From 58fc4dead559901cad648fb695f31d0f6de9945a Mon Sep 17 00:00:00 2001
From: blackshirt <blackshirt@users.noreply.github.com>
Date: Thu, 21 Nov 2024 18:05:00 +0700
Subject: [PATCH] x.encoding.asn1: clean up the source code of the module after
 the recent compiler changes and bugfixes (#22932)

---
 vlib/x/encoding/asn1/bitstring.v          |  12 +-
 vlib/x/encoding/asn1/boolean.v            |   6 +-
 vlib/x/encoding/asn1/boolean_test.v       |   4 -
 vlib/x/encoding/asn1/core.v               |  23 ---
 vlib/x/encoding/asn1/element.v            |  24 ---
 vlib/x/encoding/asn1/element_decode.v     |  21 +--
 vlib/x/encoding/asn1/element_encode.v     |   3 +-
 vlib/x/encoding/asn1/errors.v             |  50 ------
 vlib/x/encoding/asn1/examples/examples0.v |  41 ++---
 vlib/x/encoding/asn1/examples/examples2.v |  31 +---
 vlib/x/encoding/asn1/examples/examples3.v |   2 +-
 vlib/x/encoding/asn1/extra0_test.v        | 115 ------------
 vlib/x/encoding/asn1/extra1_test.v        | 207 ----------------------
 vlib/x/encoding/asn1/integer.v            |  14 ++
 vlib/x/encoding/asn1/null.v               |  13 +-
 vlib/x/encoding/asn1/oid.v                |   7 +-
 vlib/x/encoding/asn1/oid_test.v           |   2 +-
 vlib/x/encoding/asn1/other_element.v      |   6 +-
 vlib/x/encoding/asn1/sequence_test.v      |  12 +-
 vlib/x/encoding/asn1/set_test.v           |   4 +-
 vlib/x/encoding/asn1/tagged_test.v        |   4 +-
 21 files changed, 62 insertions(+), 539 deletions(-)
 delete mode 100644 vlib/x/encoding/asn1/errors.v
 delete mode 100644 vlib/x/encoding/asn1/extra0_test.v
 delete mode 100644 vlib/x/encoding/asn1/extra1_test.v

diff --git a/vlib/x/encoding/asn1/bitstring.v b/vlib/x/encoding/asn1/bitstring.v
index 6c371b95d..0cf318b6c 100644
--- a/vlib/x/encoding/asn1/bitstring.v
+++ b/vlib/x/encoding/asn1/bitstring.v
@@ -25,6 +25,16 @@ mut:
 	pad  u8 // numbers of unused bits
 }
 
+// data returns underlying BitString data.
+pub fn (bs BitString) data() []u8 {
+	return bs.data
+}
+
+// pad returns underlying BitString pad byte.
+pub fn (bs BitString) pad() u8 {
+	return bs.pad
+}
+
 // check performs check internal validity of the BitString data.
 fn (bs BitString) check() ! {
 	// to align with octet size, ie, 8 in length, pad bits only need maximum 7 bits
@@ -147,7 +157,7 @@ fn (bs BitString) bytes_len() int {
 // Utility function
 
 // maximum allowed binary bits string length
-const max_bitstring_len = 8192
+const max_bitstring_len = 65536
 
 // valid_bitstring checks whether this s string is a valid of arrays of binary string `0` and `1`.
 fn valid_bitstring(s string) bool {
diff --git a/vlib/x/encoding/asn1/boolean.v b/vlib/x/encoding/asn1/boolean.v
index 3852908eb..f90d6049c 100644
--- a/vlib/x/encoding/asn1/boolean.v
+++ b/vlib/x/encoding/asn1/boolean.v
@@ -62,12 +62,8 @@ fn (b Boolean) payload_with_rule(rule EncodingRule) ![]u8 {
 	return [b.value]
 }
 
-fn parse_boolean(mut p Parser) !Boolean {
-	return Boolean.parse(mut p)!
-}
-
 // parse tries to read a Boolean type from parser or return error on fails
-fn Boolean.parse(mut p Parser) !Boolean {
+pub fn Boolean.parse(mut p Parser) !Boolean {
 	tag := p.read_tag()!
 	if !tag.equal(default_boolean_tag) {
 		return error('Get unexpected non boolean tag')
diff --git a/vlib/x/encoding/asn1/boolean_test.v b/vlib/x/encoding/asn1/boolean_test.v
index 3aa3bd4bf..a26056741 100644
--- a/vlib/x/encoding/asn1/boolean_test.v
+++ b/vlib/x/encoding/asn1/boolean_test.v
@@ -36,10 +36,6 @@ fn test_parse_boolean_with_parser() ! {
 	// out := p.read_element[Boolean]()!
 	// assert out.str() == 'Boolean (TRUE)'
 
-	// this is OK
-	out_2nd := parse[Boolean](data, parse_boolean)!
-	assert out_2nd.str() == 'Boolean (TRUE)'
-
 	// THis is ok
 	mut p2 := Parser.new(data)
 	out_3th := Boolean.parse(mut p2)!
diff --git a/vlib/x/encoding/asn1/core.v b/vlib/x/encoding/asn1/core.v
index 312e5baa0..c88d39373 100644
--- a/vlib/x/encoding/asn1/core.v
+++ b/vlib/x/encoding/asn1/core.v
@@ -210,11 +210,6 @@ fn (t Tag) str() string {
 	return '${cls}-${form}-${number}'
 }
 
-// uniqid_with_id the id of this tag for special purposes identifying in decode
-fn (t Tag) uniqid_with_id(id string) string {
-	return '${t.str()}-${id}'
-}
-
 // bytes_len tells amount of bytes needed to store tag in base 128
 fn (t Tag) bytes_len() int {
 	if t.number == 0 {
@@ -525,24 +520,6 @@ fn universal_tag_from_int(v int) !Tag {
 	}
 }
 
-// Params is optional params passed to encode or decodeing
-// of tag, length or ASN.1 element to drive how encoding works.
-@[params]
-struct Params {
-mut:
-	rule EncodingRule = .der
-}
-
-fn default_params() &Params {
-	return &Params{}
-}
-
-fn params_with_rule(rule EncodingRule) &Params {
-	return &Params{
-		rule: .der
-	}
-}
-
 // EncodingRule is standard of rule thats drives how some ASN.1
 // element was encoded or deserialized.
 pub enum EncodingRule {
diff --git a/vlib/x/encoding/asn1/element.v b/vlib/x/encoding/asn1/element.v
index e5f4aeb75..4a39ec174 100644
--- a/vlib/x/encoding/asn1/element.v
+++ b/vlib/x/encoding/asn1/element.v
@@ -224,11 +224,6 @@ fn (el Element) equal_payload(other Element) bool {
 	return constant_time_compare(x, y) == 1
 }
 
-fn Element.parse(mut p Parser) !Element {
-	el := p.read_tlv()!
-	return el
-}
-
 fn Element.decode(src []u8) !(Element, int) {
 	el, pos := Element.decode_with_rule(src, 0, .der)!
 	return el, pos
@@ -305,22 +300,3 @@ pub fn ElementList.from_bytes(src []u8) ![]Element {
 	}
 	return els
 }
-
-// Utility function
-//
-// is_element check whethers T is fullfills Element
-fn is_element[T]() bool {
-	s := $if T is Element { true } $else { false }
-	return s
-}
-
-fn has_tag_method[T]() bool {
-	$for method in T.methods {
-		$if method.name == 'tag' {
-			$if method.return_type is Tag {
-				return true
-			}
-		}
-	}
-	return false
-}
diff --git a/vlib/x/encoding/asn1/element_decode.v b/vlib/x/encoding/asn1/element_decode.v
index e901ac095..82afa218d 100644
--- a/vlib/x/encoding/asn1/element_decode.v
+++ b/vlib/x/encoding/asn1/element_decode.v
@@ -151,7 +151,7 @@ pub fn (el Element) unwrap_with_field_options(fo FieldOptions) !Element {
 		// checks inner tag from payload
 		tag, _ := Tag.decode_with_rule(el.payload()!, 0, .der)!
 		if !tag.equal(inner_tag) {
-			asn1_error(.unexpected_tag_value, 'Get unexpected inner tag from payload')!
+			return error('Get unexpected inner tag from payload')
 		}
 	}
 	inner_form := inner_tag.constructed
@@ -177,25 +177,6 @@ pub fn (el Element) unwrap_with_field_options(fo FieldOptions) !Element {
 
 // unwrap the provided element, turn into inner element.
 fn unwrap(el Element, mode TaggedMode, inner_tag Tag) !Element {
-	if el.tag().class == .universal {
-		return error('you cant unwrap universal element')
-	}
-	if mode == .explicit {
-		if !el.tag().constructed {
-			return error('explicit mode should have constructed tag')
-		}
-		// checks inner tag within payload
-		tag, _ := Tag.decode_with_rule(el.payload()!, 0, .der)!
-		if !tag.equal(inner_tag) {
-			asn1_error(.unexpected_tag_value, 'Get unexpected inner tag from payload')!
-		}
-	}
-	if mode == .implicit {
-		// the form should derived from inner element
-		if el.tag().constructed != inner_tag.constructed {
-			return error('Different form between element and provided inner_tag')
-		}
-	}
 	match mode {
 		.explicit {
 			// el.payload is serialized of inner element
diff --git a/vlib/x/encoding/asn1/element_encode.v b/vlib/x/encoding/asn1/element_encode.v
index d25ede7a5..fcfa2a016 100644
--- a/vlib/x/encoding/asn1/element_encode.v
+++ b/vlib/x/encoding/asn1/element_encode.v
@@ -19,7 +19,8 @@ module asn1
 // assert out == [u8(0x0C), 0x02, 0x68, 0x69]
 // ```
 pub fn encode(el Element) ![]u8 {
-	return encode_with_options(el, '')!
+	// without options, we call `.encode_with_rule` directly on element.
+	return encode_with_rule(el, .der)!
 }
 
 // `encode_with_options` serializes element into bytes array with options string passed to drive the result.
diff --git a/vlib/x/encoding/asn1/errors.v b/vlib/x/encoding/asn1/errors.v
deleted file mode 100644
index cf872dd57..000000000
--- a/vlib/x/encoding/asn1/errors.v
+++ /dev/null
@@ -1,50 +0,0 @@
-module asn1
-
-// Unified error handling
-//
-enum ErrorKind {
-	// vfmt off
-	unexpected_tag_value 	= 0
-	unexpected_length_value	= 1
-	unexpected_limit_exceed	= 2
-	unexpected_bytes_data	= 3
-	unexpected_bytes_offset	= 4
-	unsupported_rule		= 5
-	unsupported_format		= 6
-	unexpected_value		= 7
-	unmeet_requirement		= 8
-	unallowed_operation		= 9
-	// vfmt on
-}
-
-fn (ek ErrorKind) str() string {
-	match ek {
-		.unexpected_tag_value { return 'unexpected_tag_value' }
-		.unexpected_length_value { return 'unexpected_length_value' }
-		.unexpected_limit_exceed { return 'unexpected_limit_exceed' }
-		.unexpected_bytes_data { return 'unexpected_bytes_data' }
-		.unexpected_bytes_offset { return 'unexpected_bytes_offset' }
-		.unsupported_rule { return 'unsupported_rule' }
-		.unsupported_format { return 'unsupported_format' }
-		.unexpected_value { return 'unexpected_value' }
-		.unmeet_requirement { return 'unmeet_requirement' }
-		.unallowed_operation { return 'unallowed_operation' }
-	}
-}
-
-struct Asn1Error {
-	Error
-	kind ErrorKind
-	msg  string
-}
-
-fn (er Asn1Error) msg() string {
-	return 'Error: ${er.kind.str()} with error ${er.msg}'
-}
-
-fn asn1_error(kind ErrorKind, msg string) !Asn1Error {
-	return Asn1Error{
-		kind: kind
-		msg:  msg
-	}
-}
diff --git a/vlib/x/encoding/asn1/examples/examples0.v b/vlib/x/encoding/asn1/examples/examples0.v
index 52a58d654..67592d996 100644
--- a/vlib/x/encoding/asn1/examples/examples0.v
+++ b/vlib/x/encoding/asn1/examples/examples0.v
@@ -2,35 +2,16 @@ module main
 
 import x.encoding.asn1
 
-// defined type KerberosString = asn1.GeneralString directly
-// produces x00000000: at ???: RUNTIME ERROR: invalid memory access
-// /tmp/v_0/examples_0.01JBJNNT0EJVN2FRKJ3ZM83EC9.tmp.c:22858: by asn1__Element_encode_with_options
-// /tmp/v_0/examples_0.01JBJNNT0EJVN2FRKJ3ZM83EC9.tmp.c:22838: by asn1__encode_with_options
-// /tmp/v_0/examples_0.01JBJNNT0EJVN2FRKJ3ZM83EC9.tmp.c:22825: by asn1__encode
-// /tmp/v_0/examples_0.01JBJNNT0EJVN2FRKJ3ZM83EC9.tmp.c:28683: by main__KerberosStringList_payload
-// /tmp/v_0/examples_0.01JBJNNT0EJVN2FRKJ3ZM83EC9.tmp.c:4319: by main__KerberosStringList_payload_Interface_asn1__Element_method_wrapper
-struct KerberosString {
-	val asn1.GeneralString
-}
-
-fn (k KerberosString) tag() asn1.Tag {
-	return asn1.default_generalstring_tag
-}
+// Previously, defined type KerberosString = asn1.GeneralString directly
+// without reduplicating required Element methods, would produces
+// RUNTIME ERROR: invalid memory access.
+// **Updates**
+// Its has been resolved in [22901](https://github.com/vlang/v/issues/22901)
+// Thanks to @felipensp
+type KerberosString = asn1.GeneralString
 
 fn KerberosString.new(s string) !KerberosString {
-	return KerberosString{
-		val: asn1.GeneralString.new(s)!
-	}
-}
-
-fn KerberosString.from_bytes(b []u8) !KerberosString {
-	return KerberosString{
-		val: asn1.GeneralString.new(b.bytestr())!
-	}
-}
-
-fn (k KerberosString) payload() ![]u8 {
-	return k.val.payload()!
+	return KerberosString(asn1.GeneralString.new(s)!)
 }
 
 type KerberosStringList = []KerberosString
@@ -70,9 +51,7 @@ fn (pn PrincipalName) tag() asn1.Tag {
 }
 
 fn (pn PrincipalName) payload() ![]u8 {
-	kd := asn1.KeyDefault(map[string]asn1.Element{})
-	// there are some issues with make_payload when your structure contains generic.
-	// see https://github.com/vlang/v/issues/22721
+	kd := asn1.new_key_default()
 	payload := asn1.make_payload[PrincipalName](pn, kd)!
 	return payload
 }
@@ -100,7 +79,7 @@ fn PrincipalName.decode(bytes []u8) !PrincipalName {
 	mut a := []KerberosString{}
 	for item in el_seq.fields() {
 		gst := item.into_object[asn1.GeneralString]()!
-		obj := KerberosString{gst}
+		obj := KerberosString(gst)
 		a << obj
 	}
 
diff --git a/vlib/x/encoding/asn1/examples/examples2.v b/vlib/x/encoding/asn1/examples/examples2.v
index e52f068c8..4fe6f05a8 100644
--- a/vlib/x/encoding/asn1/examples/examples2.v
+++ b/vlib/x/encoding/asn1/examples/examples2.v
@@ -166,33 +166,13 @@ fn EmployeeNumber.new(val asn1.Integer) !asn1.ApplicationElement {
 	return asn1.ApplicationElement.from_element(val, 2, .implicit)!
 }
 
-// Issues: without defines this required tag and payload, this leads into panic RUNTIME ERROR
-// 0x00000000: at ???: RUNTIME ERROR: invalid memory access
-fn (e EmployeeNumber) tag() asn1.Tag {
-	return e.RawElement.tag()
-}
-
-fn (e EmployeeNumber) payload() ![]u8 {
-	return e.RawElement.payload()!
-}
-
-// // Date ::= [APPLICATION 3] IMPLICIT VisibleString -- YYYYMMDD
+// Date ::= [APPLICATION 3] IMPLICIT VisibleString -- YYYYMMDD
 type Date = asn1.ApplicationElement
 
 fn Date.new(val asn1.VisibleString) !asn1.ApplicationElement {
 	return asn1.ApplicationElement.from_element(val, 3, .implicit)!
 }
 
-// Issues: without defines this required tag and payload, this leads into panic RUNTIME ERROR
-// 0x00000000: at ???: RUNTIME ERROR: invalid memory access
-fn (d Date) tag() asn1.Tag {
-	return d.RawElement.tag()
-}
-
-fn (d Date) payload() ![]u8 {
-	return d.RawElement.payload()!
-}
-
 // Name ::= [APPLICATION 1] IMPLICIT SEQUENCE {
 //      givenName       VisibleString,
 //      initial         VisibleString,
@@ -204,15 +184,6 @@ fn Name.new(el NameEntry) !asn1.ApplicationElement {
 	return asn1.ApplicationElement.from_element(el, 1, .implicit)!
 }
 
-// Issues: without defines this required tag and payload, this leads into panic RUNTIME ERROR
-fn (n Name) tag() asn1.Tag {
-	return n.RawElement.tag()
-}
-
-fn (n Name) payload() ![]u8 {
-	return n.RawElement.payload()!
-}
-
 struct NameEntry {
 	given_name  asn1.VisibleString
 	initial     asn1.VisibleString
diff --git a/vlib/x/encoding/asn1/examples/examples3.v b/vlib/x/encoding/asn1/examples/examples3.v
index 139feac64..b356b1aed 100644
--- a/vlib/x/encoding/asn1/examples/examples3.v
+++ b/vlib/x/encoding/asn1/examples/examples3.v
@@ -58,7 +58,7 @@ fn Example.decode(bytes []u8) !Example {
 	oid_tipe := fields[2].unwrap_with_options('context_specific:1;explicit; inner:6')!
 	tipe := oid_tipe.into_object[asn1.ObjectIdentifier]()!
 
-	// then build your Example struc
+	// then build your Example structure
 	ex := Example{
 		greeting: greeting
 		answer:   answer
diff --git a/vlib/x/encoding/asn1/extra0_test.v b/vlib/x/encoding/asn1/extra0_test.v
deleted file mode 100644
index 35138ce27..000000000
--- a/vlib/x/encoding/asn1/extra0_test.v
+++ /dev/null
@@ -1,115 +0,0 @@
-module asn1
-
-import math.big
-
-fn test_parse_sequence_match_length() ! {
-	// from https://en.wikipedia.org/wiki/ASN.1#Example_encoded_in_DER
-	data := [u8(0x30), 0x13, 0x02, 0x01, 0x05, 0x16, 0x0e, 0x41, 0x6e, 0x79, 0x62, 0x6f, 0x64,
-		0x79, 0x20, 0x74, 0x68, 0x65, 0x72, 0x65, 0x3f]
-
-	seq, n := Sequence.decode(data)!
-	assert n == data.len
-	assert seq.payload()!.len == 19 // 0x13
-	assert encoded_len(seq) == 21
-	assert seq.tag().tag_class() == .universal
-	assert seq.tag().is_constructed() == true
-	assert seq.tag().tag_number() == 16
-
-	els := seq.fields()
-	assert els.len == 2
-	assert els[0] is Integer
-	assert els[1] is IA5String
-
-	assert els[0].tag().tag_number() == int(TagType.integer)
-	assert els[1].tag().tag_number() == int(TagType.ia5string)
-	assert els[1].payload()! == 'Anybody there?'.bytes()
-
-	/*
-	30 — type tag indicating SEQUENCE
-		13 — length in octets of value that follows
-  			02 — type tag indicating INTEGER
-  				01 — length in octets of value that follows
-    			05 — value (5)
- 			16 — type tag indicating IA5String
-     			(IA5 means the full 7-bit ISO 646 set, including variants,
-      			but is generally US-ASCII)
-  				0e — length in octets of value that follows
-    			41 6e 79 62 6f 64 79 20 74 68 65 72 65 3f — value ("Anybody there?")
-	*/
-}
-
-/*
-Certificate  ::=  SEQUENCE  {
-        tbsCertificate       TBSCertificate,
-        signatureAlgorithm   AlgorithmIdentifier,
-        signatureValue       BIT STRING  }
-
-TBSCertificate  ::=  SEQUENCE  {
-     version         [0]  EXPLICIT Version DEFAULT v1,
-     serialNumber         CertificateSerialNumber,
-     signature            AlgorithmIdentifier,
-     issuer               Name,SubjectPublicKeyInfo
-     validity             Validity,
-     subject              Name,
-     subjectPublicKeyInfo SubjectPublicKeyInfo,
-     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
-                          -- If present, version MUST be v2 or v3
-     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
-                          -- If present, version MUST be v2 or v3
-     extensions      [3]  EXPLICIT Extensions OPTIONAL
-                          -- If present, version MUST be v3 }
-
-Validity ::= SEQUENCE {
-     notBefore      Time,
-     notAfter       Time }
-
-AlgorithmIdentifier  ::=  SEQUENCE  {
-        algorithm   OBJECT IDENTIFIER,
-        parameters  ANY DEFINED BY algorithm OPTIONAL
-      }
-*/
-
-// FIXED: NOTE: Need to be fixed
-fn test_x509_certificate_version() ! {
-	// version         [0]  EXPLICIT Version DEFAULT v1,
-	// Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
-	val := Integer.from_int(2)
-	version := ContextElement.explicit_context(val, 0)!
-
-	out := encode(version)!
-	exp := [u8(0xA0), 0x03, 0x02, 0x01, 0x02]
-
-	assert out == exp
-}
-
-fn test_x509_certificate_signature() ! {
-	// signature            AlgorithmIdentifier,
-	// AlgorithmIdentifier  ::=  SEQUENCE  {
-	//    algorithm   OBJECT IDENTIFIER,
-	//    parameters  ANY DEFINED BY algorithm OPTIONAL
-	//  }
-	oid := ObjectIdentifier.new('1.3.101.112')!
-
-	mut seq := Sequence{}
-	seq.add_element(oid)!
-
-	out := encode(seq)!
-	exp := [u8(0x30), 0x05, 0x06, 0x03, 0x2B, 0x65, 0x70]
-
-	assert out == exp
-	seqback := decode(exp)!
-
-	assert seqback.equal(seq)
-}
-
-fn test_x509_certificate_serialnumber() ! {
-	// serialNumber         CertificateSerialNumber,
-	// CertificateSerialNumber  ::=  INTEGER
-	sn := Integer.from_bigint(big.integer_from_string('711090297755414526861352146244170174161660335942')!)
-
-	mut out := encode(sn)!
-	exp := [u8(0x02), 0x14, 0x7C, 0x8E, 0x64, 0x49, 0xD7, 0x0E, 0xD9, 0x2D, 0x3E, 0x2E, 0x4A, 0x5D,
-		0x2F, 0x76, 0xF6, 0x55, 0x42, 0x46, 0xD7, 0x46]
-
-	assert out == exp
-}
diff --git a/vlib/x/encoding/asn1/extra1_test.v b/vlib/x/encoding/asn1/extra1_test.v
deleted file mode 100644
index dc4206796..000000000
--- a/vlib/x/encoding/asn1/extra1_test.v
+++ /dev/null
@@ -1,207 +0,0 @@
-module asn1
-
-import encoding.hex
-import crypto.pem
-
-fn test_rsa_public_key() ! {
-	// from https://asecuritysite.com/digitalcert/sigs4cd
-	/*
-       // from https://asecuritysite.com/ecc/sigs4?a0=30819f300d06092a864886f70d010101050003818d0030818902818100a399caf6d93b62a6b6a5311efe93c4d647397ca05a98fa5cddb72d6816ab16fc85f940efe9cf2233975c8925c60f4cd356767cc8445686313a0caeae32930070ca90591a1b249c2fcef9280f5a11d8f1990579d86a05b2523f52c4a876da2d635ca27fbff195e6f7015f834928f033a20b2cd0216a852958b3e58d0f9bd542330203010001
-	DER: 30819f300d06092a864886f70d010101050003818d0030818902818100a399caf6d93b62a6b6a5311efe93c4d647397ca05a98fa5cddb72d6816ab16fc85f940efe9cf2233975c8925c60f4cd356767cc8445686313a0caeae32930070ca90591a1b249c2fcef9280f5a11d8f1990579d86a05b2523f52c4a876da2d635ca27fbff195e6f7015f834928f033a20b2cd0216a852958b3e58d0f9bd542330203010001
-
-[U] SEQUENCE (30)
-  [U] SEQUENCE (30)
-    [U] OBJECT (06): 1.2.840.113549.1.1.1 - RSA Encryption
-    [U] NULL: None
-  [U] BIT STRING (03): 0xb'0030818902818100A399CAF6D93B62A6B6A5311EFE93C4D647397CA05A98FA5CDDB72D6816AB16FC85F940EFE9CF2233975C8925C60F4CD356767CC8445686313A0CAEAE32930070CA90591A1B249C2FCEF9280F5A11D8F1990579D86A05B2523F52C4A876DA2D635CA27FBFF195E6F7015F834928F033A20B2CD0216A852958B3E58D0F9BD542330203010001'
-81
-  RSA Modulus (1024) bits: a399caf6d93b62a6b6a5311efe93c4d647397ca05a98fa5cddb72d6816ab16fc85f940efe9cf2233975c8925c60f4cd356767cc8445686313a0caeae32930070ca90591a1b249c2fcef9280f5a11d8f1990579d86a05b2523f52c4a876da2d635ca27fbff195e6f7015f834928f033a20b2cd0216a852958b3e58d0f9bd54233
-RSA e: 10001
-
------BEGIN PUBLIC KEY-----
-MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCjmcr22TtipralMR7+k8TWRzl8oFqY+lzdty1oFqsW/IX5QO/pzyIzl1yJJcYPTNNWdnzIRFaGMToMrq4ykwBwypBZGhsknC/O+SgPWhHY8ZkFedhqBbJSP1LEqHbaLWNcon+/8ZXm9wFfg0ko8DOiCyzQIWqFKViz5Y0Pm9VCMwIDAQAB
------END PUBLIC KEY-----
-	*/
-	data := '30819f300d06092a864886f70d010101050003818d0030818902818100a399caf6d93b62a6b6a5311efe93c4d647397ca05a98fa5cddb72d6816ab16fc85f940efe9cf2233975c8925c60f4cd356767cc8445686313a0caeae32930070ca90591a1b249c2fcef9280f5a11d8f1990579d86a05b2523f52c4a876da2d635ca27fbff195e6f7015f834928f033a20b2cd0216a852958b3e58d0f9bd542330203010001'
-
-	bytes := hex.decode(data)!
-	seq, n := Sequence.decode(bytes)!
-
-	els := seq.fields()
-	assert els.len == 2
-	assert els[0] is Sequence
-	assert els[1] is BitString
-
-	els0 := els[0] as Sequence
-	assert els0.fields.len == 2
-	assert els0.fields[0] is ObjectIdentifier
-	oid := els0.fields[0] as ObjectIdentifier
-	assert oid.str() == 'OID (1.2.840.113549.1.1.1)'
-	assert els0.fields[1] is Null
-}
-
-// NOTE: Need to be fixed
-fn test_x25519_private_key() ! {
-	// taken from https://www.rfc-editor.org/rfc/rfc8410#section-10
-	// 10.3 Examples of Ed25519 Private Key
-
-	data := '-----BEGIN PRIVATE KEY-----
-MC4CAQAwBQYDK2VwBCIEINTuctv5E1hK1bbY8fdp+K06/nwoy/HU++CXqI9EdVhC
------END PRIVATE KEY-----'
-
-	// The same item dumped as asn1 yields:
-	/*
-	0 30   46: SEQUENCE {
- 	2 02    1:   INTEGER 0
-	5 30    5:   SEQUENCE {
- 	7 06    3:     OBJECT IDENTIFIER
-          :       Ed 25519 signature algorithm { 1 3 101 112 }
-          :     }
-	12 04   34:   OCTET STRING
-          :     04 20 D4 EE 72 DB F9 13 58 4A D5 B6 D8 F1 F7 69
-          :     F8 AD 3A FE 7C 28 CB F1 D4 FB E0 97 A8 8F 44 75
-          :     58 42
-          :   }
-	*/
-	block, _ := pem.decode(data)?
-
-	seq, n := Sequence.decode(block.data)!
-
-	assert seq.payload()!.len == 46
-
-	els := seq.fields()
-	assert els[0] is Integer
-	assert els[1] is Sequence
-	b := els[1] as Sequence
-
-	assert b.fields()[0] is ObjectIdentifier
-	assert b.fields()[0].length()! == 3
-
-	oid := b.fields()[0] as ObjectIdentifier
-	assert oid.str() == 'OID (1.3.101.112)'
-
-	assert els[2] is OctetString
-	assert els[2].payload()!.len == 34
-}
-
-/*
-// NEED TO BE FIXED
-// TODO: This test still failed on `Sequence.parse_contents` with error `next: truncated bytes`
-// FIXME: need to be investigated, bad data, or sequence handling or others source of fail
-// so just disable this test, would be moved into related module when ready
-fn test_example_x25519_certificate() {
-	// taken from https://www.rfc-editor.org/rfc/rfc8410.html#section-10
-	// 10.2.  Example X25519 Certificate
-	data := '-----BEGIN CERTIFICATE-----
-MIIBLDCB36ADAgECAghWAUdKKo3DMDAFBgMrZXAwGTEXMBUGA1UEAwwOSUVURiBUZX
-N0IERlbW8wHhcNMTYwODAxMTIxOTI0WhcNNDAxMjMxMjM1OTU5WjAZMRcwFQYDVQQD
-DA5JRVRGIFRlc3QgRGVtbzAqMAUGAytlbgMhAIUg8AmJMKdUdIt93LQ+91oNvzoNJj
-ga9OukqY6qm05qo0UwQzAPBgNVHRMBAf8EBTADAQEAMA4GA1UdDwEBAAQEAwIDCDAg
-BgNVHQ4BAQAEFgQUmx9e7e0EM4Xk97xiPFl1uQvIuzswBQYDK2VwA0EAryMB/t3J5v
-/BzKc9dNZIpDmAgs3babFOTQbs+BolzlDUwsPrdGxO3YNGhW7Ibz3OGhhlxXrCe1Cg
-w1AH9efZBw==
------END CERTIFICATE-----'
-
-	// The same item dumped as asn1 yields:
-	/*
-	0 300: SEQUENCE {
-     4 223:   SEQUENCE {
-     7   3:     [0] {
-     9   1:       INTEGER 2
-          :       }
-    12   8:     INTEGER 56 01 47 4A 2A 8D C3 30
-    22   5:     SEQUENCE {
-    24   3:       OBJECT IDENTIFIER
-          :         Ed 25519 signature algorithm { 1 3 101 112 }
-          :       }
-    29  25:     SEQUENCE {
-    31  23:       SET {
-    33  21:         SEQUENCE {
-    35   3:           OBJECT IDENTIFIER commonName (2 5 4 3)
-    40  14:           UTF8String 'IETF Test Demo'
-          :           }
-          :         }
-          :       }
-    56  30:     SEQUENCE {
-    58  13:       UTCTime 01/08/2016 12:19:24 GMT
-    73  13:       UTCTime 31/12/2040 23:59:59 GMT
-          :       }
-    88  25:     SEQUENCE {
-    90  23:       SET {
-    92  21:         SEQUENCE {
-    94   3:           OBJECT IDENTIFIER commonName (2 5 4 3)
-    99  14:           UTF8String 'IETF Test Demo'
-          :           }
-          :         }
-          :       }
-   115  42:     SEQUENCE {
-   117   5:       SEQUENCE {
-   119   3:         OBJECT IDENTIFIER
-          :           ECDH 25519 key agreement { 1 3 101 110 }
-          :         }
-   124  33:       BIT STRING
-          :         85 20 F0 09 89 30 A7 54 74 8B 7D DC B4 3E F7 5A
-          :         0D BF 3A 0D 26 38 1A F4 EB A4 A9 8E AA 9B 4E 6A
-          :       }
-   159  69:     [3] {
-   161  67:       SEQUENCE {
-   163  15:         SEQUENCE {
-   165   3:           OBJECT IDENTIFIER basicConstraints (2 5 29 19)
- 170   1:           BOOLEAN TRUE
-   173   5:           OCTET STRING, encapsulates {
-   175   3:             SEQUENCE {
-   177   1:               BOOLEAN FALSE
-          :               }
-          :             }
-          :           }
-   180  14:         SEQUENCE {
-   182   3:           OBJECT IDENTIFIER keyUsage (2 5 29 15)
-   187   1:           BOOLEAN FALSE
-   190   4:           OCTET STRING, encapsulates {
-   192   2:             BIT STRING 3 unused bits
-          :               '10000'B (bit 4)
-          :             }
-          :           }
-   196  32:         SEQUENCE {
-   198   3:           OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14)
-   203   1:           BOOLEAN FALSE
-   206  22:           OCTET STRING, encapsulates {
-   208  20:             OCTET STRING
-          :               9B 1F 5E ED ED 04 33 85 E4 F7 BC 62 3C 59 75
-          :               B9 0B C8 BB 3B
-          :             }
-          :           }
-          :         }
-          :       }
-          :     }
-   230   5:   SEQUENCE {
-   232   3:     OBJECT IDENTIFIER
-          :       Ed 25519 signature algorithm { 1 3 101 112 }
-          :     }
-   237  65:   BIT STRING
-          :     AF 23 01 FE DD C9 E6 FF C1 CC A7 3D 74 D6 48 A4
-          :     39 80 82 CD DB 69 B1 4E 4D 06 EC F8 1A 25 CE 50
-          :     D4 C2 C3 EB 74 6C 4E DD 83 46 85 6E C8 6F 3D CE
-          :     1A 18 65 C5 7A C2 7B 50 A0 C3 50 07 F5 E7 D9 07
-          :   }
-	*/
-	block, _ := pem.decode(data)?
-	seq, n := Sequence.decode(block.data)!
-
-	assert seq.payload()!.len == 302
-
-	// certificate is arrays of 3 element
-	assert seq.fields().len == 3
-
-	els := seq.fields()
-	// last element
-	assert els[2] is BitString
-	bts := BitString.from_bytes(seq.fields[2].payload()!)!
-	exp := [u8(0xAF), 0x23, 0x01, 0xFE, 0xDD, 0xC9, 0xE6, 0xFF, 0xC1, 0xCC, 0xA7, 0x3D, 0x74, 0xD6,
-		0x48, 0xA4, 0x39, 0x80, 0x82, 0xCD, 0xDB, 0x69, 0xB1, 0x4E, 0x4D, 0x06, 0xEC, 0xF8, 0x1A,
-		0x25, 0xCE, 0x50, 0xD4, 0xC2, 0xC3, 0xEB, 0x74, 0x6C, 0x4E, 0xDD, 0x83, 0x46, 0x85, 0x6E,
-		0xC8, 0x6F, 0x3D, 0xCE, 0x1A, 0x18, 0x65, 0xC5, 0x7A, 0xC2, 0x7B, 0x50, 0xA0, 0xC3, 0x50,
-		0x07, 0xF5, 0xE7, 0xD9, 0x07]
-	assert bts.data == exp
-}
-*/
diff --git a/vlib/x/encoding/asn1/integer.v b/vlib/x/encoding/asn1/integer.v
index 6f89e2b09..7ba78cd1c 100644
--- a/vlib/x/encoding/asn1/integer.v
+++ b/vlib/x/encoding/asn1/integer.v
@@ -36,6 +36,20 @@ pub:
 	value IntValue
 }
 
+// hex returns Integer value as a hex string.
+pub fn (v Integer) hex() string {
+	match v.value {
+		i64 {
+			val := v.value as i64
+			return val.hex_full()
+		}
+		big.Integer {
+			val := v.value as big.Integer
+			return val.hex()
+		}
+	}
+}
+
 fn (v Integer) str() string {
 	return 'Integer ${v.value.str()}'
 }
diff --git a/vlib/x/encoding/asn1/null.v b/vlib/x/encoding/asn1/null.v
index a923a1efa..cac3c3feb 100644
--- a/vlib/x/encoding/asn1/null.v
+++ b/vlib/x/encoding/asn1/null.v
@@ -13,11 +13,6 @@ pub const default_null_tag = Tag{.universal, false, int(TagType.null)}
 // The NULL type can be used in situations where the presence of a type is important, but no concrete value is needed.
 pub struct Null {}
 
-// new creates a Null element.
-pub fn Null.new() Null {
-	return Null{}
-}
-
 // tag returns the tag of Null element.
 pub fn (n Null) tag() Tag {
 	return default_null_tag
@@ -42,9 +37,7 @@ fn Null.parse(mut p Parser) !Null {
 	if length != 0 {
 		return error('Get unexpected non-null length for Null type')
 	}
-	null := Null.new()
-
-	return null
+	return Null{}
 }
 
 // Null.decode read Null from bytes.
@@ -62,10 +55,6 @@ fn Null.decode(bytes []u8) !(Null, int) {
 }
 
 fn Null.from_bytes(b []u8) !Null {
-	return Null.from_bytes_with_rule(b, .der)!
-}
-
-fn Null.from_bytes_with_rule(b []u8, rule EncodingRule) !Null {
 	if b.len != 0 {
 		return error('Null: bad non-null bytes')
 	}
diff --git a/vlib/x/encoding/asn1/oid.v b/vlib/x/encoding/asn1/oid.v
index bd53f7198..c8c41b196 100644
--- a/vlib/x/encoding/asn1/oid.v
+++ b/vlib/x/encoding/asn1/oid.v
@@ -17,6 +17,11 @@ mut:
 	value []int
 }
 
+// value returns underlying ObjectIdentifier values as arrays of int.
+pub fn (o ObjectIdentifier) value() []int {
+	return o.value
+}
+
 // tag returns the tag of ObjectIdentifier type.
 pub fn (oid ObjectIdentifier) tag() Tag {
 	return default_oid_tag
@@ -179,7 +184,7 @@ fn (oid ObjectIdentifier) str() string {
 	}
 	res := s.join('.')
 
-	return 'OID (${res})'
+	return '${res}'
 }
 
 fn (oid ObjectIdentifier) validate() bool {
diff --git a/vlib/x/encoding/asn1/oid_test.v b/vlib/x/encoding/asn1/oid_test.v
index 2b21c534d..035d264e9 100644
--- a/vlib/x/encoding/asn1/oid_test.v
+++ b/vlib/x/encoding/asn1/oid_test.v
@@ -210,7 +210,7 @@ fn test_oid_encode_decode() ! {
 
 	oidback, _ := ObjectIdentifier.decode(out)!
 
-	assert oidback.str() == 'OID ' + '(${inp})'
+	assert oidback.str() == '${inp}'
 	assert oidback.tag().tag_number() == 6
 }
 
diff --git a/vlib/x/encoding/asn1/other_element.v b/vlib/x/encoding/asn1/other_element.v
index 747db01ae..267d213da 100644
--- a/vlib/x/encoding/asn1/other_element.v
+++ b/vlib/x/encoding/asn1/other_element.v
@@ -190,7 +190,7 @@ fn (mut r RawElement) set_default_value_with_flag(value Element, force bool) ! {
 
 // inner_tag returns the inner tag of the RawElement if it exists, or error on fails.
 pub fn (r RawElement) inner_tag() !Tag {
-	inner_tag := r.inner_tag or { return asn1_error(.unexpected_value, ' r.inner_tag is not set')! }
+	inner_tag := r.inner_tag or { return error(' r.inner_tag is not set') }
 
 	return inner_tag
 }
@@ -198,14 +198,14 @@ pub fn (r RawElement) inner_tag() !Tag {
 // inner_element returns the inner element of the RawElement if its exists.
 pub fn (r RawElement) inner_element() !Element {
 	if r.tag.class == .universal {
-		asn1_error(.unallowed_operation, 'inner element from universal class is not availables')!
+		return error('inner element from universal class is not availables')
 	}
 	mode := r.mode or { return err }
 	inner_tag := r.inner_tag or { return err }
 
 	if mode == .explicit {
 		if !r.tag.constructed {
-			asn1_error(.unmeet_requirement, 'tag should be constructed when in explicit')!
+			return error('tag should be constructed when in explicit')
 		}
 	}
 	// in implicit, r.content is inner element content with inner tag
diff --git a/vlib/x/encoding/asn1/sequence_test.v b/vlib/x/encoding/asn1/sequence_test.v
index 8a633cef9..3726c7ffe 100644
--- a/vlib/x/encoding/asn1/sequence_test.v
+++ b/vlib/x/encoding/asn1/sequence_test.v
@@ -33,7 +33,7 @@ fn test_sequence_contains_other_seq() ! {
 	mut seq1 := Sequence{}
 	// add two primitive elements to the sequence
 	seq1.add_element(Boolean.new(true))!
-	seq1.add_element(Null.new())!
+	seq1.add_element(Null{})!
 	seq1.add_element(Boolean.new(false))!
 
 	// lets create another sequences, where it contains primitive element and first sequence created above.
@@ -88,7 +88,7 @@ fn test_sequence_der_decode() ! {
 fn test_sequence_add_and_encode_boolean() {
 	o1 := Boolean.new(false)
 	o2 := Boolean.new(true)
-	o3 := Null.new()
+	o3 := Null{}
 	mut seq := Sequence{}
 	seq.add_element(o1)!
 	seq.add_element(o2)!
@@ -204,7 +204,7 @@ fn test_sequence_integer_bigint() ! {
 
 	o1 := Integer.from_bigint(inp)
 	o2 := Boolean.new(true)
-	o3 := Null.new()
+	o3 := Null{}
 	seq.add_element(o1)!
 	seq.add_element(o2)!
 	seq.add_element(o3)!
@@ -240,7 +240,7 @@ fn test_sequence_integer_bigint() ! {
 fn test_sequence_of_string() ! {
 	str := 'iloveyou' // 8
 	mut seq := Sequence.new()!
-	o1 := Null.new()
+	o1 := Null{}
 	o2 := Utf8String.new(str)!
 	o3 := IA5String.new(str)!
 	seq.add_element(o1)!
@@ -266,7 +266,7 @@ fn test_sequence_of_string() ! {
 fn test_sequnce_of_sequence() {
 	mut seq := Sequence.new()!
 
-	seq.add_element(Null.new())!
+	seq.add_element(Null{})!
 	seq.add_element(Boolean.new(false))!
 
 	mut out := encode(seq)!
@@ -338,7 +338,7 @@ fn test_sequence_algorithm_identifier() ! {
 		0x05, 0x00]
 	algo := AlgorithmIdentifier{
 		algorithm:  ObjectIdentifier.new('1.2.840.113549.1.1.11')!
-		parameters: AnyDefinedBy.new(Null.new())
+		parameters: AnyDefinedBy.new(Null{})
 	}
 	out := encode(algo)!
 	assert out == expected
diff --git a/vlib/x/encoding/asn1/set_test.v b/vlib/x/encoding/asn1/set_test.v
index 3bc0bd1f9..f6de8d3a9 100644
--- a/vlib/x/encoding/asn1/set_test.v
+++ b/vlib/x/encoding/asn1/set_test.v
@@ -9,7 +9,7 @@ fn test_sort_the_set() {
 	val12 := Integer.from_i64(12)
 	val32 := Integer.from_i64(32)
 	valbol := Boolean.new(false)
-	valnull := Null.new()
+	valnull := Null{}
 	valapp := RawElement.new(Tag{.application, false, 34}, [u8(44), 45])!
 	valctx := RawElement.new(Tag{.context_specific, false, 35}, [u8(50), 55])!
 
@@ -74,7 +74,7 @@ fn test_set_encode() ! {
 	mut set1 := Set.new()!
 
 	set1.add_element(Boolean.new(false))!
-	set1.add_element(Null.new())!
+	set1.add_element(Null{})!
 	set1.add_element(Integer.from_int(4))!
 	// boolean tag:1 length: 3, integer tag:2 length: 3, null tag: 5 length: 2, total length: 8
 	// so, it should sort to
diff --git a/vlib/x/encoding/asn1/tagged_test.v b/vlib/x/encoding/asn1/tagged_test.v
index 244a5acb3..12dfa442f 100644
--- a/vlib/x/encoding/asn1/tagged_test.v
+++ b/vlib/x/encoding/asn1/tagged_test.v
@@ -4,7 +4,7 @@
 module asn1
 
 fn test_explicit_context_null_pack_unpack() ! {
-	el := Null.new()
+	el := Null{}
 	ex1 := ContextElement.from_element(el, 0, .explicit)!
 
 	out := encode(ex1)!
@@ -21,7 +21,7 @@ fn test_explicit_context_null_pack_unpack() ! {
 }
 
 fn test_explicit_context_nested_pack_unpack() ! {
-	el := Null.new()
+	el := Null{}
 
 	ex1 := ContextElement.from_element(el, 1, .explicit)!
 
-- 
2.39.5