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MD5 alternatives

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csharpalgorithmsdata-structurescryptographyperformance
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  • C Offline
    C Offline
    Christian Graus
    wrote on last edited by
    #1

    I spent the last day making MD5 hashing work on the Palm, and we've decided that because it's 32 characters, it's too long. Does anyone know of a similar algorithm that generates a 16 character key ? Personally, I'm all for using half of the MD5. I've written a program to check for collisions, in the top or bottom half, on randomly generated strings that are hashed. It's up to 8,500 with no collisions, but slowing down because the hash table is starting to have performance problems. I'll have to do some reading to see why that is, I thought it would behave better than this. I'm getting four inserts a second now. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
    C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
    It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

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    0
    • C Christian Graus

      I spent the last day making MD5 hashing work on the Palm, and we've decided that because it's 32 characters, it's too long. Does anyone know of a similar algorithm that generates a 16 character key ? Personally, I'm all for using half of the MD5. I've written a program to check for collisions, in the top or bottom half, on randomly generated strings that are hashed. It's up to 8,500 with no collisions, but slowing down because the hash table is starting to have performance problems. I'll have to do some reading to see why that is, I thought it would behave better than this. I'm getting four inserts a second now. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
      C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
      It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

      L Offline
      L Offline
      Lost User
      wrote on last edited by
      #2

      This isn't a programming forum it's the Soapbox. Where's your crude suggestive undertone and bad language? Not only do you use 3 different date formats in your signature. It appears broken when I view it in the Soapbox but correct after I click reply. Michael Martin Australia mjm68@tpg.com.au "I personally love it because I can get as down and dirty as I want on the backend, while also being able to dabble with fun scripting and presentation games on the front end." - Chris Maunder 15/07/2002

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      • C Christian Graus

        I spent the last day making MD5 hashing work on the Palm, and we've decided that because it's 32 characters, it's too long. Does anyone know of a similar algorithm that generates a 16 character key ? Personally, I'm all for using half of the MD5. I've written a program to check for collisions, in the top or bottom half, on randomly generated strings that are hashed. It's up to 8,500 with no collisions, but slowing down because the hash table is starting to have performance problems. I'll have to do some reading to see why that is, I thought it would behave better than this. I'm getting four inserts a second now. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
        C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
        It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

        F Offline
        F Offline
        Felix Gartsman
        wrote on last edited by
        #3

        Christian Graus wrote: I spent the last day making MD5 hashing work on the Palm, and we've decided that because it's 32 characters, it's too long. Actually MD5 considered out-dated due its length. Christian Graus wrote: I've written a program to check for collisions, in the top or bottom half, I recommend result=top xor bottom, it'll give better results.

        C 1 Reply Last reply
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        • F Felix Gartsman

          Christian Graus wrote: I spent the last day making MD5 hashing work on the Palm, and we've decided that because it's 32 characters, it's too long. Actually MD5 considered out-dated due its length. Christian Graus wrote: I've written a program to check for collisions, in the top or bottom half, I recommend result=top xor bottom, it'll give better results.

          C Offline
          C Offline
          Christian Graus
          wrote on last edited by
          #4

          Felix Gartsman wrote: Actually MD5 considered out-dated due its length. So what is 'in' then ? Felix Gartsman wrote: I recommend result=top xor bottom, it'll give better results. I suggested that and my boss started to worry about messing with the MD5 and diluting it's security. I did 225,538 MD5s before I ran out of memory and crashed, not one collision. So I'll argue my case based on that today. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
          C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
          It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

          F 1 Reply Last reply
          0
          • L Lost User

            This isn't a programming forum it's the Soapbox. Where's your crude suggestive undertone and bad language? Not only do you use 3 different date formats in your signature. It appears broken when I view it in the Soapbox but correct after I click reply. Michael Martin Australia mjm68@tpg.com.au "I personally love it because I can get as down and dirty as I want on the backend, while also being able to dabble with fun scripting and presentation games on the front end." - Chris Maunder 15/07/2002

            C Offline
            C Offline
            Christian Graus
            wrote on last edited by
            #5

            I tried to post in the lounge and accidentally posted here. Then it didn't use HTML in my post. Then it disappeared. I thought it had been deleted and I reposted it in the lounge, where it belonged. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
            C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
            It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

            L 1 Reply Last reply
            0
            • C Christian Graus

              Felix Gartsman wrote: Actually MD5 considered out-dated due its length. So what is 'in' then ? Felix Gartsman wrote: I recommend result=top xor bottom, it'll give better results. I suggested that and my boss started to worry about messing with the MD5 and diluting it's security. I did 225,538 MD5s before I ran out of memory and crashed, not one collision. So I'll argue my case based on that today. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
              C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
              It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

              F Offline
              F Offline
              Felix Gartsman
              wrote on last edited by
              #6

              Christian Graus wrote: So what is 'in' then ? SHA-1 160 bit at least. Christian Graus wrote: I suggested that and my boss started to worry about messing with the MD5 and diluting it's security. He is right partially. In theory every bit in the hash is sensitive to input - random. So xor of two random parts is "more" random and better. So, in theory xoring is better. However, both methods are weak. With probability > 1/2 after 2^32 tries you'll collide, google for 'yuval birthday paradox'. But since the methods are not hash functions (your boss is right about messing) it'll be sooner. If you really need shorter hash (I highly recommend against it) use DES with CBC chaining.

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              • C Christian Graus

                I tried to post in the lounge and accidentally posted here. Then it didn't use HTML in my post. Then it disappeared. I thought it had been deleted and I reposted it in the lounge, where it belonged. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
                C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
                It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

                L Offline
                L Offline
                Lost User
                wrote on last edited by
                #7

                Christian Graus wrote: I tried to post in the lounge and accidentally posted here. Then it didn't use HTML in my post. Then it disappeared. I thought it had been deleted and I reposted it in the lounge, where it belonged. I was just being a pain in the arse. Funny how the HTML didn't work. You still haven't answered why you have 3 different date formats. Michael Martin Australia mjm68@tpg.com.au "I personally love it because I can get as down and dirty as I want on the backend, while also being able to dabble with fun scripting and presentation games on the front end." - Chris Maunder 15/07/2002

                C 1 Reply Last reply
                0
                • L Lost User

                  Christian Graus wrote: I tried to post in the lounge and accidentally posted here. Then it didn't use HTML in my post. Then it disappeared. I thought it had been deleted and I reposted it in the lounge, where it belonged. I was just being a pain in the arse. Funny how the HTML didn't work. You still haven't answered why you have 3 different date formats. Michael Martin Australia mjm68@tpg.com.au "I personally love it because I can get as down and dirty as I want on the backend, while also being able to dabble with fun scripting and presentation games on the front end." - Chris Maunder 15/07/2002

                  C Offline
                  C Offline
                  Christian Graus
                  wrote on last edited by
                  #8

                  Michael Martin wrote: You still haven't answered why you have 3 different date formats. That would definately be due to my astounding level of incompetence.... Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
                  C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
                  It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003

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