# OTP Component

The OTP component allows creation of single use passwords.

## Syntax

```text
nsoftware.IPWorksAuth.OTP
```

## Remarks

The OTP component implements the HOTP algorithm defined in RFC 4226 (HMAC-Based One-Time Password) and the TOTP algorithm defined in RFC 6238 (Time-Based One-Time Password). These types of passwords are commonly used as a second factor of authentication in multi-factor authentication scenarios.

To begin decide which algorithm you wish to use and set [PasswordAlgorithm](#passwordalgorithm-property-otp-component). Specify the shared secret in the [Secret](#secret-property-otp-component) property.

Next, depending on the algorithm chosen you may set [Counter](#counter-property-otp-component) (HOTP) or [TimeStep](#timestep-property-otp-component) (TOTP). If these properties are not set, the component will use a default value.

To create the password call [CreatePassword](#createpassword-method-otp-component). The [Password](#password-property-otp-component) property will be populated with the new password.

To validate a password set the [Password](#password-property-otp-component) property and call [ValidatePassword](#validatepassword-method-otp-component). The method will return True or False to indicate success or failure.

## Property List

*The following is the full list of the properties of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Counter](#counter-property-otp-component) | The counter used for HMAC-Based One Time Password creation or validation. |
| [Password](#password-property-otp-component) | The HMAC-Based or Time-Based One Time Password. |
| [PasswordAlgorithm](#passwordalgorithm-property-otp-component) | The algorithm used to create or validate the password. |
| [Secret](#secret-property-otp-component) | The Base32 encoded shared secret used when creating and validating a password. |
| [TimeStep](#timestep-property-otp-component) | The time step (in seconds) used for Time-Based One Time Password creation or validation. |
| [ValidityTime](#validitytime-property-otp-component) | The validity time of the created password. |

## Method List

*The following is the full list of the methods of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Config](#config-method-otp-component) | Sets or retrieves a configuration setting. |
| [CreatePassword](#createpassword-method-otp-component) | Creates a Time-Based or HMAC-Based One Time Password. |
| [Reset](#reset-method-otp-component) | Reset the variables to default value. |
| [ValidatePassword](#validatepassword-method-otp-component) | Validates a Time-Based or HMAC-Based One Time Password. |

## Event List

*The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Error](#error-event-otp-component) | Fired when information is available about errors during data delivery. |

## Config Settings

*The following is a list of config settings for the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [CurrentTime](#CurrentTime) | The current time in milliseconds. |
| [FuturePasswordsAccepted](#FuturePasswordsAccepted) | The number of future passwords to accept. |
| [HashAlgorithm](#HashAlgorithm) | The hash algorithm used to sign the password. |
| [PasswordLength](#PasswordLength) | The length of the generated password. |
| [PreviousPasswordsAccepted](#PreviousPasswordsAccepted) | The number of previous passwords to accept. |
| [QRCodeURI](#QRCodeURI) | Returns a URI suitable for encoding as a QR code. |
| [SecretLength](#SecretLength) | The length of secret to generate. |
| [ValidityTime](#ValidityTime) | The validity time of the created TOTP password. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [GUIAvailable](#GUIAvailable) | Whether or not a message loop is available for processing events. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) | Tells the component whether or not to use FIPS certified APIs. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# Counter Property ([OTP](#otp-component) Component)

The counter used for HMAC-Based One Time Password creation or validation.

## Syntax

```text
public long Counter { get; set; }
```

## Default Value

0

## Remarks

This property holds the counter value used for HMAC-Based One Time Password creation or validation. When [PasswordAlgorithm](#passwordalgorithm-property-otp-component) is set to paHOTP this value must be specified before calling [CreatePassword](#createpassword-method-otp-component) or [ValidatePassword](#validatepassword-method-otp-component). The value should be incremented each time a password is created.

The default value is 0.

This property is not applicable when using the Time-Based One Time Password algorithm.

# Password Property ([OTP](#otp-component) Component)

The HMAC-Based or Time-Based One Time Password.

## Syntax

```text
public string Password { get; set; }
```

## Default Value

""

## Remarks

This property holds the HMAC-Based or Time-Based One Time Password. This property is populated after calling [CreatePassword](#createpassword-method-otp-component). This property must be set before calling [ValidatePassword](#validatepassword-method-otp-component).

# PasswordAlgorithm Property ([OTP](#otp-component) Component)

The algorithm used to create or validate the password.

## Syntax

```text
public OTPPasswordAlgorithms PasswordAlgorithm { get; set; }
enum OTPPasswordAlgorithms {
  paTOTP,
  paHOTP
}
```

## Default Value

0

## Remarks

This property specifies whether to use the HMAC-Based or Time-Based One Time Password algorithm. Possible values are:

|  |  |
| --- | --- |
| 0 (paTOTP - default) | Time-Based One Time Password Algorithm. |
| 1 (paHOTP) | HMAC-Based One Time Password Algorithm. |

# Secret Property ([OTP](#otp-component) Component)

The Base32 encoded shared secret used when creating and validating a password.

## Syntax

```text
public string Secret { get; set; }
```

## Default Value

""

## Remarks

This property specifies the Base32 encoded shared secret used when creating and validating a password. This should be set before calling [CreatePassword](#createpassword-method-otp-component) or [ValidatePassword](#validatepassword-method-otp-component).

If this is not set before calling [CreatePassword](#createpassword-method-otp-component) a random secret will be automatically generated. This functionality provides an easy way to create new secret values. The length of the secret is defined by [SecretLength](#SecretLength).

# TimeStep Property ([OTP](#otp-component) Component)

The time step (in seconds) used for Time-Based One Time Password creation or validation.

## Syntax

```text
public int TimeStep { get; set; }
```

## Default Value

30

## Remarks

This property specifies the time step (in seconds) used for Time-Based One Time Password creation or validation. When [PasswordAlgorithm](#passwordalgorithm-property-otp-component) is set to paTOTP this value must be specified before calling [CreatePassword](#createpassword-method-otp-component) or [ValidatePassword](#validatepassword-method-otp-component).

The default value is 30.

This property is not applicable when using the HMAC-Based One Time Password algorithm.

# ValidityTime Property ([OTP](#otp-component) Component)

The validity time of the created password.

## Syntax

```text
public int ValidityTime { get; }
```

## Default Value

0

## Remarks

This property returns the remaining validity time in seconds of the created password. After calling [CreatePassword](#createpassword-method-otp-component) this property may be queried to determine for how many more seconds the password will be valid. If the password is no longer valid this property returns 0.

This property is read-only.

# Config Method ([OTP](#otp-component) Component)

Sets or retrieves a configuration setting.

## Syntax

```text
public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
```

## Remarks

Config is a generic method available in every component. It is used to set and retrieve [configuration settings](#config-settings-otp-component) for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the Config method.

To set a configuration setting named *PROPERTY*, you must call *Config("PROPERTY=VALUE")*, where *VALUE* is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a [configuration setting](#config-settings-otp-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# CreatePassword Method ([OTP](#otp-component) Component)

Creates a Time-Based or HMAC-Based One Time Password.

## Syntax

```text
public void CreatePassword();

Async Version
public async Task CreatePassword();
public async Task CreatePassword(CancellationToken cancellationToken);
```

## Remarks

This method creates either a Time-Based or HMAC-Based One Time Password. The [PasswordAlgorithm](#passwordalgorithm-property-otp-component) property specifies which algorithm to use.

The following properties are applicable when calling CreatePassword.

- [PasswordAlgorithm](#passwordalgorithm-property-otp-component)
- [Secret](#secret-property-otp-component)
- [Counter](#counter-property-otp-component) (required for HMAC-Based One Time Password)
- [TimeStep](#timestep-property-otp-component) (applicable for Time-Based One Time Password)

Calling CreatePassword populates the [Password](#password-property-otp-component) property with the created password.

If [Secret](#secret-property-otp-component) is not specified before calling this method a random secret will be automatically generated.

# Reset Method ([OTP](#otp-component) Component)

Reset the variables to default value.

## Syntax

```text
public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
```

## Remarks

This method will reset the variables to default value.

# ValidatePassword Method ([OTP](#otp-component) Component)

Validates a Time-Based or HMAC-Based One Time Password.

## Syntax

```text
public bool ValidatePassword();

Async Version
public async Task<bool> ValidatePassword();
public async Task<bool> ValidatePassword(CancellationToken cancellationToken);
```

## Remarks

This method validates a Time-Based or HMAC-Based One Time Password. The [PasswordAlgorithm](#passwordalgorithm-property-otp-component) property specifies which algorithm to use.

The following properties are applicable when calling ValidatePassword.

- [Password](#password-property-otp-component) (required)
- [PasswordAlgorithm](#passwordalgorithm-property-otp-component)
- [Secret](#secret-property-otp-component) (required)
- [Counter](#counter-property-otp-component) (required for HMAC-Based One Time Password)
- [TimeStep](#timestep-property-otp-component) (applicable for Time-Based One Time Password)

The method will return True if the password is validated, False otherwise.

# Error Event ([OTP](#otp-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

```text
public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, OTPErrorEventArgs e);

public class OTPErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component throws an exception.

The *ErrorCode* parameter contains an error code, and the *Description* parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the [Error Codes](#trappable-errors-otp-component) section.

# Config Settings ([OTP](#otp-component) Component)

 The component accepts one or more of the following *configuration settings*. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the [Config](#config-method-otp-component) method.

### OTP Config Settings

**CurrentTime**: The current time in milliseconds.Specifies the current time Unix time in milliseconds (time since January 1 1970). Normally the component will query the system for the current time when creating or validating TOTP passwords. In the event that the system time is incorrect or cannot be retrieved you may set this value to the current time. This value will be reset to 0 after calling [CreatePassword](#createpassword-method-otp-component).

**FuturePasswordsAccepted**: The number of future passwords to accept.When set to a positive value, the component will accept passwords which are generated {FuturePasswordsAccepted} * [TimeStep](#timestep-property-otp-component) seconds in the future. The default value is 0.

**HashAlgorithm**: The hash algorithm used to sign the password.This setting specifies the hash algorithm used to sign the password. Possible values are:

- SHA1 (default)
- SHA256
- SHA512

**PasswordLength**: The length of the generated password.This setting specifies the length of the generated password. Possible values are:

- 6 (default)
- 7
- 8

**PreviousPasswordsAccepted**: The number of previous passwords to accept.When set to a positive value, the component will accept passwords which were generated {PreviousPasswordsAccepted} * [TimeStep](#timestep-property-otp-component) seconds in the past. The default value is 0.

**QRCodeURI**: Returns a URI suitable for encoding as a QR code.This setting provides a way to generate a URI which can be encoded into a QR code, suitable for using in any authenticator application. The URI format is well defined and is an easy way to transfer the secret key and other relevant parameters.

To use this setting first set [Secret](#secret-property-otp-component) to a valid value, then execute code like:

```csharp
string MyQRCodeURI = component.Config("QRCodeURI=MyServiceName:account@company.com");
```

In the above example the *MyServiceName* value is the issuer. This is typically used in authenticator applications to identify the service to which the account belongs. The *account@company.com* value is the account name and identifies the specific account with which the key is associated. The use of an issuer is not required but is recommended. An account name is required.

The return value from this operation is a URI in one of the following formats:

```text
//TOTP
otpauth://totp/MyServiceName:account@company.com?secret=JBSWY3DPEHPK3PXP&digits=6&period=30

//HOTP
otpauth://hotp/MyServiceName:account@company.com?secret=JBSWY3DPEHPK3PXP&digits=6&counter=0
```

The following values are applicable when using this setting:

- [Secret](#secret-property-otp-component)
- [PasswordLength](#PasswordLength)
- [HashAlgorithm](#HashAlgorithm)
- [TimeStep](#timestep-property-otp-component) (TOTP)
- [Counter](#counter-property-otp-component) (HOTP)

**SecretLength**: The length of secret to generate.When [Secret](#secret-property-otp-component) is empty and [CreatePassword](#createpassword-method-otp-component) is called a random secret value will be generated. This setting determines the length of the randomly generated secret. The default value is 32.

**ValidityTime**: The validity time of the created TOTP password.This setting returns the remaining validity time in seconds of the created TOTP password. After calling [CreatePassword](#createpassword-method-otp-component) this setting may be queried to determine for how many more seconds the password will be valid. If the password is no longer valid this setting returns 0. This is not applicable to HOTP passwords.

### Base Config Settings

**BuildInfo**: Information about the product's build.When queried, this setting will return a string containing information about the product's build.

**GUIAvailable**: Whether or not a message loop is available for processing events.In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting [GUIAvailable](#GUIAvailable) to *false* will ensure that the component does not attempt to process external events.

**LicenseInfo**: Information about the current license.When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *true* to mask sensitive data. The default is *true*.

**UseFIPSCompliantAPI**: Tells the component whether or not to use FIPS certified APIs.When set to *true*, the component will utilize the underlying operating system's certified APIs. Java editions, regardless of OS, utilize Bouncy Castle Federal Information Processing Standards (FIPS), while all other Windows editions make use of Microsoft security libraries.

FIPS mode can be enabled by setting the *UseFIPSCompliantAPI* configuration setting to *true*. This is a static setting that applies to all instances of all components of the toolkit within the process. It is recommended to enable or disable this setting once before the component has been used to establish a connection. Enabling FIPS while an instance of the component is active and connected may result in unexpected behavior.

For more details, please see the [FIPS 140-2 Compliance](https://www.nsoftware.com/kb/articles/fips.rst) article.

NOTE: This setting is applicable only on Windows.

NOTE: Enabling FIPS compliance requires a special license; please contact [sales@nsoftware.com](mailto:sales@nsoftware.com) for details.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, calls to unmanaged code will be made. In certain environments, this is not desirable. To use a completely managed security implementation, set this setting to *true*.

Setting this configuration setting to *true* tells the component to use the internal implementation instead of using the system security libraries.

 On Windows, this setting is set to *false* by default. On Linux/macOS, this setting is set to *true* by default.

NOTE: This setting is static. The value set is applicable to all components used in the application.

When this value is set, the product's system dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

# Trappable Errors ([OTP](#otp-component) Component)

### OTP Errors

|  |  |
| --- | --- |
| 114 | Can't create password. |
| 115 | Can't validate password. |