dotp

dotp is a dart package to generate and verify one-time passwords that were used to implement 2FA and MFA authentication method in web applications and other login-required systems.

The package was implement based on RFC4226 (HOTP: An HMAC-Based One-Time Password Algorithm) and RFC6238 (TOTP: Time-Based One-Time Password Algorithm).

Feature

• Generate a otpauth url with the b32 encoded string
• Create a HOTP object with verification
• Verify a HOTP token
• Create a TOTP object with verification
• Verify a TOTP token

Installation

Pubspec

Add dotp as a dependency in your pubspec.yaml file.

dependencies:
  dotp: ^1.0.2

Example

Time-based OTPs

import 'package:dotp/dotp.dart';

void main() {
  TOTP totp = TOTP("J22U6B3WIWRRBTAV");
  totp.now(); /// => 432143
  
  /// verify for the current time
  totp.verify(432143); /// => true
  
  /// verify after 30s
  totp.verify(432143); /// => false
}

Counter-based OTPs

import 'package:dotp/dotp.dart';

void main() {
  HOTP hotp = HOTP("J22U6B3WIWRRBTAV");
  hotp.at(0); /// => 432143
  hotp.at(1); /// => 231434
  hotp.at(2132); /// => 242432
  
  /// verify with a counter
  hotp.verify(242432, 2132); /// => true
  hotp.verify(242432, 2133); /// => false
}

Api

• TOTP(String secret)

param: secret
type: String
return: TOTP
desc: generate TOTP instance.

• TOTP.now()

return: String
desc: get the one-time password with current time.

• TOTP.verify(String otp, [Datetime time])

param: otp
type: String
param: time
type: Datetime
return: Boolean
desc: verify the totp code.

• TOTP.urlGen(String issuer)

param: issuer
type: String
return: String
desc: generate url with TOTP instance

• HOTP(String secret)

param: secret
type: String
return: HOTP
desc: generate HOTP instance.

• HOTP.at(int counter)

param: counter
type: int
return: String
desc: generate one-time password with counter.

• HOTP.verify(String otp, int counter)

param: otp
type: String
param: counter
type: int
return: Boolean
desc: verify the hotp code.

• HOTP.urlGen(String issuer)

param: issuer
type: String
return: String
desc: generate url with HOTP instance

Release notes

See CHANGELOG.md.