What I mean by Amazon like securtiy is described in this article http://www.thebuzzmedia.com/designing-a-secure-rest-api-with...
But per the blog article, you'd only want to do this if you are willing to support client libraries/sdks that implement it as well. No one wants to spend the time to implement non-standard custom HMAC algorithms.
I have to disagree with the other comments here regarding the client library. I think that given the precedence of Amazon API, given that people understand how to sign APIs like amazon, this method will be accepted even without a client library.
Being a Java / Scala dev, I prefer that an API provider allow me to select the HTTP client libraries to use and prevent from forcing me to use a specific library & version via SDK transitive dependencies.