CSharp : Convert a GUID to a Darwin Descriptor and back

Here's how to convert/decode a GUID into Darwin Descriptor in C-Sharp

A Darwin Descriptor is an encoded string and when decoded produces a combination of the ProductCode, Feature & ComponentId(s) and generally used for Windows installer, because it provides feature resilience through a mechanism called COM Advertising.

Here's an example of a Darwin Descriptor, which you may have though was a virus entry in your registry!

"w_1^VX!!!!!!!!!MKKSkEXCELFiles>tW{~$4Q]c@II=l2xaTO5Z"

decoded yields a GUID, feature name, and a GUID.

{91120000-0030-0000-0000-0000000ff1ce}EXCELFiles{0638c49d-bb8b-4cd1-b191-052e8f325736}

"Darwin Descriptor," is actually an encoded representation of a specific product, component, and feature. 

Note: A "Compressed GUID" is a intermediate format, that rearranges the GUID and is Base85 encoded (using a restricted set) and has a length of 20 characters long and used to create Darwin Descriptors. 

Those cryptic-looking strings (that looks like malware) in your registry are actually Darwin Descriptors and can be located at the following locations; 

• HKCR\Installer\Assemblies and HKCR\Installer\Components
• HKCR\Installer\Win32Assemblies
• HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\{aSID}\Products\{compressed}\Features{targetpath}

To decode Darwin Descriptors en masse, use RegtoText tool (free demo available). 

Here's the code to convert a regular GUID into Darwin Descriptor in C-Sharp and vice-versa

 

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using System; //##################################################################################################################### //https://metadataconsulting.blogspot.com/2019/12/CSharp-Convert-a-GUID-to-a-Darwin-Descriptor-and-back.html //##################################################################################################################### public static class Program { class GUID2DD { // Conversion of this VB code to C# by http://metadataconsulting.blogspot.com/ // Some portions modernized, but an interesting exercise converting from a old language unexpressive to more modern lang // Source Code: https://www.symantec.com/connect/articles/working-darwin-descriptors // // Auto VB translators // 1.https://www.developerfusion.com/tools/convert/vb-to-csharp/?batchId=8e249124-06d2-4955-a238-dc2914a9cd3d - not good // 2.https://www.carlosag.net/tools/codetranslator/ - super fast! // 'VB Code - Copyright EdT 2012 // 'Script converts standard GUID to Darwin Descriptor and vice versa // 'A standard GUID requires 38 characters and contains 5 groups of hexadecimal characters separated by dashes. // 'The valid format for a standard GUID is: // '{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} // 'where X is a hex digit (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F). // // 'This program can copy the result of the conversion process to the clipboard. // 'To do this it uses the MS Office Word automation object, so for this to work, // 'a version of MSOffice must be present. Unfortunately, VBScript does not have // 'a native method for copying variables to the clipboard. public string GetConvertedGUID(string strProductCode) { string Block1; string Block2; string Block3; string Block4; string strMungedCode = string.Empty; long Dec1; long Dec2; long Dec3; long Dec4; string strPart1; string strPart2; string strPart3; string strPart4; const int intArraySize = 32; int[] arrSequence = new int[]{2, 3, 4, 5, 6, 7, 8, 9, 16, 17, 18, 19, 11, 12, 13, 14, 28, 29, 26, 27, 23, 24, 21, 22, 36, 37, 34, 35, 32, 33, 30, 31}; // Generate the RegProduct Code for (int intIndex = 0; intIndex <= (intArraySize - 1); intIndex++) { strMungedCode = (strMungedCode + strProductCode.Substring((arrSequence[intIndex] - 1), 1)); } Block1 = strMungedCode.Substring(0, 8); Block2 = strMungedCode.Substring(8, 8); Block3 = strMungedCode.Substring(16, 8); Block4 = strMungedCode.Substring(24, 8); Dec1 = HextoDec(Block1); strPart1 = DecToBase85(Dec1); Dec2 = HextoDec(Block2); strPart2 = DecToBase85(Dec2); Dec3 = HextoDec(Block3); strPart3 = DecToBase85(Dec3); Dec4 = HextoDec(Block4); strPart4 = DecToBase85(Dec4); return (strPart1.ReverseString() + (strPart2 + (strPart3 + strPart4.ReverseString()))); } public long HextoDec(string strHex) { //string strDigit; //int intDigit; //int intValue; long lngResult = 0; ////for (int intIndex = strHex.Length; (intIndex <= 1); intIndex = (intIndex + -1)) //for (int intIndex = strHex.Length; intIndex >= 1; intIndex--) //{ // strDigit = strHex.Substring((intIndex - 1), 1); // intDigit = (("0123456789ABCDEF".IndexOf(strDigit.ToUpper()) + 1) - 1); // if ((intDigit >= 0)) { // //intValue = (intDigit * (16 | (strHex.Length - intIndex))); // // TODO: Warning!!! The operator should be an XOR ^ instead of an OR, but not available in CodeDOM // //Mon 09-Dec-19 6:54pm metadataconsulting.ca - XOR used // intValue = (intDigit * (16 ^ (strHex.Length - intIndex))); // lngResult = (lngResult + intValue); // } // else { // lngResult = 0; // intIndex = 0; // //stop the loop // } //} lngResult = Convert.ToInt64(strHex, 16); return lngResult; } private string DecitoHex(int ddec) { //// Must return eight hex bytes //decimal hex1; //string hex2 = ""; //int hexlen; //while ((strDec > 15)) { // hex1 = (( (strDec / 16) - (int)(strDec / 16) ) * 16); // hex2 = ("0123456789ABCDEF".Substring(hex1.ToString(), 1) + hex2); // strDec = int((strDec / 16)); // hex2 = ("0123456789ABCDEF".Substring(strDec, 1) + hex2); // hexlen = hex2.Length; // DecToHex = (string((8 - hexlen), "0") + hex2); //} return ddec.ToString("X8"); } public string DecToBase85(long strDecimal) { // Multiples of 85 = 85, 7225, 614125, 52200625 int strDec = (int)strDecimal; string Base85 = "!$%&\'()*+,-.0123456789=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmnopqrstuvwxyz{}~"; int num; string quint1; string quint2; string quint3; string quint4; string quint5; //int Offset; quint1 = "!"; quint2 = "!"; quint3 = "!"; quint4 = "!"; quint5 = "!"; if ((strDecimal < 85)) { //quint1 = Base85.Substring(strDec, 1); long mod = strDecimal % 85; num = (int)mod; quint1 = Base85.Substring(num, 1); } if (strDecimal > 84 && strDecimal < 7225) { // Offset = strDec; // strDec = (int)((strDec / 85)); // num = (((Offset / 85) // - strDec) // * 85); // quint1 = Base85.Substring(num, 1); // quint2 = Base85.Substring(strDec, 1); num = (int)(strDecimal / 85) % 85; quint1 = Base85.Substring(num, 1); long mod = strDecimal % 85; num = (int)mod; quint2 = Base85.Substring(num, 1); } if (((strDecimal > 7224) && (strDecimal < 614125))) { //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); //quint1 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); //quint2 = Base85.Substring(num, 1); //quint3 = Base85.Substring(strDec, 1); num = (int)(strDecimal / 7225) % 85; quint1 = Base85.Substring(num, 1); num = (int)(strDecimal / 85) % 85; quint2 = Base85.Substring(num, 1); long mod = strDecimal % 85; num = (int)mod; quint3 = Base85.Substring(num, 1); } if (((strDecimal > 614124) && (strDecimal < 52200625))) { //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); //quint1 = Base85.Substring(num, 1); num = (int)(strDecimal / 614125) % 85; quint1 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); //quint2 = Base85.Substring(num, 1); num = (int)(strDecimal / 7225) % 85; quint2 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); //quint3 = Base85.Substring(num, 1); //quint4 = Base85.Substring(strDec, 1); num = (int)(strDecimal / 85) % 85; quint3 = Base85.Substring(num, 1); long mod = strDecimal % 85; num = (int)mod; quint4 = Base85.Substring(num, 1); } if ((strDecimal > 52200624)) { //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); num = (int)(strDecimal/52200625) % 85; quint1 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); num = (int)(strDecimal / 614125) % 85; quint2 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); num = (int)(strDecimal / 7225) % 85; quint3 = Base85.Substring(num, 1); //Offset = strDec; //strDec = (int)((strDec / 85)); //num = (((Offset / 85) // - strDec) // * 85); num = (int)(strDecimal / 85) % 85; quint4 = Base85.Substring(num, 1); long mod = strDecimal % 85; num = (int)mod; quint5 = Base85.Substring(num, 1); } return (quint1 + (quint2 + (quint3 + (quint4 + quint5)))); } //Function DDtoHex(darwin) renamed from VB public string DDtoGUID(string darwin) { string quad1; string quad2; string quad3; string quad4; string mungedStr; quad1 = darwin.Substring(0, 5); quad1 = QuadtoHex(quad1); quad2 = darwin.Substring(5, 5); quad2 = QuadtoHex(quad2); quad3 = darwin.Substring(10, 5); quad3 = QuadtoHex(quad3); quad4 = darwin.Substring(15, 5); quad4 = QuadtoHex(quad4); mungedStr = (quad1 + (quad2 + (quad3 + quad4))); return ReconstructProductCode(mungedStr); } public string QuadtoHex(string quad) { char chr; string Base85; int b85; int ddec; Base85 = "!$%&\'()*+,-.0123456789=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmnopqrstuvwxyz{}~"; ddec = 0; for (int i = 5; i >= 1; i--) { //chr = (char)quad.Substring((i - 1), 1); chr = quad[(i-1)]; b85 = ((Base85.IndexOf(chr) + 1) - 1); ddec = (ddec + b85); if ((i > 1)) { ddec = (ddec * 85); } } return DecitoHex(ddec); } public string ReconstructProductCode(string munged) { string strProductCode; const int intArraySize = 32; strProductCode = "{"; int[] arrSequence = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 13, 14, 15, 16, 9, 10, 11, 12, 23, 24, 21, 22, 19, 20, 17, 18, 31, 32, 29, 30, 27, 28, 25, 26}; // // Generate the Product Code for (int intIndex = 0; (intIndex <= (intArraySize - 1)); intIndex++) { strProductCode = (strProductCode + munged.Substring((arrSequence[intIndex] - 1), 1)); if (((intIndex == 7) || ((intIndex == 11) || ((intIndex == 15) || (intIndex == 19))))) { strProductCode = (strProductCode + "-"); } } return (strProductCode + "}"); } } public static string ReverseString(this string s) { if (string.IsNullOrEmpty(s)) return s; char[] array = new char[s.Length]; int forward = 0; for (int i = s.Length - 1; i >= 0; i--) { array[forward++] = s[i]; } return new string(array); } public static void Main() { GUID2DD conv = new GUID2DD(); string code = "w_1^VX!!!!!!!!!MKKSk"; //string code = "{91120000-0030-0000-0000-0000000ff1ce}"; //expect from above string result = string.Empty; // check if this is a GUID if ((code.Length == 38)) { if ((code.Substring(0, 1) == "{")) result = conv.GetConvertedGUID(code); } else if ((code.Length == 20)) { result = conv.DDtoGUID(code); } else { result = "Format of string submitted does not match that of a regular GUID or a Darwin Descriptor. Entries must" + " be of the form {xxxxxxxx-xxxx-xxxx-xxxx-Xxxxxxxxxxxx} or xxxxxxxxxxxxxxxxxxxx (len=20)"; } Console.WriteLine(code+" => " + result); } }