otpauth

Documentation

Overview

Package otpauth handles the URL format used to specify OTP parameters.

This package conforms to the specification at: https://github.com/google/google-authenticator/wiki/Key-Uri-Format

The general form of an OTP URL is:

otpauth://TYPE/LABEL?PARAMETERS

Index

• type URL
  • func ParseMigrationURL(s string) ([]*URL, error)
  • func ParseURL(s string) (*URL, error)
  • func (u *URL) MarshalText() ([]byte, error)
  • func (u *URL) Secret() ([]byte, error)
  • func (u *URL) SetSecret(key []byte)
  • func (u *URL) String() string
  • func (u *URL) UnmarshalText(data []byte) error

Types

type URL

type URL struct {
	Type      string // normalized to lowercase, e.g., "totp"
	Issuer    string // also called "provider" in some docs
	Account   string // without provider prefix
	RawSecret string // base32-encoded, no padding
	Algorithm string // normalized to uppercase; default is "SHA1"
	Digits    int    // default is 6
	Period    int    // in seconds; default is 30
	Counter   uint64
}

A URL contains the parsed representation of an otpauth URL.

func ParseMigrationURL

func ParseMigrationURL(s string) ([]*URL, error)

ParseMigrationURL parses an otpauth-migration URL in the format generated by the Google Authenticator for "exported" configurations. Typically these URLs are embedded as QR codes, encoding a proprietary URL in this format:

otpauth-migration://offline?data=<content>

The content is a protocol buffer message encoded as base64 in standard encoding. Note that a single migration URL may encode multiple OTP settings; on success this function returns all the otpauth URLs encoded by the content. It will always return at least one URL, or report an error.

func ParseURL

func ParseURL(s string) (*URL, error)

ParseURL parses s as a URL in the otpauth scheme.

The input may omit a scheme, but if present the scheme must be otpauth://. The parser will report an error for invalid syntax, including unknown URL parameters, but does not otherwise validate the results. In particular, the values of the Type and Algorithm fields are not checked.

Fields of the URL corresponding to unset parameters are populated with default values as described on the URL struct. If a different issuer is set on the label and in the parameters, the parameter takes priority.

func (*URL) MarshalText

func (u *URL) MarshalText() ([]byte, error)

MarshalText implemens the encoding.TextMarshaler interface. It emits the same URL string produced by the String method.

func (*URL) Secret

func (u *URL) Secret() ([]byte, error)

Secret parses the contents of the RawSecret field.

func (*URL) SetSecret

func (u *URL) SetSecret(key []byte)

SetSecret encodes key as base32 and updates the RawSecret field.

func (*URL) String

func (u *URL) String() string

String converts u to a URL in the standard encoding.

func (*URL) UnmarshalText

func (u *URL) UnmarshalText(data []byte) error

UnmarshalText implements the encoding.TextUnmarshaler interface. It expects its input to be a URL in the standard encoding.