Practising encodings

Encoding and encryptionOverview of encodings and ciphers in real lifeJuraj Vano93. prstav vodnch skautov a skautiek Tortuga Trenn

Sep 2013

AgendaEncoding and encryptionEncodings in real lifeMorse codeWhere to findQ codesQSLSSL encryptionDigital signature

Encoding and encryptionEncodingprocedure with goal to change information to be easier in practiseevery information needed to proceed is available for everyoneexample: Morse codeEncryptionprocedure with goal to hide information that cannot be read from those who do not have the knowledge how to extract (decrypt) the useful informationexample: private translation table

Encodings in real lifePictograms, abbreviations with the only meaningMorse codeWhere? Telegraph + air communication: aviation, navy, HAM radioInformation: table + procedureLossless compression / decompression (LZHA = zip, gzip, bzip, rar) (information accumulation)Information: procedure = algorithmEmail encodings with base64 algorithmInformation: procedure = algorithm

Morse codeWhat for? Frequency band and filteringTiming encryptedConsequences: messaging (transmitting) procedure can take much time compared to speech => issues with oscillators characteristics bias in timeSolution: timing as fast as human can (200 letters / min)Solution: using Q-codes (encodings)Dots and lines? No use case in real lifeReplacement: phone (codes and spelling alphabet)Q codes3 letters codes replacing more complex informationExamples:QSLQTHQSOQRAQRL

Example of QSOQRL? CQ CQ CQ de OM4ATNOM4ATN de HB9ASD KHB9ASD de OM4ATN TNX FER QSO QTH QTH TRENCIN RST 577 NAME JURAJ PSE QSL KOM4ATN de HB9ASD TNX UR RST 599 QTH QTH GENEVA NAME JEAN WX CLOUDY PSE UR WX UR WX KHB9ASD DE OM4ATN TNX FER QSL WX WX SUNNY 23C KOM4ATN DE HB9ASD R R OK DR JURAJ TNX CU KHB9ASD DE OM4ATN TNX CU SKEncryption in real lifePrivate translation table (can have additional key= shift etc.)Code Navaho (table= key)Security = Privacy, Integrity, AuthenticationSymmetric 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 kapitna pirtov)IT- compute power: bunch of methods => easy to find the translationAlgorithm based encryption= no key= vulnerable algorithmKey based= algorithm is known= find the key (brutal force attack) Encryption: symmetric and asymmetricKeys: both must know the key, how to?

Authentication: certificates & PKI

Example of certificate #1

Example of certificate #2

Example of certificate #3

Digital signatureHash = Digitally encoded abstractintegrity number, no real information insideDigital signature = hash + certificate

Other risksUnsecured WiFi networkRunning untrusted software without certification (Windows)Use sigverif.exe in Windows command promptUnknown hardwareKeyboards, computers, fingerprint scanners

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