diff --git a/ccadb2OneCRL/utils/normalize.go b/ccadb2OneCRL/utils/normalize.go
index e305cf7..13bb5c2 100644
--- a/ccadb2OneCRL/utils/normalize.go
+++ b/ccadb2OneCRL/utils/normalize.go
@@ -19,7 +19,7 @@ type tbsCertWithRawSerial struct {
 	SerialNumber asn1.RawValue
 }
 
-// Extract the raw bytes of the serial number field from a tbsCertificate..
+// Extract the raw bytes of the serial number field from a tbsCertificate.
 func RawSerialBytes(rawTBSCertificate []byte) ([]byte, error) {
 	var tbsCert tbsCertWithRawSerial
 	_, err := asn1.Unmarshal(rawTBSCertificate, &tbsCert)
diff --git a/ccadb2OneCRL/utils/utils_test.go b/ccadb2OneCRL/utils/utils_test.go
index eeac962..a3c05b7 100644
--- a/ccadb2OneCRL/utils/utils_test.go
+++ b/ccadb2OneCRL/utils/utils_test.go
@@ -20,16 +20,166 @@ func assertBytes(t *testing.T, data string, expected []byte) {
 	}
 }
 
-func TestRawSerialBytes(t *testing.T) {
-	// DER for the version and serialNumber fields of a tbsCertificate.
+func TestRawSerialBytesLeadingZero(t *testing.T) {
+	// DER of the tbsCertificate of TeliaSonera Gateway CA v2
 	tbsCertPrefix := []byte{
-		0x30, 0x0f,
-		0xa0, 0x03, 0x02, 0x01, 0x02,
-		0x02, 0x08, 0x00, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+		0x30, 0x82, 0x05, 0x08, 0xA0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x11, 0x00,
+		0x86, 0x3C, 0x75, 0x64, 0x11, 0x95, 0x85, 0x4F, 0xB4, 0x31, 0x38, 0xA0,
+		0xA0, 0xCF, 0x8A, 0xA3, 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86,
+		0xF7, 0x0D, 0x01, 0x01, 0x0B, 0x05, 0x00, 0x30, 0x37, 0x31, 0x14, 0x30,
+		0x12, 0x06, 0x03, 0x55, 0x04, 0x0A, 0x0C, 0x0B, 0x54, 0x65, 0x6C, 0x69,
+		0x61, 0x53, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x31, 0x1F, 0x30, 0x1D, 0x06,
+		0x03, 0x55, 0x04, 0x03, 0x0C, 0x16, 0x54, 0x65, 0x6C, 0x69, 0x61, 0x53,
+		0x6F, 0x6E, 0x65, 0x72, 0x61, 0x20, 0x52, 0x6F, 0x6F, 0x74, 0x20, 0x43,
+		0x41, 0x20, 0x76, 0x31, 0x30, 0x1E, 0x17, 0x0D, 0x31, 0x34, 0x31, 0x30,
+		0x31, 0x36, 0x30, 0x38, 0x32, 0x31, 0x32, 0x32, 0x5A, 0x17, 0x0D, 0x33,
+		0x32, 0x31, 0x30, 0x31, 0x36, 0x30, 0x35, 0x30, 0x34, 0x30, 0x30, 0x5A,
+		0x30, 0x47, 0x31, 0x0B, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13,
+		0x02, 0x46, 0x49, 0x31, 0x14, 0x30, 0x12, 0x06, 0x03, 0x55, 0x04, 0x0A,
+		0x0C, 0x0B, 0x54, 0x65, 0x6C, 0x69, 0x61, 0x53, 0x6F, 0x6E, 0x65, 0x72,
+		0x61, 0x31, 0x22, 0x30, 0x20, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0C, 0x19,
+		0x54, 0x65, 0x6C, 0x69, 0x61, 0x53, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x20,
+		0x47, 0x61, 0x74, 0x65, 0x77, 0x61, 0x79, 0x20, 0x43, 0x41, 0x20, 0x76,
+		0x32, 0x30, 0x82, 0x02, 0x22, 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48,
+		0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03, 0x82, 0x02, 0x0F,
+		0x00, 0x30, 0x82, 0x02, 0x0A, 0x02, 0x82, 0x02, 0x01, 0x00, 0x8E, 0xF9,
+		0xF4, 0x7C, 0x75, 0xD6, 0xCE, 0x6E, 0x95, 0x5E, 0x1B, 0xFD, 0x44, 0x80,
+		0x56, 0x9C, 0xCB, 0x78, 0xBF, 0x96, 0x26, 0xC1, 0x62, 0x99, 0x77, 0x57,
+		0x55, 0x0A, 0xD7, 0x20, 0xEF, 0xF0, 0x78, 0x72, 0xCF, 0x53, 0x44, 0x38,
+		0x3A, 0x71, 0x4E, 0x2D, 0x67, 0x9E, 0x2B, 0x9F, 0xA8, 0x64, 0x29, 0xD1,
+		0xB9, 0x20, 0xD1, 0xD8, 0x7C, 0x06, 0x9C, 0x89, 0xA4, 0x9C, 0x7A, 0xC6,
+		0x4A, 0xBA, 0xED, 0x9B, 0xB3, 0xD7, 0xD5, 0x1C, 0x41, 0x36, 0xE2, 0x11,
+		0x60, 0xFF, 0x3D, 0xC3, 0x8B, 0x64, 0x15, 0x4D, 0xC8, 0xBF, 0xDA, 0x39,
+		0x81, 0xE4, 0xF4, 0x4E, 0xFA, 0x7D, 0xC7, 0x70, 0x50, 0xE6, 0xD7, 0xAA,
+		0x59, 0xC1, 0x11, 0x97, 0x20, 0x17, 0x03, 0x27, 0x1B, 0x61, 0xB5, 0x41,
+		0x4C, 0x62, 0xCF, 0x53, 0x50, 0x13, 0x4D, 0x75, 0xD1, 0xDF, 0x55, 0xBD,
+		0x5D, 0x9A, 0x8B, 0x87, 0xF9, 0x3B, 0x51, 0x02, 0x1D, 0x72, 0x2E, 0xC8,
+		0x2B, 0x5C, 0x65, 0x49, 0x63, 0xD1, 0xA8, 0x04, 0x6C, 0x61, 0x14, 0x67,
+		0x84, 0x76, 0xE4, 0xE7, 0xD7, 0xF5, 0x9A, 0x02, 0x5E, 0xF8, 0xFF, 0x5F,
+		0x9E, 0x57, 0x67, 0x36, 0x21, 0x90, 0x67, 0x5A, 0x37, 0xC4, 0xE3, 0xF2,
+		0x9C, 0x1E, 0x05, 0x7C, 0x04, 0x72, 0x4F, 0x86, 0x1B, 0x71, 0xCD, 0xB8,
+		0x2B, 0x50, 0x39, 0x2F, 0xE7, 0x9C, 0x30, 0xF2, 0xF4, 0xF3, 0x81, 0x8E,
+		0x13, 0x1A, 0x80, 0x04, 0x75, 0x4A, 0x3C, 0x42, 0x07, 0x88, 0xFD, 0x20,
+		0x1D, 0x6E, 0x6A, 0xDA, 0x1F, 0x49, 0xAF, 0xA0, 0xE2, 0x33, 0x9E, 0x19,
+		0xDE, 0x0A, 0x5B, 0x1B, 0x86, 0xA5, 0x51, 0xFB, 0x54, 0xBF, 0x8D, 0x82,
+		0x7F, 0xEA, 0xE8, 0xCA, 0xC5, 0x68, 0xEC, 0xB1, 0x75, 0xF6, 0x2E, 0x61,
+		0x57, 0xF3, 0x68, 0xE9, 0x21, 0x15, 0x42, 0x6B, 0x89, 0xC9, 0x0A, 0xD4,
+		0x29, 0x2D, 0xDC, 0x3F, 0xB1, 0xEC, 0xE4, 0xC0, 0x96, 0x2A, 0x35, 0x4C,
+		0xAD, 0xFE, 0x5A, 0x96, 0x6D, 0x2D, 0x9C, 0xFB, 0x1B, 0x7C, 0x1D, 0x56,
+		0x68, 0xDD, 0xDA, 0xFD, 0xCF, 0x87, 0x71, 0x5C, 0x24, 0x88, 0x78, 0x47,
+		0x69, 0x7B, 0x71, 0xA3, 0xDC, 0x0F, 0x7C, 0x6C, 0xC3, 0x05, 0x15, 0x19,
+		0x2C, 0xA7, 0x8A, 0xE5, 0x0F, 0x7E, 0x63, 0xB0, 0x45, 0xF5, 0x75, 0xE5,
+		0x07, 0x79, 0x31, 0x79, 0x1D, 0xFC, 0x26, 0x7E, 0xD9, 0x18, 0xC4, 0xAE,
+		0x9B, 0x6A, 0x6E, 0x14, 0x63, 0xCB, 0xC3, 0xC3, 0xC5, 0xD3, 0x55, 0xB9,
+		0xCD, 0x91, 0x86, 0xC7, 0x4F, 0x0B, 0x2F, 0x33, 0x5C, 0xB7, 0x42, 0xBD,
+		0x39, 0x3A, 0xB3, 0xB3, 0x98, 0x5C, 0x1A, 0x09, 0x99, 0xA4, 0x7B, 0xC9,
+		0x8C, 0xBF, 0xEA, 0x62, 0xDF, 0x01, 0x11, 0x9E, 0x2D, 0x6B, 0x7B, 0x8B,
+		0xCB, 0x38, 0x10, 0x8B, 0x15, 0x65, 0x29, 0x04, 0x3A, 0xA3, 0xAE, 0x48,
+		0x5F, 0x1E, 0x50, 0xEA, 0xF2, 0x81, 0x91, 0x1C, 0x57, 0x72, 0x0D, 0xBD,
+		0x67, 0xF5, 0xFE, 0x1F, 0x20, 0xFB, 0x4B, 0x24, 0xC9, 0x24, 0x33, 0x99,
+		0xFA, 0x2C, 0x5E, 0x97, 0xBD, 0x05, 0x35, 0xA2, 0x5D, 0x5D, 0x7D, 0x13,
+		0xB1, 0x85, 0xBE, 0xE3, 0x10, 0xA0, 0x75, 0xC1, 0xE2, 0xC6, 0xF6, 0xA1,
+		0x2A, 0xAD, 0xDA, 0x71, 0x47, 0x24, 0x39, 0xBD, 0xA8, 0x93, 0x0D, 0x9A,
+		0x61, 0x4A, 0xAC, 0x97, 0x99, 0xAA, 0x77, 0xDA, 0x0A, 0x17, 0x70, 0x49,
+		0xB7, 0xB9, 0x02, 0xF4, 0xF4, 0xCB, 0xB9, 0x1C, 0x7A, 0xC5, 0x30, 0x83,
+		0x24, 0x5C, 0x75, 0xFE, 0x4B, 0x9D, 0x6D, 0xC9, 0x53, 0xDA, 0xBB, 0x11,
+		0x75, 0xB4, 0xF8, 0x54, 0x1C, 0xC6, 0x7B, 0x80, 0x1F, 0x94, 0xAA, 0x99,
+		0x92, 0x74, 0xF0, 0xC4, 0x7C, 0x86, 0x48, 0x9A, 0x67, 0x9A, 0x5F, 0x71,
+		0x11, 0xEF, 0x37, 0xB2, 0x18, 0x15, 0x02, 0x03, 0x01, 0x00, 0x01, 0xA3,
+		0x82, 0x02, 0x15, 0x30, 0x82, 0x02, 0x11, 0x30, 0x81, 0x8A, 0x06, 0x08,
+		0x2B, 0x06, 0x01, 0x05, 0x05, 0x07, 0x01, 0x01, 0x04, 0x7E, 0x30, 0x7C,
+		0x30, 0x2D, 0x06, 0x08, 0x2B, 0x06, 0x01, 0x05, 0x05, 0x07, 0x30, 0x01,
+		0x86, 0x21, 0x68, 0x74, 0x74, 0x70, 0x3A, 0x2F, 0x2F, 0x6F, 0x63, 0x73,
+		0x70, 0x2E, 0x74, 0x72, 0x75, 0x73, 0x74, 0x2E, 0x74, 0x65, 0x6C, 0x69,
+		0x61, 0x73, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x2E, 0x63, 0x6F, 0x6D, 0x30,
+		0x4B, 0x06, 0x08, 0x2B, 0x06, 0x01, 0x05, 0x05, 0x07, 0x30, 0x02, 0x86,
+		0x3F, 0x68, 0x74, 0x74, 0x70, 0x3A, 0x2F, 0x2F, 0x72, 0x65, 0x70, 0x6F,
+		0x73, 0x69, 0x74, 0x6F, 0x72, 0x79, 0x2E, 0x74, 0x72, 0x75, 0x73, 0x74,
+		0x2E, 0x74, 0x65, 0x6C, 0x69, 0x61, 0x73, 0x6F, 0x6E, 0x65, 0x72, 0x61,
+		0x2E, 0x63, 0x6F, 0x6D, 0x2F, 0x74, 0x65, 0x6C, 0x69, 0x61, 0x73, 0x6F,
+		0x6E, 0x65, 0x72, 0x61, 0x72, 0x6F, 0x6F, 0x74, 0x63, 0x61, 0x76, 0x31,
+		0x2E, 0x63, 0x65, 0x72, 0x30, 0x12, 0x06, 0x03, 0x55, 0x1D, 0x13, 0x01,
+		0x01, 0xFF, 0x04, 0x08, 0x30, 0x06, 0x01, 0x01, 0xFF, 0x02, 0x01, 0x00,
+		0x30, 0x55, 0x06, 0x03, 0x55, 0x1D, 0x20, 0x04, 0x4E, 0x30, 0x4C, 0x30,
+		0x4A, 0x06, 0x0C, 0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x0F, 0x02, 0x03,
+		0x01, 0x01, 0x02, 0x30, 0x3A, 0x30, 0x38, 0x06, 0x08, 0x2B, 0x06, 0x01,
+		0x05, 0x05, 0x07, 0x02, 0x01, 0x16, 0x2C, 0x68, 0x74, 0x74, 0x70, 0x73,
+		0x3A, 0x2F, 0x2F, 0x72, 0x65, 0x70, 0x6F, 0x73, 0x69, 0x74, 0x6F, 0x72,
+		0x79, 0x2E, 0x74, 0x72, 0x75, 0x73, 0x74, 0x2E, 0x74, 0x65, 0x6C, 0x69,
+		0x61, 0x73, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x2E, 0x63, 0x6F, 0x6D, 0x2F,
+		0x43, 0x50, 0x53, 0x30, 0x0E, 0x06, 0x03, 0x55, 0x1D, 0x0F, 0x01, 0x01,
+		0xFF, 0x04, 0x04, 0x03, 0x02, 0x01, 0x06, 0x30, 0x81, 0xC6, 0x06, 0x03,
+		0x55, 0x1D, 0x1F, 0x04, 0x81, 0xBE, 0x30, 0x81, 0xBB, 0x30, 0x40, 0xA0,
+		0x3E, 0xA0, 0x3C, 0x86, 0x3A, 0x68, 0x74, 0x74, 0x70, 0x3A, 0x2F, 0x2F,
+		0x63, 0x72, 0x6C, 0x2D, 0x33, 0x2E, 0x74, 0x72, 0x75, 0x73, 0x74, 0x2E,
+		0x74, 0x65, 0x6C, 0x69, 0x61, 0x73, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x2E,
+		0x63, 0x6F, 0x6D, 0x2F, 0x74, 0x65, 0x6C, 0x69, 0x61, 0x73, 0x6F, 0x6E,
+		0x65, 0x72, 0x61, 0x72, 0x6F, 0x6F, 0x74, 0x63, 0x61, 0x76, 0x31, 0x2E,
+		0x63, 0x72, 0x6C, 0x30, 0x77, 0xA0, 0x75, 0xA0, 0x73, 0x86, 0x71, 0x6C,
+		0x64, 0x61, 0x70, 0x3A, 0x2F, 0x2F, 0x63, 0x72, 0x6C, 0x2D, 0x31, 0x2E,
+		0x74, 0x72, 0x75, 0x73, 0x74, 0x2E, 0x74, 0x65, 0x6C, 0x69, 0x61, 0x73,
+		0x6F, 0x6E, 0x65, 0x72, 0x61, 0x2E, 0x63, 0x6F, 0x6D, 0x2F, 0x63, 0x6E,
+		0x3D, 0x54, 0x65, 0x6C, 0x69, 0x61, 0x53, 0x6F, 0x6E, 0x65, 0x72, 0x61,
+		0x25, 0x32, 0x30, 0x52, 0x6F, 0x6F, 0x74, 0x25, 0x32, 0x30, 0x43, 0x41,
+		0x25, 0x32, 0x30, 0x76, 0x31, 0x2C, 0x6F, 0x3D, 0x54, 0x65, 0x6C, 0x69,
+		0x61, 0x53, 0x6F, 0x6E, 0x65, 0x72, 0x61, 0x3F, 0x63, 0x65, 0x72, 0x74,
+		0x69, 0x66, 0x69, 0x63, 0x61, 0x74, 0x65, 0x72, 0x65, 0x76, 0x6F, 0x63,
+		0x61, 0x74, 0x69, 0x6F, 0x6E, 0x6C, 0x69, 0x73, 0x74, 0x3B, 0x62, 0x69,
+		0x6E, 0x61, 0x72, 0x79, 0x30, 0x1D, 0x06, 0x03, 0x55, 0x1D, 0x0E, 0x04,
+		0x16, 0x04, 0x14, 0x87, 0xAA, 0xE3, 0x13, 0x12, 0x9F, 0x11, 0x8B, 0xCA,
+		0x68, 0xCD, 0x1E, 0x2D, 0xC4, 0x29, 0xA8, 0xFA, 0x10, 0x1A, 0xCB, 0x30,
+		0x1F, 0x06, 0x03, 0x55, 0x1D, 0x23, 0x04, 0x18, 0x30, 0x16, 0x80, 0x14,
+		0xF0, 0x8F, 0x59, 0x38, 0x00, 0xB3, 0xF5, 0x8F, 0x9A, 0x96, 0x0C, 0xD5,
+		0xEB, 0xFA, 0x7B, 0xAA, 0x17, 0xE8, 0x13, 0x12,
 	}
 
 	b, _ := RawSerialBytes(tbsCertPrefix)
-	if !bytes.Equal(b, []byte{0x00, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}) {
+	if !bytes.Equal(b, []byte{0x00, 0x86, 0x3c, 0x75, 0x64, 0x11, 0x95, 0x85,
+		0x4f, 0xb4, 0x31, 0x38, 0xa0, 0xa0, 0xcf, 0x8a, 0xa3}) {
+		t.Errorf("error")
+	}
+}
+
+func TestRawSerialBytesNoLeadingZero(t *testing.T) {
+	// DER of the tbsCertificate of AffirmTrust Premium ECC
+	tbsCertPrefix := []byte{
+		0x30, 0x82, 0x01, 0x85, 0xA0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x08, 0x74,
+		0x97, 0x25, 0x8A, 0xC7, 0x3F, 0x7A, 0x54, 0x30, 0x0A, 0x06, 0x08, 0x2A,
+		0x86, 0x48, 0xCE, 0x3D, 0x04, 0x03, 0x03, 0x30, 0x45, 0x31, 0x0B, 0x30,
+		0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x14,
+		0x30, 0x12, 0x06, 0x03, 0x55, 0x04, 0x0A, 0x0C, 0x0B, 0x41, 0x66, 0x66,
+		0x69, 0x72, 0x6D, 0x54, 0x72, 0x75, 0x73, 0x74, 0x31, 0x20, 0x30, 0x1E,
+		0x06, 0x03, 0x55, 0x04, 0x03, 0x0C, 0x17, 0x41, 0x66, 0x66, 0x69, 0x72,
+		0x6D, 0x54, 0x72, 0x75, 0x73, 0x74, 0x20, 0x50, 0x72, 0x65, 0x6D, 0x69,
+		0x75, 0x6D, 0x20, 0x45, 0x43, 0x43, 0x30, 0x1E, 0x17, 0x0D, 0x31, 0x30,
+		0x30, 0x31, 0x32, 0x39, 0x31, 0x34, 0x32, 0x30, 0x32, 0x34, 0x5A, 0x17,
+		0x0D, 0x34, 0x30, 0x31, 0x32, 0x33, 0x31, 0x31, 0x34, 0x32, 0x30, 0x32,
+		0x34, 0x5A, 0x30, 0x45, 0x31, 0x0B, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04,
+		0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x14, 0x30, 0x12, 0x06, 0x03, 0x55,
+		0x04, 0x0A, 0x0C, 0x0B, 0x41, 0x66, 0x66, 0x69, 0x72, 0x6D, 0x54, 0x72,
+		0x75, 0x73, 0x74, 0x31, 0x20, 0x30, 0x1E, 0x06, 0x03, 0x55, 0x04, 0x03,
+		0x0C, 0x17, 0x41, 0x66, 0x66, 0x69, 0x72, 0x6D, 0x54, 0x72, 0x75, 0x73,
+		0x74, 0x20, 0x50, 0x72, 0x65, 0x6D, 0x69, 0x75, 0x6D, 0x20, 0x45, 0x43,
+		0x43, 0x30, 0x76, 0x30, 0x10, 0x06, 0x07, 0x2A, 0x86, 0x48, 0xCE, 0x3D,
+		0x02, 0x01, 0x06, 0x05, 0x2B, 0x81, 0x04, 0x00, 0x22, 0x03, 0x62, 0x00,
+		0x04, 0x0D, 0x30, 0x5E, 0x1B, 0x15, 0x9D, 0x03, 0xD0, 0xA1, 0x79, 0x35,
+		0xB7, 0x3A, 0x3C, 0x92, 0x7A, 0xCA, 0x15, 0x1C, 0xCD, 0x62, 0xF3, 0x9C,
+		0x26, 0x5C, 0x07, 0x3D, 0xE5, 0x54, 0xFA, 0xA3, 0xD6, 0xCC, 0x12, 0xEA,
+		0xF4, 0x14, 0x5F, 0xE8, 0x8E, 0x19, 0xAB, 0x2F, 0x2E, 0x48, 0xE6, 0xAC,
+		0x18, 0x43, 0x78, 0xAC, 0xD0, 0x37, 0xC3, 0xBD, 0xB2, 0xCD, 0x2C, 0xE6,
+		0x47, 0xE2, 0x1A, 0xE6, 0x63, 0xB8, 0x3D, 0x2E, 0x2F, 0x78, 0xC4, 0x4F,
+		0xDB, 0xF4, 0x0F, 0xA4, 0x68, 0x4C, 0x55, 0x72, 0x6B, 0x95, 0x1D, 0x4E,
+		0x18, 0x42, 0x95, 0x78, 0xCC, 0x37, 0x3C, 0x91, 0xE2, 0x9B, 0x65, 0x2B,
+		0x29, 0xA3, 0x42, 0x30, 0x40, 0x30, 0x1D, 0x06, 0x03, 0x55, 0x1D, 0x0E,
+		0x04, 0x16, 0x04, 0x14, 0x9A, 0xAF, 0x29, 0x7A, 0xC0, 0x11, 0x35, 0x35,
+		0x26, 0x51, 0x30, 0x00, 0xC3, 0x6A, 0xFE, 0x40, 0xD5, 0xAE, 0xD6, 0x3C,
+		0x30, 0x0F, 0x06, 0x03, 0x55, 0x1D, 0x13, 0x01, 0x01, 0xFF, 0x04, 0x05,
+		0x30, 0x03, 0x01, 0x01, 0xFF, 0x30, 0x0E, 0x06, 0x03, 0x55, 0x1D, 0x0F,
+		0x01, 0x01, 0xFF, 0x04, 0x04, 0x03, 0x02, 0x01, 0x06,
+	}
+
+	b, _ := RawSerialBytes(tbsCertPrefix)
+	if !bytes.Equal(b, []byte{0x74, 0x97, 0x25, 0x8A, 0xC7, 0x3F, 0x7A, 0x54}) {
 		t.Errorf("error")
 	}
 }
diff --git a/go.mod b/go.mod
index c5a86b5..32c94d5 100644
--- a/go.mod
+++ b/go.mod
@@ -16,6 +16,7 @@ require (
 	github.com/termie/go-shutil v0.0.0-20140729215957-bcacb06fecae
 	github.com/wellington/go-libsass v0.9.2
 	golang.org/x/crypto v0.0.0-20200728195943-123391ffb6de
+	golang.org/x/sys v0.0.0-20220708085239-5a0f0661e09d // indirect
 	gopkg.in/yaml.v2 v2.3.0
 )
 
diff --git a/go.sum b/go.sum
index eeb3b13..13ba177 100644
--- a/go.sum
+++ b/go.sum
@@ -46,6 +46,8 @@ golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/p
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd h1:xhmwyvizuTgC2qz7ZlMluP20uW+C3Rm0FD/WLDX8884=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20220708085239-5a0f0661e09d h1:/m5NbqQelATgoSPVC2Z23sR4kVNokFwDDyWh/3rGY+I=
+golang.org/x/sys v0.0.0-20220708085239-5a0f0661e09d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=