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Thread: File MD5# and SHA# Calculator

  1. #1

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    PowerPoster i00's Avatar
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    Lightbulb File MD5# and SHA# Calculator

    After seeing a long-winded version on the forums about how to generate a MD5# for a file I thought I'd post how to do this here...

    vb.net Code:
    1. Private Function CalcMD5(ByVal File As String) As String
    2.         Dim f = New IO.FileStream(File, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.Read, 4096)
    3.         Dim md5 As New System.Security.Cryptography.MD5CryptoServiceProvider
    4.         Return Join((From xItem In md5.ComputeHash(f) Select xItem.ToString("X2")).ToArray, "")
    5.     End Function

    Also you could use the following to calculate the older (and slower) SHA#:
    vb.net Code:
    1. Private Function CalcSHA(ByVal File As String) As String
    2.         Dim f = New IO.FileStream(File, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.Read, 4096)
    3.         Dim sha1 As New System.Security.Cryptography.SHA1CryptoServiceProvider
    4.         Return Join((From xItem In sha1.ComputeHash(f) Select xItem.ToString("X2")).ToArray, "")
    5.     End Function

    Hope this helps some people ...
    Also please provide feedback and say thanks if this helped you

    Kris

  2. #2
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    Re: File MD5# and SHA# Calculator

    You've got your facts a bit backwards there... SHA-X is much newer than MD5 and MD5 is now deemed somewhat insecure. Several collisions have been found for MD5 but none for SHA at all (except for reduced SHA). Also, a test has shown that .NET MD5 and SHA-1 implementations are about the same speed.

  3. #3

    Thread Starter
    PowerPoster i00's Avatar
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    Re: File MD5# and SHA# Calculator

    Hrm interesting ... i know that SHA is more accurate... but MD5 should be quite accurate also as the chances of duplication are 1 in 16^32 arn't they, also i remember old zip programs using sha and now they all seem to use md5?

    Kris

  4. #4
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    Re: File MD5# and SHA# Calculator

    I've never used hashing ZIP programs so I wouldn't know. Maybe they've always supported SHA but had nothing to do so decided to add other options?

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