ChaCha Component

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

Syntax

ipworksencrypt.ChaCha

Remarks

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

Data may be encrypted and decrypted in its entirety by calling Encrypt and Decrypt or chunk by chunk by calling EncryptBlock and DecryptBlock.

In all operations a Key and IV must be used. If IV is not set one is automatically generated. KeyPassword may be set in order to automatically generate both a Key and IV when a method is called. The same KeyPassword, or Key and IV pair are used on both sides of the operation data can be encrypted and decrypted.

Encrypt Notes

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

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:

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

Additional Notes

The Key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If KeyPassword is set both Key and IV will be automatically generated when Encrypt is called.

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

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 event will fire as data is encrypted.

Encrypt Example

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 is True AdditionalAuthData optionally holds data that is authenticated but not encrypted.

After encrypting the message the AuthTag property will be populated. To include the AuthTag in the output set IncludeAuthTag to True.

Encrypt with AEAD Example

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 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 (required)
  • Key (required)

InputBuffer specifies the input data to encrypt.

LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the struct will calculate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.

EncryptBlock Example

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

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:

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

Additional Notes

The Key property must be set to the 256 bit (32 byte) value originally used to encrypt the data. IV must be set to the original IV value used to encrypt the data.

If using a password, KeyPassword must be set to the same KeyPassword used when encrypting the data. This will automatically generate both Key and IV when Decrypt is called.

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 event will fire as data is decrypted.

Decrypt Example

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 must be set to the same value that was specified when encrypting. AuthTag must be set to the AuthTag value produced when encrypting.

Note: IncludeAuthTag may be set to True if the AuthTag value was included in the encrypted message.

Decrypt with AEAD Example

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 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 (required)
  • Key (required)

InputBuffer specifies the input data to decrypt.

LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the struct will validate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.

DecryptBlock Example

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 component with short descriptions. Click on the links for further details.

AdditionalAuthDataAdditional Authentication Data (AAD) used when UseAEAD is True.
AuthTagThe authentication tag used when UseAEAD is set to True.
InputFileThe file to process.
InputMessageThe message to process.
IVThe initialization vector (IV).
KeyThe secret key for the symmetric algorithm.
KeyPasswordA password to generate the Key and IV .
OutputFileThe output file when encrypting or decrypting.
OutputMessageThe output message after processing.
OverwriteIndicates whether or not the class should overwrite files.
UseAEADWhether to use AEAD (Authenticated Encryption with Additional Data).
UseHexWhether 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.

ConfigSets or retrieves a configuration setting.
DecryptDecrypts the data.
DecryptBlockDecrypts a block and returns the decrypted data.
EncryptEncrypts the data.
EncryptBlockEncrypts data and returns the encrypted block.
ResetResets the class.

Event List

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

ErrorFired when information is available about errors during data delivery.
ProgressFired 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.

ChaCha20AlgorithmSpecifies the ChaCha implementation to use.
EncryptedDataEncodingThe encoding of the encrypted input or output data.
IncludeAuthTagWhether to append the authentication tag to the cipher text when UseAEAD is True.
IncludeIVWhether to prepend the IV to the output data and read the IV from the input data.
InitialCounterThe initial counter value.
IVLengthThe IV length in bytes.
KeyPasswordAlgorithmThe hash algorithm used to derive the Key and IV from the KeyPassword property.
KeyPasswordIterationsThe number of iterations performed when using KeyPassword to derive the Key and IV.
KeyPasswordSaltThe salt value used in conjunction with the KeyPassword to derive the Key and IV.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
MaskSensitiveDataWhether sensitive data is masked in log messages.
UseInternalSecurityAPIWhether or not to use the system security libraries or an internal implementation.

AdditionalAuthData Property (ChaCha Component)

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

Syntax

func (obj *ChaCha) AdditionalAuthData() ([]byte, error)
func (obj *ChaCha) SetAdditionalAuthData(value []byte) error

Default Value

""

Remarks

This property specifies data that is authentication but not encrypted. This is only applicable when UseAEAD is True.

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

Data Type

[]byte

AuthTag Property (ChaCha Component)

The authentication tag used when UseAEAD is set to True.

Syntax

func (obj *ChaCha) AuthTag() ([]byte, error)
func (obj *ChaCha) SetAuthTag(value []byte) error

Default Value

""

Remarks

This property holds the 128 bit authentication tag used when UseAEAD is set to True. It is only applicable when UseAEAD is True.

This is populated after calling Encrypt. To also include the value in the output set IncludeAuthTag to True.

This must be set before calling Decrypt. If the auth tag is included in the encrypted data set IncludeAuthTag to True before calling Decrypt.

Data Type

[]byte

InputFile Property (ChaCha Component)

The file to process.

Syntax

func (obj *ChaCha) InputFile() (string, error)
func (obj *ChaCha) 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:

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

Data Type

string

InputMessage Property (ChaCha Component)

The message to process.

Syntax

func (obj *ChaCha) InputMessage() ([]byte, error)
func (obj *ChaCha) 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:

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

Data Type

[]byte

IV Property (ChaCha Component)

The initialization vector (IV).

Syntax

func (obj *ChaCha) IV() ([]byte, error)
func (obj *ChaCha) SetIV(value []byte) error

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 struct will automatically generate a new IV value if KeyPassword or Key is set before Encrypt or EncryptBlock 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 struct supports both lengths.

Note: If Key is specified but IV is not, an IV will be automatically generated. To control the length of the IV that is generated set IVLength.

Data Type

[]byte

Key Property (ChaCha Component)

The secret key for the symmetric algorithm.

Syntax

func (obj *ChaCha) Key() ([]byte, error)
func (obj *ChaCha) SetKey(value []byte) error

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 is specified, a Key value will be generated by the struct as necessary.

Data Type

[]byte

KeyPassword Property (ChaCha Component)

A password to generate the Key and IV .

Syntax

func (obj *ChaCha) KeyPassword() (string, error)
func (obj *ChaCha) SetKeyPassword(value string) error

Default Value

""

Remarks

When this property is set the struct will calculate values for Key and IV using the PKCS5 password digest algorithm. This provides a simpler alternative to creating and managing Key and IV values directly.

Data Type

string

OutputFile Property (ChaCha Component)

The output file when encrypting or decrypting.

Syntax

func (obj *ChaCha) OutputFile() (string, error)
func (obj *ChaCha) 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:

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

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

Data Type

string

OutputMessage Property (ChaCha Component)

The output message after processing.

Syntax

func (obj *ChaCha) OutputMessage() ([]byte, error)

Default Value

""

Remarks

This property will be populated with the output from the operation if OutputFile 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:

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

  • OutputFile
  • 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 (ChaCha Component)

Indicates whether or not the class should overwrite files.

Syntax

func (obj *ChaCha) Overwrite() (bool, error)
func (obj *ChaCha) SetOverwrite(value bool) error

Default Value

false

Remarks

This property indicates whether or not the struct will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

Data Type

bool

UseAEAD Property (ChaCha Component)

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

Syntax

func (obj *ChaCha) UseAEAD() (bool, error)
func (obj *ChaCha) SetUseAEAD(value bool) error

Default Value

false

Remarks

If this property is set to True the struct uses the algorithm AEAD_CHACHA20_POLY1305 as defined in RFC 7539 to construct a message using AEAD. See Encrypt and Decrypt for details.

Data Type

bool

UseHex Property (ChaCha Component)

Whether input or output is hex encoded.

Syntax

func (obj *ChaCha) UseHex() (bool, error)
func (obj *ChaCha) SetUseHex(value bool) error

Default Value

false

Remarks

This property specifies whether the encrypted data is hex encoded.

If set to True, when Encrypt is called the struct will perform the encryption as normal and then hex encode the output. OutputMessage or OutputFile will hold hex encoded data.

If set to True, when Decrypt is called the struct will expect InputMessage or InputFile to hold hex encoded data. The struct will then hex decode the data and perform decryption as normal.

AEAD Notes

When UseAEAD is set to True this property also applies to AuthTag. After calling Encrypt AuthTag will hold a hex encoded value. Before calling Decrypt AuthTag must be set to a hex encoded value.

Data Type

bool

Config Method (ChaCha Component)

Sets or retrieves a configuration setting.

Syntax

func (obj *ChaCha) Config(ConfigurationString string) (string, error)

Remarks

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

Decrypt Method (ChaCha Component)

Decrypts the data.

Syntax

func (obj *ChaCha) Decrypt() error

Remarks

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

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:

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

Additional Notes

The Key property must be set to the 256 bit (32 byte) value originally used to encrypt the data. IV must be set to the original IV value used to encrypt the data.

If using a password, KeyPassword must be set to the same KeyPassword used when encrypting the data. This will automatically generate both Key and IV when Decrypt is called.

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 event will fire as data is decrypted.

Decrypt Example

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 must be set to the same value that was specified when encrypting. AuthTag must be set to the AuthTag value produced when encrypting.

Note: IncludeAuthTag may be set to True if the AuthTag value was included in the encrypted message.

Decrypt with AEAD Example

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!"

DecryptBlock Method (ChaCha Component)

Decrypts a block and returns the decrypted data.

Syntax

func (obj *ChaCha) DecryptBlock(InputBuffer []byte, LastBlock bool) ([]byte, error)

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 (required)
  • Key (required)

InputBuffer specifies the input data to decrypt.

LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the struct will validate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.

DecryptBlock Example

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);

Encrypt Method (ChaCha Component)

Encrypts the data.

Syntax

func (obj *ChaCha) Encrypt() error

Remarks

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

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:

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

Additional Notes

The Key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If KeyPassword is set both Key and IV will be automatically generated when Encrypt is called.

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

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 event will fire as data is encrypted.

Encrypt Example

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 is True AdditionalAuthData optionally holds data that is authenticated but not encrypted.

After encrypting the message the AuthTag property will be populated. To include the AuthTag in the output set IncludeAuthTag to True.

Encrypt with AEAD Example

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}

EncryptBlock Method (ChaCha Component)

Encrypts data and returns the encrypted block.

Syntax

func (obj *ChaCha) EncryptBlock(InputBuffer []byte, LastBlock bool) ([]byte, error)

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 (required)
  • Key (required)

InputBuffer specifies the input data to encrypt.

LastBlock specifies whether the block is the last block. Required when UseAEAD is True. When LastBlock is True the struct will calculate the AuthTag value. If UseAEAD is False the value of LastBlock is not used.

EncryptBlock Example

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;

Reset Method (ChaCha Component)

Resets the class.

Syntax

func (obj *ChaCha) Reset() error

Remarks

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

Error Event (ChaCha Component)

Fired when information is available about errors during data delivery.

Syntax

// ChaChaErrorEventArgs carries the ChaCha Error event's parameters.
type ChaChaErrorEventArgs struct {...}

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

func (obj *ChaCha) GetOnErrorHandler() ChaChaErrorEvent
func (obj *ChaCha) SetOnErrorHandler(handlerFunc ChaChaErrorEvent)

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 section.

Progress Event (ChaCha Component)

Fired as progress is made.

Syntax

// ChaChaProgressEventArgs carries the ChaCha Progress event's parameters.
type ChaChaProgressEventArgs struct {...}

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

func (obj *ChaCha) GetOnProgressHandler() ChaChaProgressEvent
func (obj *ChaCha) SetOnProgressHandler(handlerFunc ChaChaProgressEvent)

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 (ChaCha 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 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 is called the struct will perform the encryption as normal and then encode the output as specified here. OutputMessage or OutputFile will hold the encoded data.

When Decrypt is called the struct will expect InputMessage or InputFile to hold the encoded data as specified here. The struct 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 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. When calling DecryptBlock AuthTag 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. When calling Decrypt 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 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 or DecryptBlock.

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 and IV from KeyPassword. 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 to calculate values for Key and IV. 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 when calculating values for Key and IV.

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:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8
The following is a list of valid code page identifiers for Mac OS only:
IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

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 section.

Trappable Errors (ChaCha Component)

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.