Bifrost
Karolinska Institutet Neuro Research Group · data bridge

How to use it

Sending and receiving data over Bifrost

Bifrost is the bridge the Karolinska Institutet Neuro Research Group opens when data has to travel between us and a partner. Each bridge is private to one collaboration: it has its own token, its own space, its own closing date. This page explains the browser. The command line tool does the same job for large transfers.

What you were given

Someone in the group sent you either a link (it ends in #bfr_…) or a token (a string starting with bfr_). Both are the same key. Treat it like a password: it is the only thing that opens your bridge. Some bridges also have a passcode, sent separately; you will be asked for it after the token.

A bridge can receive files from you, give files to you, or both. What yours does is written at the top of the page once you open it, together with the date it closes and, if there is one, the amount of space you may use.

Opening the bridge

  1. Open the link, or go to bifrost.kineuro.se and paste the token.
  2. Enter the passcode if asked.
  3. You are on your bridge. Two tabs may appear: Files for you and Send files.

The browser remembers you for twelve hours. Close in the top right ends the session; the token itself keeps working until the group revokes it or the bridge closes.

Sending files to the group

  1. Open the Send files tab.
  2. Drag files or whole folders onto the dashed area, or use Choose files / Choose a folder. Folder structure is kept exactly as it is on your computer.
  3. Watch the list: each file shows its progress and ends with verified. Verified means the bridge computed the checksum of what it received and it matches your file byte for byte.
  4. Keep the tab open until the summary line says done.
If the connection drops, nothing is lost: uploads resume from where they stopped as long as the tab stays open. If you closed the tab or the computer went to sleep, drop the same files again; files already received are recognised and skipped.

Under Already received you see the names and sizes of what has arrived. For your protection you cannot download from there: a bridge that receives is a one-way door.

Hidden files (names starting with a dot, such as .DS_Store) are skipped automatically. There is no size limit per file. If the bridge has a space limit it is shown as a bar at the top; an upload that would exceed it is refused with a clear message.

Downloading files from the group

  1. Open the Files for you tab.
  2. Click a folder to enter it, the path above the list to go back.
  3. Download next to a file saves it; zip next to a folder, or Download this folder as zip, packs a whole folder. The zip is built on the fly, so it starts immediately.

Large single files resume by themselves if the connection drops: the browser asks the bridge only for the part it is missing.

For terabytes or for tens of thousands of files (a DICOM study, for instance) use the command line tool: it runs several streams in parallel, resumes from any interruption without a browser tab, and verifies every file.

When the bridge closes

On the closing date the bridge stops accepting transfers. What you sent stays with the group; what was prepared for you is no longer downloadable. If you need more time, ask your contact in the group: a bridge can be extended in a minute.

Security, briefly

  • Everything travels over HTTPS to bifrost.kineuro.se; the machine behind it can only see its own exchange area, never the group's archives.
  • Your token is stored on our side only as a salted hash. If you lose it, the group issues a new one and revokes the old.
  • Every transfer is checked byte for byte and written to an audit log that the group can read.
  • The bridge can be restricted to your organisation's network addresses; ask if you want that.

Questions or problems: admin@kineuro.se.