Forum Discussion

Sarazin73's avatar
Sarazin73
Frequent Visitor
7 years ago
Solved

Decrypt string values from a column of a table in a query

Hello, i search to decrypt string values from a crypted column on a table imported as a query in my Power BI report. The string is crypted in input with a XOR algorythm as follow : String ToCr...
Need Help
  • Nolock's avatar
    Nolock
    7 years ago

    Hi Sarazin73,

    I've written a custom function for you:

    fnXorCrypt = (
    string as text, 
    xorValue as number
) as text =>
    // concat encrypted characters
    List.Accumulate(
        // get a list of chars
        Text.ToList(string),
        // initial string
        "",
        // accumulate last state and a new encrypted character
        (state, current) =>
            state 
            & 
            Character.FromNumber(
                Number.BitwiseXor(
                    Character.ToNumber(current), 
                    xorValue
                )
            )
    )

    The usage:

    EncodedString = fnXorCrypt("Lundi", 42)

    A test:

     

Nolock's avatar
Nolock
Icon for Resident Rockstar rankResident Rockstar
7 years ago

Hi Sarazin73,

do you also have the decryption algorithm in c-like code? If I had one, I'd develop a function in M for you.

And can you please post some examples for testing?

Thank you :)

 

Sarazin73's avatar
Sarazin73
Frequent Visitor
7 years ago

Hi,

 

Thanks for helphing me !
The algorythm used is the same to decryt than to encrypt. The initial outside script that crypt data as source is in java language. We have finally do tests with XOR 42 instead of XOR 24. Below, some samples with their corresponding encoding string.

Lundi : f_DNC

Mardi : gKXNC

Mercredi : gOXIXONC

Jeudi : `O_NC

Vendredi : |ODNXONC

Samedi : yKGONC

Dimanche : nCGKDIBO

  • Nolock's avatar
    Nolock
    Icon for Resident Rockstar rankResident Rockstar
    7 years ago

    Hi Sarazin73,

    I've written a custom function for you:

    fnXorCrypt = (
    string as text, 
    xorValue as number
) as text =>
    // concat encrypted characters
    List.Accumulate(
        // get a list of chars
        Text.ToList(string),
        // initial string
        "",
        // accumulate last state and a new encrypted character
        (state, current) =>
            state 
            & 
            Character.FromNumber(
                Number.BitwiseXor(
                    Character.ToNumber(current), 
                    xorValue
                )
            )
    )

    The usage:

    EncodedString = fnXorCrypt("Lundi", 42)

    A test:

     

    • Sarazin73's avatar
      Sarazin73
      Frequent Visitor
      7 years ago

      Hi NoLock,

      thanks for your job. It's perfect !