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Retrieve original password from MD5 Hashed Password

  • February 24, 2009 at 3:43 pm

    #206924

    Hello all,

    In my application we stored the password using MD5 algorithm

    (System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(passWord.Text, "MD5")) like this.

    But now we would like to transfer the hashed password to another table which need original text as password. So How can i get the original password from hashed one?

    I am using SQL Server 2005 standard Edition and my application runs on .NET Framework.

    Thanks to everyone.

  • February 24, 2009 at 3:49 pm

    #949687

    You can't get it from the hashed password. A hash is one-way.

  • February 24, 2009 at 3:59 pm

    #949691

    you mean to say that its impossible.

  • February 25, 2009 at 12:25 am

    #949815

    senyorita (2/24/2009)

    you mean to say that its impossible.

    Yup.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • February 25, 2009 at 2:00 pm

    #950269

    It's not impossible. You just can't perform the operation in reverse. It's like if you put a piece of paper through a high speed shredder. You aren't going to be able to reverse the process to get what was on the paper again. With a hash, it's one way. Once you get the hash, you can't use some formula or algorithm to go back and get the text.

    However, it might be possible to do so using a rainbow table. A rainbow table is where a given text string is then hashed and then both the text string and the hash are stored. This allows you to look up the text string via the hash. This might help:

    Rainbow Tables - MD5[/url]

    K. Brian Kelley
    @kbriankelley

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