sb.WriteRune(':')
		}
	}
	return sb.String()
}

func certificateIdentifier(c *x509.Certificate) string {
	return fmt.Sprintf(
		"SN=%d, SKID=%s, AKID=%s",
		c.SerialNumber,
		columnSeparatedHex(c.SubjectKeyId),
		columnSeparatedHex(c.AuthorityKeyId),
	)
}

// VerifyOptionFunc is function which provides a shallow copy of the VerifyOptions to the authenticator.  This allows

		},
		{
			name: "empty SKID",
			cert: func() *x509.Certificate {
				c := getCert(t, clientCNCert)
				c.SubjectKeyId = nil
				return c
			}(),
			expectedIdentifier: "SN=1, SKID=, AKID=D3:07:CD:72:E6:BE:0A:5A:D8:E9:60:20:AF:C2:F2:36:7E:33:62:0B",
		},
		{
			name: "empty AKID",
			cert: func() *x509.Certificate {

				}
				val := cryptobyte.String(e.Value)
				var skid cryptobyte.String
				if !val.ReadASN1(&skid, cryptobyte_asn1.OCTET_STRING) {
					return errors.New("x509: invalid subject key identifier")
				}
				out.SubjectKeyId = skid
			case 32:
				out.Policies, err = parseCertificatePoliciesExtension(e.Value)
				if err != nil {
					return err
				}
				out.PolicyIdentifiers = make([]asn1.ObjectIdentifier, 0, len(out.Policies))