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Wouldn't It Be Nice If MD5 Was A Two Way Street?

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  • Wouldn't It Be Nice If MD5 Was A Two Way Street?

    5d2a88f03d596ad7bf4307b59f44f751

    That's 14 pages worth of "The quick brown fox jumped over the lazy dog." (generated by typing `=rand(200)` in MS Word without the quotes).
    All of that text, compressed into a tiny string. Wouldn't it be great if there was some other type of MDx, so we could transfer huge files as 32 char lines?

    Yeah, just something I was thinking about today. Would be cool.

    EDIT: And now, here's this entire post (excluding the EDIT) in MD5: c6b889800ffeab67c070e4d5ea991a1a - Tiny, ain't it?
    "63,000 bugs in the code, 63,000 bugs, you get 1 whacked with a service pack, now there's 63,005 bugs in the code."
    "Before you critisize someone, walk a mile in their shoes. That way, when you critisize them, you're a mile away and you have their shoes."
    Utopia Software - Current Software: Utopia News Pro (news management system)

  • #2
    When you md5() something you arn't "compressing" it or "encrypting" it. Md5 is a hashing algorithm, more akin to a fingerprint of the given input than any converted version of it.

    That is why md5 cannot be a two-way-street. Becuase it doesn't actually contain the original input.

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    • #3
      Wouldn't it be nice if I could have a dollar every time someone asked how to "decrypt" MD5'd strings?
      Chen Avinadav
      Better to remain silent and be thought a fool than to speak out and remove all doubt.

      גם אני מאוכזב מסיקור תחרות לתור מוטור של NRG הרשת ע"י מעריב

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      • #4
        Originally posted by Chen
        Wouldn't it be nice if I could have a dollar every time someone asked how to "decrypt" MD5'd strings?
        lol......

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        • #5
          Originally posted by xCRYINGoutLOUDx
          Bah.. use mcrypt_encrypt and mcrypt_decrypt.... a little more work, but so much better then just using md5.

          Plus it's real encryption
          The problem is that most (all?) encryption algorithms inflate the data size...
          Chen Avinadav
          Better to remain silent and be thought a fool than to speak out and remove all doubt.

          גם אני מאוכזב מסיקור תחרות לתור מוטור של NRG הרשת ע"י מעריב

          Comment


          • #6
            Originally posted by Grumble
            When you md5() something you arn't "compressing" it or "encrypting" it. Md5 is a hashing algorithm, more akin to a fingerprint of the given input than any converted version of it.

            That is why md5 cannot be a two-way-street. Becuase it doesn't actually contain the original input.
            Eh? Well... uh.. same thing.
            "63,000 bugs in the code, 63,000 bugs, you get 1 whacked with a service pack, now there's 63,005 bugs in the code."
            "Before you critisize someone, walk a mile in their shoes. That way, when you critisize them, you're a mile away and you have their shoes."
            Utopia Software - Current Software: Utopia News Pro (news management system)

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            • #7
              right it would be really nice, because of the compression rate, but mathematically impossible

              a 32 char string (or more exactly a 32 number hex value) can just differ between 3.4 * 10^38 different texts, but there are much more possible combinations on a 14 page text

              so a nice dream, but not realistic
              The price of freedom is eternal vigilance!
              - Thomas Jefferson

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              • #8
                Not to mention it is theoretically possible (yet HIGHLY unlikely) to get the same MD5 on two entirely different data items.

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                • #9
                  Originally posted by xCRYINGoutLOUDx
                  Bah.. use mcrypt_encrypt and mcrypt_decrypt.... a little more work, but so much better then just using md5.

                  Plus it's real encryption
                  Why not have a TRUELY secure system? Beam messages to people in photons.
                  :)

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                  • #10
                    Originally posted by NetherChris
                    Not to mention it is theoretically possible (yet HIGHLY unlikely) to get the same MD5 on two entirely different data items.
                    1 in 6.3340286662973277706162286946812e+49, to be specific.
                    --filburt1, vBulletin.org/vBulletinTemplates.com moderator
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                    • #11
                      I'd say that's highly unlikely... hahahaha. I wonder if any have ever been discovered. That would be truly interesting.

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                      • #12
                        BTW, it's actually 1 in 16^32 because it's a 32-char hex string, so my mistake, it's a less ungodly 1 in 18,446,744,073,709,551,616.
                        --filburt1, vBulletin.org/vBulletinTemplates.com moderator
                        Web Design Forums.net: vB Board of the Month
                        vBulletin Mail System (vBMS): webmail for your forum users

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                        • #13
                          Originally posted by Chen
                          The problem is that most (all?) encryption algorithms inflate the data size...
                          Not all. At the very simlest, Ceasar Cypher has exactly the same length. Or text which is run length encoded can be less. etc.
                          Motorsport Forums

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                          • #14
                            Originally posted by Chen
                            Wouldn't it be nice if I could have a dollar every time someone asked how to "decrypt" MD5'd strings?
                            You could earn 5$ for every successfull brute-force at least!

                            Comment


                            • #15
                              Originally posted by Mark Hewitt
                              Not all. At the very simlest, Ceasar Cypher has exactly the same length. Or text which is run length encoded can be less. etc.
                              With all due respect to Caesar... I'm talking about "real" encryption methods.
                              Chen Avinadav
                              Better to remain silent and be thought a fool than to speak out and remove all doubt.

                              גם אני מאוכזב מסיקור תחרות לתור מוטור של NRG הרשת ע"י מעריב

                              Comment

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