To find a certificate by SHA1 thumbprint using Chilkat, you can use the LoadByThumbprint or FindCert methods, depending on the language you are using. The LoadByThumbprint method, available in languages like C# and C++, loads a certificate based on a thumbprint, while the FindCert method (available in C++ and other languages) searches within a certificate store and returns the certificate if found. Both methods require the SHA1 thumbprint, which can be a hexadecimal string