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Ciphertext Analysis with Excel?

  1. #1
    Registered User
    Join Date
    07-24-2006
    Posts
    2

    Ciphertext Analysis with Excel?

    Hey guys, I have written a quick spreadsheet that does a character frequency analysis on a given ciphertext string.

    I have a question on improving the functionality:

    Q: Is there a way to print out the ten most frequent bigrams (two letter combinations) and trigrams (three letter combinations) with a formula or VBscript?

    I have attached the file for your review.

    Thank you in advance for your assistance.

    -JJ
    Attached Files Attached Files

  2. #2
    Tom Ogilvy
    Guest

    RE: Ciphertext Analysis with Excel?

    Write the combinations to a page with their frequency, sort on frequency and
    then print the top 10 or use an autofilter on the new data to show the top 10
    and print that.

    --
    Regards,
    Tom Ogilvy


    "jjunginger" wrote:

    >
    > Hey guys, I have written a quick spreadsheet that does a character
    > frequency analysis on a given ciphertext string.
    >
    > I have a question on improving the functionality:
    >
    > Q: Is there a way to print out the ten most frequent bigrams (two
    > letter combinations) and trigrams (three letter combinations) with a
    > formula or VBscript?
    >
    > I have attached the file for your review.
    >
    > Thank you in advance for your assistance.
    >
    > -JJ
    >
    >
    > +-------------------------------------------------------------------+
    > |Filename: Cryptanalysis Worksheet.zip |
    > |Download: http://www.excelforum.com/attachment.php?postid=5083 |
    > +-------------------------------------------------------------------+
    >
    > --
    > jjunginger
    > ------------------------------------------------------------------------
    > jjunginger's Profile: http://www.excelforum.com/member.php...o&userid=36703
    > View this thread: http://www.excelforum.com/showthread...hreadid=564366
    >
    >


  3. #3
    Registered User
    Join Date
    07-24-2006
    Posts
    2
    Thanks for the reply, Tom. How do I get all of the unique combinations to a page, so I can sort them? Could you give me a snippet of code/script or walk me through how to get that done?

    Thanks again!

    -Jeremy

  4. #4
    Tom Ogilvy
    Guest

    Re: Ciphertext Analysis with Excel?

    Sub ABC()
    Dim i As Long, j As Long
    Dim rw As Long, s As String
    Dim s1 As String, k As Long
    Dim kk As Long
    s = Range("A2")
    rw = 31
    For i = 1 To 26
    For j = 1 To 26
    s1 = Chr(i + 64) & Chr(j + 64)
    Cells(rw, 1) = s1

    For kk = 1 To Len(s) - 1
    If Mid(s, kk, 2) = s1 Then
    Cells(rw, 2) = Cells(rw, 2) + 1
    End If
    Next
    rw = rw + 1
    Next j
    Next i
    Range("A31").Resize(rw - 31, 2).Sort Key1:=Range("B31"), _
    Order1:=xlDescending, header:=xlNo
    Range("A41:A706").EntireRow.Delete

    rw = 43
    For i = 1 To 26
    For j = 1 To 26
    For k = 1 To 26
    s1 = Chr(i + 64) & Chr(j + 64) & Chr(k + 64)
    Cells(rw, 1) = s1

    For kk = 1 To Len(s) - 1
    If Mid(s, kk, 3) = s1 Then
    Cells(rw, 2) = Cells(rw, 2) + 1
    End If
    Next
    rw = rw + 1
    Next k
    Next j
    Next i
    Range("A43").Resize(rw - 43, 2).Sort Key1:=Range("B43"), _
    Order1:=xlDescending, header:=xlNo
    Range("A53:A65536").EntireRow.Delete
    End Sub

    --
    Regards,
    Tom Ogilvy


    "jjunginger" wrote:

    >
    > Thanks for the reply, Tom. How do I get all of the unique combinations
    > to a page, so I can sort them? Could you give me a snippet of
    > code/script or walk me through how to get that done?
    >
    > Thanks again!
    >
    > -Jeremy
    >
    >
    > --
    > jjunginger
    > ------------------------------------------------------------------------
    > jjunginger's Profile: http://www.excelforum.com/member.php...o&userid=36703
    > View this thread: http://www.excelforum.com/showthread...hreadid=564366
    >
    >


  5. #5
    keepITcool
    Guest

    Re: Ciphertext Analysis with Excel?

    Tom

    elegant. you missed the fact that "a2" has mixed case!

    change s= Range("A2")
    to s= UCase(Range("A2")

    and you'll notice different results.


    OP,

    what are you doing in Column B and C??
    those formulas are "hardcoded" and prone to errors.

    I've shortened the formula in B by replacing the nested substitute to
    upper

    in b4:
    =LEN($A$2)-LEN(SUBSTITUTE(UPPER($A$2),$A4,""))
    in c4:
    =$B4/LEN($A$2)*100

    then copy down.

    pls study Excel HELP
    about Absolute and Relative references!

    --
    keepITcool
    | www.XLsupport.com | keepITcool chello nl | amsterdam


    Tom Ogilvy wrote in
    <news:<[email protected]>


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