"Session ID: BUD17-203 Session Name: Universal Keyring - The Time has Come - BUD17-203 Speaker: Anders Rundgren Track: Security ★ Session Summary ★ The SKS/KeyGen2 project is about establishing an security architecture, provisioning and management scheme for cryptographic keys targeting a wide variety of applications including on-line banking, payments, e-government access, and enterprise login. A TEE (possibly aided by a local security processor) is a core component of the envisioned architecture. In order to enable easy enrollment, a browser-based provisioning protocol is another core component. Since a cryptographic key (unlike a file), usually represents a relationship to a remote party which also typically imply a policy for ""their"" keys, the system supports key ACLs which through an OS/TEE layer governs which applications a key may be used with. A consequence of this arrangement is that cryptographic keys become first-class OS objects like files. The protocol and basic key store is already running as an application which is used for testing and evaluation. What's missing is the OS/TEE/Browser integration, something which requires a set of rather different --------------------------------------------------- ★ Resources ★ Event Page: http://connect.linaro.org/resource/bud17/bud17-203/ Presentation: https://www.slideshare.net/linaroorg/bud17203-universal-keyring-the-time-has-come Video: https://youtu.be/PvySBboUwPM --------------------------------------------------- ★ Event Details ★ Linaro Connect Budapest 2017 (BUD17) 6-10 March 2017 Corinthia Hotel, Budapest, Erzsébet krt. 43-49, 1073 Hungary --------------------------------------------------- Keyword: keyring, universal-keyring, security http://www.linaro.org http://connect.linaro.org --------------------------------------------------- Follow us on Social Media https://www.facebook.com/LinaroOrg https://twitter.com/linaroorg https://www.youtube.com/user/linaroorg?sub_confirmation=1 https://www.linkedin.com/company/1026961"

1. © WebPKI.org 2017-02-09 1/11
Universal Key Ring – The Time Has Come!
Anders Rundgren, WebPKI.org
This presentation outlines a security architecture, provisioning, and management scheme for secure
cryptographic keys, targeting a wide variety of applications including Virtual SIMs, On-line Banking,
Payments, e-Government Access, and Enterprise Login.
In the core of the architecture there is component coined SKS (Secure Key Store), which leverages the
TEE (possibly aided by a local security processor).
To facilitate easy enrollment of SKS keys, a matching browser-based provisioning protocol called
KeyGen2 has been developed as well.
Since cryptographic keys (unlike files), usually represent “relationships” to external parties, the scheme
provides extensive support for different policies including an ACL system which through the OS/TEE
layers, governs which applications a key may be used with.
A side-effect of this arrangement is that cryptographic keys become first-class OS objects like files.
This effort is complementary to FIDO alliance. In fact, it seems quite feasible building FIDO alliance
products and SKS/KeyGen2 on the very same security platform.

2. © WebPKI.org 2017-02-09 2/11
Core OS ObjectsFiles
Devices
Users
Processes Keys

3. © WebPKI.org 2017-02-09 3/11
Typical Applications
e-Government
Income declaration
Year:
Name:
Citizen code:
Declared income:
2016
Marion Anderson
19950710-1518
Fair ($30000-$99999)
eGovernment signature applications
like income declarations, change of
address and permits requests
Virtual SIM-cards enable you
to buy, carry and use multiple
subscriptions in an easy way
Secure payments on the web as
well as in brick and mortar shops
Virtualized SKS SIM Credentials =

4. © WebPKI.org 2017-02-09 4/11
Key ID ACL User PIN Status Pointer
Key ID ACL User PIN Status Pointer
SKS-SecureKeyStore
SKS Driver Module
Device
Certificate
SE- Security Element
(Optional Crypto Peripheral
inside of the CPU)
Attestation
Private Key
Symmetric
Master Key
Crypto
Processor
TEE – Trusted
Execution Environment
(like ARM TrustZoneTM
)
Operating System
Key ID ACL User PIN Status Pointer
Credential Database
Key Entries
The SE only holds static data: a Device Certificate, a matching Attestation Key and a Master Key which is used for wrapping user keys.
The Attestation Key signs session keys which KeyGen2 uses for secure key provisioning and management. The SE generates wrapped
keys and as well as performing standard cryptographic operations on wrapped keys. That is, user keys are never exposed in clear.
The TEE performs all access control to keys as well as having exclusive access to the SE. Core key data is
stored in the TEE while encrypted key material, logotypes and attributes are stored in the Credential Database.
The Operating System invokes the TEE and also provides the TEE with
User and Application data required for key access control based on ACLs
attached to key entries.
SKS Native API
Secure Key Store – A Three Layer Architecture

5. © WebPKI.org 2017-02-09 5/11
Element Description
Mandatory: Asymmetric (private) or Symmetric (secret) key
Mandatory: X.509 certificate having two uses:
• Support for PKI-based applications
• Providing a “name” for key management operations
Algorithms Optional: Set of algorithms permitted to use with the key
Images
Optional: For usage in GUIs. Type information enable
selecting appropriate images for different scenarios
PIN
Optional: For key unlock. May be substituted or complemented with biometrics
if the hardware supports that
Attributes
Optional: Arbitrary text and binary properties containing things like URIs, Public
keys, and Constants to be used by associated applications
ACL Optional: Access Control List protecting keys from illicit access
Key + “Decoration” = Credential
MyBank
Code Not Supported. Trusted Credentials != Trusted Applications

6. © WebPKI.org 2017-02-09 6/11
Demo - Saturn (Payment Authorization)

7. © WebPKI.org 2017-02-09 7/11
“AuthorizationResponse”
“AuthorizationRequest”
“PayerAuthorization”
(Signed & Encrypted)
Merchant User + Wallet
User BankMerchant Bank
Bank-to-Bank Payments
State Diagram “Checkout/Pay”
“PaymentClientRequest”
“Result”
Merchant Lookup
and Verification*
User Authorization
• Decryption
• Verification
User Bank Verification*
②
③
④
⑤
⑥
①
Existing Payment Rails
(Bank-to-Bank Payments)
Sample application that was built using SKS and KeyGen2 for Storing/Using respectively Issuing Virtual Cards
⑦
User Bank Lookup*
(HTTP POST)
(HTTP Response)
SKS
Select Card
● ● ● ●
Authorize
PIN
(Scenario-dependent “channel”
technology used for Merchant
to Wallet communication)
(Scenario-dependent)
Decryption Key
All transaction steps are now available
in a single object where each layer is
signed and embeds inner layers
Commit Signature
Request Signature
“Accept”
Virtual Cards
Virtual Card Properties
Signature Key
Encryption Key
• Account Type URI
• URL to User Bank
• User Account ID
• PIN
• Card Logotype
• …

8. © WebPKI.org 2017-02-09 8/11
SKS Native API
The Missing Link – Credential Provisioning
Standard Crypto API
App
AppApplication
Application Level
KeyGen2: End-to-end-secured credential
provisioning and management protocol
specifically designed for SKS
Browser
KeyGen2 Proxy • Networking
• JSON Processing
• Content Aggregation
• User Interaction
Bank Government Etc…
Credential Issuers
(CAs or IdPs)

9. © WebPKI.org 2017-02-09 9/11
Demo – Enrollment using KeyGen2

10. © WebPKI.org 2017-02-09 10/11
Project Status – February 2017
• SKS software emulator in Java
• Android “App” implementing SKS, KeyGen2 and two test
applications available on PlayStore
• Public test applications on the Web
• Extensive documentation
• Published on GitHub: https://github.com/cyberphone
Currently Missing
• SKS/TEE integration
• Browser integration
• and most of all, device vendor partners…

11. © WebPKI.org 2017-02-09 11/11
Related Standardization Efforts
JCS – JSON Clear-text Signature. Fully implemented reference
implementation in Java. JCS also runs in browsers and Node.js
{
"myProperty": "Some data",
"signature": {
"algorithm": "ES256",
"publicKey": {
"type": "EC",
"curve": "P-256",
"x": "vlYxD4dtFJOp1_8_QUcieWCW-4KrLMmFL2rpkY1bQDs",
"y": "fxEF70yJenP3SPHM9hv-EnvhG6nXr3_S-fDqoj-F6yM"
},
"value": "gNfr9Es0cnc263tmOYMsctBh … Qd2h8QSePPGsKdkLILVJDBlAbkQ1eA"
}
}