Common ways this path breaks

• The directory has updated the row for the wrong string, either by accident or because whoever supplied the row is not the operator of the market.
• The copy widget on the page is wired to a different string than the one shown. The reader sees the right run and the clipboard receives the wrong one.
• The directory has been silently taken over. The domain looks the same, the layout looks the same, but the row has been swapped for a lookalike.
• The reader copied one row and then pasted a different row from a copy earlier in the session. The clipboard is a single slot and the last thing to fill it wins.

Lifeline

How the string ages on the directory

A nexus market address on a directory ages in a way the reader cannot see. The row on the page might be exactly the same run of letters for months, but the meaning of that run can change under it. If the mirror stops answering, the row still reads the same. If the mirror is replaced by a different string, a good directory updates the row, but the update might not be pushed to every place that mirrors the page. A reader can copy a stale row off a copy of a directory long after the original was fixed.

The path also drops any warning the directory might have put next to the row. Notes above and below the string do not travel with the string. A row with a note that reads as unverified produces the same clipboard as a row with no note at all. The reader has to read the page to catch a warning, and readers in a hurry rarely do.

What to check before pasting

• The row on the directory has a source. If the page does not say where the string came from, the string is being taken on the reputation of the directory alone.
• The visible run and the copied run match. Some copy widgets can be tested by pasting into a plain text buffer first and reading the paste back.
• The vanity prefix on the paste reads as expected. A different prefix from the one this site publishes is one of the ways a lookalike gets in.
• The paste is a single line with no spaces, no newlines and no wrapping. A wrapped paste is a clipboard that picked up markup along with the text.

Engagement

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