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Debunking a Bogus Encryption Statement?

Posted by ryuzaki0 on from the this-and-other-gems dept.

deviantphil asks: "Recently, a coworker tried to assert that encrypting a file twice with a 64 bit algorithm is equivalent to encrypting it once with a 128 bit algorithm. I know enough about encryption to know that isn't true, but I am having difficulties explaining why and how. Doesn't each pass of the encryption create a separate file header which makes this assertion untrue? Can anyone point me to references that would better help me explain this?" What other laughable claims have you heard attributed to encryption, and how were you able to properly lay them to rest?

11 of 215 comments (clear)

  1. While you're at it... by unitron · · Score: 3, Funny

    While you're double super secret encrypting that file why not keep compressing and re-compressing it until you have it down to 1 bit as well? :-)

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    1. Re:While you're at it... by QuantumG · · Score: 3, Funny

      Bruce Schneier can compress arbitary random data... with his fists.

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      How we know is more important than what we know.
    2. Re:While you're at it... by RuBLed · · Score: 2, Funny

      but Chuck Norris can roundhouse kick that compressed data back into its' raw format.

    3. Re:While you're at it... by QuantumG · · Score: 4, Funny

      Geologists recently discovered that "earthquakes" are nothing more than Bruce Schneier and Chuck Norris communicating via a roundhouse kick-based cryptosystem.

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      How we know is more important than what we know.
    4. Re:While you're at it... by Anonymous Coward · · Score: 1, Funny

      you win at the internet.

      -j

  2. Re:Your keyspace wouldn't be that much bigger by sr180 · · Score: 5, Funny

    Think of it as this: If you encrypt something as rot-13 twice, does it become any more secure?

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  3. Bad math by Dan+East · · Score: 5, Funny

    Your both wrong. Encrypting twice at 64 bit is like 64*64=4096 bit encryption. Personally, I like to encrypt 7 times at 2 bit encryption for 128 bit strength. If its something I really want to keep secret, I encrypt four times at 128 bit for 268435456 bit encryption. However, don't make the mistake I made once of encrypting 128 times at 1 bit. Because that is just 1^128, which yields nothing more than 1 bit encryption.

    In case anyone is wondering, I'm hoping some DRM coder will gain valuable insight from this post.

    Dan East

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    1. Re:Bad math by Miffe · · Score: 2, Funny
      Naturally, this means the most number of guesses you'd need to make is 256.
      Well, you only have to guess 255, since the last one wont really be a guess. =)
  4. Re:Your keyspace wouldn't be that much bigger by Anonymous Coward · · Score: 1, Funny

    Yeah genius, how about asking them to give *you* either two tens or a hundred. Trust me, it works out better that way.

  5. Re:Your keyspace wouldn't be that much bigger by mgblst · · Score: 4, Funny

    Do you hear whoosh sound? It is as if something just went flying over your head.

  6. Re:Your keyspace wouldn't be that much bigger by Jim+Hall · · Score: 2, Funny

    Absolutely! That's why I double-rot13 all my emails before sending them! :-)