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Aeronautical Information Security Aeronautical Information Security ATN Conference September 24-25 2002 Honeywell Advanced Systems Technology Group 7000.

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Presentation on theme: "Aeronautical Information Security Aeronautical Information Security ATN Conference September 24-25 2002 Honeywell Advanced Systems Technology Group 7000."— Presentation transcript:

1 Aeronautical Information Security Aeronautical Information Security ATN Conference September Honeywell Advanced Systems Technology Group 7000 Columbia Gateway Drive Columbia, MD 21046

2 Aeronautical Information Security 2002 ATN Conference, London UK 2 AgendaAgenda What is Information Security Overview of Cryptography ATN Security Secure ACARS

3 Aeronautical Information Security 2002 ATN Conference, London UK 3 What is Information Security? Information security is concerned with providing: Confidentiality, Authentication, Integrity, and Availability of data (during both storage and communication).

4 Aeronautical Information Security 2002 ATN Conference, London UK 4 Critical Considerations for Aeronautical INFOSEC Thorough Vulnerability analysis to identify relevant risks Bandwidth and computation constraints Standardization – use of proven security solutions Cost of implementation,deployment and maintenance

5 Aeronautical Information Security 2002 ATN Conference, London UK 5 Vulnerability and Risk Analysis PrivacyAuthentication Integrity Monitoring Spoofing Modification Data Corruption Virus Viruses

6 Aeronautical Information Security 2002 ATN Conference, London UK 6 Overview of Cryptography

7 Aeronautical Information Security 2002 ATN Conference, London UK 7 Overview of Cryptography [1/5] Symmetric Cryptography – a.k.a., Secret Key Cryptography – A single shared secret key (  ) is used to both encrypt and decrypt a message – Common algorithms  DES, Triple-DES, IDEA, AES – Strengths  Excellent performance (fast)  Very strong security – Weaknesses  Secret key management requires sending and receiving parties to obtain shared secret key via secure means  Not practical for digital signing or authentication  Scalability Encryption Encrypt  Decrypt    Bob Alice  

8 Aeronautical Information Security 2002 ATN Conference, London UK 8 Overview of Cryptography [2/5] Asymmetric Cryptography – a.k.a., Public Key Cryptography – Keys come in pairs -- one private (  ), one public (  )  Operation “done” with one key is “undone” with other – Common algorithms  RSA, DSA, ECC – Strengths  Minimizes exposure of keys –Only public keys are shared –Knowing public key provides no information about private key  Enables digital signatures – Weaknesses  Computationally slow compared to symmetric key  Requires “trust” in public keys Encryption Digital Signature Encryption Digital Signature Encrypt  Bob Decrypt  Bob   Bob Alice Sign  Alice Verify  Alice   Bob Alice   ++ ++

9 Aeronautical Information Security 2002 ATN Conference, London UK 9 Overview of Cryptography [3/5] Hybrid Cryptography – Takes advantage of symmetric and asymmetric strengths – Encrypt messages using high performance symmetric algorithms – Securely manage message encryption keys and digitally sign messages using slower asymmetric algorithms Encrypt   Bob Alice   Encrypt  Bob Hash & Sign  Alice Hash & Verify   Decrypt  Alice Decrypt  Bob Note:  is a public key certificate which contains Alice’s public key  signed by a trusted Certificate Authority (CA).              Confidentiality and Authentication Confidentiality Only

10 Aeronautical Information Security 2002 ATN Conference, London UK 10 Overview of Cryptography [4/5] Session Key Derivation – Shared secret key is derived independently from parameters that are exchanged in the open – Mathematical properties ensure that session keys generated independently by both parties are identical – Conserves system resources Sign Bob  Alice Derive Key  Alice   Alice  Bob  Note: Alice generates some session Parameters and sends them to Bob. Her signature ensures authenticity. Note:  is a public key certificate which contains Alice’s public key  signed by a trusted Certificate Authority (CA). Verify    Bob  Derive KeyHMAC TAG     Alice  Alice Note: Alice and Bob derives the session key from parameters exchanged between them, their respective addresses, and their public/private key pairs.

11 Aeronautical Information Security 2002 ATN Conference, London UK 11 Overview of Cryptography [5/5] Basic Contents of a Public Key Certificate Public Key Certificate Distinguished Name: cn= Identifier ou= ATN-Aircraft o= Honeywell c= US Serial No.: Valid Not Before:Date/Time Valid Not After:Date/Time Public Key:  Key Usage:Signing Issuing CA Distinguished Name: cn= ‘State’-CA ou= ATN o= Honeywell c= US  Unique name of public key owner Unique public key certificate number Certificate validity dates Public key Key Usage (signing or encryption) Name of certificate issuer Certificate issuer’s digital signature

12 Aeronautical Information Security 2002 ATN Conference, London UK 12 ATN Security

13 Aeronautical Information Security 2002 ATN Conference, London UK 13 Security in ATN Risk analysis performed by Eurocontrol has identified the following threats: – Masquerade/modification/replay of air-ground application communications. – Denial of service by flooding ground IDRP databases. Airlines desire to ensure the confidentiality of operational data. ATN SARPs (Edition 3) provides the following security services: – Authentication and integrity of air-ground applications. – Authentication and integrity of IDRP communications. – Supporting Public Key Infrastructure (PKI). ATNP WG-B/Sub-Group 3 is enhancing the ATN SARPs to add confidentiality services

14 Aeronautical Information Security 2002 ATN Conference, London UK 14 ATN Security Solution Uses both symmetric & public-key cryptography. Based on ISO Generic Upper Layer Security (GULS) standard. Mutual authentication during initial CM contact is provided by Elliptic Curve Digital Signature Algorithm (ECDSA). Initial CM contact also establishes shared public value using (EC Diffie-Hellman) Required public keys of applications are delivered to aircraft during initial CMA exchange. Application (and location) specific session keys derived by applications from their key pairs and shared public value. Subsequent application communications secured by Hashed Message Authentication Code (HMAC) under session key Message Counter and source included to prevent replay.

15 Aeronautical Information Security 2002 ATN Conference, London UK 15 Secure Session Establishment Process

16 Aeronautical Information Security 2002 ATN Conference, London UK 16 ATN PKI Major components: Certificate Authorities (CA) and Certificate Delivery Services. Each State is required to establish and maintain a CA and Delivery Services. Aircraft operators may maintain subordinate CAs. CAs issue X.509 certificates and CRLs. Sharing of CAs among States is recommended to reduce cross certification. Delivery Services deliver certificates and CRLs to ATN entities.

17 Aeronautical Information Security 2002 ATN Conference, London UK 17 Relationship of ATN CAs State CA Ground CMAAOE CAsGround Apps Ground Routers Aircraft CMAs Aircraft Routers

18 Aeronautical Information Security 2002 ATN Conference, London UK 18 Certificate Delivery Services May use X.500 directories for automated certificate delivery. Ground scenarios: – All applications and routers have directory access. – CMA has directory access and provides certificates and CRLs as needed to other applications. – Certificates may be cashed locally or pre-stored. Air scenarios: – Short-lived certificates for CMA/routers sent to aircraft. – Certificate fields known by aircraft in advance not sent on RF. Certificate reconstructed by aircraft before verification. – CMA certificates may be pre-stored.

19 Aeronautical Information Security 2002 ATN Conference, London UK 19 Secure ACARS

20 Aeronautical Information Security 2002 ATN Conference, London UK 20 Secure ACARS Overview US Air Force Dual Use Science and Technology (DUS&T) Program – Objective of DUS&T: Leverage Commercial Know-how, Investments, and Markets for Dual Commercial and Military Use – Cooperative Agreement Between Government and Contractor – 50/50 Cost Share between Honeywell and USAF Phase 1: Extend ACARS protocol to support standard-based security solution – Honeywell, Columbia MD – Expected completion of laboratory prototype by 2/2003

21 Aeronautical Information Security 2002 ATN Conference, London UK 21 System Capabilities Security Services – Authentication: Provide strong authentication of the terrestrial and airborne communicating peer entities – Data Integrity: Provide data integrity for the ACARS payload – Data Confidentiality: Provide data confidentiality for the ACARS payload Migration to ATN – Implements cryptographic primitives, functions, and Public Key Infrastructure (PKI) specified in the ATN SARPs, Security Services (ICAO Doc 9705, SV 8) Compatibility/Interoperability – Support full backward compatibility with the existing ACARS message traffic when operating in non-secure mode – Permit the DSP to route ACARS security message traffic in the same manner as current non-secure message traffic – Ensure media independence to facilitate operation over VHF, HF, SATCOM or other future communication links Data Compression to preserve ACARS bandwidth

22 Aeronautical Information Security 2002 ATN Conference, London UK 22 Proposed Security Framework for ACARS Mechanism Notes Note 2 Note 1 ITU-T X.509 ECDSA FIPS SHA-1 FIPS AES FIPS-197 ATN SARPs ECDH ANSI X9.63 HMAC-SHA-1 RFC2104 Notes: 1.HMAC is published as FIPS-198, as of 6 Mar Currently there is no FIPS for key exchange; however for Elliptic Curve Cryptosystems, ANSI X9.63 is likely to be the basis for FIPS. Security Service PK Certificates Digital Signature Hash Encryption Key Exchange Message Authentication Data Integrity / Authentication Confidentiality Key Management Cryptographic Algorithms ITU-T X.509 ECDSA FIPS SHA-1 FIPS AES FIPS-197 S-ACARS ECDH ANSI X9.63 HMAC-SHA-1 RFC 2104 Standards-based, COTS-supported Security Framework

23 Aeronautical Information Security 2002 ATN Conference, London UK 23 Secure ACARS Overhead Analysis Based on Proposed ACARS Security Framework Session Establishment  Key Establishment  Downlink:~ 60 bytes  Uplink:~ 21 bytes Data Exchange  Confidentiality, Data Authentication/Integrity Services  Down/Uplink:Single-block or Multi-block ACARS message + Security Overhead (7 bytes) Session Termination  Data Authentication/Integrity – Explicit  Downlink:~ 10 bytes  Uplink:~ 10 bytes – Implicit  Down/Uplink:0 bytes Compression can negate overhead and achieve savings!

24 Aeronautical Information Security 2002 ATN Conference, London UK 24 ContactContact Aloke Roy Honeywell International Phone #: , Fax #:

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