ChaCha Class
Properties Methods Events Config Settings Errors
The ChaCha class can be used to encrypt and decrypt data with the ChaCha20 algorithm.
Syntax
class ipworksencrypt.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 use_aead to True.
Data may be encrypted and decrypted in its entirety by calling encrypt and decrypt or chunk by chunk by calling encrypt_block and decrypt_block.
In all operations a key and iv must be used. If iv is not set one is automatically generated. key_password may be set in order to automatically generate both a key and iv when a method is called. The same key_password, 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:
- iv (required)
- key (required)
- use_aead (optional)
- additional_auth_data (optional - applicable if use_aead 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
Additional Notes
The key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If key_password 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 class 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 on_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 use_aead is True additional_auth_data optionally holds data that is authenticated but not encrypted.
After encrypting the message the auth_tag property will be populated. To include the auth_tag 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
encrypt_block 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:
InputBuffer specifies the input data to encrypt.
LastBlock specifies whether the block is the last block. Required when use_aead is True. When LastBlock is True the class will calculate the auth_tag value. If use_aead 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[] authTab = chacha.AuthTagB;
Decrypt Notes
decrypt will decrypt the specified data. The following properties are applicable:
- iv (required)
- key (required)
- use_aead (optional)
- auth_tag (conditional - required if use_aead is True)
- additional_auth_data (optional - applicable if use_aead 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
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, key_password must be set to the same key_password 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 on_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 additional_auth_data must be set to the same value that was specified when encrypting. auth_tag must be set to the auth_tag value produced when encrypting.
Note: IncludeAuthTag may be set to True if the auth_tag 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
decrypt_block 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:
InputBuffer specifies the input data to decrypt.
LastBlock specifies whether the block is the last block. Required when use_aead is True. When LastBlock is True the class will validate the auth_tag value. If use_aead 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;
cahcha.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.
| additional_auth_data | Additional Authentication Data (AAD) used when UseAEAD is True. |
| auth_tag | The authentication tag used when UseAEAD is set to True. |
| input_file | The file to process. |
| input_message | The message to process. |
| iv | The initialization vector (IV). |
| key | The secret key for the symmetric algorithm. |
| key_password | A password to generate the Key and IV . |
| output_file | The output file when encrypting or decrypting. |
| output_message | The output message after processing. |
| overwrite | Indicates whether or not the class should overwrite files. |
| use_aead | Whether to use AEAD (Authenticated Encryption with Additional Data). |
| use_hex | 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 | Sets or retrieves a configuration setting. |
| decrypt | Decrypts the data. |
| decrypt_block | Decrypts a block and returns the decrypted data. |
| encrypt | Encrypts the data. |
| encrypt_block | Encrypts data and returns the encrypted block. |
| reset | Resets the class. |
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.
| on_error | Fired when information is available about errors during data delivery. |
| on_progress | 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.
| EncryptedDataEncoding | The encoding of the encrypted input or output data. |
| IncludeAuthTag | Whether to append the authentication tag to the cipher text when UseAEAD is True. |
| IncludeIV | Whether to prepend the IV to the output data and read the IV from the input data. |
| InitialCounter | The initial counter value. |
| IVLength | The IV length in bytes. |
| KeyPasswordAlgorithm | The hash algorithm used to derive the Key and IV from the KeyPassword property. |
| KeyPasswordIterations | The number of iterations performed when using KeyPassword to derive the Key and IV. |
| KeyPasswordSalt | The salt value used in conjunction with the KeyPassword to derive the Key and IV. |
| BuildInfo | Information about the product's build. |
| CodePage | The system code page used for Unicode to Multibyte translations. |
| LicenseInfo | Information about the current license. |
| MaskSensitive | Whether sensitive data is masked in log messages. |
| ProcessIdleEvents | Whether the class uses its internal event loop to process events when the main thread is idle. |
| SelectWaitMillis | The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process. |
| UseInternalSecurityAPI | Whether or not to use the system security libraries or an internal implementation. |
additional_auth_data Property
Additional Authentication Data (AAD) used when UseAEAD is True.
Syntax
def get_additional_auth_data() -> bytes: ... def set_additional_auth_data(value: bytes) -> None: ...
additional_auth_data = property(get_additional_auth_data, set_additional_auth_data)
Default Value
""
Remarks
This property specifies data that is authentication but not encrypted. This is only applicable when use_aead is True.
Note that AAD data is authenticated but not encrypted, so it is not included in the output.
auth_tag Property
The authentication tag used when UseAEAD is set to True.
Syntax
def get_auth_tag() -> bytes: ... def set_auth_tag(value: bytes) -> None: ...
auth_tag = property(get_auth_tag, set_auth_tag)
Default Value
""
Remarks
This property holds the 128 bit authentication tag used when use_aead is set to True. It is only applicable when use_aead 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.
input_file Property
The file to process.
Syntax
def get_input_file() -> str: ... def set_input_file(value: str) -> None: ...
input_file = property(get_input_file, set_input_file)
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:
- input_file
- input_message
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
input_message Property
The message to process.
Syntax
def get_input_message() -> bytes: ... def set_input_message(value: bytes) -> None: ...
input_message = property(get_input_message, set_input_message)
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:
- input_file
- input_message
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
iv Property
The initialization vector (IV).
Syntax
def get_iv() -> bytes: ... def set_iv(value: bytes) -> None: ...
iv = property(get_iv, set_iv)
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 key_password or key is set before encrypt or encrypt_block 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 is specified but iv is not, an iv will be automatically generated. To control the length of the iv that is generated set IVLength.
key Property
The secret key for the symmetric algorithm.
Syntax
def get_key() -> bytes: ... def set_key(value: bytes) -> None: ...
key = property(get_key, set_key)
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 key_password is specified, a key value will be generated by the class as necessary.
key_password Property
A password to generate the Key and IV .
Syntax
def get_key_password() -> str: ... def set_key_password(value: str) -> None: ...
key_password = property(get_key_password, set_key_password)
Default Value
""
Remarks
When this property is set the class 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.
output_file Property
The output file when encrypting or decrypting.
Syntax
def get_output_file() -> str: ... def set_output_file(value: str) -> None: ...
output_file = property(get_output_file, set_output_file)
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 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
output_message Property
The output message after processing.
Syntax
def get_output_message() -> bytes: ...
output_message = property(get_output_message, None)
Default Value
""
Remarks
This property will be populated with the output from the operation if output_file 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
This property is read-only.
overwrite Property
Indicates whether or not the class should overwrite files.
Syntax
def get_overwrite() -> bool: ... def set_overwrite(value: bool) -> None: ...
overwrite = property(get_overwrite, set_overwrite)
Default Value
FALSE
Remarks
This property indicates whether or not the class will overwrite output_file. If overwrite is False, an error will be thrown whenever output_file exists before an operation. The default value is False.
use_aead Property
Whether to use AEAD (Authenticated Encryption with Additional Data).
Syntax
def get_use_aead() -> bool: ... def set_use_aead(value: bool) -> None: ...
use_aead = property(get_use_aead, set_use_aead)
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 and decrypt for details.
use_hex Property
Whether input or output is hex encoded.
Syntax
def get_use_hex() -> bool: ... def set_use_hex(value: bool) -> None: ...
use_hex = property(get_use_hex, set_use_hex)
Default Value
FALSE
Remarks
This property specifies whether the encrypted data is hex encoded.
If set to True, when encrypt is called the class will perform the encryption as normal and then hex encode the output. output_message or output_file will hold hex encoded data.
If set to True, when decrypt is called the class will expect input_message or input_file to hold hex encoded data. The class will then hex decode the data and perform decryption as normal.
AEAD Notes
When use_aead is set to True this property also applies to auth_tag. After calling encrypt auth_tag will hold a hex encoded value. Before calling decrypt auth_tag must be set to a hex encoded value.
config Method
Sets or retrieves a configuration setting.
Syntax
def config(configuration_string: str) -> str: ...
Remarks
config is a generic method available in every class. It is used to set and retrieve configuration settings 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, you must call Config("PROPERTY"). The value will be returned as a string.
decrypt Method
Decrypts the data.
Syntax
def decrypt() -> None: ...
Remarks
decrypt will decrypt the specified data. The following properties are applicable:
- iv (required)
- key (required)
- use_aead (optional)
- auth_tag (conditional - required if use_aead is True)
- additional_auth_data (optional - applicable if use_aead 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
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, key_password must be set to the same key_password 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 on_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 additional_auth_data must be set to the same value that was specified when encrypting. auth_tag must be set to the auth_tag value produced when encrypting.
Note: IncludeAuthTag may be set to True if the auth_tag 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 Method
Decrypts a block and returns the decrypted data.
Syntax
def decrypt_block(input_buffer: bytes, last_block: bool) -> bytes: ...
Remarks
decrypt_block 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:
InputBuffer specifies the input data to decrypt.
LastBlock specifies whether the block is the last block. Required when use_aead is True. When LastBlock is True the class will validate the auth_tag value. If use_aead 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;
cahcha.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
Encrypts the data.
Syntax
def encrypt() -> None: ...
Remarks
encrypt will encrypt the specified data. The following properties are applicable:
- iv (required)
- key (required)
- use_aead (optional)
- additional_auth_data (optional - applicable if use_aead 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
Additional Notes
The key property must be set to a 256 bit (32 byte) value. This is the only allowed value for ChaCha20. If key_password 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 class 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 on_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 use_aead is True additional_auth_data optionally holds data that is authenticated but not encrypted.
After encrypting the message the auth_tag property will be populated. To include the auth_tag 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 Method
Encrypts data and returns the encrypted block.
Syntax
def encrypt_block(input_buffer: bytes, last_block: bool) -> bytes: ...
Remarks
encrypt_block 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:
InputBuffer specifies the input data to encrypt.
LastBlock specifies whether the block is the last block. Required when use_aead is True. When LastBlock is True the class will calculate the auth_tag value. If use_aead 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[] authTab = chacha.AuthTagB;
reset Method
Resets the class.
Syntax
def reset() -> None: ...
Remarks
When called, the class will reset all of its properties to their default values.
on_error Event
Fired when information is available about errors during data delivery.
Syntax
class ChaChaErrorEventParams(object): @property def error_code() -> int: ... @property def description() -> str: ... # In class ChaCha: @property def on_error() -> Callable[[ChaChaErrorEventParams], None]: ... @on_error.setter def on_error(event_hook: Callable[[ChaChaErrorEventParams], None]) -> None: ...
Remarks
The on_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 section.
on_progress Event
Fired as progress is made.
Syntax
class ChaChaProgressEventParams(object): @property def bytes_processed() -> int: ... @property def percent_processed() -> int: ... # In class ChaCha: @property def on_progress() -> Callable[[ChaChaProgressEventParams], None]: ... @on_progress.setter def on_progress(event_hook: Callable[[ChaChaProgressEventParams], None]) -> None: ...
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.
ChaCha Config Settings
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 method.ChaCha Config Settings
When encrypt is called the class will perform the encryption as normal and then encode the output as specified here. output_message or output_file will hold the encoded data.
When decrypt is called the class will expect input_message or input_file 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)
Note: This setting cannot be used in conjunction with decrypt_block. When calling decrypt_block auth_tag must be set explicitly and the cipher text being decrypted must not include the auth tag.
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 decrypt_block.
- "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.
Base Config Settings
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 |
| 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 |
- 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.
This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.
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 section.
ChaCha Errors
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. |