JSON Web Tokens in a microservice architecture (PHPBenelux)

In this talk I'll introduce you to JSON Web Tokens (JWT) and how they might change your view on securely transmitting data bewteen services. We'll take a look on what's inside of a JSON Web Token, what makes them secure and how you can use them in a microservice architecture,

Transcript

1. JSON WEB TOKENS JENS SEGERS
4. GITHUB PACKAGES • jenssegers/op+mus - ID obfusca+on • jenssegers/agent - User agent parsing, mobile & bot detec+on • jenssegers/date - Localized dates • jenssegers/imagehash - Perceptual image hashes
6. JSON WEB TOKENS AKA. JWT
7. JSON WEB TOKENS AKA. JWT AKA. JOT?
8. JWT, WHAT? JSON Web Token is an open standard that defines a compact and self-contained way for securely transmi>ng informa@on between par@es as a JSON object
9. JWT, WHAT? JSON Web Token is an open standard that defines a compact and self-contained way for securely transmi.ng informa2on between par2es as a JSON object
10. JWT EXAMPLE eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ
11. JWT EXAMPLE eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ 1. Header 2. Payload 3. Signature
12. HEADER eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ { "alg": "HS256", "typ": "JWT" }
13. PAYLOAD (CLAIMS) eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ { "iss": "acme.com" "sub": "1234567890", "exp": 1483711650, "name": "John Doe", "admin": true }
14. SIGNATURE eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ hash_hmac( 'sha256', base64_encode(header).'.'.base64_decode(payload), 'secret-passphrase' )
15. SIGNATURE eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9. TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ openssl_sign( base64_encode(header).'.'.base64_decode(payload), $signature, openssl_pkey_get_private('file://key.pem'), OPENSSL_ALGO_SHA256 )
16. SIGNATURE PURPOSE It provides proof of authen'city and integrity for the JWT data.
17. CRYPTOGRAPHY 101
21. SYMMETRIC SIGNATURES • All par(es involved share a secret key • The sender calculates the signature using the secret key • The receiver re-calculates the signature and compares it with the received signature
24. ASYMMETRIC SIGNATURES • The sender shares his public key with the receiver • The sender calculates the signature by hashing the data and encryp7ng it with his private key • The receiver validates the signature by decryp7ng the signature with the public key and compares the result with the original message
25. SIGNATURE RECAP • Authen'city: Only trusted par0es can generate and verify signatures • Integrity: You can't change the JWT data without regenera0ng a new signature • No secrecy! Alterna0ve: JSON Web Encryp0on (JWE)
27. USE CASES
28. JWT, WHAT? JSON Web Token is an open standard that defines a compact and self-contained way for securely transmi.ng informa2on between par2es as a JSON object
29. INFORMATION EXCHANGE
30. INFORMATION EXCHANGE POST /transfer { "to": "171RaSzy9GYHCA8TuLYN5mwTWs3nnARfMZ", "amount": 1, "currency": "BTC" } POST /transfer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJ0byI6IjE3MVJhU3p5OUdZSENBOFR1TFlONW13VFdzM25uQVJmTVoiLCJhbW91bnQiOjF9. MW_K5DZTYCJADOp9ArTKIwB8m4knAG-Pdv_V9xXId2I
31. TEMPORARY LINKS public.acme.com/mQsh79zqGb9pxGz2...
33. TEMPORARY LINKS { "sub": 1234567890, "exp": 1483711650, "version": 1 } eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9. eyJzdWIiOiIxMjM0NTY3ODkwIiwiZXhwIjoxNDgzNzExNjUwfQ. NkHLOdRpIcDahCuJyRpOEUwebxWcs4LobzCksk1z_lc
34. STATELESS AUTHENTICATION
35. BUT FIRST ... WHAT IS STATEFUL AUTHENTICATION?
36. STATEFUL AUTHENTICATION 1. User submits creden0als 2. Server generate a unique session id 3. Session informa0on is stored server side 4. Responds with cookie containing session id 5. On every request the session and user data is fetched from the database/redis
37. STATEFUL AUTHENTICATION • Cookies are bad for caching • Cookies are bad for CORS • Servers need a shared session storage • Servers needs to query the storage to verify and get user/session informa<on
38. HELLO 2018
39. STATELESS AUTHENTICATION WITH JWT
40. STATELESS AUTHENTICATION WITH JWT 1. User submits creden0als 2. (Authen0ca0on) Server response with a JWT iden0fying the user 3. On every request the client sends the received JWT in the Authoriza0on header 4. The server verifies the JWT by checking the signature
41. OAUTH2?
43. OAUTH2 AND JWT JWT access tokens containing user iden2fier and scopes. { "iss": "teamleader", "sub": "423523:534534", "exp": 1483711650, "iat": 1483708050, "scopes": ["companies", "contacts"] }
44. ADVANTAGES • No need for an access token table • The client can check if the token is expired • No database calls to validate the access token, get the user id, scopes, ... • Possibility to have shared tokens across mul>ple micro-services
47. DISADVANTAGES • Access tokens can't easily be revoked, unless you keep a list of tokens to revoke • Best prac9ce to have short TTL • The more embedded data, the bigger the JWT. No fixed size. • Not encrypted, unless you use JWE • Token data can go stale
48. PHP PACKAGES • league/oauth2-server • lcobucci/jwt • firebase/php-jwt
49. MIDDLEWARE EXAMPLE $token = $this->getBearerTokenFromRequest($request); $jwt = (new \Lcobucci\JWT\Parser())->parse($token); if (!$jwt->verify(new \Lcobucci\JWT\Signer\Hmac\Sha256(), 'secret')) { throw new BadRequestException('Invalid token'); } $identifier = $jwt->getClaim('sub'); $scopes = $jwt->getClaim('scopes');
50. JWT AT TEAMLEADER • JWT OAuth2 access tokens, RSA signed (league/oauth2-server) • Separated OAuth2 micro-service, accept access tokens across micro-services API's • Temporary access links • Store JWT data in cookie for some small micro-services
51. Ques%ons?