Encoding and encryption Overview of encodings and ciphers in real life Juraj Vančo 93. prístav vodných skautov a skautiek Tortuga Trenčín Sep 2013
Encoding and encryption
Overview of encodings and ciphers in real life
Juraj Vančo93. prístav vodných skautov a skautiek Tortuga Trenčín
Sep 2013
Agenda
• Encoding and encryption• Encodings in real life• Morse code– Where to find– Q codes– QSL
• SSL encryption• Digital signature
Encoding and encryption
• Encoding– procedure with goal to change information to be easier in
practise– every information needed to proceed is available for
everyone– example: Morse code
• Encryption– procedure with goal to hide information that cannot be
read from those who do not have the knowledge how to extract (decrypt) the useful information
– example: private translation table
Encodings in real life
• Pictograms, abbreviations with the only meaning• Morse code– Where? Telegraph + air communication: aviation, navy,
HAM radio– Information: table + procedure
• Lossless compression / decompression (LZHA = zip, gzip, bzip, rar) (information accumulation)– Information: procedure = algorithm
• Email encodings with base64 algorithm– Information: procedure = algorithm
Morse code
• What for? Frequency band and filtering• Timing encrypted– Consequences: messaging (transmitting) procedure
can take much time compared to speech => issues with oscillators characteristics bias in time• Solution: timing as fast as human can (200 letters / min)• Solution: using Q-codes (encodings)
• Dots and lines? No use case in real life…• Replacement: phone (codes and spelling
alphabet)
Example of QSO
»QRL? »CQ CQ CQ de OM4ATN«OM4ATN de HB9ASD K»HB9ASD de OM4ATN TNX FER QSO QTH QTH TRENCIN RST
577 NAME JURAJ PSE QSL K«OM4ATN de HB9ASD TNX UR RST 599 QTH QTH GENEVA
NAME JEAN WX CLOUDY PSE UR WX UR WX K»HB9ASD DE OM4ATN TNX FER QSL WX WX SUNNY 23C K«OM4ATN DE HB9ASD R R OK DR JURAJ TNX CU K»HB9ASD DE OM4ATN TNX CU SK
Encryption in real life
• Private translation table (can have additional key= shift etc.)• Code Navaho (table= key)• Security = Privacy, Integrity, Authentication• Symmetric and asymmetric encryption algorithms (AES, DES,
3DES, DSA, RSA…)- (known algorithm, unknown key)• Challenge: decrypt!
– Scouting: messages that are “easy” to decrypt but take time (“4 ohne, Boj o poklad kapitána pirátov”)
– IT- compute power: bunch of methods => easy to find the translation
– Algorithm based encryption= no key= vulnerable algorithm– Key based= algorithm is known= find the key (brutal force attack)
Digital signature
• Hash = Digitally encoded „abstract“– integrity number, no real information inside
• Digital signature = hash + certificate
Other risks
• Unsecured WiFi network• Running untrusted software without
certification (Windows)– Use sigverif.exe in Windows command prompt
• Unknown hardware– Keyboards, computers, fingerprint scanners…