asn1

package standard library
go1.21.5 Latest Latest
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 Go to latest Published: Dec 5, 2023 License: BSD-3-Clause Imports: 12 Imported by: 17,716

Documentation

Overview

Package asn1 implements parsing of DER-encoded ASN.1 data structures, as defined in ITU-T Rec X.690.

See also “A Layman's Guide to a Subset of ASN.1, BER, and DER,” http://luca.ntop.org/Teaching/Appunti/asn1.html.

Index

Constants

View Source 
const (
	TagBoolean         = 1
	TagInteger         = 2
	TagBitString       = 3
	TagOctetString     = 4
	TagNull            = 5
	TagOID             = 6
	TagEnum            = 10
	TagUTF8String      = 12
	TagSequence        = 16
	TagSet             = 17
	TagNumericString   = 18
	TagPrintableString = 19
	TagT61String       = 20
	TagIA5String       = 22
	TagUTCTime         = 23
	TagGeneralizedTime = 24
	TagGeneralString   = 27
	TagBMPString       = 30
)

ASN.1 tags represent the type of the following object.

View Source 
const (
	ClassUniversal       = 0
	ClassApplication     = 1
	ClassContextSpecific = 2
	ClassPrivate         = 3
)

ASN.1 class types represent the namespace of the tag.

Variables

View Source 
var NullBytes = []byte{TagNull, 0}

NullBytes contains bytes representing the DER-encoded ASN.1 NULL type.

View Source 
var NullRawValue = RawValue{Tag: TagNull}

NullRawValue is a RawValue with its Tag set to the ASN.1 NULL type tag (5).

Functions

func Marshal 

func Marshal(val any) ([]byte, error)

Marshal returns the ASN.1 encoding of val.

In addition to the struct tags recognised by Unmarshal, the following can be used: 

ia5:         causes strings to be marshaled as ASN.1, IA5String values
omitempty:   causes empty slices to be skipped
printable:   causes strings to be marshaled as ASN.1, PrintableString values
utf8:        causes strings to be marshaled as ASN.1, UTF8String values
utc:         causes time.Time to be marshaled as ASN.1, UTCTime values
generalized: causes time.Time to be marshaled as ASN.1, GeneralizedTime values

func MarshalWithParams added in go1.10 

func MarshalWithParams(val any, params string) ([]byte, error)

MarshalWithParams allows field parameters to be specified for the top-level element. The form of the params is the same as the field tags.

func Unmarshal