OCRA Component

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The OCRA component implements the OATH Challenge-Response Algorithm.

Syntax

nsoftware.IPWorksAuth.OCRA

Remarks

The OCRA component provides a simple way to create challenges, calculate responses, and verify responses using the OATH Challenge-Response Algorithm.

The first step to using the component is creating the Challenge and generating the OCRASuite. This is done by calling the CreateChallenge method. After creating the Challenge and OCRASuite these values are sent to the other party.

When receiving a challenge and OCRASuite the component is use to calculate a response. Set OCRASuite, Challenge, and any other required properties and call CalculateResponse to calculate the Response. Send the Response back to the original party for verification.

After receiving the verification set Challenge, OCRASuite, and Response and call VerifyResponse. VerifyResponse returns True if the response is verified, False otherwise.

Creating the Challenge

The CreateChallenge method creates a Challenge. After calling this method the Challenge property will be populated with the created value.

When ChallengeType is set to ctRandom the following properties are applicable:

When ChallengeType is set to ctSignature the following properties are applicable:

In addition to creating the Challenge this method will also create the OCRASuite which defines parameters required by the other party to calculate a response. The following properties are applicable to OCRASuite creation:

Calculating the Response

CalculateResponse calculates Response to the given Challenge.

Before calling this method set OCRASuite to the suite obtained from the other party and set Challenge to the received challenge.

After setting OCRASuite the following properties are populated, which provide requirements for the response:

Inspect these properties to determine the requirements and provide any required values such as Counter or Password. Set Key to the key used during the HMAC computation. Set Challenge to the received challenge.

Call this method to calculate the response. After calling this method the Response property is populated. The response may then be transmitted to the other party for verification.

The following properties are applicable when calling this method:

Verifying the Response

VerifyResponse verifies the response and returns True or False depending on the result.

Before calling this method set OCRASuite, Challenge, and Response.

After setting OCRASuite the following properties are populated, which provide requirements for the response:

These properties may be inspected to determine the requirements. Provide any required values such as Counter or Password. Set Challenge to the original challenge that was issued. Set Response to the received response. Set Key to the key used during the HMAC computation.

Call this method to verify the response. The method will return True if the verification was successful, False otherwise.

The following properties are applicable when calling this method:

Random Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctRandom; ocra.ChallengeLength = 10; ocra.ChallengeFormat = OcraChallengeFormats.cfNumeric; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "3891592139" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QN10" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified Signature Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctSignature; ocra.ChallengeInput = "test input"; ocra.Key = "signature key"; ocra.ChallengeFormat = OcraChallengeFormats.cfHex; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "973131F0" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QH08" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified

Property List

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

ChallengeThe challenge value.
ChallengeFormatThe format in which the challenge will be created.
ChallengeInputThe input for the signature challenge.
ChallengeLengthThe challenge length.
ChallengeTypeThe challenge type.
CounterThe counter.
HashAlgorithmThe HMAC Hash Algorithm.
KeyThe secret key.
OCRASuiteThe OCRASuite defines parameters about the challenge and response.
PasswordThe password.
RequireCounterWhether a Counter value is required to create the response.
RequirePasswordWhether a Password is required to create the response.
RequireTimeStampWhether a TimeStamp is required to create the response.
ResponseThe OCRA response.
ResponseLengthDefines the length of the response.

Method List

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

CalculateResponseThis method calculates the response to the given challenge.
ConfigSets or retrieves a configuration setting.
CreateChallengeCreates the challenge.
ResetReset the variables to default value.
VerifyResponseThis method verifies the response.

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.

ErrorFired 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.

CounterHexThe counter value as a hexadecimal string.
CurrentTimeThe current time in milliseconds.
PasswordHashAlgorithmThe password hash algorithm.
RequireSessionInfoWhether to use session information.
SessionInfoThe session information.
SessionInfoLengthThe length of the session information.
TimeStepSizeThe time step.
TimeStepUnitThe time step unit.
BuildInfoInformation about the product's build.
GUIAvailableWhether or not a message loop is available for processing events.
LicenseInfoInformation about the current license.
MaskSensitiveDataWhether sensitive data is masked in log messages.
UseFIPSCompliantAPITells the component whether or not to use FIPS certified APIs.
UseInternalSecurityAPIWhether or not to use the system security libraries or an internal implementation.

Challenge Property (OCRA Component)

The challenge value.

Syntax

public string Challenge { get; set; }
public byte[] ChallengeB { get; set; }

Public Property Challenge As String
Public Property ChallengeB As Byte()

Default Value

""

Remarks

This property is populated after calling CreateChallenge. The format is specified by the ChallengeFormat property and the length is defined by the ChallengeLength property.

This property must be specified before calling CalculateResponse or VerifyResponse.

ChallengeFormat Property (OCRA Component)

The format in which the challenge will be created.

Syntax

public OCRAChallengeFormats ChallengeFormat { get; set; }

enum OCRAChallengeFormats {
  cfAlphanumeric,
  cfNumeric,
  cfHex
}

Public Property ChallengeFormat As OcraChallengeFormats

Enum OCRAChallengeFormats
  cfAlphanumeric
  cfNumeric
  cfHex
End Enum

Default Value

0

Remarks

This setting specifies the format of the created challenge. This is applicable when calling CreateChallenge. Possible values are:

0 (cfAlphanumeric - default) Alphanumeric characters
1 (cfNumeric) Digits
2 (cfHex) Hex characters

ChallengeInput Property (OCRA Component)

The input for the signature challenge.

Syntax

public string ChallengeInput { get; set; }
public byte[] ChallengeInputB { get; set; }

Public Property ChallengeInput As String
Public Property ChallengeInputB As Byte()

Default Value

""

Remarks

This property specifies the data used when creating the signature challenge. This is only used when calling CreateChallenge when ChallengeType is set to Signature.

ChallengeLength Property (OCRA Component)

The challenge length.

Syntax

public int ChallengeLength { get; set; }

Public Property ChallengeLength As Integer

Default Value

8

Remarks

This setting specifies the length of the Challenge that is created when calling CreateChallenge. Valid values are from 4 to 64. The default value is 8.

ChallengeType Property (OCRA Component)

The challenge type.

Syntax

public OCRAChallengeTypes ChallengeType { get; set; }

enum OCRAChallengeTypes {
  ctRandom,
  ctSignature
}

Public Property ChallengeType As OcraChallengeTypes

Enum OCRAChallengeTypes
  ctRandom
  ctSignature
End Enum

Default Value

0

Remarks

This property defines the type of challenge created. Possible values are:

0 (ctRandom - default) A random challenge is created.
1 (ctSignature) A signature challenge is created by signing ChallengeInput.

When setting this property to 0 (ctRandom) and calling CreateChallenge the component will populate Challenge with a randomly generated value.

When setting this property to 1 (ctSignature) and calling CreateChallenge the component creates a Hash-based Message Authentication Code (HMAC) value using the data specified in ChallengeInput and then populate Challenge with the formatted result.

Counter Property (OCRA Component)

The counter.

Syntax

public long Counter { get; set; }

Public Property Counter As Long

Default Value

0

Remarks

This property specifies the counter.

If a counter is required this must be set before calling CalculateResponse and VerifyResponse. To determine if a counter is required assign OCRASuite to the OCRA suite and check the value of RequireCounter.

The counter value should begin at 0 be incremented until the maximum value is reached. After the maximum is reached the counter value should start again at 0.

HashAlgorithm Property (OCRA Component)

The HMAC Hash Algorithm.

Syntax

public OCRAHashAlgorithms HashAlgorithm { get; set; }

enum OCRAHashAlgorithms {
  haSHA1,
  haSHA256,
  haSHA512
}

Public Property HashAlgorithm As OcraHashAlgorithms

Enum OCRAHashAlgorithms
  haSHA1
  haSHA256
  haSHA512
End Enum

Default Value

0

Remarks

This property specifies the hash algorithm used by the component. Possible values are:

  • 0 (SHA-1 - default)
  • 1 (SHA-256)
  • 2 (SHA-512)

Key Property (OCRA Component)

The secret key.

Syntax

public string Key { get; set; }
public byte[] KeyB { get; set; }

Public Property Key As String
Public Property KeyB As Byte()

Default Value

""

Remarks

This property holds the secret key used when calling CalculateResponse and VerifyResponse.

This property is also used when calling CreateChallenge when ChallengeType is set to Signature.

An empty key is valid, however it is recommended to provide a key value.

OCRASuite Property (OCRA Component)

The OCRASuite defines parameters about the challenge and response.

Syntax

public string OCRASuite { get; set; }

Public Property OCRASuite As String

Default Value

""

Remarks

This property holds the OCRASuite value which defines parameters about the challenge and response.

This property will be populated after calling CreateChallenge. This property must be set before calling CalculateResponse or VerifyResponse.

When calling CreateChallenge the following properties will be used to create the OCRASuite:

When this property is set the value is parsed and the above properties are populated to reflect the requirements defined by the OCRASuite.

Password Property (OCRA Component)

The password.

Syntax

public string Password { get; set; }
public byte[] PasswordB { get; set; }

Public Property Password As String
Public Property PasswordB As Byte()

Default Value

""

Remarks

This property specifies the password.

If a password is required this must be set before calling CalculateResponse and VerifyResponse. To determine if a password is required assign OCRASuite to the OCRA suite and check the value of RequirePassword.

RequireCounter Property (OCRA Component)

Whether a Counter value is required to create the response.

Syntax

public bool RequireCounter { get; set; }

Public Property RequireCounter As Boolean

Default Value

False

Remarks

This property specifies whether a Counter value is required to create the response.

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite

RequirePassword Property (OCRA Component)

Whether a Password is required to create the response.

Syntax

public bool RequirePassword { get; set; }

Public Property RequirePassword As Boolean

Default Value

False

Remarks

This property specifies whether a Password is required to create the response.

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite

RequireTimeStamp Property (OCRA Component)

Whether a TimeStamp is required to create the response.

Syntax

public bool RequireTimeStamp { get; set; }

Public Property RequireTimeStamp As Boolean

Default Value

False

Remarks

This property specifies whether a TimeStamp is required to create the response.

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite

The component will automatically use the current system time when calling CalculateResponse and VerifyResponse if this property is True. The CurrentTime setting may be set to specify the time instead of using the system time.

The following settings are also applicable when this value is True:

Response Property (OCRA Component)

The OCRA response.

Syntax

public string Response { get; set; }
public byte[] ResponseB { get; set; }

Public Property Response As String
Public Property ResponseB As Byte()

Default Value

""

Remarks

This property holds the challenge response.

This is populated after calling CalculateResponse. This must be set before calling VerifyResponse.

ResponseLength Property (OCRA Component)

Defines the length of the response.

Syntax

public int ResponseLength { get; set; }

Public Property ResponseLength As Integer

Default Value

6

Remarks

This property specifies the desired response length. Valid values are 4-10, and 0. Values 4-10 will result in a numeric value of that length. The value 0 indicates no truncation and the raw HMAC value is returned in the response

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite. When calling CalculateResponse the calculated Response will be a value with this length.

The default value is 6.

CalculateResponse Method (OCRA Component)

This method calculates the response to the given challenge.

Syntax

public void CalculateResponse();

Async Version
public async Task CalculateResponse();
public async Task CalculateResponse(CancellationToken cancellationToken);

Public Sub CalculateResponse()

Async Version
Public Sub CalculateResponse() As Task
Public Sub CalculateResponse(cancellationToken As CancellationToken) As Task

Remarks

This method calculates Response to the given Challenge.

Before calling this method set OCRASuite to the suite obtained from the other party and set Challenge to the received challenge.

After setting OCRASuite the following properties are populated, which provide requirements for the response:

Inspect these properties to determine the requirements and provide any required values such as Counter or Password. Set Key to the key used during the HMAC computation. Set Challenge to the received challenge.

Call this method to calculate the response. After calling this method the Response property is populated. The response may then be transmitted to the other party for verification.

The following properties are applicable when calling this method:

Random Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctRandom; ocra.ChallengeLength = 10; ocra.ChallengeFormat = OcraChallengeFormats.cfNumeric; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "3891592139" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QN10" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified Signature Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctSignature; ocra.ChallengeInput = "test input"; ocra.Key = "signature key"; ocra.ChallengeFormat = OcraChallengeFormats.cfHex; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "973131F0" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QH08" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified

Config Method (OCRA Component)

Sets or retrieves a configuration setting.

Syntax

public string Config(string configurationString);

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

Public Function Config(ByVal ConfigurationString As String) As String

Async Version
Public Function Config(ByVal ConfigurationString As String) As Task(Of String)
Public Function Config(ByVal ConfigurationString As String, cancellationToken As CancellationToken) As Task(Of String)

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings 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, you must call Config("PROPERTY"). The value will be returned as a string.

CreateChallenge Method (OCRA Component)

Creates the challenge.

Syntax

public void CreateChallenge();

Async Version
public async Task CreateChallenge();
public async Task CreateChallenge(CancellationToken cancellationToken);

Public Sub CreateChallenge()

Async Version
Public Sub CreateChallenge() As Task
Public Sub CreateChallenge(cancellationToken As CancellationToken) As Task

Remarks

This method creates a Challenge. After calling this method the Challenge property will be populated with the created value.

When ChallengeType is set to ctRandom the following properties are applicable:

When ChallengeType is set to ctSignature the following properties are applicable:

In addition to creating the Challenge this method will also create the OCRASuite which defines parameters required by the other party to calculate a response. The following properties are applicable to OCRASuite creation:

Random Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctRandom; ocra.ChallengeLength = 10; ocra.ChallengeFormat = OcraChallengeFormats.cfNumeric; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "3891592139" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QN10" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified Signature Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctSignature; ocra.ChallengeInput = "test input"; ocra.Key = "signature key"; ocra.ChallengeFormat = OcraChallengeFormats.cfHex; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "973131F0" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QH08" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified

Reset Method (OCRA Component)

Reset the variables to default value.

Syntax

public void Reset();

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

Public Sub Reset()

Async Version
Public Sub Reset() As Task
Public Sub Reset(cancellationToken As CancellationToken) As Task

Remarks

This method will reset the variables to default value.

VerifyResponse Method (OCRA Component)

This method verifies the response.

Syntax

public bool VerifyResponse();

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

Public Function VerifyResponse() As Boolean

Async Version
Public Function VerifyResponse() As Task(Of Boolean)
Public Function VerifyResponse(cancellationToken As CancellationToken) As Task(Of Boolean)

Remarks

This method verifies the response and returns True or False depending on the result.

Before calling this method set OCRASuite, Challenge, and Response.

After setting OCRASuite the following properties are populated, which provide requirements for the response:

These properties may be inspected to determine the requirements. Provide any required values such as Counter or Password. Set Challenge to the original challenge that was issued. Set Response to the received response. Set Key to the key used during the HMAC computation.

Call this method to verify the response. The method will return True if the verification was successful, False otherwise.

The following properties are applicable when calling this method:

Random Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctRandom; ocra.ChallengeLength = 10; ocra.ChallengeFormat = OcraChallengeFormats.cfNumeric; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "3891592139" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QN10" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified Signature Challenge Example //First create the challenge on machine A Ocra ocra = new Ocra(); ocra.ChallengeType = OcraChallengeTypes.ctSignature; ocra.ChallengeInput = "test input"; ocra.Key = "signature key"; ocra.ChallengeFormat = OcraChallengeFormats.cfHex; ocra.CreateChallenge(); string challenge = ocra.Challenge; //Value like "973131F0" string ocraSuite = ocra.OCRASuite; //Value "OCRA-1:HOTP-SHA1-6:QH08" //Send Challenge and OCRASuite to Machine B //Upon receiving the challenge on Machine B, calculate a response ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Received from other party ocra.Challenge = challenge; //Received from other party ocra.Key = "shared secret key"; ocra.CalculateResponse(); string response = ocra.Response; //Value like "574464" //Send Response back to Machine A //Upon receiving the response on Machine A, verify it ocra = new Ocra(); ocra.OCRASuite = ocraSuite; //Original OCRASuite saved before sending the original challenge ocra.Challenge = challenge; //Original challenge that was sent ocra.Response = response; //Received from other party ocra.Key = "shared secret key"; bool isValid = ocra.VerifyResponse(); //Returns True if verified

Error Event (OCRA Component)

Fired when information is available about errors during data delivery.

Syntax

public event OnErrorHandler OnError;

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

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

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As OCRAErrorEventArgs)

Public Class OCRAErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

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 section.

Config Settings (OCRA 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 method.

OCRA Config Settings

CounterHex:   The counter value as a hexadecimal string.

This setting may be used instead of Counter to supply the counter value. This is specified as a Hexadecimal string and may be used to provide large values like "FFFFFFFFFFFFFFFF".

CurrentTime:   The current time in milliseconds.

This setting specifies the current time in milliseconds since the Unix epoch (January 1, 1970). By default the component will use the system time when CalculateResponse or VerifyResponse is called and RequireTimeStamp is True. This setting overrides the value returned by the system.

PasswordHashAlgorithm:   The password hash algorithm.

This setting specifies the password hash algorithm. Possible values are:

0 SHA1
1 (default) SHA-256
2 SHA-512
RequireSessionInfo:   Whether to use session information.

This setting specifies whether session info is required to create the response.

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite

SessionInfo:   The session information.

This setting specifies the session info when RequireSessionInfo is set to True. This value should be specified before calling CalculateResponse or VerifyResponse, and should be of length SessionInfoLength.

SessionInfoLength:   The length of the session information.

This setting specifies the length of the session information.

This may be set before calling CreateChallenge, when the OCRASuite is generated.

When OCRASuite is assigned this value is updated to reflect the options specified in the OCRASuite

Common values are 64, 128, 256, and 512.

TimeStepSize:   The time step.

The size of the time step. The default value is 1.

TimeStepUnit:   The time step unit.

This setting specifies the time step unit. Possible values are:

0 Seconds
1 (default) Minutes
2 Hours

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 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.

This setting only works on these components: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

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 article.

Note: This setting is applicable only on Windows.

Note: Enabling FIPS compliance requires a special license; please contact 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.

If using the .NET Standard Library, this setting will be true on all platforms. The .NET Standard library does not support using the system security libraries.

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 (OCRA Component)

OCRA Errors

101   Invalid challenge type.
102   Invalid challenge length.
103   Invalid response length.
104   Response must be specified.
105   Invalid hash algorithm.
106   Invalid challenge format.
107   Invalid password hash algorithm.
108   Invalid time step unit.
109   Invalid OCRASuite.
110   OCRASuite must be specified.
111   Challenge must be specified.
112   ChallengeInput must be specified.
113   Password must be specified.