V2 certificate format (#1216)

Co-authored-by: Nate Brown <nbrown.us@gmail.com>
Co-authored-by: Jack Doan <jackdoan@rivian.com>
Co-authored-by: brad-defined <77982333+brad-defined@users.noreply.github.com>
Co-authored-by: Jack Doan <me@jackdoan.com>

cert/asn1.go

@@ -0,0 +1,52 @@
+package cert
+
+import (
+	"golang.org/x/crypto/cryptobyte"
+	"golang.org/x/crypto/cryptobyte/asn1"
+)
+
+// readOptionalASN1Boolean reads an asn.1 boolean with a specific tag instead of a asn.1 tag wrapping a boolean with a value
+// https://github.com/golang/go/issues/64811#issuecomment-1944446920
+func readOptionalASN1Boolean(b *cryptobyte.String, out *bool, tag asn1.Tag, defaultValue bool) bool {
+	var present bool
+	var child cryptobyte.String
+	if !b.ReadOptionalASN1(&child, &present, tag) {
+		return false
+	}
+
+	if !present {
+		*out = defaultValue
+		return true
+	}
+
+	// Ensure we have 1 byte
+	if len(child) == 1 {
+		*out = child[0] > 0
+		return true
+	}
+
+	return false
+}
+
+// readOptionalASN1Byte reads an asn.1 uint8 with a specific tag instead of a asn.1 tag wrapping a uint8 with a value
+// Similar issue as with readOptionalASN1Boolean
+func readOptionalASN1Byte(b *cryptobyte.String, out *byte, tag asn1.Tag, defaultValue byte) bool {
+	var present bool
+	var child cryptobyte.String
+	if !b.ReadOptionalASN1(&child, &present, tag) {
+		return false
+	}
+
+	if !present {
+		*out = defaultValue
+		return true
+	}
+
+	// Ensure we have 1 byte
+	if len(child) == 1 {
+		*out = child[0]
+		return true
+	}
+
+	return false
+}