[HN Gopher] An encrypted ZIP file can have two correct passwords...
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       An encrypted ZIP file can have two correct passwords - here's why
        
       Author : arkadiyt
       Score  : 21 points
       Date   : 2022-08-21 20:33 UTC (2 hours ago)
        
 (HTM) web link (www.bleepingcomputer.com)
 (TXT) w3m dump (www.bleepingcomputer.com)
        
       | realitysballs wrote:
       | It's an interesting but mostly useless finding cuz The hash is
       | also incredibly strong password
        
       | [deleted]
        
       | V__ wrote:
       | Since hash functions are fixed-length, aren't there always
       | infinitely many collisions and therefore passwords which would
       | work?
        
         | omoikane wrote:
         | In theory yes, but finding SHA1 collisions is nontrivial.
         | shattered.io has one, but they used up quite a bit of compute
         | to get it.
        
         | riotman wrote:
         | Unless it's invertible.
        
       | modeless wrote:
       | The same thing is true of Zoom meeting passwords. When you share
       | a URL to a meeting with a password, a hashed version of the
       | password is included in the URL. That hash works the same as the
       | password. You can manually type it in the password box when
       | joining the meeting and it will let you in.
        
       | netsharc wrote:
       | The article seems to be very repetitive in the way it explains
       | things, but TL;DR:
       | 
       | > When producing password-protected ZIP archives with AES-256
       | mode enabled, the ZIP format uses the PBKDF2 algorithm and hashes
       | the password provided by the user, if the password is too long.
       | By too long, we mean longer than 64 bytes (characters), explains
       | the researcher.
       | 
       | So the first accepted password would be the overly long one, and
       | the second accepted password is the ASCII representation of the
       | SHA1 hash of that long password. The researcher used a modified
       | version hashcat to get a password which SHA1 hash is also ASCII.
        
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       (page generated 2022-08-21 23:01 UTC)