Encode Sitecore Contact Ids

EncodeSitecoreContactIds.cs

// Id of the Contact in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
string contactId = "50638e2f-43b2-46ee-806d-665f4fb08954";
		
var guid = Guid.Parse(contactId);
var bytes = guid.ToByteArray();

string encodedId = Convert.ToBase64String(bytes);