ocsp: pre-serialized responses and improved ASN.1

OCSP responders sometimes rely on pre-generated responses to increase
performance. In such cases, RFC 5019 allows responders to respond with
responseStatus unauthorized if they do not have a pre-generated response for
a certificate. This patch provides a pre-serialized unauthorized response.

This change also updates the serialization of OCSP responses so that the
resulting DER encoding is compatible with other parsers.

Note: This change depends on updates to encoding/asn1 to improve handling
of flags and time values.

https://go-review.googlesource.com/#/c/5970/

Change-Id: I77e042de6535a70b0996e058cb38a00076a16dd4
Reviewed-on: https://go-review.googlesource.com/4121
Reviewed-by: Adam Langley <agl@golang.org>
2 files changed