RC4 Class

Properties   Methods   Events   Config Settings   Errors  

Encrypt and decrypt data with the RC4 (ARC4 / ARCFOUR ) stream cipher.

Syntax

class ipworksencrypt.RC4

Remarks

The RC4 component is used to encrypt and decrypt data with the RC4 (ARC4 / ARCFOUR ) stream cipher.

To begin simply specify the data you wish 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:

• 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.

Before encrypting you must have a valid key and iv. There are a few options available to you in regards to key management. The easiest option is to simply set key_password. When key_password is set the component will automatically create a key and iv using the PKCS5 password digest algorithm. This means there is only one value you need to keep track of.

If you wish to have more control over the key and iv values you may specify the properties yourself. If iv is left empty, one will be created for you when you call encrypt or decrypt.

A simple example: Component.InputFile = "C:\MyFile.txt"; Component.OutputFile = "C:\Encrypted.txt"; Component.KeyPassword = "password"; Component.Encrypt();

Property List

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

Method List

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

Event List

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

Config Settings

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

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). 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 property must be equal to the BlockSize divided by 8.

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. The legal key size varies depending on the algorithm.

If this property is left empty and key_password is specified, a key value will be generated by the class as necessary.

Legal Key and Block Sizes (in bits)

Note: When using TEA if algorithm is set to XXTEA valid block sizes are 64 + n * 32. Where n is any positive integer.

The default KeySize is the Maximum Key Size.

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.

The size of the key generated is dependent on the value of KeySize.

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:

• 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.

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:

• 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.

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_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.

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

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

• iv (required)
• key (required)
• cipher_mode
• padding_mode

Note that cipher_mode must be set to the same value used during encryption or the results may be unexpected. If the cipher_mode value does not match the value used during encryption the operation may succeed but the decrypted data may not be correct.

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.

decrypt_block Method

Decrypts a block and returns the decrypted data.

Syntax

def decrypt_block(input_buffer: bytes) -> bytes: ...

Remarks

This method decrypted the data specified by InputBuffer and returns the decrypted data.

encrypt Method

Encrypts the data.

Syntax

def encrypt() -> None: ...

Remarks

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

• iv (required)
• key (required)
• padding_mode
• cipher_mode

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.

encrypt_block Method

Encrypts data and returns the encrypted block.

Syntax

def encrypt_block(input_buffer: bytes) -> bytes: ...

Remarks

This method encrypts the data specified by InputBuffer and returns the encrypted block.

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

Information about errors during data delivery.

Syntax

class RC4ErrorEventParams(object):
  @property
  def error_code() -> int: ...

  @property
  def description() -> str: ...

# In class RC4:
@property
def on_error() -> Callable[[RC4ErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[RC4ErrorEventParams], None]) -> None: ...

Remarks

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

ErrorCode contains an error code and Description 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 RC4ProgressEventParams(object):
  @property
  def bytes_processed() -> int: ...

  @property
  def percent_processed() -> int: ...

# In class RC4:
@property
def on_progress() -> Callable[[RC4ProgressEventParams], None]: ...
@on_progress.setter
def on_progress(event_hook: Callable[[RC4ProgressEventParams], 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.

RC4 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.

RC4 Config Settings

Base Config Settings

RC4 Errors

RC4 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.