# OCRA Class

The OCRA class implements the OATH Challenge-Response Algorithm.

## Syntax

```text
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 class is creating the [Challenge](#challenge-property-ocra-class) and generating the [OCRASuite](#ocrasuite-property-ocra-class). This is done by calling the [CreateChallenge](#createchallenge-method-ocra-class) method. After creating the [Challenge](#challenge-property-ocra-class) and [OCRASuite](#ocrasuite-property-ocra-class) these values are sent to the other party.

When receiving a challenge and OCRASuite the class is use to calculate a response. Set [OCRASuite](#ocrasuite-property-ocra-class), [Challenge](#challenge-property-ocra-class), and any other required properties and call [CalculateResponse](#calculateresponse-method-ocra-class) to calculate the [Response](#response-property-ocra-class). Send the [Response](#response-property-ocra-class) back to the original party for verification.

After receiving the verification set [Challenge](#challenge-property-ocra-class), [OCRASuite](#ocrasuite-property-ocra-class), and [Response](#response-property-ocra-class) and call [VerifyResponse](#verifyresponse-method-ocra-class). [VerifyResponse](#verifyresponse-method-ocra-class) returns True if the response is verified, False otherwise.

**Creating the Challenge**

The [CreateChallenge](#createchallenge-method-ocra-class) method creates a [Challenge](#challenge-property-ocra-class). After calling this method the [Challenge](#challenge-property-ocra-class) property will be populated with the created value.

When [ChallengeType](#challengetype-property-ocra-class) is set to ctRandom the following properties are applicable:

- [ChallengeType](#challengetype-property-ocra-class)
- [ChallengeFormat](#challengeformat-property-ocra-class)
- [ChallengeLength](#challengelength-property-ocra-class)

When [ChallengeType](#challengetype-property-ocra-class) is set to ctSignature the following properties are applicable:

- [ChallengeType](#challengetype-property-ocra-class)
- [ChallengeFormat](#challengeformat-property-ocra-class)
- [ChallengeLength](#challengelength-property-ocra-class)
- [ChallengeInput](#challengeinput-property-ocra-class) (required)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)

In addition to creating the [Challenge](#challenge-property-ocra-class) this method will also create the [OCRASuite](#ocrasuite-property-ocra-class) which defines parameters required by the other party to calculate a response. The following properties are applicable to [OCRASuite](#ocrasuite-property-ocra-class) creation:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

**Calculating the Response**

[CalculateResponse](#calculateresponse-method-ocra-class) calculates [Response](#response-property-ocra-class) to the given [Challenge](#challenge-property-ocra-class).

Before calling this method set [OCRASuite](#ocrasuite-property-ocra-class) to the suite obtained from the other party and set [Challenge](#challenge-property-ocra-class) to the received challenge.

After setting [OCRASuite](#ocrasuite-property-ocra-class) the following properties are populated, which provide requirements for the response:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

Inspect these properties to determine the requirements and provide any required values such as [Counter](#counter-property-ocra-class) or [Password](#password-property-ocra-class). Set [Key](#key-property-ocra-class) to the key used during the HMAC computation. Set [Challenge](#challenge-property-ocra-class) to the received challenge.

Call this method to calculate the response. After calling this method the [Response](#response-property-ocra-class) property is populated. The response may then be transmitted to the other party for verification.

The following properties are applicable when calling this method:

- [Challenge](#challenge-property-ocra-class)
- [Counter](#counter-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)
- [OCRASuite](#ocrasuite-property-ocra-class)
- [Password](#password-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [CurrentTime](#CurrentTime)
- [SessionInfo](#SessionInfo)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)

**Verifying the Response**

[VerifyResponse](#verifyresponse-method-ocra-class) verifies the response and returns True or False depending on the result.

Before calling this method set [OCRASuite](#ocrasuite-property-ocra-class), [Challenge](#challenge-property-ocra-class), and [Response](#response-property-ocra-class).

After setting [OCRASuite](#ocrasuite-property-ocra-class) the following properties are populated, which provide requirements for the response:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

These properties may be inspected to determine the requirements. Provide any required values such as [Counter](#counter-property-ocra-class) or [Password](#password-property-ocra-class). Set [Challenge](#challenge-property-ocra-class) to the original challenge that was issued. Set [Response](#response-property-ocra-class) to the received response. Set [Key](#key-property-ocra-class) 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:

- [Challenge](#challenge-property-ocra-class)
- [Response](#response-property-ocra-class)
- [Counter](#counter-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)
- [OCRASuite](#ocrasuite-property-ocra-class)
- [Password](#password-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [CurrentTime](#CurrentTime)
- [SessionInfo](#SessionInfo)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)

**Random Challenge Example**

```text
//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**

```text
//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 class with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Challenge](#challenge-property-ocra-class) | The challenge value. |
| [ChallengeFormat](#challengeformat-property-ocra-class) | The format in which the challenge will be created. |
| [ChallengeInput](#challengeinput-property-ocra-class) | The input for the signature challenge. |
| [ChallengeLength](#challengelength-property-ocra-class) | The challenge length. |
| [ChallengeType](#challengetype-property-ocra-class) | The challenge type. |
| [Counter](#counter-property-ocra-class) | The counter. |
| [HashAlgorithm](#hashalgorithm-property-ocra-class) | The HMAC Hash Algorithm. |
| [Key](#key-property-ocra-class) | The secret key. |
| [OCRASuite](#ocrasuite-property-ocra-class) | The OCRASuite defines parameters about the challenge and response. |
| [Password](#password-property-ocra-class) | The password. |
| [RequireCounter](#requirecounter-property-ocra-class) | Whether a Counter value is required to create the response. |
| [RequirePassword](#requirepassword-property-ocra-class) | Whether a Password is required to create the response. |
| [RequireTimeStamp](#requiretimestamp-property-ocra-class) | Whether a TimeStamp is required to create the response. |
| [Response](#response-property-ocra-class) | The OCRA response. |
| [ResponseLength](#responselength-property-ocra-class) | Defines the length of the response. |

## Method List

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

|  |  |
| --- | --- |
| [CalculateResponse](#calculateresponse-method-ocra-class) | This method calculates the response to the given challenge. |
| [Config](#config-method-ocra-class) | Sets or retrieves a configuration setting. |
| [CreateChallenge](#createchallenge-method-ocra-class) | Creates the challenge. |
| [Reset](#reset-method-ocra-class) | Reset the variables to default value. |
| [VerifyResponse](#verifyresponse-method-ocra-class) | This method verifies the response. |

## Event List

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

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

## Config Settings

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

|  |  |
| --- | --- |
| [CounterHex](#CounterHex) | The counter value as a hexadecimal string. |
| [CurrentTime](#CurrentTime) | The current time in milliseconds. |
| [PasswordHashAlgorithm](#PasswordHashAlgorithm) | The password hash algorithm. |
| [RequireSessionInfo](#RequireSessionInfo) | Whether to use session information. |
| [SessionInfo](#SessionInfo) | The session information. |
| [SessionInfoLength](#SessionInfoLength) | The length of the session information. |
| [TimeStepSize](#TimeStepSize) | The time step. |
| [TimeStepUnit](#TimeStepUnit) | The time step unit. |
| [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. |
| [UseDaemonThreads](#UseDaemonThreads) | Whether threads created by the class are daemon threads. |
| [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) | Tells the class whether or not to use FIPS certified APIs. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |
| [UseVirtualThreads](#UseVirtualThreads) | Whether threads created by the class use virtual threads instead of platform threads. |

# Challenge Property ([OCRA](#ocra-class) Class)

The challenge value.

## Syntax

```text
public byte[] getChallenge();
public void setChallenge(byte[] challenge);
```

## Default Value

""

## Remarks

This property is populated after calling [CreateChallenge](#createchallenge-method-ocra-class). The format is specified by the [ChallengeFormat](#challengeformat-property-ocra-class) property and the length is defined by the [ChallengeLength](#challengelength-property-ocra-class) property.

This property must be specified before calling [CalculateResponse](#calculateresponse-method-ocra-class) or [VerifyResponse](#verifyresponse-method-ocra-class).

# ChallengeFormat Property ([OCRA](#ocra-class) Class)

The format in which the challenge will be created.

## Syntax

```text
public int getChallengeFormat();
public void setChallengeFormat(int challengeFormat);

Enumerated values:
  public final static int cfAlphanumeric = 0;
  public final static int cfNumeric = 1;
  public final static int cfHex = 2;
```

## Default Value

0

## Remarks

This setting specifies the format of the created challenge. This is applicable when calling [CreateChallenge](#createchallenge-method-ocra-class). Possible values are:

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

# ChallengeInput Property ([OCRA](#ocra-class) Class)

The input for the signature challenge.

## Syntax

```text
public byte[] getChallengeInput();
public void setChallengeInput(byte[] challengeInput);
```

## Default Value

""

## Remarks

This property specifies the data used when creating the signature challenge. This is only used when calling [CreateChallenge](#createchallenge-method-ocra-class) when [ChallengeType](#challengetype-property-ocra-class) is set to Signature.

# ChallengeLength Property ([OCRA](#ocra-class) Class)

The challenge length.

## Syntax

```text
public int getChallengeLength();
public void setChallengeLength(int challengeLength);
```

## Default Value

8

## Remarks

This setting specifies the length of the [Challenge](#challenge-property-ocra-class) that is created when calling [CreateChallenge](#createchallenge-method-ocra-class). Valid values are from 4 to 64. The default value is 8.

# ChallengeType Property ([OCRA](#ocra-class) Class)

The challenge type.

## Syntax

```text
public int getChallengeType();
public void setChallengeType(int challengeType);

Enumerated values:
  public final static int ctRandom = 0;
  public final static int ctSignature = 1;
```

## 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](#challengeinput-property-ocra-class). |

When setting this property to 0 (ctRandom) and calling [CreateChallenge](#createchallenge-method-ocra-class) the class will populate [Challenge](#challenge-property-ocra-class) with a randomly generated value.

When setting this property to 1 (ctSignature) and calling [CreateChallenge](#createchallenge-method-ocra-class) the class creates a Hash-based Message Authentication Code (HMAC) value using the data specified in [ChallengeInput](#challengeinput-property-ocra-class) and then populate [Challenge](#challenge-property-ocra-class) with the formatted result.

# Counter Property ([OCRA](#ocra-class) Class)

The counter.

## Syntax

```text
public long getCounter();
public void setCounter(long counter);
```

## Default Value

0

## Remarks

This property specifies the counter.

If a counter is required this must be set before calling [CalculateResponse](#calculateresponse-method-ocra-class) and [VerifyResponse](#verifyresponse-method-ocra-class). To determine if a counter is required assign [OCRASuite](#ocrasuite-property-ocra-class) to the OCRA suite and check the value of [RequireCounter](#requirecounter-property-ocra-class).

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](#ocra-class) Class)

The HMAC Hash Algorithm.

## Syntax

```text
public int getHashAlgorithm();
public void setHashAlgorithm(int hashAlgorithm);

Enumerated values:
  public final static int haSHA1 = 0;
  public final static int haSHA256 = 1;
  public final static int haSHA512 = 2;
```

## Default Value

0

## Remarks

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

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

# Key Property ([OCRA](#ocra-class) Class)

The secret key.

## Syntax

```text
public byte[] getKey();
public void setKey(byte[] key);
```

## Default Value

""

## Remarks

This property holds the secret key used when calling [CalculateResponse](#calculateresponse-method-ocra-class) and [VerifyResponse](#verifyresponse-method-ocra-class).

This property is also used when calling [CreateChallenge](#createchallenge-method-ocra-class) when [ChallengeType](#challengetype-property-ocra-class) is set to Signature.

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

# OCRASuite Property ([OCRA](#ocra-class) Class)

The OCRASuite defines parameters about the challenge and response.

## Syntax

```text
public String getOCRASuite();
public void setOCRASuite(String OCRASuite);
```

## 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](#createchallenge-method-ocra-class). This property must be set before calling [CalculateResponse](#calculateresponse-method-ocra-class) or [VerifyResponse](#verifyresponse-method-ocra-class).

When calling [CreateChallenge](#createchallenge-method-ocra-class) the following properties will be used to create the OCRASuite:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

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](#ocra-class) Class)

The password.

## Syntax

```text
public byte[] getPassword();
public void setPassword(byte[] password);
```

## Default Value

""

## Remarks

This property specifies the password.

If a password is required this must be set before calling [CalculateResponse](#calculateresponse-method-ocra-class) and [VerifyResponse](#verifyresponse-method-ocra-class). To determine if a password is required assign [OCRASuite](#ocrasuite-property-ocra-class) to the OCRA suite and check the value of [RequirePassword](#requirepassword-property-ocra-class).

# RequireCounter Property ([OCRA](#ocra-class) Class)

Whether a Counter value is required to create the response.

## Syntax

```text
public boolean isRequireCounter();
public void setRequireCounter(boolean requireCounter);
```

## Default Value

False

## Remarks

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

This may be set before calling [CreateChallenge](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class)

# RequirePassword Property ([OCRA](#ocra-class) Class)

Whether a Password is required to create the response.

## Syntax

```text
public boolean isRequirePassword();
public void setRequirePassword(boolean requirePassword);
```

## Default Value

False

## Remarks

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

This may be set before calling [CreateChallenge](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class)

# RequireTimeStamp Property ([OCRA](#ocra-class) Class)

Whether a TimeStamp is required to create the response.

## Syntax

```text
public boolean isRequireTimeStamp();
public void setRequireTimeStamp(boolean requireTimeStamp);
```

## Default Value

False

## Remarks

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

This may be set before calling [CreateChallenge](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class)

The class will automatically use the current system time when calling [CalculateResponse](#calculateresponse-method-ocra-class) and [VerifyResponse](#verifyresponse-method-ocra-class) if this property is True. The [CurrentTime](#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:

- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

# Response Property ([OCRA](#ocra-class) Class)

The OCRA response.

## Syntax

```text
public byte[] getResponse();
public void setResponse(byte[] response);
```

## Default Value

""

## Remarks

This property holds the challenge response.

This is populated after calling [CalculateResponse](#calculateresponse-method-ocra-class). This must be set before calling [VerifyResponse](#verifyresponse-method-ocra-class).

# ResponseLength Property ([OCRA](#ocra-class) Class)

Defines the length of the response.

## Syntax

```text
public int getResponseLength();
public void setResponseLength(int responseLength);
```

## 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](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class). When calling [CalculateResponse](#calculateresponse-method-ocra-class) the calculated [Response](#response-property-ocra-class) will be a value with this length.

The default value is 6.

# CalculateResponse Method ([OCRA](#ocra-class) Class)

This method calculates the response to the given challenge.

## Syntax

```text
public void calculateResponse();
```

## Remarks

This method calculates [Response](#response-property-ocra-class) to the given [Challenge](#challenge-property-ocra-class).

Before calling this method set [OCRASuite](#ocrasuite-property-ocra-class) to the suite obtained from the other party and set [Challenge](#challenge-property-ocra-class) to the received challenge.

After setting [OCRASuite](#ocrasuite-property-ocra-class) the following properties are populated, which provide requirements for the response:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

Inspect these properties to determine the requirements and provide any required values such as [Counter](#counter-property-ocra-class) or [Password](#password-property-ocra-class). Set [Key](#key-property-ocra-class) to the key used during the HMAC computation. Set [Challenge](#challenge-property-ocra-class) to the received challenge.

Call this method to calculate the response. After calling this method the [Response](#response-property-ocra-class) property is populated. The response may then be transmitted to the other party for verification.

The following properties are applicable when calling this method:

- [Challenge](#challenge-property-ocra-class)
- [Counter](#counter-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)
- [OCRASuite](#ocrasuite-property-ocra-class)
- [Password](#password-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [CurrentTime](#CurrentTime)
- [SessionInfo](#SessionInfo)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)

**Random Challenge Example**

```text
//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**

```text
//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](#ocra-class) Class)

Sets or retrieves a configuration setting.

## Syntax

```text
public String config(String configurationString);
```

## Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, 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-ocra-class), you must call *Config("PROPERTY")*. The value will be returned as a string.

# CreateChallenge Method ([OCRA](#ocra-class) Class)

Creates the challenge.

## Syntax

```text
public void createChallenge();
```

## Remarks

This method creates a [Challenge](#challenge-property-ocra-class). After calling this method the [Challenge](#challenge-property-ocra-class) property will be populated with the created value.

When [ChallengeType](#challengetype-property-ocra-class) is set to ctRandom the following properties are applicable:

- [ChallengeType](#challengetype-property-ocra-class)
- [ChallengeFormat](#challengeformat-property-ocra-class)
- [ChallengeLength](#challengelength-property-ocra-class)

When [ChallengeType](#challengetype-property-ocra-class) is set to ctSignature the following properties are applicable:

- [ChallengeType](#challengetype-property-ocra-class)
- [ChallengeFormat](#challengeformat-property-ocra-class)
- [ChallengeLength](#challengelength-property-ocra-class)
- [ChallengeInput](#challengeinput-property-ocra-class) (required)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)

In addition to creating the [Challenge](#challenge-property-ocra-class) this method will also create the [OCRASuite](#ocrasuite-property-ocra-class) which defines parameters required by the other party to calculate a response. The following properties are applicable to [OCRASuite](#ocrasuite-property-ocra-class) creation:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

**Random Challenge Example**

```text
//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**

```text
//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](#ocra-class) Class)

Reset the variables to default value.

## Syntax

```text
public void reset();
```

## Remarks

This method will reset the variables to default value.

# VerifyResponse Method ([OCRA](#ocra-class) Class)

This method verifies the response.

## Syntax

```text
public boolean verifyResponse();
```

## Remarks

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

Before calling this method set [OCRASuite](#ocrasuite-property-ocra-class), [Challenge](#challenge-property-ocra-class), and [Response](#response-property-ocra-class).

After setting [OCRASuite](#ocrasuite-property-ocra-class) the following properties are populated, which provide requirements for the response:

- [ChallengeFormat](#challengeformat-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [RequireCounter](#requirecounter-property-ocra-class)
- [RequirePassword](#requirepassword-property-ocra-class)
- [RequireTimeStamp](#requiretimestamp-property-ocra-class)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)
- [RequireSessionInfo](#RequireSessionInfo)
- [SessionInfoLength](#SessionInfoLength)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)

These properties may be inspected to determine the requirements. Provide any required values such as [Counter](#counter-property-ocra-class) or [Password](#password-property-ocra-class). Set [Challenge](#challenge-property-ocra-class) to the original challenge that was issued. Set [Response](#response-property-ocra-class) to the received response. Set [Key](#key-property-ocra-class) 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:

- [Challenge](#challenge-property-ocra-class)
- [Response](#response-property-ocra-class)
- [Counter](#counter-property-ocra-class)
- [HashAlgorithm](#hashalgorithm-property-ocra-class)
- [Key](#key-property-ocra-class)
- [OCRASuite](#ocrasuite-property-ocra-class)
- [Password](#password-property-ocra-class)
- [ResponseLength](#responselength-property-ocra-class)
- [CurrentTime](#CurrentTime)
- [SessionInfo](#SessionInfo)
- [TimeStepSize](#TimeStepSize)
- [TimeStepUnit](#TimeStepUnit)
- [PasswordHashAlgorithm](#PasswordHashAlgorithm)

**Random Challenge Example**

```text
//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**

```text
//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](#ocra-class) Class)

Fired when information is available about errors during data delivery.

## Syntax

```text
public class DefaultOCRAEventListener implements OCRAEventListener {
  ...
  public void error(OCRAErrorEvent e) {}
  ...
}

public class OCRAErrorEvent {
  public int errorCode;
  public String description;
}
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class 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-ocra-class) section.

# Config Settings ([OCRA](#ocra-class) Class)

 The class 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 class, access to these *internal properties* is provided through the [Config](#config-method-ocra-class) method.

### OCRA Config Settings

**CounterHex**: The counter value as a hexadecimal string.This setting may be used instead of [Counter](#counter-property-ocra-class) 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 class will use the system time when [CalculateResponse](#calculateresponse-method-ocra-class) or [VerifyResponse](#verifyresponse-method-ocra-class) is called and [RequireTimeStamp](#requiretimestamp-property-ocra-class) 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](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class)

**SessionInfo**: The session information.This setting specifies the session info when [RequireSessionInfo](#RequireSessionInfo) is set to True. This value should be specified before calling [CalculateResponse](#calculateresponse-method-ocra-class) or [VerifyResponse](#verifyresponse-method-ocra-class), and should be of length [SessionInfoLength](#SessionInfoLength).

**SessionInfoLength**: The length of the session information.This setting specifies the length of the session information.

This may be set before calling [CreateChallenge](#createchallenge-method-ocra-class), when the [OCRASuite](#ocrasuite-property-ocra-class) is generated.

When [OCRASuite](#ocrasuite-property-ocra-class) is assigned this value is updated to reflect the options specified in the [OCRASuite](#ocrasuite-property-ocra-class)

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 class 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 class 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 class 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*.

**UseDaemonThreads**: Whether threads created by the class are daemon threads.If set to True (default), when the class creates a thread, the thread's Daemon property will be explicitly set to True. When set to False, the class will not set the Daemon property on the created thread. The default value is True.

**UseFIPSCompliantAPI**: Tells the class whether or not to use FIPS certified APIs.When set to *true*, the class 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.

The Java edition requires installation of the FIPS-certified Bouncy Castle library regardless of the target operating system. This can be downloaded from [https://www.bouncycastle.org/fips-java/](https://www.bouncycastle.org/fips-java/). Only the "Provider" library is needed. The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

```text
import java.security.Security;
import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;
```

The Bouncy Castle provider must be added as a valid provider and must also be configured to operate in FIPS mode:

```text
System.setProperty("org.bouncycastle.fips.approved_only","true");
Security.addProvider(new BouncyCastleFipsProvider());
```

When [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) is *true*, Secure Sockets Layer (SSL)-enabled classes can optionally be configured to use the Transport Layer Security (TLS) Bouncy Castle library. When SSLProvider is set to *sslpAutomatic* (default) or *sslpInternal*, an internal TLS implementation is used, but all cryptographic operations are offloaded to the Bouncy Castle FIPS provider to achieve FIPS-compliant operation. If SSLProvider is set to *sslpPlatform*, the Bouncy Castle JSSE will be used in place of the internal TLS implementation.

To enable the use of the Bouncy Castle JSSE take the following steps in addition to the steps above. Both the Bouncy Castle FIPS provider and the Bouncy Castle JSSE must be configured to use the Bouncy Castle TLS library in FIPS mode. Obtain the Bouncy Castle TLS library from [https://www.bouncycastle.org/fips-java/](https://www.bouncycastle.org/fips-java/). The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

```text
import java.security.Security;
import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;

//required to use BCJSSE when SSLProvider is set to sslpPlatform
import org.bouncycastle.jsse.provider.BouncyCastleJsseProvider;
```

The Bouncy Castle provider must be added as a valid provider and also must be configured to operate in FIPS mode:

```text
System.setProperty("org.bouncycastle.fips.approved_only","true");
Security.addProvider(new BouncyCastleFipsProvider());

//required to use BCJSSE when SSLProvider is set to sslpPlatform
Security.addProvider(new BouncyCastleJsseProvider("fips:BCFIPS"));

//optional - configure logging level of BCJSSE
Logger.getLogger("org.bouncycastle.jsse").setLevel(java.util.logging.Level.OFF);

//configure the class to use BCJSSE
component.setSSLProvider(1); //platform
component.config("UseFIPSCompliantAPI=true");
```

 NOTE: TLS 1.3 support requires the Bouncy Castle TLS library version 1.0.14 or later.

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 classes 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: 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 class will use the system security libraries by default to perform cryptographic functions where applicable.

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

 This setting is set to *false* by default on all platforms.

**UseVirtualThreads**: Whether threads created by the class use virtual threads instead of platform threads.If set to *true*, when the class creates a thread, it will be created as a virtual thread instead of a platform thread. Virtual threads are lightweight threads managed by the JVM that are multiplexed onto a small pool of carrier threads, significantly reducing memory usage and platform thread count under high-concurrency workloads. Requires Java 24 or later. The default value is *false*.

# Trappable Errors ([OCRA](#ocra-class) Class)

### 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. |