1. Mell, P., Grance, T.: The NIST Definition of Cloud Computing. National Institute of Standards and Technology (2011)
2. Top Threats Working Group: The Notorious Nine: Cloud Computing Top Threats in 2013. Cloud Security Alliance (2013)
3. XML Signature.
https://zh.wikipedia.org/wiki/XML_Signature
4. XML Signature Wrapping.
http://www.ws-attacks.org/XML_Signature_Wrapping
5. XML Signature Syntax and Processing Version 2.0,
https://wwww.3.org/TR/xmldsig-core2/