# HMAC Component

The HMAC component may be used to produce a MAC (or Tag) value using the HMAC algorithm.

## Syntax

```text
nsoftware.IPWorksEncrypt.HMAC
```

## Remarks

The HMAC component allows you to compute a MAC value using various algorithms including HMACMD5, HMACSHA1, HMACSHA224, HMACSHA256, HMACSHA384, HMACSHA512, etc.

**ComputeMAC Notes**

[ComputeMAC](#computemac-method-hmac-component) computes the MAC (Message Authentication Code) from the input data.

Before calling this method set [Key](#key-property-hmac-component) to a key. If [EncodeMAC](#encodemac-property-hmac-component) is set to True (default) the output data will be hex encoded.

**Input Notes**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked are as follows:

- [SetInputStream](#setinputstream-method-hmac-component)
- [InputFile](#inputfile-property-hmac-component)
- [InputMessage](#inputmessage-property-hmac-component)

 When a valid source is found the search stops.

After calling this method [MACValue](#macvalue-property-hmac-component) will be populated with the computed MAC value.

**ComputeMAC Example**

```csharp
HMAC hmac = new HMAC();
hmac.Algorithm = HMACAlgorithms.hmacSHA256;
hmac.KeyB = new byte[] { 0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0, 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0 };
hmac.InputMessage = "Hello HMAC";
hmac.EncodeMAC = true; //hex output
hmac.ComputeMAC();

//This outputs "FDFB2DD7121E743D933718E165659A46DF431CFBCCDEA121C68CE13EA83153B3"
Console.WriteLine(hmac.MACValue);
```

**ComputeMACBlock Notes**

[ComputeMACBlock](#computemacblock-method-hmac-component) allows input to the component to be specified in blocks. This method will return the MAC value only when the parameter LastBlock is True.

*InputBuffer* specifies the input data.

*LastBlock* specifies whether the block is the last block. If this is False the method will return an empty byte array.

To calculate the MAC value of data that is broken apart into multiple blocks make multiple calls to this method. For instance:

```text
//Encode output in hex
hmac.EncodeMAC = true; //hex output

//Pass any number of parts, of any size
hmac.ComputeMACBlock(part1,false);
hmac.ComputeMACBlock(part2,false);
hmac.ComputeMACBlock(part3,false);

//Pass true for the last block
hmac.ComputeMACBlock(lastPart,true);

//The MACValue property holds the MAC value
Console.WriteLine(hmac.MACValue);
```

## Property List

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

|  |  |
| --- | --- |
| [Algorithm](#algorithm-property-hmac-component) | The algorithm used to create the HMAC. |
| [EncodeMAC](#encodemac-property-hmac-component) | Whether the MAC value is hex encoded. |
| [InputFile](#inputfile-property-hmac-component) | The file to process. |
| [InputMessage](#inputmessage-property-hmac-component) | The message to process. |
| [Key](#key-property-hmac-component) | The key to be used when computing a MAC (Message Authentication Code). |
| [MACValue](#macvalue-property-hmac-component) | The computed MAC value. |

## Method List

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

|  |  |
| --- | --- |
| [ComputeMAC](#computemac-method-hmac-component) | Computes the MAC. |
| [ComputeMACBlock](#computemacblock-method-hmac-component) | Computes the MAC value of specified data. |
| [Config](#config-method-hmac-component) | Sets or retrieves a configuration setting. |
| [Reset](#reset-method-hmac-component) | Resets the component. |
| [SetInputStream](#setinputstream-method-hmac-component) | Sets the stream from which the component will read data. |

## 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-hmac-component) | Fired when information is available about errors during data delivery. |
| [Progress](#progress-event-hmac-component) | Fired as progress is made. |

## Config Settings

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

|  |  |
| --- | --- |
| [CloseInputStreamAfterProcessing](#CloseInputStreamAfterProcessing) | Determines whether or not the input stream is closed after processing. |
| [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. |

# Algorithm Property ([HMAC](#hmac-component) Component)

The algorithm used to create the HMAC.

## Syntax

```text
public HMACAlgorithms Algorithm { get; set; }
enum HMACAlgorithms {
  hmacMD5,
  hmacSHA1,
  hmacSHA224,
  hmacSHA256,
  hmacSHA384,
  hmacSHA512,
  hmacRIPEMD160
}
```

## Default Value

3

## Remarks

This property specifies the algorithm used when calling [ComputeMAC](#computemac-method-hmac-component). Possible values are:

|  |  |
| --- | --- |
| 0 (hmacMD5) | HMAC-MD5 |
| 1 (hmacSHA1) | HMAC-SHA1 |
| 2 (hmacSHA224) | HMAC-SHA224 |
| 3 (hmacSHA256) | HMAC-SHA256 |
| 4 (hmacSHA384) | HMAC-SHA384 |
| 5 (hmacSHA512) | HMAC-SHA512 |
| 6 (hmacRIPEMD160) | HMAC-RIPEMD-160 |

# EncodeMAC Property ([HMAC](#hmac-component) Component)

Whether the MAC value is hex encoded.

## Syntax

```text
public bool EncodeMAC { get; set; }
```

## Default Value

True

## Remarks

This property specifies whether the computed MAC value is hex encoded. When set to True (default) the component will hex encode the computed MAC for easier use. Set this value to False to obtain the MAC value in an unmodified form.

The default value is True.

# InputFile Property ([HMAC](#hmac-component) Component)

The file to process.

## Syntax

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

## Default Value

""

## Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file which will be processed.

**Input and Output Properties**

The component will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-hmac-component)
- InputFile
- [InputMessage](#inputmessage-property-hmac-component)

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set [CloseInputStreamAfterProcessing](#CloseInputStreamAfterProcessing) or [CloseOutputStreamAfterProcessing](#CloseOutputStreamAfterProcessing).

# InputMessage Property ([HMAC](#hmac-component) Component)

The message to process.

## Syntax

```text
public string InputMessage { get; set; }
public byte[] InputMessageB { get; set; }
```

## Default Value

""

## Remarks

This property specifies the message to be processed.

**Input and Output Properties**

The component will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

- [SetInputStream](#setinputstream-method-hmac-component)
- [InputFile](#inputfile-property-hmac-component)
- InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

- SetOutputStream
- OutputFile
- OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set [CloseInputStreamAfterProcessing](#CloseInputStreamAfterProcessing) or [CloseOutputStreamAfterProcessing](#CloseOutputStreamAfterProcessing).

# Key Property ([HMAC](#hmac-component) Component)

The key to be used when computing a MAC (Message Authentication Code).

## Syntax

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

## Default Value

""

## Remarks

This property holds the secret key used when computing the [MACValue](#macvalue-property-hmac-component). The key can be arbitrarily long.

It is recommended that the length of the key be equal to or larger than the hash size of the algorithm. Use of keys shorter than the hash size is discouraged.

**Sizes (in bytes)**

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  | SHA1 | SHA224 | SHA256 | SHA384 | SHA512 | MD5 | RIPEMD160 |
| Recommended Key Size | 20 | 28 | 32 | 48 | 64 | 16 | 20 |
| Hash Size | 20 | 28 | 32 | 48 | 64 | 16 | 20 |
| Block Size | 64 | 64 | 64 | 128 | 128 | 64 | 64 |

**Key Length Details**

As mentioned above it is recommended to use a key size equal to the hash size. Use of keys larger than the hash size does not typically significantly increase the function strength. Keys of any length are technically valid however see the below processing rules to understand how keys of varying lengths are treated:

- If the key length is equal to the hash size (recommended) it is used without modification.
- If the key length is less than the hash size it is used without modification.
- If the key length is less than or equal to the block size it is used without modification.
- If the key length is larger than the block size it is first hashed with the same algorithm.

# MACValue Property ([HMAC](#hmac-component) Component)

The computed MAC value.

## Syntax

```text
public string MACValue { get; }
public byte[] MACValueB { get; }
```

## Default Value

""

## Remarks

The computed MAC value. This property is populated after calling [ComputeMAC](#computemac-method-hmac-component).

This property is read-only.

# ComputeMAC Method ([HMAC](#hmac-component) Component)

Computes the MAC.

## Syntax

```text
public void ComputeMAC();

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

## Remarks

ComputeMAC computes the MAC (Message Authentication Code) from the input data.

Before calling this method set [Key](#key-property-hmac-component) to a key. If [EncodeMAC](#encodemac-property-hmac-component) is set to True (default) the output data will be hex encoded.

**Input Notes**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked are as follows:

- [SetInputStream](#setinputstream-method-hmac-component)
- [InputFile](#inputfile-property-hmac-component)
- [InputMessage](#inputmessage-property-hmac-component)

 When a valid source is found the search stops.

After calling this method [MACValue](#macvalue-property-hmac-component) will be populated with the computed MAC value.

**ComputeMAC Example**

```csharp
HMAC hmac = new HMAC();
hmac.Algorithm = HMACAlgorithms.hmacSHA256;
hmac.KeyB = new byte[] { 0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0, 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0 };
hmac.InputMessage = "Hello HMAC";
hmac.EncodeMAC = true; //hex output
hmac.ComputeMAC();

//This outputs "FDFB2DD7121E743D933718E165659A46DF431CFBCCDEA121C68CE13EA83153B3"
Console.WriteLine(hmac.MACValue);
```

# ComputeMACBlock Method ([HMAC](#hmac-component) Component)

Computes the MAC value of specified data.

## Syntax

```text
public byte[] ComputeMACBlock(byte[] inputBuffer, bool lastBlock);

Async Version
public async Task<byte[]> ComputeMACBlock(byte[] inputBuffer, bool lastBlock);
public async Task<byte[]> ComputeMACBlock(byte[] inputBuffer, bool lastBlock, CancellationToken cancellationToken);
```

## Remarks

ComputeMACBlock allows input to the component to be specified in blocks. This method will return the MAC value only when the parameter LastBlock is True.

*InputBuffer* specifies the input data.

*LastBlock* specifies whether the block is the last block. If this is False the method will return an empty byte array.

To calculate the MAC value of data that is broken apart into multiple blocks make multiple calls to this method. For instance:

```text
//Encode output in hex
hmac.EncodeMAC = true; //hex output

//Pass any number of parts, of any size
hmac.ComputeMACBlock(part1,false);
hmac.ComputeMACBlock(part2,false);
hmac.ComputeMACBlock(part3,false);

//Pass true for the last block
hmac.ComputeMACBlock(lastPart,true);

//The MACValue property holds the MAC value
Console.WriteLine(hmac.MACValue);
```

# Config Method ([HMAC](#hmac-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-hmac-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-hmac-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# Reset Method ([HMAC](#hmac-component) Component)

Resets the component.

## Syntax

```text
public void Reset();

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

## Remarks

When called, the component will reset all of its properties to their default values.

# SetInputStream Method ([HMAC](#hmac-component) Component)

Sets the stream from which the component will read data.

## Syntax

```text
public void SetInputStream(System.IO.Stream inputStream);

Async Version
public async Task SetInputStream(System.IO.Stream inputStream);
public async Task SetInputStream(System.IO.Stream inputStream, CancellationToken cancellationToken);
```

## Remarks

This method sets the stream from which the component will read data.

**Input Notes**

The component will determine the source of the input based on which properties are set.

The order in which the input properties are checked are as follows:

- SetInputStream
- [InputFile](#inputfile-property-hmac-component)
- [InputMessage](#inputmessage-property-hmac-component)

 When a valid source is found the search stops.

# Error Event ([HMAC](#hmac-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

```text
public event OnErrorHandler OnError;

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

public class HMACErrorEventArgs : 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-hmac-component) section.

# Progress Event ([HMAC](#hmac-component) Component)

Fired as progress is made.

## Syntax

```text
public event OnProgressHandler OnProgress;

public delegate void OnProgressHandler(object sender, HMACProgressEventArgs e);

public class HMACProgressEventArgs : EventArgs {
  public long BytesProcessed { get; }
  public int PercentProcessed { get; }
}
```

## Remarks

This event is fired automatically as data is processed by the component.

The *PercentProcessed* parameter indicates the current status of the operation.

The *BytesProcessed* parameter holds the total number of bytes processed so far.

# Config Settings ([HMAC](#hmac-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-hmac-component) method.

### HMAC Config Settings

**CloseInputStreamAfterProcessing**: Determines whether or not the input stream is closed after processing.Determines whether or not the input stream set by [SetInputStream](#setinputstream-method-hmac-component) is closed after processing is complete. The default value is True.

### 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 ([HMAC](#hmac-component) Component)

### HMAC Errors

|  |  |
| --- | --- |
| 104 | Cannot read or write file. |
| 108 | Invalid key size. |
| 304 | Cannot write file. |
| 305 | Cannot read file. |