A test RSA private key was missing "-" in the END delimiter. While working fine with encoding/pem, other tools like openssl seem to have more strict requirements. See https://github.com/golang/crypto/commit/1777f3ba8c1fed80fcaec3317e3aaa4f627764d2#commitcomment-17343818 for more details. Change-Id: I5153bb9cf405755d6621f69c1329da8290695eed Reviewed-on: https://go-review.googlesource.com/22871 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>