encoding and encryption overview of encodings and ciphers in real life juraj vančo 93. prístav...

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Encoding and encryption Overview of encodings and ciphers in real life Juraj Vančo 93. prístav vodných skautov a skautiek Tortuga Trenčín Sep 2013

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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)

Q codes

• 3 letters codes replacing more complex information

• Examples:– QSL– QTH– QSO– QRA– QRL

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)

Encryption: symmetric and asymmetric

• Keys: both must know the key, how to?

Authentication: certificates & PKI

Example of certificate #1

Example of certificate #2

Example of certificate #3

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…

Q & A

• Thanks for watching