var sb strings.Builder
	for i, r := range h {
		sb.WriteRune(r)
		if i%2 == 1 && i != len(h)-1 {
			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),
	)
}

		},
	}

	for _, tc := range tt {
		t.Run(tc.name, func(t *testing.T) {
			got := certificateIdentifier(tc.cert)
			if got != tc.expectedIdentifier {
				t.Errorf("expected %q, got %q", tc.expectedIdentifier, got)
			}
		})
	}