# ChaCha Class

The ChaCha class can be used to encrypt and decrypt data with the ChaCha20 algorithm.

## Syntax

```text
ChaCha
```

## Remarks

The class implements ChaCha20 as defined in RFC 7539. This may be used to both encrypt and decrypt data. The class also support Authenticated Encryption with Additional Data (AEAD) via AEAD_CHACHA20_POLY1305. To enable the use of AEAD set [UseAEAD](#useaead-property-chacha-class) to True.

Data may be encrypted and decrypted in its entirety by calling [Encrypt](#encrypt-method-chacha-class) and [Decrypt](#decrypt-method-chacha-class) or chunk by chunk by calling [EncryptBlock](#encryptblock-method-chacha-class) and [DecryptBlock](#decryptblock-method-chacha-class).

In all operations a [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) must be used. If [IV](#iv-property-chacha-class) is not set one is automatically generated. [KeyPassword](#keypassword-property-chacha-class) may be set in order to automatically generate both a [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) when a method is called. The same [KeyPassword](#keypassword-property-chacha-class), or [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) pair are used on both sides of the operation data can be encrypted and decrypted.

## Encrypt Notes

[Encrypt](#encrypt-method-chacha-class) will encrypt the specified data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)
- [UseAEAD](#useaead-property-chacha-class) (optional)
- [AdditionalAuthData](#additionalauthdata-property-chacha-class) (optional - applicable if [UseAEAD](#useaead-property-chacha-class) is True);

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

**Additional Notes**

The [Key](#key-property-chacha-class) property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If [KeyPassword](#keypassword-property-chacha-class) is set both [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) will be automatically generated when [Encrypt](#encrypt-method-chacha-class) is called.

The [IV](#iv-property-chacha-class) should typically be set to a 96 bit (12 byte) value. See the [IV](#iv-property-chacha-class) property for details on using a 64 bit (8 byte) value. If [IV](#iv-property-chacha-class) is not set a 96 bit (12 byte) value will automatically be generated by the class when [Encrypt](#encrypt-method-chacha-class) is called.

[InitialCounter](#InitialCounter) may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.

During encryption the [Progress](#progress-event-chacha-class) event will fire as data is encrypted.

**Encrypt Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[]{ 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();

//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes.
// {0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76}
```

**AEAD Notes**

When encrypting and [UseAEAD](#useaead-property-chacha-class) is True [AdditionalAuthData](#additionalauthdata-property-chacha-class) optionally holds data that is authenticated but not encrypted.

After encrypting the message the [AuthTag](#authtag-property-chacha-class) property will be populated. To include the [AuthTag](#authtag-property-chacha-class) in the output set [IncludeAuthTag](#IncludeAuthTag) to True.

**Encrypt with AEAD Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };

chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();

//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes:
// {0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65}

//chacha.AuthTagB contains the byte[] of the AuthTag. The above code produces the following authentication tag:
// {0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78}
```

## Encrypt Block Notes

[EncryptBlock](#encryptblock-method-chacha-class) will encrypt the input data and return the encrypted block. The encrypted block will always be the same length as the decrypted data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)

*InputBuffer* specifies the input data to encrypt.

*LastBlock* specifies whether the block is the last block. Required when [UseAEAD](#useaead-property-chacha-class) is True. When *LastBlock* is True the class will calculate the [AuthTag](#authtag-property-chacha-class) value. If [UseAEAD](#useaead-property-chacha-class) is False the value of *LastBlock* is not used.

**EncryptBlock Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;

byte[] tempEncryptedBlock;

//Encrypt any number of blocks of any size
tempEncryptedBlock = chacha.EncryptBlock(part1, false);
tempEncryptedBlock = chacha.EncryptBlock(part2, false);

//Pass true for the last block
tempEncryptedBlock = chacha.EncryptBlock(part3, true);

//Save AuthTag for use when decrypting
byte[] authTag = chacha.AuthTagB;
```

## Decrypt Notes

[Decrypt](#decrypt-method-chacha-class) will decrypt the specified data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)
- [UseAEAD](#useaead-property-chacha-class) (optional)
- [AuthTag](#authtag-property-chacha-class) (conditional - required if [UseAEAD](#useaead-property-chacha-class) is True)
- [AdditionalAuthData](#additionalauthdata-property-chacha-class) (optional - applicable if [UseAEAD](#useaead-property-chacha-class) is True);

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

**Additional Notes**

The [Key](#key-property-chacha-class) property must be set to the 256 bit (32 byte) value originally used to encrypt the data. [IV](#iv-property-chacha-class) must be set to the original IV value used to encrypt the data.

If using a password, [KeyPassword](#keypassword-property-chacha-class) must be set to the same [KeyPassword](#keypassword-property-chacha-class) used when encrypting the data. This will automatically generate both [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) when [Decrypt](#decrypt-method-chacha-class) is called.

[InitialCounter](#InitialCounter) may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.

During decryption the [Progress](#progress-event-chacha-class) event will fire as data is decrypted.

**Decrypt Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessageB = new byte[] { 0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76 };
chacha.Decrypt();

Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
```

**AEAD Notes**

When decrypting [AdditionalAuthData](#additionalauthdata-property-chacha-class) must be set to the same value that was specified when encrypting. [AuthTag](#authtag-property-chacha-class) must be set to the [AuthTag](#authtag-property-chacha-class) value produced when encrypting.

Note: [IncludeAuthTag](#IncludeAuthTag) may be set to True if the [AuthTag](#authtag-property-chacha-class) value was included in the encrypted message.

**Decrypt with AEAD Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.AuthTagB = new byte[] { 0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78 };
chacha.InputMessageB = new byte[] { 0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65 };

chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.Decrypt();

Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
```

## Decrypt Block Notes

[DecryptBlock](#decryptblock-method-chacha-class) will decrypt the input data and return the decrypted block. The decrypted block will always be the same length as the encrypted data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)

*InputBuffer* specifies the input data to decrypt.

*LastBlock* specifies whether the block is the last block. Required when [UseAEAD](#useaead-property-chacha-class) is True. When *LastBlock* is True the class will validate the [AuthTag](#authtag-property-chacha-class) value. If [UseAEAD](#useaead-property-chacha-class) is False the value of *LastBlock* is not used.

**DecryptBlock Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
chacha.AuthTagB = authTag; //Value calculated during encryption.

byte[] tempDecryptedBlock;

//Decrypt any number of blocks of any size
tempDecryptedBlock = chacha.DecryptBlock(part1, false);
tempDecryptedBlock = chacha.DecryptBlock(part2, false);

//Pass true for the last block
tempDecryptedBlock = chacha.DecryptBlock(part3, true);
```

## Property List

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

|  |  |
| --- | --- |
| [AdditionalAuthData](#additionalauthdata-property-chacha-class) | Additional Authentication Data (AAD) used when UseAEAD is True. |
| [AuthTag](#authtag-property-chacha-class) | The authentication tag used when UseAEAD is set to True. |
| [InputFile](#inputfile-property-chacha-class) | The file to process. |
| [InputMessage](#inputmessage-property-chacha-class) | The message to process. |
| [IV](#iv-property-chacha-class) | The initialization vector (IV). |
| [Key](#key-property-chacha-class) | The secret key for the symmetric algorithm. |
| [KeyPassword](#keypassword-property-chacha-class) | A password to generate the Key and IV . |
| [OutputFile](#outputfile-property-chacha-class) | The output file when encrypting or decrypting. |
| [OutputMessage](#outputmessage-property-chacha-class) | The output message after processing. |
| [Overwrite](#overwrite-property-chacha-class) | Indicates whether or not the class should overwrite files. |
| [UseAEAD](#useaead-property-chacha-class) | Whether to use AEAD (Authenticated Encryption with Additional Data). |
| [UseHex](#usehex-property-chacha-class) | Whether input or output is hex encoded. |

## Method List

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

|  |  |
| --- | --- |
| [Config](#config-method-chacha-class) | Sets or retrieves a configuration setting. |
| [Decrypt](#decrypt-method-chacha-class) | Decrypts the data. |
| [DecryptBlock](#decryptblock-method-chacha-class) | Decrypts a block and returns the decrypted data. |
| [Encrypt](#encrypt-method-chacha-class) | Encrypts the data. |
| [EncryptBlock](#encryptblock-method-chacha-class) | Encrypts data and returns the encrypted block. |
| [Reset](#reset-method-chacha-class) | Resets the class. |
| [SetInputStream](#setinputstream-method-chacha-class) | Sets the stream from which the class will read data to encrypt or decrypt. |
| [SetOutputStream](#setoutputstream-method-chacha-class) | Sets the stream to which the class will write encrypted or decrypted data. |

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

## Config Settings

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

|  |  |
| --- | --- |
| [ChaCha20Algorithm](#ChaCha20Algorithm) | Specifies the ChaCha implementation to use. |
| [EncryptedDataEncoding](#EncryptedDataEncoding) | The encoding of the encrypted input or output data. |
| [IncludeAuthTag](#IncludeAuthTag) | Whether to append the authentication tag to the cipher text when UseAEAD is True. |
| [IncludeIV](#IncludeIV) | Whether to prepend the IV to the output data and read the IV from the input data. |
| [InitialCounter](#InitialCounter) | The initial counter value. |
| [IVLength](#IVLength) | The IV length in bytes. |
| [KeyPasswordAlgorithm](#KeyPasswordAlgorithm) | The hash algorithm used to derive the Key and IV from the KeyPassword property. |
| [KeyPasswordIterations](#KeyPasswordIterations) | The number of iterations performed when using KeyPassword to derive the Key and IV. |
| [KeyPasswordSalt](#KeyPasswordSalt) | The salt value used in conjunction with the KeyPassword to derive the Key and IV. |
| [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. |
| [ProcessIdleEvents](#ProcessIdleEvents) | Whether the class uses its internal event loop to process events when the main thread is idle. |
| [SelectWaitMillis](#SelectWaitMillis) | The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process. |
| [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. |

# AdditionalAuthData Property ([ChaCha](#chacha-class) Class)

Additional Authentication Data (AAD) used when UseAEAD is True.

## Syntax

```text
ANSI (Cross Platform)
int GetAdditionalAuthData(char* &lpAdditionalAuthData, int &lenAdditionalAuthData);int SetAdditionalAuthData(const char* lpAdditionalAuthData, int lenAdditionalAuthData);

Unicode (Windows)
INT GetAdditionalAuthData(LPSTR &lpAdditionalAuthData, INT &lenAdditionalAuthData);INT SetAdditionalAuthData(LPCSTR lpAdditionalAuthData, INT lenAdditionalAuthData);
```

## Default Value

""

## Remarks

This property specifies data that is authentication but not encrypted. This is only applicable when [UseAEAD](#useaead-property-chacha-class) is True.

Note that AAD data is authenticated but not encrypted, so it is not included in the output.

## Data Type

Binary String

# AuthTag Property ([ChaCha](#chacha-class) Class)

The authentication tag used when UseAEAD is set to True.

## Syntax

```text
ANSI (Cross Platform)
int GetAuthTag(char* &lpAuthTag, int &lenAuthTag);int SetAuthTag(const char* lpAuthTag, int lenAuthTag);

Unicode (Windows)
INT GetAuthTag(LPSTR &lpAuthTag, INT &lenAuthTag);INT SetAuthTag(LPCSTR lpAuthTag, INT lenAuthTag);
```

## Default Value

""

## Remarks

This property holds the 128 bit authentication tag used when [UseAEAD](#useaead-property-chacha-class) is set to True. It is only applicable when [UseAEAD](#useaead-property-chacha-class) is True.

This is populated after calling [Encrypt](#encrypt-method-chacha-class). To also include the value in the output set [IncludeAuthTag](#IncludeAuthTag) to True.

This must be set before calling [Decrypt](#decrypt-method-chacha-class). If the auth tag is included in the encrypted data set [IncludeAuthTag](#IncludeAuthTag) to True before calling [Decrypt](#decrypt-method-chacha-class).

## Data Type

Binary String

# InputFile Property ([ChaCha](#chacha-class) Class)

The file to process.

## Syntax

```text
ANSI (Cross Platform)
char* GetInputFile();int SetInputFile(const char* lpszInputFile);

Unicode (Windows)
LPWSTR GetInputFile();INT SetInputFile(LPCWSTR lpszInputFile);
```

## 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 class 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-chacha-class)
- InputFile
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

## Data Type

String

# InputMessage Property ([ChaCha](#chacha-class) Class)

The message to process.

## Syntax

```text
ANSI (Cross Platform)
int GetInputMessage(char* &lpInputMessage, int &lenInputMessage);int SetInputMessage(const char* lpInputMessage, int lenInputMessage);

Unicode (Windows)
INT GetInputMessage(LPSTR &lpInputMessage, INT &lenInputMessage);INT SetInputMessage(LPCSTR lpInputMessage, INT lenInputMessage);
```

## Default Value

""

## Remarks

This property specifies the message to be processed.

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- InputMessage

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

## Data Type

Binary String

# IV Property ([ChaCha](#chacha-class) Class)

The initialization vector (IV).

## Syntax

```text
ANSI (Cross Platform)
int GetIV(char* &lpIV, int &lenIV);int SetIV(const char* lpIV, int lenIV);

Unicode (Windows)
INT GetIV(LPSTR &lpIV, INT &lenIV);INT SetIV(LPCSTR lpIV, INT lenIV);
```

## Default Value

""

## Remarks

This property specifies the initialization vector (IV). This is also referred to as the nonce. By default this property is empty and the class will automatically generate a new IV value if [KeyPassword](#keypassword-property-chacha-class) or [Key](#key-property-chacha-class) is set before [Encrypt](#encrypt-method-chacha-class) or [EncryptBlock](#encryptblock-method-chacha-class) is called.

The size of the IV may be either 96 bits in length (12 bytes) or 64 bits in length (8 bytes).

**Compatibility Notes**

A 96 bit length value is used for implementations implementing RFC 7539. A 64 bit length value may be used by implementations that follow the original draft of ChaCha. When using a 96 bit length value the maximum file size of data is 256 GB.

If another entity is performing the decryption and it is not known whether it supports 64 bit length values, choose a 96 bit length value by default. This follows the RFC and should be the most widely implemented value.

The class supports both lengths.

Note: If [Key](#key-property-chacha-class) is specified but IV is not, an IV will be automatically generated. To control the length of the IV that is generated set [IVLength](#IVLength).

## Data Type

Binary String

# Key Property ([ChaCha](#chacha-class) Class)

The secret key for the symmetric algorithm.

## Syntax

```text
ANSI (Cross Platform)
int GetKey(char* &lpKey, int &lenKey);int SetKey(const char* lpKey, int lenKey);

Unicode (Windows)
INT GetKey(LPSTR &lpKey, INT &lenKey);INT SetKey(LPCSTR lpKey, INT lenKey);
```

## Default Value

""

## Remarks

This secret key is used both for encryption and decryption. The secret key should be known only to the sender and the receiver. This key must be 256 bits in length (32 bytes).

If this property is left empty and [KeyPassword](#keypassword-property-chacha-class) is specified, a Key value will be generated by the class as necessary.

## Data Type

Binary String

# KeyPassword Property ([ChaCha](#chacha-class) Class)

A password to generate the Key and IV .

## Syntax

```text
ANSI (Cross Platform)
char* GetKeyPassword();int SetKeyPassword(const char* lpszKeyPassword);

Unicode (Windows)
LPWSTR GetKeyPassword();INT SetKeyPassword(LPCWSTR lpszKeyPassword);
```

## Default Value

""

## Remarks

When this property is set the class will calculate values for [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) using the PKCS5 password digest algorithm. This provides a simpler alternative to creating and managing [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) values directly.

## Data Type

String

# OutputFile Property ([ChaCha](#chacha-class) Class)

The output file when encrypting or decrypting.

## Syntax

```text
ANSI (Cross Platform)
char* GetOutputFile();int SetOutputFile(const char* lpszOutputFile);

Unicode (Windows)
LPWSTR GetOutputFile();INT SetOutputFile(LPCWSTR lpszOutputFile);
```

## Default Value

""

## Remarks

This property specifies the file to which the output will be written when [Encrypt](#encrypt-method-chacha-class) or [Decrypt](#decrypt-method-chacha-class) is called. This may be set to an absolute or relative path.

This property is only applicable to [Encrypt](#encrypt-method-chacha-class) and [Decrypt](#decrypt-method-chacha-class).

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- OutputFile
- [OutputMessage](#outputmessage-property-chacha-class): 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).

## Data Type

String

# OutputMessage Property ([ChaCha](#chacha-class) Class)

The output message after processing.

## Syntax

```text
ANSI (Cross Platform)
int GetOutputMessage(char* &lpOutputMessage, int &lenOutputMessage);

Unicode (Windows)
INT GetOutputMessage(LPSTR &lpOutputMessage, INT &lenOutputMessage);
```

## Default Value

""

## Remarks

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

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- 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).

This property is read-only and not available at design time.

## Data Type

Binary String

# Overwrite Property ([ChaCha](#chacha-class) Class)

Indicates whether or not the class should overwrite files.

## Syntax

```text
ANSI (Cross Platform)
int GetOverwrite();int SetOverwrite(int bOverwrite);

Unicode (Windows)
BOOL GetOverwrite();INT SetOverwrite(BOOL bOverwrite);
```

## Default Value

FALSE

## Remarks

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

## Data Type

Boolean

# UseAEAD Property ([ChaCha](#chacha-class) Class)

Whether to use AEAD (Authenticated Encryption with Additional Data).

## Syntax

```text
ANSI (Cross Platform)
int GetUseAEAD();int SetUseAEAD(int bUseAEAD);

Unicode (Windows)
BOOL GetUseAEAD();INT SetUseAEAD(BOOL bUseAEAD);
```

## Default Value

FALSE

## Remarks

If this property is set to True the class uses the algorithm AEAD_CHACHA20_POLY1305 as defined in RFC 7539 to construct a message using AEAD. See [Encrypt](#encrypt-method-chacha-class) and [Decrypt](#decrypt-method-chacha-class) for details.

## Data Type

Boolean

# UseHex Property ([ChaCha](#chacha-class) Class)

Whether input or output is hex encoded.

## Syntax

```text
ANSI (Cross Platform)
int GetUseHex();int SetUseHex(int bUseHex);

Unicode (Windows)
BOOL GetUseHex();INT SetUseHex(BOOL bUseHex);
```

## Default Value

FALSE

## Remarks

This property specifies whether the encrypted data is hex encoded.

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

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

**AEAD Notes**

When [UseAEAD](#useaead-property-chacha-class) is set to True this property also applies to [AuthTag](#authtag-property-chacha-class). After calling [Encrypt](#encrypt-method-chacha-class) [AuthTag](#authtag-property-chacha-class) will hold a hex encoded value. Before calling [Decrypt](#decrypt-method-chacha-class) [AuthTag](#authtag-property-chacha-class) must be set to a hex encoded value.

## Data Type

Boolean

# Config Method ([ChaCha](#chacha-class) Class)

Sets or retrieves a configuration setting.

## Syntax

```text
ANSI (Cross Platform)
char* Config(const char* lpszConfigurationString);

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);
```

## Remarks

Config is a generic method available in every class. It is used to set and retrieve [configuration settings](#config-settings-chacha-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-chacha-class), you must call *Config("PROPERTY")*. The value will be returned as a string.

## Error Handling (C++)

This method returns a String value; after it returns, call the *GetLastErrorCode()* method to obtain its result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message.

# Decrypt Method ([ChaCha](#chacha-class) Class)

Decrypts the data.

## Syntax

```text
ANSI (Cross Platform)
int Decrypt();

Unicode (Windows)
INT Decrypt();
```

## Remarks

Decrypt will decrypt the specified data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)
- [UseAEAD](#useaead-property-chacha-class) (optional)
- [AuthTag](#authtag-property-chacha-class) (conditional - required if [UseAEAD](#useaead-property-chacha-class) is True)
- [AdditionalAuthData](#additionalauthdata-property-chacha-class) (optional - applicable if [UseAEAD](#useaead-property-chacha-class) is True);

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

**Additional Notes**

The [Key](#key-property-chacha-class) property must be set to the 256 bit (32 byte) value originally used to encrypt the data. [IV](#iv-property-chacha-class) must be set to the original IV value used to encrypt the data.

If using a password, [KeyPassword](#keypassword-property-chacha-class) must be set to the same [KeyPassword](#keypassword-property-chacha-class) used when encrypting the data. This will automatically generate both [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) when Decrypt is called.

[InitialCounter](#InitialCounter) may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.

During decryption the [Progress](#progress-event-chacha-class) event will fire as data is decrypted.

**Decrypt Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessageB = new byte[] { 0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76 };
chacha.Decrypt();

Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
```

**AEAD Notes**

When decrypting [AdditionalAuthData](#additionalauthdata-property-chacha-class) must be set to the same value that was specified when encrypting. [AuthTag](#authtag-property-chacha-class) must be set to the [AuthTag](#authtag-property-chacha-class) value produced when encrypting.

Note: [IncludeAuthTag](#IncludeAuthTag) may be set to True if the [AuthTag](#authtag-property-chacha-class) value was included in the encrypted message.

**Decrypt with AEAD Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.AuthTagB = new byte[] { 0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78 };
chacha.InputMessageB = new byte[] { 0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65 };

chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.Decrypt();

Console.WriteLine(chacha.OutputMessage); //outputs "hello chacha!"
```

## Error Handling (C++)

This method returns a result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the *GetLastErrorCode()* method after it returns.)

# DecryptBlock Method ([ChaCha](#chacha-class) Class)

Decrypts a block and returns the decrypted data.

## Syntax

```text
ANSI (Cross Platform)
char* DecryptBlock(const char* lpInputBuffer, int lenInputBuffer, int bLastBlock, int *lpSize = NULL);

Unicode (Windows)
LPSTR DecryptBlock(LPCSTR lpInputBuffer, INT lenInputBuffer, BOOL bLastBlock, LPINT lpSize = NULL);
```

## Remarks

DecryptBlock will decrypt the input data and return the decrypted block. The decrypted block will always be the same length as the encrypted data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)

*InputBuffer* specifies the input data to decrypt.

*LastBlock* specifies whether the block is the last block. Required when [UseAEAD](#useaead-property-chacha-class) is True. When *LastBlock* is True the class will validate the [AuthTag](#authtag-property-chacha-class) value. If [UseAEAD](#useaead-property-chacha-class) is False the value of *LastBlock* is not used.

**DecryptBlock Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;
chacha.AuthTagB = authTag; //Value calculated during encryption.

byte[] tempDecryptedBlock;

//Decrypt any number of blocks of any size
tempDecryptedBlock = chacha.DecryptBlock(part1, false);
tempDecryptedBlock = chacha.DecryptBlock(part2, false);

//Pass true for the last block
tempDecryptedBlock = chacha.DecryptBlock(part3, true);
```

## Error Handling (C++)

This method returns a Binary String value (with length *lpSize*); after it returns, call the *GetLastErrorCode()* method to obtain its result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message.

# Encrypt Method ([ChaCha](#chacha-class) Class)

Encrypts the data.

## Syntax

```text
ANSI (Cross Platform)
int Encrypt();

Unicode (Windows)
INT Encrypt();
```

## Remarks

Encrypt will encrypt the specified data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)
- [UseAEAD](#useaead-property-chacha-class) (optional)
- [AdditionalAuthData](#additionalauthdata-property-chacha-class) (optional - applicable if [UseAEAD](#useaead-property-chacha-class) is True);

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

**Additional Notes**

The [Key](#key-property-chacha-class) property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If [KeyPassword](#keypassword-property-chacha-class) is set both [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) will be automatically generated when Encrypt is called.

The [IV](#iv-property-chacha-class) should typically be set to a 96 bit (12 byte) value. See the [IV](#iv-property-chacha-class) property for details on using a 64 bit (8 byte) value. If [IV](#iv-property-chacha-class) is not set a 96 bit (12 byte) value will automatically be generated by the class when Encrypt is called.

[InitialCounter](#InitialCounter) may be set for specific cases where an initial counter of 1 is needed. The default value is 0 and is recommended.

During encryption the [Progress](#progress-event-chacha-class) event will fire as data is encrypted.

**Encrypt Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[]{ 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();

//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes.
// {0x35, 0xBA, 0x31, 0x60, 0x02, 0x77, 0x57, 0x06, 0x5F, 0x6E, 0xE0, 0xD4, 0x76}
```

**AEAD Notes**

When encrypting and [UseAEAD](#useaead-property-chacha-class) is True [AdditionalAuthData](#additionalauthdata-property-chacha-class) optionally holds data that is authenticated but not encrypted.

After encrypting the message the [AuthTag](#authtag-property-chacha-class) property will be populated. To include the [AuthTag](#authtag-property-chacha-class) in the output set [IncludeAuthTag](#IncludeAuthTag) to True.

**Encrypt with AEAD Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };

chacha.UseAEAD = true;
chacha.AdditionalAuthData = "my auth data.";
chacha.InputMessage = "hello chacha!";
chacha.Encrypt();

//chacha.OutputMessageB contains the byte[] of the encrypted data. The above code produces the following encrypted bytes:
// {0x67, 0xF5, 0xC7, 0xE4, 0xE6, 0xD6, 0xC2, 0xF4, 0x09, 0xE3, 0x90, 0xF2, 0x65}

//chacha.AuthTagB contains the byte[] of the AuthTag. The above code produces the following authentication tag:
// {0x46, 0x35, 0xFD, 0x33, 0x30, 0x52, 0xAA, 0x6B, 0xBA, 0x32, 0x16, 0xA6, 0x48, 0x12, 0x52, 0x78}
```

## Error Handling (C++)

This method returns a result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the *GetLastErrorCode()* method after it returns.)

# EncryptBlock Method ([ChaCha](#chacha-class) Class)

Encrypts data and returns the encrypted block.

## Syntax

```text
ANSI (Cross Platform)
char* EncryptBlock(const char* lpInputBuffer, int lenInputBuffer, int bLastBlock, int *lpSize = NULL);

Unicode (Windows)
LPSTR EncryptBlock(LPCSTR lpInputBuffer, INT lenInputBuffer, BOOL bLastBlock, LPINT lpSize = NULL);
```

## Remarks

EncryptBlock will encrypt the input data and return the encrypted block. The encrypted block will always be the same length as the decrypted data. The following properties are applicable:

- [IV](#iv-property-chacha-class) (required)
- [Key](#key-property-chacha-class) (required)

*InputBuffer* specifies the input data to encrypt.

*LastBlock* specifies whether the block is the last block. Required when [UseAEAD](#useaead-property-chacha-class) is True. When *LastBlock* is True the class will calculate the [AuthTag](#authtag-property-chacha-class) value. If [UseAEAD](#useaead-property-chacha-class) is False the value of *LastBlock* is not used.

**EncryptBlock Example**

```csharp
Chacha chacha = new Chacha();
chacha.KeyB = new byte[] { 0xBB, 0x76, 0x17, 0xC9, 0x05, 0x73, 0x4A, 0x8D, 0x59, 0x9D, 0x7B, 0x0D, 0x86, 0x2A, 0x03, 0x82, 0x50, 0x6A, 0x70, 0xFB, 0xA8, 0x56, 0x47, 0x1B, 0x1E, 0x68, 0x0B, 0x2B, 0x34, 0x18, 0x0F, 0xE2 };
chacha.IVB = new byte[] { 0x0D, 0xE4, 0x43, 0x40, 0x29, 0xAD, 0x70, 0x7D, 0x7B, 0x32, 0xB5, 0xC7 };
chacha.UseAEAD = true;

byte[] tempEncryptedBlock;

//Encrypt any number of blocks of any size
tempEncryptedBlock = chacha.EncryptBlock(part1, false);
tempEncryptedBlock = chacha.EncryptBlock(part2, false);

//Pass true for the last block
tempEncryptedBlock = chacha.EncryptBlock(part3, true);

//Save AuthTag for use when decrypting
byte[] authTag = chacha.AuthTagB;
```

## Error Handling (C++)

This method returns a Binary String value (with length *lpSize*); after it returns, call the *GetLastErrorCode()* method to obtain its result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message.

# Reset Method ([ChaCha](#chacha-class) Class)

Resets the class.

## Syntax

```text
ANSI (Cross Platform)
int Reset();

Unicode (Windows)
INT Reset();
```

## Remarks

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

## Error Handling (C++)

This method returns a result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the *GetLastErrorCode()* method after it returns.)

# SetInputStream Method ([ChaCha](#chacha-class) Class)

Sets the stream from which the class will read data to encrypt or decrypt.

## Syntax

```text
ANSI (Cross Platform)
int SetInputStream(IPWorksEncryptStream* sInputStream);

Unicode (Windows)
INT SetInputStream(IPWorksEncryptStream* sInputStream);
```

## Remarks

This method sets the stream from which the class will read data to encrypt or decrypt.

**Input and Output Properties**

The class 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
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- [SetOutputStream](#setoutputstream-method-chacha-class)
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

## Error Handling (C++)

This method returns a result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the *GetLastErrorCode()* method after it returns.)

# SetOutputStream Method ([ChaCha](#chacha-class) Class)

Sets the stream to which the class will write encrypted or decrypted data.

## Syntax

```text
ANSI (Cross Platform)
int SetOutputStream(IPWorksEncryptStream* sOutputStream);

Unicode (Windows)
INT SetOutputStream(IPWorksEncryptStream* sOutputStream);
```

## Remarks

This method sets the stream to which the class will write encrypted or decrypted data.

**Input and Output Properties**

The class 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-chacha-class)
- [InputFile](#inputfile-property-chacha-class)
- [InputMessage](#inputmessage-property-chacha-class)

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

- SetOutputStream
- [OutputFile](#outputfile-property-chacha-class)
- [OutputMessage](#outputmessage-property-chacha-class): 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).

## Error Handling (C++)

This method returns a result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the *GetLastErrorCode()* method after it returns.)

# Error Event ([ChaCha](#chacha-class) Class)

Fired when information is available about errors during data delivery.

## Syntax

```text
ANSI (Cross Platform)
virtual int FireError(ChaChaErrorEventParams *e);
typedef struct {  int ErrorCode;  const char *Description;
  int reserved;
} ChaChaErrorEventParams;

Unicode (Windows)
virtual INT FireError(ChaChaErrorEventParams *e);
typedef struct {  INT ErrorCode;  LPCWSTR Description;
  INT reserved;
} ChaChaErrorEventParams;
```

## Remarks

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

# Progress Event ([ChaCha](#chacha-class) Class)

Fired as progress is made.

## Syntax

```text
ANSI (Cross Platform)
virtual int FireProgress(ChaChaProgressEventParams *e);
typedef struct {  int64 BytesProcessed;  int PercentProcessed;
  int reserved;
} ChaChaProgressEventParams;

Unicode (Windows)
virtual INT FireProgress(ChaChaProgressEventParams *e);
typedef struct {  LONG64 BytesProcessed;  INT PercentProcessed;
  INT reserved;
} ChaChaProgressEventParams;
```

## Remarks

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

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

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

# IPWorksEncryptStream Type

## Syntax

 *IPWorksEncryptStream* (declared in *ipworksencrypt.h*)

## Remarks

 The ChaCha class includes one or more API members that take a stream object as a parameter. To use such API members, create a concrete class that implements the IPWorksEncryptStream interface and pass the ChaCha class an instance of that concrete class.

 When implementing the IPWorksEncryptStream interface's properties and methods, they must behave as described below. If the concrete class's implementation does not behave as expected, undefined behavior may occur.

```text
bool CanRead() { return true; }
```

```text
bool CanSeek() { return true; }
```

```text
bool CanWrite() { return true; }
```

```text
int64 GetLength() = 0;
```

```text
void Close() {}
```

```text
int Flush() { return 0; }
```

```text
int Read(void* buffer, int count) = 0;
```

```text
int64 Seek(int64 offset, int seekOrigin) = 0;
```

```text
int Write(const void* buffer, int count) = 0;
```

|  |  |
| --- | --- |
| Properties |  |
| CanRead | Whether the stream supports reading. |
| CanSeek | Whether the stream supports seeking. |
| CanWrite | Whether the stream supports writing. |
| Length | Gets the length of the stream, in bytes. |
| Methods |  |
| Close | Closes the stream, releasing all resources currently allocated for it. This method is called automatically when an IPWorksEncryptStream object is deleted. |
| Flush | Forces all data held by the stream's buffers to be written out to storage. Must return 0 if flushing is successful; or -1 if an error occurs or the stream is closed. If the stream does not support writing, this method must do nothing and return 0. |
| Read | Reads a sequence of bytes from the stream and advances the current position within the stream by the number of bytes read. Buffer specifies the buffer to populate with data from the stream. Count specifies the number of bytes that should be read from the stream. Must return the total number of bytes read into Buffer; this may be less than Count if that many bytes are not currently available, or 0 if the end of the stream has been reached. Must return -1 if an error occurs, if reading is not supported, or if the stream is closed. |
| Seek | Sets the current position within the stream based on a particular point of origin. Offset specifies the offset in the stream to seek to, relative to SeekOrigin. Valid values for SeekOrigin are: 0: Seek from beginning. 1: Seek from current position. 2: Seek from end. Must return the new position within the stream; or -1 if an error occurs, if seeking is not supported, or if the stream is closed (however, see note below). If -1 is returned, the current position within the stream must remain unchanged. Note: If the stream is not closed, it must always be possible to call this method with an Offset of 0 and a SeekOrigin of 1 to obtain the current position within the stream, even if seeking is not otherwise supported. |
| Write | Writes a sequence of bytes to the stream and advances the current position within the stream by the number of bytes written. Buffer specifies the buffer with data to write to the stream. Count specifies the number of bytes that should be written to the stream. Must return the total number of bytes written to the stream; this may be less than Count if that many bytes could not be written. Must return -1 if an error occurs, if writing is not supported, or if the stream is closed. |

# Config Settings ([ChaCha](#chacha-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-chacha-class) method.

### ChaCha Config Settings

**ChaCha20Algorithm**: Specifies the ChaCha implementation to use.This setting specifies the ChaCha implementation to use. Possible values are:

- 0 (ChaCha20 - default)
- 1 (XChaCha20)

The XChaCha20 implementation is generally considered to be more secure.

**EncryptedDataEncoding**: The encoding of the encrypted input or output data.This configuration setting specifies how the encrypted data is encoded (if at all).

When [Encrypt](#encrypt-method-chacha-class) is called the class will perform the encryption as normal and then encode the output as specified here. [OutputMessage](#outputmessage-property-chacha-class) or [OutputFile](#outputfile-property-chacha-class) will hold the encoded data.

When [Decrypt](#decrypt-method-chacha-class) is called the class will expect [InputMessage](#inputmessage-property-chacha-class) or [InputFile](#inputfile-property-chacha-class) to hold the encoded data as specified here. The class will then decode the data and perform decryption as normal.

Possible values are:

- 0 (none - default)
- 1 (Base64)
- 2 (Hex)
- 3 (Base64URL)

**IncludeAuthTag**: Whether to append the authentication tag to the cipher text when UseAEAD is True.This setting controls whether [AuthTag](#AuthTag) is appended to the cipher text. This may be useful in cases where the other party knows to look for the authentication tag at the end of the data. The default value is False.

Note: This setting cannot be used in conjunction with [DecryptBlock](#decryptblock-method-chacha-class). When calling [DecryptBlock](#decryptblock-method-chacha-class) [AuthTag](#authtag-property-chacha-class) must be set explicitly and the cipher text being decrypted must not include the auth tag.

**IncludeIV**: Whether to prepend the IV to the output data and read the IV from the input data.If this config is true, the IV will be automatically prepended to the output data when calling [Encrypt](#encrypt-method-chacha-class). When calling [Decrypt](#decrypt-method-chacha-class) and this setting is True, the IV is automatically extracted form the ciphertext. The default value is False.

**InitialCounter**: The initial counter value. This setting specifies the initial counter value. In most cases this is 0 (default), but some protocols may use a value of 1. The default value is *0*.

**IVLength**: The IV length in bytes.This setting specifies the IV length. In most cases this is 12 bytes (default), but some protocols may use a value of 8 bytes. The default value is *12*.

Note: When decrypting, if [IncludeIV](#IncludeIV) is set to True and the IV length was NOT 12 bytes when originally encrypting the data, this setting must be set to the appropriate value before calling [Decrypt](#decrypt-method-chacha-class) or [DecryptBlock](#decryptblock-method-chacha-class).

**KeyPasswordAlgorithm**: The hash algorithm used to derive the Key and IV from the KeyPassword property.This configuration setting specifies which hash algorithm will be used when deriving the [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class) from [KeyPassword](#keypassword-property-chacha-class). The default value is "MD5". Possible values are:

- "SHA1"
- "MD2"
- "MD5" (default)
- "HMAC-SHA1"
- "HMAC-SHA224"
- "HMAC-SHA256"
- "HMAC-SHA384"
- "HMAC-SHA512"
- "HMAC-MD5"
- "HMAC-RIPEMD160"

When using any HMAC algorithm the PBKDF#2 method from RFC 2898 is used. Any other algorithm uses PBKDF#1 from the same RFC.

**KeyPasswordIterations**: The number of iterations performed when using KeyPassword to derive the Key and IV.This configuration setting specifies the number of iterations performed when using [KeyPassword](#keypassword-property-chacha-class) to calculate values for [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class). When using PBKDF#2 the default number of iterations is 10,000. When using PBKDF#1 the default number is 10.

**KeyPasswordSalt**: The salt value used in conjunction with the KeyPassword to derive the Key and IV.This configuration setting specifies the hex encoded salt value to be used along with the [KeyPassword](#keypassword-property-chacha-class) when calculating values for [Key](#key-property-chacha-class) and [IV](#iv-property-chacha-class).

### 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 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*.

**ProcessIdleEvents**: Whether the class uses its internal event loop to process events when the main thread is idle.If set to False, the class will not fire internal idle events. Set this to False to use the class in a background thread on Mac OS. By default, this setting is True.

**SelectWaitMillis**: The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.If there are no events to process when DoEvents is called, the class will wait for the amount of time specified here before returning. The default value is 20.

**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.

On Linux, the C++ edition requires installation of the FIPS-enabled OpenSSL library. The OpenSSL FIPS provider version must be at least 3.0.0. For additional information and instructions regarding the installation and activation of the FIPS-enabled OpenSSL library, please refer to the following link: [https://github.com/openssl/openssl/blob/master/README-FIPS.md](https://github.com/openssl/openssl/blob/master/README-FIPS.md)

To ensure the class utilizes the FIPS-enabled OpenSSL library, the obfuscated source code should first be compiled with OpenSSL enabled, as described in the Supported Platforms section. Additionally, the FIPS module should be enabled and active. If the obfuscated source code is not compiled as mentioned, or the FIPS module is inactive, the class will throw an appropriate error assuming FIPS mode is enabled.

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: 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 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.

 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 ([ChaCha](#chacha-class) Class)

## Error Handling (C++)

Call the *GetLastErrorCode()* method to obtain the last called method's result code; *0* indicates success, while a non-zero error code indicates that this method encountered an error during its execution. Known error codes are listed below. If an error occurs, the *GetLastError()* method can be called to retrieve the associated error message.

### ChaCha Errors

|  |  |
| --- | --- |
| 101 | Unsupported algorithm. |
| 102 | No Key specified. |
| 103 | No IV specified. |
| 104 | Cannot read or write file. |
| 107 | Block size is not valid for this algorithm. |
| 108 | Key size is not valid for this algorithm. |
| 111 | OutputFile already exists and Overwrite is False. |
| 121 | The specified key is invalid. |
| 123 | IV size is not valid for this algorithm. |
| 304 | Cannot write file. |
| 305 | Cannot read file. |
| 306 | Cannot create file. |
| 2004 | Invalid padding. This may be an indication that the key is incorrect. |