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JSON Web Tokens DAMIR SVRTAN

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01 JSON API AUTHENTICATION

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CLIENT SERVER [email protected]&PASSWORD=PASS123 ACCESS_TOKEN=RAND0M$TR1N6

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CLIENT SERVER ARTICLES?ACCESS_TOKEN=RAND0M$TR1N6

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02 SINGLE ACCESS TOKEN PER USER

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id email password auth_token 1 [email protected] $2a$10$5FkD.. 23ZS921a USERS TABLE

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GENERATE A RANDOM AUTH TOKEN class User before_save :generate_auth_token def generate_auth_token loop do self.auth_token = Devise.friendly_token break if User.find_by_auth_token(auth_token).nil? end end end

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PROBLEMS WITH THE SINGLE ACCESS TOKEN APPROACH

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STORING IT IN PLAIN TEXT

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Is it the same as storing passwords in plain text? ALMOST.

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Passwords • when compromised are difficult to change • reveal information about people who created them • people use them across several services

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Authentication Tokens • auto-generated, random, unique (not shared across multiple services). • when compromised can be renewed easily with little user inconvenience

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NAIVE IMPLEMENTATIONS NEVER EXPIRE THEM

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03 SINGLE HASHED ACCESS TOKEN PER USER

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NOT STORING IT IN PLAIN TEXT

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PROBLEMS WITH THE SINGLE HASHED ACCESS TOKEN APPROACH

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BROWSER SERVER EM AIL=DAM IR@ EXAM PLE.COM &PASSW ORD=PASS123 ACCESS_TOKEN=RAND0M $TR1N6 EM AIL=DAM IR@ EXAM PLE.COM &PASSW ORD=PASS123 MOBILE ACCESS_TOKEN=ANOTHER-RAND0M $TR1N6

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04 MULTIPLE HASHED ACCESS TOKENS PER USER

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MAINTAINING A SEPARATE TABLE OF ACCESS TOKENS

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COMPLICATING TOO MUCH..

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ROLLING YOUR OWN AUTHENTICATION SYSTEM

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01 WHO ARE WE?

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WHY DON’T WE TRY TO DO THE SAME THING AS RAILS APPS REGULARLY DO?

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05 RAILS SESSION STORAGE

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session[:user_id] = current_user.id

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CLIENT SERVER [email protected]&PASSWORD=PASS123 SET-COOKIE: PRODUCTIVE_SESSION=23OFSKL932RDASDAFSFJ23

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User.find(session[:user_id])

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STATELESS

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WE COULD DO SOMETHING SIMILAR… …OR FOLLOW AN INDUSTRY STANDARD

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06 JSON WEB TOKENS

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JSON Web Tokens are an open, industry standard method for representing claims securely between two parties.

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CLIENT SERVER [email protected]&PASSWORD=PASS123 ACCESS_TOKEN=33WE.DAS3Q.ADAS

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TO THE API CONSUMER IT CAN LOOK RANDOM.. BUT IT’S MUCH MORE

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IT STORES INFORMATION INSIDE OF IT.

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07 JWT STRUCTURE

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ABASASD.U93RJADSF.ASASD

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HEADER.PAYLOAD.SIGNATURE

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{ "typ": "JWT", "alg": "HS256" } HEADER

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eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9 BASE64 ENCODED HEADER

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{ "iss": "infinum.co", "exp": 1300819380, "name": "Kolega Frend", "user_id": 231 } BODY

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iss: The issuer of the token sub: The subject of the token aud: The audience of the token exp: This will define the expiration in NumericDate value. nbf: Defines the time before which the JWT MUST NOT be accepted for processing iat: The time the JWT was issued. Can be used to determine the age of the JWT BODY CLAIMS

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eyJpc3MiOiJzY290Y2guaW8iLCJleHAiOjE BASE64 ENCODED BODY

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encoded_string = Base64.encode64(header) + "." + Base64.encode64(payload); OpenSSL::HMAC.hexdigest( OpenSSL::Digest.new(‘sha256'), Rails.application.secrets.secret_key_base, encoded_string ) GENERATE A SIGNATURE

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SIGNATURE 03f329983b86f7d9a9f5fef85305880101d

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JSON WEB TOKEN eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJpc3MiOiJzY290Y2guaW8iLCJleHAiOjE. 03f329983b86f7d9a9f5fef85305880101d

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THEY CARRY INFORMATION INSIDE OF THEMSELVES JUST LIKE RAILS SESSIONS DO

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08 JWT AND RAILS SESSION DIFFERENCES

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RAILS SESSIONS ARE ENCRYPTED JWT’S ARE SIGNED

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RAILS SESSIONS CAN’T BE READ ON THE CLIENT SIDE JWT’S CAN BE READ ON THE CLIENT SIDE

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SECRET INFORMATION IN JWT’S MUST BE EXPLICITLY ENCRYPTED

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09 JWT ADVANTAGES

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SAFELY SHARE DATA WITH THE CLIENT APP

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NOT REINVENTING THE WHEEL - USING AN INDUSTRY STANDARD.

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PERSISTENCE LAYER AGNOSTIC - SINCE YOU DON’T PERSIST IT! ACTIVERECORD/SEQUEL/MONGODB/NEO4J

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AUTOMATIC TIME-BASED EXPIRATION HANDLING

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NO SESSION LOOKUP

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SINGLE-SIGN-ON ACROSS MULTIPLE APPLICATIONS WITH UUIDS

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MACHINE-TO-MACHINE INFORMATION SHARING

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09 JWT DISADVANTAGES

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NO LOGOUTS

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HARDER TOKEN REVOCATION

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10 JWT REVOCATION

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FLAG A USER AS DISABLED

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DISABLE TOKENS WITH AN IAT CLAIM OLDER THAN 14.09.2016

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INSERT AN USERS ENCRYPTED PASSWORD HASH INTO THE PAYLOAD

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10 STORING TOKENS ON THE FRONTEND

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LOCALSTORAGE XSS

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COOKIES XSS + CSRF

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HTTP ONLY COOKIE CSRF

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11 RAILS IMPLEMENTATIONS

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12 DEBUG JSON WEB TOKENS

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