whisper_library::MorseCoder Class Reference

converts messages and timing intervals back and forth (used by TimingCovertChannel) More...

Public Member Functions
	MorseCoder (unsigned int delay_short, unsigned int delay_long, unsigned int delay_letter, unsigned int delay_space)
	Constructor. More...
vector< unsigned int >	encodeMessage (string message)
string	decodeMessage (vector< unsigned int > delays)
vector< char >	checkString (string message)

Private Member Functions
vector< bool >	encodeLetter (char letter)
char	decodeLetter (vector< bool > morse_code)

Private Attributes
unsigned int	m_delay_short
	Represents a short signal (in milliseconds)
unsigned int	m_delay_long
	Represents a long signal (in milliseconds)
unsigned int	m_delay_letter
	Represents a short pause (in milliseconds)
unsigned int	m_delay_space
	Represents a long pause (in milliseconds)
morse_map	m_morse_map
	Contains the mapping between characters and morse.

Detailed Description

converts messages and timing intervals back and forth (used by TimingCovertChannel)

MorseCoder converts a message into time intervals using morse and decodes morse back to a message. To do so, call 'encodeMessage' with the message or 'decodeMessage' with time intervals. Use 'checkString' to check if the given message contains characters, that are not supported by morse.

Constructor & Destructor Documentation

whisper_library::MorseCoder::MorseCoder	(	unsigned int	delay_short,
		unsigned int	delay_long,
		unsigned int	delay_letter,
		unsigned int	delay_space
	)

Constructor.

Parameters

delay_short	is used to encode a short signal (in milliseconds)
delay_long	is used to encode a long signal (in milliseconds)
delay_letter	is used to encode the end of a letter (in milliseconds)
delay_space	is used to encode space between words (in milliseconds)

Member Function Documentation

vector< char > whisper_library::MorseCoder::checkString

(

string

message

)

Checks the given string for characters, that are not supported by morse. If none were found, the returned vector is empty. Otherwise it contains unsupported characters.

Parameters

message

the string that is checked

Returns

all unsupported characters in the message

char whisper_library::MorseCoder::decodeLetter ( vector< bool >  morse_code )

private

Decodes morse for a single character The passed vector of bool has to contain the encoded letter in which 0 (false) means short and 1 (true) means long.

Parameters

morse_code

the morse of a single letter

Returns

the letter as char

string whisper_library::MorseCoder::decodeMessage

(

vector< unsigned int >

delays

)

decodeMessage takes a sequence of delays representing morse and converts them back to a message. The delays have to be exactly the ones set in the constructor.

Parameters

delays

a vector containing delays

vector< bool > whisper_library::MorseCoder::encodeLetter ( char  letter )

private

Encodes a single character to morse.

Parameters

letter

the character to decode

Returns

the morse of the letter, 0 (false) means short and 1 (true) means long

vector< unsigned int > whisper_library::MorseCoder::encodeMessage

(

string

message

)

encodeMessage converts a message into a sequence of delays using morse. Unsupported characters are encoded as '#'.

Parameters

message

the message as string