# DPAPI Component

The DPAPI class allows you to protect and unprotect data.

## Syntax

```text
ipworksencrypt.DPAPI
```

## Remarks

On Windows, the struct supports the classic Microsoft Windows Data Protection API (DPAPI) or CNG DPAPI implementation. The use of [UseCNG](#usecng-property-dpapi-component) determines which implementation is used. Support for macOS is also available via the macOS keychain.

The classic DPAPI functionality protects data on a single system. The CNG DPAPI is designed with modern use cases involved. In many cases, especially with cloud computing, protection and unprotection may be done on different systems. With this in mind the Microsoft CNG DPAPI allows encrypting to a set of principals that can be used to unprotect the data on other systems after authenticating. On macOS, a key is saved in the Keychain which is used to protect and uprotect data.

### Protecting Data

[Protect](#protect-method-dpapi-component) protects the specified data.

On Windows, the struct supports the classic Microsoft Windows Data Protection API (DPAPI) or CNG DPAPI implementation. The use of [UseCNG](#usecng-property-dpapi-component) determines which implementation is used. Support for macOS is also available via the macOS keychain.

When using classic DPAPI ([UseCNG](#usecng-property-dpapi-component) is *False*), the following optional properties are applicable:

- [DataDescription](#datadescription-property-dpapi-component)
- [Password](#password-property-dpapi-component)
- [PromptTitle](#prompttitle-property-dpapi-component)
- [PromptUser](#promptuser-property-dpapi-component)

When using CNG DPAPI ([UseCNG](#usecng-property-dpapi-component) is *True*), the following properties are applicable:

- [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) (required)
- [EscapeDescriptor](#EscapeDescriptor)
- [UseStreamMode](#UseStreamMode)

On macOS, the following settings are applicable:

- [UseSystemKeychain](#UseSystemKeychain)
- [KeychainServiceName](#KeychainServiceName)

 **Input and Output Properties**

The struct 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:

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

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

**Code Example (Classic DPAPI - [UseCNG](#usecng-property-dpapi-component) is False)**

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (CNG DPAPI - [UseCNG](#usecng-property-dpapi-component) is True**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.ProtectionDescriptor = "LOCAL=user";
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (macOS**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

### Unprotecting Data

[Unprotect](#unprotect-method-dpapi-component) unprotects the specified data.

On Windows, the struct supports the classic Microsoft Windows Data Protection API (DPAPI) or CNG DPAPI implementation. The use of [UseCNG](#usecng-property-dpapi-component) determines which implementation is used. Support for macOS is also available via the macOS keychain.

When using classic DPAPI ([UseCNG](#usecng-property-dpapi-component) is *False*), the following optional properties are applicable:

- [DataDescription](#datadescription-property-dpapi-component) (populated after completion)
- [Password](#password-property-dpapi-component)

When using CNG DPAPI ([UseCNG](#usecng-property-dpapi-component) is *True*), the following properties are applicable:

- [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) (populated after completion)
- [UseStreamMode](#UseStreamMode)

On macOS, the following settings are applicable:

- [UseSystemKeychain](#UseSystemKeychain)
- [KeychainServiceName](#KeychainServiceName)

**Input and Output Properties**

The struct 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:

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

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

**Code Example (Classic DPAPI - [UseCNG](#usecng-property-dpapi-component) is False)**

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (CNG DPAPI - [UseCNG](#usecng-property-dpapi-component) is True**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.ProtectionDescriptor = "LOCAL=user";
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (macOS**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

## Property List

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

|  |  |
| --- | --- |
| [DataDescription](#datadescription-property-dpapi-component) | The description of data. |
| [InputFile](#inputfile-property-dpapi-component) | The file to process. |
| [InputMessage](#inputmessage-property-dpapi-component) | The message to process. |
| [OutputFile](#outputfile-property-dpapi-component) | The output file when encrypting or decrypting. |
| [OutputMessage](#outputmessage-property-dpapi-component) | The output message after processing. |
| [Overwrite](#overwrite-property-dpapi-component) | Indicates whether or not the class should overwrite files. |
| [Password](#password-property-dpapi-component) | An optional password to further protect data. |
| [PromptTitle](#prompttitle-property-dpapi-component) | The title of the prompt window. |
| [PromptUser](#promptuser-property-dpapi-component) | Whether to display a prompt. |
| [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) | The CNG protection descriptor. |
| [UseCNG](#usecng-property-dpapi-component) | Whether to use CNG DPAPI. |
| [UseHex](#usehex-property-dpapi-component) | Whether input or output is hex encoded. |

## Method List

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

|  |  |
| --- | --- |
| [Config](#config-method-dpapi-component) | Sets or retrieves a configuration setting. |
| [Protect](#protect-method-dpapi-component) | Protects the data. |
| [Reset](#reset-method-dpapi-component) | Resets the class. |
| [Unprotect](#unprotect-method-dpapi-component) | Unprotects the 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-dpapi-component) | Fired when information is available about errors during data delivery. |
| [Progress](#progress-event-dpapi-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.*

|  |  |
| --- | --- |
| [EscapeDescriptor](#EscapeDescriptor) | Whether to escape the protection descriptor. |
| [KeychainServiceName](#KeychainServiceName) | Service name for the keychain on macOS. |
| [ProtectionFlags](#ProtectionFlags) | Used to specify additional options. |
| [UseStreamMode](#UseStreamMode) | Whether to use the CNG streaming operations. |
| [UseSystemKeychain](#UseSystemKeychain) | Whether to save the key and IV in the macOS System keychain. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [CodePage](#CodePage) | The system code page used for Unicode to Multibyte translations. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# DataDescription Property ([DPAPI](#dpapi-component) Component)

The description of data.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) DataDescription() (string, error)func (obj *DPAPI) SetDataDescription(value string) error
```

## Default Value

""

## Remarks

This property specifies an optional description of the protected data.

This may be set before calling [Protect](#protect-method-dpapi-component). This property will be populated when calling [Unprotect](#unprotect-method-dpapi-component).

This setting is not applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

## Data Type

**string**

# InputFile Property ([DPAPI](#dpapi-component) Component)

The file to process.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) InputFile() (string, error)func (obj *DPAPI) SetInputFile(value string) error
```

## 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 struct 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:

- InputFile
- [InputMessage](#inputmessage-property-dpapi-component)

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

## Data Type

**string**

# InputMessage Property ([DPAPI](#dpapi-component) Component)

The message to process.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) InputMessage() ([]byte, error)func (obj *DPAPI) SetInputMessage(value []byte) error
```

## Default Value

""

## Remarks

This property specifies the message to be processed.

**Input and Output Properties**

The struct 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:

- [InputFile](#inputfile-property-dpapi-component)
- InputMessage

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

## Data Type

**[]byte**

# OutputFile Property ([DPAPI](#dpapi-component) Component)

The output file when encrypting or decrypting.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) OutputFile() (string, error)func (obj *DPAPI) SetOutputFile(value string) error
```

## Default Value

""

## Remarks

This property specifies the file to which the output will be written when Encrypt or Decrypt is called. This may be set to an absolute or relative path.

This property is only applicable to Encrypt and Decrypt.

**Input and Output Properties**

The struct 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:

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

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

- OutputFile
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

## Data Type

**string**

# OutputMessage Property ([DPAPI](#dpapi-component) Component)

The output message after processing.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) OutputMessage() ([]byte, error)
```

## Default Value

""

## Remarks

This property will be populated with the output from the operation if [OutputFile](#outputfile-property-dpapi-component) is not set.

**Input and Output Properties**

The struct 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:

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

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

- [OutputFile](#outputfile-property-dpapi-component)
- OutputMessage: The output data is written to this property if no other destination is specified.

This property is read-only.

## Data Type

**[]byte**

# Overwrite Property ([DPAPI](#dpapi-component) Component)

Indicates whether or not the class should overwrite files.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Overwrite() (bool, error)func (obj *DPAPI) SetOverwrite(value bool) error
```

## Default Value

false

## Remarks

This property indicates whether or not the struct will overwrite [OutputFile](#outputfile-property-dpapi-component). If Overwrite is False, an error will be thrown whenever [OutputFile](#outputfile-property-dpapi-component) exists before an operation. The default value is False.

## Data Type

**bool**

# Password Property ([DPAPI](#dpapi-component) Component)

An optional password to further protect data.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Password() (string, error)func (obj *DPAPI) SetPassword(value string) error
```

## Default Value

""

## Remarks

This property may be set to a password to protect the data further.

When protecting data without specifying a password any application running under the same user account can unprotect the data. By specifying a password another piece of information is required to unprotect the data.

This may be set before calling [Protect](#protect-method-dpapi-component). If a password was specified when protecting data it must be set before calling [Unprotect](#unprotect-method-dpapi-component).

This setting is not applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

## Data Type

**string**

# PromptTitle Property ([DPAPI](#dpapi-component) Component)

The title of the prompt window.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) PromptTitle() (string, error)func (obj *DPAPI) SetPromptTitle(value string) error
```

## Default Value

""

## Remarks

This property specifies the title of the prompt dialog if [PromptUser](#promptuser-property-dpapi-component) is True. The default value is empty string.

This setting is not applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

## Data Type

**string**

# PromptUser Property ([DPAPI](#dpapi-component) Component)

Whether to display a prompt.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) PromptUser() (bool, error)func (obj *DPAPI) SetPromptUser(value bool) error
```

## Default Value

false

## Remarks

This property specifies whether a prompt is displayed when calling [Protect](#protect-method-dpapi-component). This dialog is created by the system and informs the user of the request action. The user may accept or cancel the request. If the user cancels the request the [Protect](#protect-method-dpapi-component) method fails with an error.

When True the [PromptTitle](#prompttitle-property-dpapi-component) may be set to customize the window title.

This setting is not applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS. ;

## Data Type

**bool**

# ProtectionDescriptor Property ([DPAPI](#dpapi-component) Component)

The CNG protection descriptor.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) ProtectionDescriptor() (string, error)func (obj *DPAPI) SetProtectionDescriptor(value string) error
```

## Default Value

""

## Remarks

This property specifies the protection descriptor rule string. The protection descriptor is used by the system to decide which entities can unprotect the data at a later time. This property must be specified before calling [Protect](#protect-method-dpapi-component). This property is populated after calling [Unprotect](#unprotect-method-dpapi-component).

Protection descriptors can be defined for the following types of authorization:

- A local user or machine
- An account or group in an Active Directory forest
- A set of web credentials
- A certificate in the user's certificate store

A local user or machine may be used for machines that are or are not on a domain. For instance:

- *LOCAL=user*
- *LOCAL=machine*

The use of *SID* and *SDDL* requires that the machine be part of a domain. For instance:

- *SID=S-1-5-21-4392301 AND SID=S-1-5-21-3101812*
- *SDDL=O:S-1-5-5-0-290724G:SYD:(A;;CCDC;;;S-1-5-5-0-290724)(A;;DC;;;WD)*

Certificates may also be used as a descriptor. To decrypt, the certificate with corresponding private key must be present in the user's certificate store. The public certificate can be specified as the SHA1 thumbprint (hash) of the certificate, or the base64 encoded certificate itself. For instance:

- *CERTIFICATE=HashID:28ac375635b82ca3e20a1c9422145bc93965dae7*
- *CERTIFICATE=CertBlob:MIIC7TCCAdWgAw...pgpVgYpppr*

 Note: The base64 certificate data should not include any headers, footers, or whitespace.

The use of *AND* and *OR* operators are accepted in order to encrypt data for multiple parties or establish multiple conditions for decryption.

For more details about protection descriptors and accepted formats please refer to the [Microsoft Documentation for Protection Descriptors](https://docs.microsoft.com/en-us/windows/desktop/seccng/protection-descriptors)

This setting is only applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

## Data Type

**string**

# UseCNG Property ([DPAPI](#dpapi-component) Component)

Whether to use CNG DPAPI.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) UseCNG() (bool, error)func (obj *DPAPI) SetUseCNG(value bool) error
```

## Default Value

false

## Remarks

The struct supports protecting data using either the classic DPAPI or CNG DPAPI implementation. When set to *True* the CNG DPAPI implementation is used. When set to *False* (default) the classic DPAPI implementation is used.

This setting is not applicable on macOS.

## Data Type

**bool**

# UseHex Property ([DPAPI](#dpapi-component) Component)

Whether input or output is hex encoded.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) UseHex() (bool, error)func (obj *DPAPI) SetUseHex(value bool) error
```

## Default Value

false

## Remarks

This property specifies whether the encrypted data is hex encoded.

If set to True, when [Protect](#protect-method-dpapi-component) is called the struct will perform the encryption as normal and then hex encode the output. [OutputMessage](#outputmessage-property-dpapi-component) or [OutputFile](#outputfile-property-dpapi-component) will hold hex encoded data.

If set to True, when [Unprotect](#unprotect-method-dpapi-component) is called the struct will expect [InputMessage](#inputmessage-property-dpapi-component) or [InputFile](#inputfile-property-dpapi-component) to hold hex encoded data. The struct will then hex decode the data and perform decryption as normal.

## Data Type

**bool**

# Config Method ([DPAPI](#dpapi-component) Component)

Sets or retrieves a configuration setting.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Config(ConfigurationString string) (string, error)
```

## Remarks

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

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

# Protect Method ([DPAPI](#dpapi-component) Component)

Protects the data.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Protect() error
```

## Remarks

Protect protects the specified data.

On Windows, the struct supports the classic Microsoft Windows Data Protection API (DPAPI) or CNG DPAPI implementation. The use of [UseCNG](#usecng-property-dpapi-component) determines which implementation is used. Support for macOS is also available via the macOS keychain.

When using classic DPAPI ([UseCNG](#usecng-property-dpapi-component) is *False*), the following optional properties are applicable:

- [DataDescription](#datadescription-property-dpapi-component)
- [Password](#password-property-dpapi-component)
- [PromptTitle](#prompttitle-property-dpapi-component)
- [PromptUser](#promptuser-property-dpapi-component)

When using CNG DPAPI ([UseCNG](#usecng-property-dpapi-component) is *True*), the following properties are applicable:

- [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) (required)
- [EscapeDescriptor](#EscapeDescriptor)
- [UseStreamMode](#UseStreamMode)

On macOS, the following settings are applicable:

- [UseSystemKeychain](#UseSystemKeychain)
- [KeychainServiceName](#KeychainServiceName)

 **Input and Output Properties**

The struct 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:

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

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

**Code Example (Classic DPAPI - [UseCNG](#usecng-property-dpapi-component) is False)**

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (CNG DPAPI - [UseCNG](#usecng-property-dpapi-component) is True**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.ProtectionDescriptor = "LOCAL=user";
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (macOS**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

# Reset Method ([DPAPI](#dpapi-component) Component)

Resets the class.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Reset() error
```

## Remarks

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

# Unprotect Method ([DPAPI](#dpapi-component) Component)

Unprotects the data.

## Syntax

*Go Syntax*

```text
func (obj *DPAPI) Unprotect() error
```

## Remarks

Unprotect unprotects the specified data.

On Windows, the struct supports the classic Microsoft Windows Data Protection API (DPAPI) or CNG DPAPI implementation. The use of [UseCNG](#usecng-property-dpapi-component) determines which implementation is used. Support for macOS is also available via the macOS keychain.

When using classic DPAPI ([UseCNG](#usecng-property-dpapi-component) is *False*), the following optional properties are applicable:

- [DataDescription](#datadescription-property-dpapi-component) (populated after completion)
- [Password](#password-property-dpapi-component)

When using CNG DPAPI ([UseCNG](#usecng-property-dpapi-component) is *True*), the following properties are applicable:

- [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) (populated after completion)
- [UseStreamMode](#UseStreamMode)

On macOS, the following settings are applicable:

- [UseSystemKeychain](#UseSystemKeychain)
- [KeychainServiceName](#KeychainServiceName)

**Input and Output Properties**

The struct 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:

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

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

- [OutputFile](#outputfile-property-dpapi-component)
- [OutputMessage](#outputmessage-property-dpapi-component): The output data is written to this property if no other destination is specified.

**Code Example (Classic DPAPI - [UseCNG](#usecng-property-dpapi-component) is False)**

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (CNG DPAPI - [UseCNG](#usecng-property-dpapi-component) is True**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.ProtectionDescriptor = "LOCAL=user";
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.UseCNG = true;
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

**Code Example (macOS**)

```csharp
//Protect
DPAPI dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessage = "test";
dpapi.Protect();
byte[] protectedData = dpapi.OutputMessageB;

//Unprotect
dpapi = new DPAPI();
dpapi.Config("UseSystemKeychain=false");
dpapi.Config("KeychainServiceName=nsoftware OSDP User Key");
dpapi.InputMessageB = protectedData;
dpapi.Unprotect();
Console.WriteLine(dpapi.OutputMessage); //outputs "test"
```

# Error Event ([DPAPI](#dpapi-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

*Go Syntax*

```text
// DPAPIErrorEventArgs carries the DPAPI Error event's parameters.
type DPAPIErrorEventArgs struct {...}

func (args *DPAPIErrorEventArgs) ErrorCode() int32
func (args *DPAPIErrorEventArgs) Description() string
// DPAPIErrorEvent defines the signature of the DPAPI Error event's handler function.
type DPAPIErrorEvent func(sender *DPAPI, args *DPAPIErrorEventArgs)

func (obj *DPAPI) GetOnErrorHandler() DPAPIErrorEvent
func (obj *DPAPI) SetOnErrorHandler(handlerFunc DPAPIErrorEvent)
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the struct fails with an error.

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-dpapi-component) section.

# Progress Event ([DPAPI](#dpapi-component) Component)

Fired as progress is made.

## Syntax

*Go Syntax*

```text
// DPAPIProgressEventArgs carries the DPAPI Progress event's parameters.
type DPAPIProgressEventArgs struct {...}

func (args *DPAPIProgressEventArgs) BytesProcessed() int64
func (args *DPAPIProgressEventArgs) PercentProcessed() int32
// DPAPIProgressEvent defines the signature of the DPAPI Progress event's handler function.
type DPAPIProgressEvent func(sender *DPAPI, args *DPAPIProgressEventArgs)

func (obj *DPAPI) GetOnProgressHandler() DPAPIProgressEvent
func (obj *DPAPI) SetOnProgressHandler(handlerFunc DPAPIProgressEvent)
```

## Remarks

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

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

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

# Config Settings ([DPAPI](#dpapi-component) Component)

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

### DPAPI Config Settings

**EscapeDescriptor**: Whether to escape the protection descriptor.This setting controls whether the [ProtectionDescriptor](#protectiondescriptor-property-dpapi-component) value is escaped when [Protect](#protect-method-dpapi-component) is called. When set to *False* (default) the value is passed exactly as provided to the underlying system libraries. When set to *True* the value is first escaped according to the escaping rules defined by Microsoft.

The default value of [EscapeDescriptor](#EscapeDescriptor) is *True*.

This setting is only applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

**KeychainServiceName**: Service name for the keychain on macOS.This setting is used to specify the service name for the keychain on macOS. By default, *nsoftware OSDP User Key* is used as the service name for the user keychain. *nsoftware OSDP System Key* is used for the system keychain when [UseSystemKeychain](#UseSystemKeychain) is set to *True*.

**ProtectionFlags**: Used to specify additional options.Additional options are available to restrict or change the behavior of the protect and unprotect operations.

By default no additional settings are specified (the value is 0). You may set this property to the binary 'OR' of one or more of the following values:

|  |  |  |
| --- | --- | --- |
| 1 (0x1) | CRYPTPROTECT_UI_FORBIDDEN | This flag is used for remote situations where presenting a user interface (UI) is not an option. When this flag is set and a UI is specified for either the protect or unprotect operation, the operation fails. |
| 4 (0x4) | CRYPTPROTECT_LOCAL_MACHINE | When this flag is set, it associates the data encrypted with the current computer instead of with an individual user. This is only applicable when calling [Protect](#protect-method-dpapi-component). |
| 8 (0x8) | CRYPTPROTECT_CRED_SYNC | When this flag is used, no data is actually protected. Instead all MasterKeys are queried from disk, which will cause re-encryption in memory, presumably under a changed password. This is only applicable when calling [Protect](#protect-method-dpapi-component). |
| 16 (0x10) | CRYPTPROTECT_AUDIT | This flag causes DPAPI to generate an audit when this data is protected or unprotected. This is only applicable when calling [Protect](#protect-method-dpapi-component). |
| 64 (0x40) | CRYPTPROTECT_VERIFY_PROTECTION | If the protected data blob would be better protected under a new call to the internal protect function and this call succeeds, then GetLastError will return a CRYPT_I_NEW_PROTECTION_REQUIRED status code. This is only applicable when calling [Unprotect](#unprotect-method-dpapi-component). |
| 536870912 (0x20000000) | CRYPTPROTECT_SYSTEM | If data was protected with this flag set, then this flag must be set to unprotect the data. |

This setting is not applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

**UseStreamMode**: Whether to use the CNG streaming operations.When set to *True* the struct will use the CNG streaming operations when [Protect](#protect-method-dpapi-component) and [Unprotect](#unprotect-method-dpapi-component) are called. When working with large amounts of data this can reduce the memory overhead during processing. Note that when enabled [InputFile](#inputfile-property-dpapi-component) and [OutputFile](#outputfile-property-dpapi-component) should be used for optimal memory usage.

The default value of [UseStreamMode](#UseStreamMode) is *False*.

This setting is only applicable when [UseCNG](#usecng-property-dpapi-component) is set to *True*.

This setting is not applicable on macOS.

**UseSystemKeychain**: Whether to save the key and IV in the macOS System keychain.When set to *True*, the key and IV will be saved in the macOS system keychain with the service name *nsoftware OSDP System Key*. Administrator privileges are required to use this config. This config is not supported on iOS.

The default value of [UseSystemKeychain](#UseSystemKeychain) is *False*, and the key and IV are stored in the user keychain with the service name *nsoftware OSDP User Key*.

### 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.

**CodePage**: The system code page used for Unicode to Multibyte translations.The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

|  |  |
| --- | --- |
| Identifier | Name |
| 037 | IBM EBCDIC - U.S./Canada |
| 437 | OEM - United States |
| 500 | IBM EBCDIC - International |
| 708 | Arabic - ASMO 708 |
| 709 | Arabic - ASMO 449+, BCON V4 |
| 710 | Arabic - Transparent Arabic |
| 720 | Arabic - Transparent ASMO |
| 737 | OEM - Greek (formerly 437G) |
| 775 | OEM - Baltic |
| 850 | OEM - Multilingual Latin I |
| 852 | OEM - Latin II |
| 855 | OEM - Cyrillic (primarily Russian) |
| 857 | OEM - Turkish |
| 858 | OEM - Multilingual Latin I + Euro symbol |
| 860 | OEM - Portuguese |
| 861 | OEM - Icelandic |
| 862 | OEM - Hebrew |
| 863 | OEM - Canadian-French |
| 864 | OEM - Arabic |
| 865 | OEM - Nordic |
| 866 | OEM - Russian |
| 869 | OEM - Modern Greek |
| 870 | IBM EBCDIC - Multilingual/ROECE (Latin-2) |
| 874 | ANSI/OEM - Thai (same as 28605, ISO 8859-15) |
| 875 | IBM EBCDIC - Modern Greek |
| 932 | ANSI/OEM - Japanese, Shift-JIS |
| 936 | ANSI/OEM - Simplified Chinese (PRC, Singapore) |
| 949 | ANSI/OEM - Korean (Unified Hangul Code) |
| 950 | ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC) |
| 1026 | IBM EBCDIC - Turkish (Latin-5) |
| 1047 | IBM EBCDIC - Latin 1/Open System |
| 1140 | IBM EBCDIC - U.S./Canada (037 + Euro symbol) |
| 1141 | IBM EBCDIC - Germany (20273 + Euro symbol) |
| 1142 | IBM EBCDIC - Denmark/Norway (20277 + Euro symbol) |
| 1143 | IBM EBCDIC - Finland/Sweden (20278 + Euro symbol) |
| 1144 | IBM EBCDIC - Italy (20280 + Euro symbol) |
| 1145 | IBM EBCDIC - Latin America/Spain (20284 + Euro symbol) |
| 1146 | IBM EBCDIC - United Kingdom (20285 + Euro symbol) |
| 1147 | IBM EBCDIC - France (20297 + Euro symbol) |
| 1148 | IBM EBCDIC - International (500 + Euro symbol) |
| 1149 | IBM EBCDIC - Icelandic (20871 + Euro symbol) |
| 1200 | Unicode UCS-2 Little-Endian (BMP of ISO 10646) |
| 1201 | Unicode UCS-2 Big-Endian |
| 1250 | ANSI - Central European |
| 1251 | ANSI - Cyrillic |
| 1252 | ANSI - Latin I |
| 1253 | ANSI - Greek |
| 1254 | ANSI - Turkish |
| 1255 | ANSI - Hebrew |
| 1256 | ANSI - Arabic |
| 1257 | ANSI - Baltic |
| 1258 | ANSI/OEM - Vietnamese |
| 1361 | Korean (Johab) |
| 10000 | MAC - Roman |
| 10001 | MAC - Japanese |
| 10002 | MAC - Traditional Chinese (Big5) |
| 10003 | MAC - Korean |
| 10004 | MAC - Arabic |
| 10005 | MAC - Hebrew |
| 10006 | MAC - Greek I |
| 10007 | MAC - Cyrillic |
| 10008 | MAC - Simplified Chinese (GB 2312) |
| 10010 | MAC - Romania |
| 10017 | MAC - Ukraine |
| 10021 | MAC - Thai |
| 10029 | MAC - Latin II |
| 10079 | MAC - Icelandic |
| 10081 | MAC - Turkish |
| 10082 | MAC - Croatia |
| 12000 | Unicode UCS-4 Little-Endian |
| 12001 | Unicode UCS-4 Big-Endian |
| 20000 | CNS - Taiwan |
| 20001 | TCA - Taiwan |
| 20002 | Eten - Taiwan |
| 20003 | IBM5550 - Taiwan |
| 20004 | TeleText - Taiwan |
| 20005 | Wang - Taiwan |
| 20105 | IA5 IRV International Alphabet No. 5 (7-bit) |
| 20106 | IA5 German (7-bit) |
| 20107 | IA5 Swedish (7-bit) |
| 20108 | IA5 Norwegian (7-bit) |
| 20127 | US-ASCII (7-bit) |
| 20261 | T.61 |
| 20269 | ISO 6937 Non-Spacing Accent |
| 20273 | IBM EBCDIC - Germany |
| 20277 | IBM EBCDIC - Denmark/Norway |
| 20278 | IBM EBCDIC - Finland/Sweden |
| 20280 | IBM EBCDIC - Italy |
| 20284 | IBM EBCDIC - Latin America/Spain |
| 20285 | IBM EBCDIC - United Kingdom |
| 20290 | IBM EBCDIC - Japanese Katakana Extended |
| 20297 | IBM EBCDIC - France |
| 20420 | IBM EBCDIC - Arabic |
| 20423 | IBM EBCDIC - Greek |
| 20424 | IBM EBCDIC - Hebrew |
| 20833 | IBM EBCDIC - Korean Extended |
| 20838 | IBM EBCDIC - Thai |
| 20866 | Russian - KOI8-R |
| 20871 | IBM EBCDIC - Icelandic |
| 20880 | IBM EBCDIC - Cyrillic (Russian) |
| 20905 | IBM EBCDIC - Turkish |
| 20924 | IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol) |
| 20932 | JIS X 0208-1990 & 0121-1990 |
| 20936 | Simplified Chinese (GB2312) |
| 21025 | IBM EBCDIC - Cyrillic (Serbian, Bulgarian) |
| 21027 | Extended Alpha Lowercase |
| 21866 | Ukrainian (KOI8-U) |
| 28591 | ISO 8859-1 Latin I |
| 28592 | ISO 8859-2 Central Europe |
| 28593 | ISO 8859-3 Latin 3 |
| 28594 | ISO 8859-4 Baltic |
| 28595 | ISO 8859-5 Cyrillic |
| 28596 | ISO 8859-6 Arabic |
| 28597 | ISO 8859-7 Greek |
| 28598 | ISO 8859-8 Hebrew |
| 28599 | ISO 8859-9 Latin 5 |
| 28605 | ISO 8859-15 Latin 9 |
| 29001 | Europa 3 |
| 38598 | ISO 8859-8 Hebrew |
| 50220 | ISO 2022 Japanese with no halfwidth Katakana |
| 50221 | ISO 2022 Japanese with halfwidth Katakana |
| 50222 | ISO 2022 Japanese JIS X 0201-1989 |
| 50225 | ISO 2022 Korean |
| 50227 | ISO 2022 Simplified Chinese |
| 50229 | ISO 2022 Traditional Chinese |
| 50930 | Japanese (Katakana) Extended |
| 50931 | US/Canada and Japanese |
| 50933 | Korean Extended and Korean |
| 50935 | Simplified Chinese Extended and Simplified Chinese |
| 50936 | Simplified Chinese |
| 50937 | US/Canada and Traditional Chinese |
| 50939 | Japanese (Latin) Extended and Japanese |
| 51932 | EUC - Japanese |
| 51936 | EUC - Simplified Chinese |
| 51949 | EUC - Korean |
| 51950 | EUC - Traditional Chinese |
| 52936 | HZ-GB2312 Simplified Chinese |
| 54936 | Windows XP: GB18030 Simplified Chinese (4 Byte) |
| 57002 | ISCII Devanagari |
| 57003 | ISCII Bengali |
| 57004 | ISCII Tamil |
| 57005 | ISCII Telugu |
| 57006 | ISCII Assamese |
| 57007 | ISCII Oriya |
| 57008 | ISCII Kannada |
| 57009 | ISCII Malayalam |
| 57010 | ISCII Gujarati |
| 57011 | ISCII Punjabi |
| 65000 | Unicode UTF-7 |
| 65001 | Unicode UTF-8 |

 The following is a list of valid code page identifiers for Mac OS only:

|  |  |
| --- | --- |
| Identifier | Name |
| 1 | ASCII |
| 2 | NEXTSTEP |
| 3 | JapaneseEUC |
| 4 | UTF8 |
| 5 | ISOLatin1 |
| 6 | Symbol |
| 7 | NonLossyASCII |
| 8 | ShiftJIS |
| 9 | ISOLatin2 |
| 10 | Unicode |
| 11 | WindowsCP1251 |
| 12 | WindowsCP1252 |
| 13 | WindowsCP1253 |
| 14 | WindowsCP1254 |
| 15 | WindowsCP1250 |
| 21 | ISO2022JP |
| 30 | MacOSRoman |
| 10 | UTF16String |
| 0x90000100 | UTF16BigEndian |
| 0x94000100 | UTF16LittleEndian |
| 0x8c000100 | UTF32String |
| 0x98000100 | UTF32BigEndian |
| 0x9c000100 | UTF32LittleEndian |
| 65536 | Proprietary |

**LicenseInfo**: Information about the current license.When queried, this setting will return a string containing information about the license this instance of a struct 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*.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the struct will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to *true* tells the struct 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.

 To use the system security libraries for Linux, OpenSSL support must be enabled. For more information on how to enable OpenSSL, please refer to the [OpenSSL Notes](platforms.md) section.

# Trappable Errors ([DPAPI](#dpapi-component) Component)

### DPAPI Errors

|  |  |
| --- | --- |
| 104 | Cannot read or write file. |
| 109 | Cannot protect data. |
| 110 | Cannot unprotect data |
| 111 | OutputFile already exists and Overwrite is False. |
| 304 | Cannot write file. |
| 305 | Cannot read file. |
| 306 | Cannot create file. |