s2n is a good rewrite of just the TLS part. I concur with everything you wrote. Re: ASN.1, you really want a compiler for it, not hand-rolled codecs -- I don'

s2n is a good rewrite of just the TLS part. I concur with everything you wrote. Re: ASN.1, you really want a compiler for it, not hand-rolled codecs -- I don't care how good your library and macros for hand-rolling ASN.1 DER codecs might be, it's going to yield very difficult to maintain code full of bugs. ASN.1 is not the biggest part. Certificate validation, revocation status checking, and everything to do with that, and all the many certificate extensions and subject alternative name forms, and... all of that requires a very large body of code, and there's no formal specifications for any of it.