Struct ipworksencrypt::CMAC

Properties   Methods   Events   Config Settings   Errors  

The CMAC struct may be used to produce a MAC (or Tag) value using the AES CMAC algorithm.

Syntax

ipworksencrypt::CMAC

Remarks

The CMAC struct implements the AES CMAC algorithm defined in RFC 4493. This may be used to compute a MAC (or Tag) value on data of any length.

The key must be set to a 128-bit (16 bytes), 192-bit (24 bytes), or 256-bit (32 bytes) key before computing the MAC. The computed MAC is 128-bit (16 bytes) in size.

ComputeMAC Notes

compute_mac computes the MAC (Message Authentication Code) from the input data.

Before calling this method set key to a 128-bit (16 bytes), 192-bit (24 bytes), or 256-bit (32 bytes) key. If encode_mac is set to True (default) the output data will be hex encoded.

Input Notes

The struct will determine the source of the input based on which properties are set.

The order in which the input properties are checked are as follows:

• input_file
• input_message

When a valid source is found the search stops.

After calling this method mac_value will be populated with the computed 128 bit (16 byte) value.

ComputeMAC Example

CMAC cmac = new CMAC(); cmac.KeyB = new byte[] { 0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0, 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0 }; cmac.InputMessage = "Hello CMAC"; cmac.EncodeMAC = true; //hex output cmac.ComputeMAC(); //This outputs "1234E6C7808BF17C1CBD951D1A139E4D" Console.WriteLine(cmac.MACValue);

ComputeMACBlock Notes

compute_mac_block allows input to the struct to be specified in blocks. This method will return the MAC value only when the parameter LastBlock is True.

InputBuffer specifies the input data.

LastBlock specifies whether the block is the last block. If this is False the method will return an empty byte array.

To calculate the MAC value of data that is broken apart into multiple blocks make multiple calls to this method. For instance: //Encode output in hex cmac.EncodeMAC = true; //hex output //Pass any number of parts, of any size cmac.ComputeMACBlock(part1,false); cmac.ComputeMACBlock(part2,false); cmac.ComputeMACBlock(part3,false); //Pass true for the last block cmac.ComputeMACBlock(lastPart,true); //The MACValue property holds the MAC value Console.WriteLine(cmac.MACValue);

Object Lifetime

The new() method returns a mutable reference to a struct instance. The object itself is kept in the global list maintained by IPWorksEncrypt. Due to this, the CMAC struct cannot be disposed of automatically. Please, call the dispose(&mut self) method of CMAC when you have finished using the instance.

Property List

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

encode_mac property (CMAC Struct)

Whether the MAC value is hex encoded.

Syntax

fn encode_mac(&self ) -> Result<bool, IPWorksEncryptError> 
fn set_encode_mac(&self, value : bool) ->  Option<IPWorksEncryptError> 

Default Value

true

Remarks

This property specifies whether the computed MAC value is hex encoded. When set to True (default) the struct will hex encode the computed MAC for easier use. Set this value to False to obtain the MAC value in an unmodified form.

The default value is True.

Data Type

bool

input_file property (CMAC Struct)

The file to process.

Syntax

fn input_file(&self ) -> Result<String, IPWorksEncryptError> 
fn set_input_file(&self, value : &str) ->  Option<IPWorksEncryptError> 
fn set_input_file_ref(&self, value : &String) ->  Option<IPWorksEncryptError> 

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:

• 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.

Data Type

String

input_message property (CMAC Struct)

The message to process.

Syntax

fn input_message(&self ) -> Result<Vec<u8>, IPWorksEncryptError> 
fn set_input_message(&self, value : Vec<u8>) ->  Option<IPWorksEncryptError> 
fn set_input_message_ref(&self, value : &[u8]) ->  Option<IPWorksEncryptError> 

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:

• 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.

Data Type

Vec

key property (CMAC Struct)

The key to be used when computing a MAC (Message Authentication Code).

Syntax

fn key(&self ) -> Result<Vec<u8>, IPWorksEncryptError> 
fn set_key(&self, value : Vec<u8>) ->  Option<IPWorksEncryptError> 
fn set_key_ref(&self, value : &[u8]) ->  Option<IPWorksEncryptError> 

Default Value

""

Remarks

This property holds the secret key used when computing the mac_value. The key must be 128-bit (16 bytes), 192-bit (24 bytes), or 256-bit (32 bytes) long.

Data Type

Vec

mac_value property (CMAC Struct)

The computed MAC value.

Syntax

fn mac_value(&self ) -> Result<Vec<u8>, IPWorksEncryptError> 

Default Value

""

Remarks

The 128 bit (16 byte) MAC value calculated after calling compute_mac.

This property is read-only.

Data Type

Vec

compute_mac method (CMAC Struct)

Computes the MAC.

Syntax

fn compute_mac(&self) -> Result<(), IPWorksEncryptError>

Remarks

compute_mac computes the MAC (Message Authentication Code) from the input data.

Before calling this method set key to a 128-bit (16 bytes), 192-bit (24 bytes), or 256-bit (32 bytes) key. If encode_mac is set to True (default) the output data will be hex encoded.

Input Notes

The struct will determine the source of the input based on which properties are set.

The order in which the input properties are checked are as follows:

• input_file
• input_message

When a valid source is found the search stops.

After calling this method mac_value will be populated with the computed 128 bit (16 byte) value.

ComputeMAC Example

CMAC cmac = new CMAC(); cmac.KeyB = new byte[] { 0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0, 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0 }; cmac.InputMessage = "Hello CMAC"; cmac.EncodeMAC = true; //hex output cmac.ComputeMAC(); //This outputs "1234E6C7808BF17C1CBD951D1A139E4D" Console.WriteLine(cmac.MACValue);

compute_mac_block method (CMAC Struct)

Computes the MAC value of specified data.

Syntax

fn compute_mac_block(&self, input_buffer : &[u8], last_block : bool) ->  Result<Vec<u8>, IPWorksEncryptError>

Remarks

compute_mac_block allows input to the struct to be specified in blocks. This method will return the MAC value only when the parameter LastBlock is True.

InputBuffer specifies the input data.

LastBlock specifies whether the block is the last block. If this is False the method will return an empty byte array.

To calculate the MAC value of data that is broken apart into multiple blocks make multiple calls to this method. For instance: //Encode output in hex cmac.EncodeMAC = true; //hex output //Pass any number of parts, of any size cmac.ComputeMACBlock(part1,false); cmac.ComputeMACBlock(part2,false); cmac.ComputeMACBlock(part3,false); //Pass true for the last block cmac.ComputeMACBlock(lastPart,true); //The MACValue property holds the MAC value Console.WriteLine(cmac.MACValue);

config method (CMAC Struct)

Sets or retrieves a configuration setting.

Syntax

fn config(&self, configuration_string : &str) ->  Result<String, IPWorksEncryptError>

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.

reset method (CMAC Struct)

Resets the struct.

Syntax

fn reset(&self) -> Result<(), IPWorksEncryptError>

Remarks

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

on_error event (CMAC Struct)

Fired when information is available about errors during data delivery.

Syntax

// CMACErrorEventArgs carries the CMAC Error event's parameters.
pub struct CMACErrorEventArgs {
  fn error_code(&self) -> i32
  fn description(&self) -> &String
}

// CMACErrorEvent defines the signature of the CMAC Error event's handler function.
pub trait CMACErrorEvent {
  fn on_error(&self, sender : CMAC, e : &mut CMACErrorEventArgs);
}

impl <'a> CMAC<'a> {
  pub fn on_error(&self) -> &'a dyn CMACErrorEvent;
  pub fn set_on_error(&mut self, value : &'a dyn CMACErrorEvent);
  ...
}

Remarks

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

The error_code 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 (CMAC Struct)

Fired as progress is made.

Syntax

// CMACProgressEventArgs carries the CMAC Progress event's parameters.
pub struct CMACProgressEventArgs {
  fn bytes_processed(&self) -> i64
  fn percent_processed(&self) -> i32
}

// CMACProgressEvent defines the signature of the CMAC Progress event's handler function.
pub trait CMACProgressEvent {
  fn on_progress(&self, sender : CMAC, e : &mut CMACProgressEventArgs);
}

impl <'a> CMAC<'a> {
  pub fn on_progress(&self) -> &'a dyn CMACProgressEvent;
  pub fn set_on_progress(&mut self, value : &'a dyn CMACProgressEvent);
  ...
}

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 (CMAC Struct)

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.

Base Config Settings

Trappable Errors (CMAC Struct)

CMAC Errors