# The key variable should be renamed to rsaKey in the "How to: Sign XML Documents with Digital Signatures" In this [doc](https://docs.microsoft.com/en-us/dotnet/standard/security/how-to-sign-xml-documents-with-digital-signatures), there's a typo in the line: `signedXml.SigningKey = key; ` it should be `signedXml.SigningKey = rsaKey; `