ChromeからMacBookのTouchIDでWebAuthenticationする

#iddance Lesson 1. 技術書典とDigital Identity技術の資料です
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Transcript

1. Chrome͔ΒMacBookͷTouch IDͰ
   WebAuthentication͢Δ
   Identity Dance School Lesson1
   ٕज़ॻయͱDigital Identityٕज़
   @kg0r0
   

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2. ࣗݾ঺հ
   • ߹࿏ ݈ਓ
   • ࣾձਓ3೥໨
   • งғؾͰOAuth΍FIDOͯ͠Δ
   

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3. Ϙπཧ༝
   • σϞ͕೿खͳͷʹॻ੶ͩͱө͑ͳ͍
   • ΄ͱΜͲSELF Attestationͷઆ໌ͰChromeͱ
   ͔Touch ID͋Μ·Γؔ܎ͳ͍
   

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4. ಈ࡞؀ڥ
   • MacBook Pro (13-inch, 2016)
   • macOS Mojave version 10.14.4
   • Chrome version 74
   

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5. σϞ
   

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6. ҧ͍
   • Yubico Security Key
   → packed FULL Attestation
   • Touch ID
   → packed SELF Attestation
   

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7. Registration Flow
   Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
   

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8. Registration
   navigator.credentials.create({
   publicKey: {
   rp: {
   id: "example.com”,
   name: "Acme"
   },
   user: {
   id: new Uint8Array(16),
   name: "john.p.smith@example.com",
   displayName: "John P. Smith "
   },
   pubKeyCredParams: [{
   type: "public-key",
   alg: -7
   }],
   attestation: "direct",
   timeout: 60000,
   // must be a cryptographically random number sent from a server
   challenge: new Uint8Array([
   0x8C, 0x0A, 0x26, 0xFF, 0x22, 0x91, 0xC1, 0xE9, ... ]).buffer
   }
   })
   

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9. Registration
   

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10. Registration
    ͪͳΈʹγʔΫϨοτϒϥ΢βͩͱཁٻ͞Εͳ͍
    

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11. Registration Flow
    Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
    

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12. AuthenticatorAttestationResponse
    {
    "rawId": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzd ... ",
    "id": ” imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzdh7qq ... ",
    "response": {
    "clientDataJSON": ”eyJjaGFsbGVuZ2UiOiJJSFdtWjFPa1MydDZLaH ... ”,
    "attestationObject": ”o2NmbXRoZmlkby11MmZnYXR0U3RtdKJjc2 ... "
    },
    "getClientExtensionResults": {},
    "type": "public-key”
    }
    

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13. AuthenticatorAttestationResponse
    {
    "rawId": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzd ... ",
    "id": ” imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzdh7qq ... ",
    "response": {
    "clientDataJSON": ”eyJjaGFsbGVuZ2UiOiJJSFdtWjFPa1MydDZLaH ... ”,
    "attestationObject": ”o2NmbXRoZmlkby11MmZnYXR0U3RtdKJjc2 ... "
    },
    "getClientExtensionResults": {},
    "type": "public-key”
    }
    

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14. Attestation Object
    CBORΤϯίʔυ͞Εͨެ։伴ͳͲΛؚΉσʔλ
    Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
    

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15. {
    fmt: 'packed',
    attStmt:
    { alg: -7,
    sig:
    74 ab 86 16 cd 53 c3 02 21 00 c1 77 e6 45 96 c9 ff 55 12 1c ... 22 more bytes>
    },
    authData:
    63 45 5c 7d 17 d1 ad ce 00 02 35 bc c6 0a 64 8b 0b 25 f1 ... 150 more bytes>
    }
    Attestation Object
    CBORΤϯίʔυ͞Εͨެ։伴ͳͲΛؚΉσʔλ
    .BD#PPL5PVDI*%
    
    

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16. Attestation Statement
    Attestationͷݕূʹඞཁͳ৘ใͳͲ
    Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
    

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17. Attestation Statement
    Attestationͷݕূʹඞཁͳ৘ใͳͲ
    • alg : ॺ໊࡞੒ΞϧΰϦζϜ
    • sig : ॺ໊
    • x5c : X.509ূ໌ॻνΣʔϯ
    

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18. {
    fmt: 'packed',
    attStmt:
    {
    alg: -7,
    sig:
    21 00 fe e4 f7 09 64 97 4d f5 bd 3d ... 22 more bytes>,
    x5c:
    [ 30 2a 06 03 55 04 03 13 23 59 75 62 ... 656 more bytes> ]
    },
    authData:
    11 f3 8c 0a 4d 15 80 06 17 11 1f ... 146 more bytes>
    }
    Attestation Statement
    Attestationͷݕূʹඞཁͳ৘ใͳͲ
    :VCJDP4FDVSJUZ,FZ
    
    

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19. {
    fmt: 'packed',
    attStmt:
    {
    alg: -7,
    sig:
    16 cd 53 c3 02 21 00 c1 77 e6 45 96 c9 ff 55 12 1c ... 22 more bytes>
    },
    authData:
    7d 17 d1 ad ce 00 02 35 bc c6 0a 64 8b 0b 25 f1 ... 150 more bytes>
    }
    Attestation Statement
    Attestationͷݕূʹඞཁͳ৘ใͳͲ
    .BD#PPL5PVDI*%
    
    

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20. FULL Attestation
    Attestation Statementʹx5cΛؚΉ
    ݕূखॱʢུ֓ʣ
    1. AuthenticatorDataͱClientDataHash͔ΒsignatureBaseΛੜ੒
    2. x5cͷূ໌ॻ͔Βެ։伴Λऔಘ
    3. algͱެ։伴ͱsignatureBaseͰsigΛݕূ
    :VCJDP4FDVSJUZ,FZ
    
    

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21. SELF Attestation
    Attestation Statementʹx5cΛؚ·ͳ͍
    ݕূखॱʢུ֓ʣ
    1. AuthenticatorDataͱClientDataHash͔ΒsignatureBaseΛੜ੒
    2. AuthenticatorData͔Βެ։伴Λऔಘ
    3. algͱެ։伴ͱsignatureBaseͰsigΛݕূ
    .BD#PPL5PVDI*%
    
    

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22. Verify Attestation
    

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23. ·ͱΊ
    • Touch IDΛೝূثͱͨ͠৔߹ͷAttestation Format͸
    packed SELF Attestation
    • ূ໌ॻ͔Βऔಘͨ͠ެ։伴Ͱ͸ͳ͘Authenticator Data
    ͔Βऔಘͨ͠ެ։伴Ͱݕূ
    • ೝূ࣌͸ͦͷଞϑΥʔϚοτͱಉ͡ (transportsͷࢦఆ
    ͸஫ҙ)
    

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24. ͓·͚
    

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25. Authentication Flow
    

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26. Authentication
    navigator.credentials.get({
    publicKey: {
    timeout: 60000,
    challenge: new Uint8Array([
    0x79, 0x50, 0x68, 0x71, 0xDA, 0xEE, 0xEE, 0xB9, 0x94, 0xC3, 0xC2, ...
    ]).buffer,
    allowCredentials: [{
    id: cred.rawId,
    type: "public-key"
    }]
    },
    })
    USBOTQPSUT ௨৴खஈ
    ͷࢦఆʹ஫ҙ
    

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27. Authentication
    

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28. Authentication Flow
    

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29. AuthenticatorAssertionResponse
    {
    "rawId": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzd ... " ,
    "id": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzdh7qq ... ",
    "response": {
    "authenticatorData": "SZYN5YgOjGh0NBcPZHZgW4_krrmihjLHmVzzuoMdl2MBAAAALQ",
    "signature": "MEUCIQCFOqnsAFZLQmcPt2qSjnCb403SisGEASSjT3fOPuD5JgIgF ...",
    "userHandle": "",
    "clientDataJSON": "eyJjaGFsbGVuZ2UiOiJDUXF5aUlrQ00yWEtvaHVSdlNqTEFoN ...”
    },
    "getClientExtensionResults": {},
    "type": "public-key”
    }
    

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30. AuthenticatorAssertionResponse
    {
    "rawId": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzd ... " ,
    "id": "imCIoe8U_N9M1rTGeCqJ96TAu5uqSPa7YUzdh7qq ... ",
    "response": {
    "authenticatorData": "SZYN5YgOjGh0NBcPZHZgW4_krrmihjLHmVzzuoMdl2MBAAAALQ",
    "signature": "MEUCIQCFOqnsAFZLQmcPt2qSjnCb403SisGEASSjT3fOPuD5JgIgF ...",
    "userHandle": "",
    "clientDataJSON": "eyJjaGFsbGVuZ2UiOiJDUXF5aUlrQ00yWEtvaHVSdlNqTEFoN ...”
    },
    "getClientExtensionResults": {},
    "type": "public-key”
    }
    

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31. Generating an assertion signature
    

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32. Verify Assertion
    ݕূखॱʢུ֓ʣ
    1. ొ࿥࣌ʹอ؅ͨ͠ެ։伴ΛऔΓग़͢
    2. AuthenticatorDataͱClientDataHash͔ΒsignatureBaseΛੜ੒
    3. algͱެ։伴ͱsignatureBaseͰsigΛݕূ
    

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33. Verify Assertion
    

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34. ͳ͔ͥॺ໊ͷݕূʹࣦഊ͢Δ
    

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35. ͳ͔ͥॺ໊ͷݕূʹࣦഊ͢Δ
    

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36. ೝূ࣌ͷAuthenticatorData͕
    Yubikeyͷ࣌ͱൺ΂ͯ௕͍ͧ??
    

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37. AuthenticatorData
    Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
    

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38. AuthenticatorData
    Ҿ༻ݩIUUQTXDHJUIVCJPXFCBVUIO
    

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39. ݕূʹࣦഊ͍ͯͨ͠ཧ༝
    • Ұ౓AuthenticatorDataΛ෼ղ͔ͯ͠ΒSignatureBaseΛ࡞͍ͬͯͨ
    • ೝূ࣌ʹAttestedCredentialData͸ؚ·Εͳ͍ͱࢥ͍ͬͯͨ
    • ೝূ࣌ʹChrome͸AttestedCredentialDataΛฦ͖͍ͯͯͨ͠
    • ݁Ռͱͯ͠SignatureBase͕ෆ଍ͨ͠
    

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40. It can be longer than 37 bytes if extensions are sent (in which
    case the extensions bit is set in the authenticatorData flags).
    You are correct though, that the authenticator should not send
    attestedCredentialData for a GetAssertion operation.
    Ҿ༻ݩIUUQTCVHTDISPNJVNPSHQDISPNJVNJTTVFTEFUBJM JE
    

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41. Should be in Chrome 75.
    If you assume that we hit our six week cadence
    then Chrome 75 would be ~mid June.
    Ҿ༻ݩIUUQTCVHTDISPNJVNPSHQDISPNJVNJTTVFTEFUBJM JE
    

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42. ࢀߟ
    • Web Authentication: An API for accessing Public Key Credentials
    https://www.w3.org/TR/webauthn/
    • FIDO2 attestation formatͷ঺հ
    https://techblog.yahoo.co.jp/advent-calendar-2018/webauthn-attestation-packed/
    • FIDO2ʹΑΔChromeͱMacBook Proͷtouch idΛར༻ͨ͠ύεϫʔυϨεϩάΠϯͷ࣮૷
    https://qiita.com/ifsec_56/items/0cc5f1d73e7d2e3029ad
    • Issue 946993: Touch ID authenticator returns attestedCredentialData in GetAssertion response
    http://kent056-n.hatenablog.com/entry/2019/03/31/140910
    • WebAuthn/FIDO2: Verifying Packed Attestation
    ɹhttps://medium.com/@herrjemand/verifying-fido2-packed-attestation-a067a9b2facd
    

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