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phphashsha1packed

Sha 1 hashes and their length with the bit torrent protocol (magnets)?

I am scraping websites for information and it involves getting sha1 hashes of magnet links.

I get all the magnet links with a simple preg_match_all but in my results I am getting weird results, I understand that a magnet hash in its hexadecimal form is 40 characters long, but I am also getting results that return strings that are 32 characters long that contain other non hexadecimal values.

Two examples from my results, firstly a normal 40 hexadecimal hash within a magnet link,

array
    0 => string 'F5AD2D170C033736FD987106F04C3ABD6DF41D14' (length=40)

And the other weird results that I do not understand where the hash is a 32 non hexadecimal value,

array
    0 => string 'VPR33QQM3L6BFU5FGOZXMBNORAFFSZWW' (length=32)

Has the hash been packed in some way? I know it is not done with pack('H*', $hash) as that returns the binary of the hash? The magnet links do work as I have tested them.

More so you can see these hashes in use at this website

http://eztv.it

By hovering over the magnet links and looking a the magnet hash.

Thanks

Solution

  • Hashes in magnet links can be encoded using Base32. In your example,

    VPR33QQM3L6BFU5FGOZXMBNORAFFSZWW

    turns into

    ABE3BDC20CDAFC12D3A533B37605AE880A5966D6

    which is a valid SHA-1 hash.