Securities in Domestic and Cross-border Data exchange

1. Securities in Domestic and Cross-border Data exchange 2012. 5

2. Security Issue • Security Issue • paperless trade process need electronic data exchanges. • cross domain, cross border data exchanges need secure, standard, technology-neutral interface • data exchanges are performed with the most economic and effective means via the Internet, anytime and anywhere. • In standard, internet environment, security issue become more and more important

3. Security Issue • Security goal (triad CIA) Confidentiality : Who is authorized.. ? Integrity : Is the data good.. ? Availability : Can access data whenever need it.. ? Security goal Integrity Availability Confidentiality Three item should be balanced.

4. Security Issue • Confidentiality • Keeping information secret from unauthorized access. • It is probably the most common aspect of information security: we need to protect confidential information. • An organization needs to guard against those malicious actions that endanger the confidentiality of its information. • Integrity • Changes should be done only by authorized users and through authorized mechanisms. • Includes data integrity (content) and origin integrity (source of data also called authentication) • Availability • The information created and stored by an organization needs to be available to authorized users and applications.

5. Security Issue • Attack - Threat to security goal (confidentiality, Integrity, availability) - Any action (active or passive) that compromises the security of information. Security Attacks` Modification Denial of Service Snooping spoofing Traffic analysis Threat availability Replaying Repudiation Threat confidentiality Threat Integrity

6. Security Issue • Attack

7. Security Issue • Network security issue – (1) • Authentication Both sender and receiver need to verify the identity of the other party in a communication: are you really who you claim to be? • Authorization prevention of the unauthorized use of a resource. does a party with a verified identity have permission to access (r/w/x/…) information? Gets into access control policies. • Confidentiality protection of data from unauthorized disclosure. encryptmessage so only sender and receiver can understand it

8. Security Issue • Network security issue – (2) • Integrity the assurance that data received are the same as send by an authorized entity. during a communication, can both sender and receiver detect whether a message has been altered? • Non-Repudiation provides protection against denial by one of the entities involved in a communication of having participated in all or part of the communication. • Availability Guaranteeing access to legitimate users. Prevention of Denial-of-Service (DOS) attacks.

9. Cryptography • Cryptography • The actual implementation of security goals needs some help from mathematics • Cryptography is a framework of methodologies used to ensure the CIA triad for our information • The need for cryptographic techs was as old as the need to keep the critical info secure, safe and authentic.

10. Cryptography • Symmetric Key Encryption • Both parties share the same key for en- and decryption • To provide privacy, this key needs to be kept secret • All classical encryption algorithms are private key(symmetric key) • Faster than asymmetric, hard to break with large key (but hard to distribute keys, too many keys required) • Used for long messages • Hard to authenticate or provide non-repudiation

11. Cryptography • Block ciphers • Blocks of bits (e.g. 64, 128) encrypted at a time • Examples of several algorithms: • Data Encryption Standard (DES) – 64 bit block, 56 key • Triple DES • Advanced Encryption Standard (AES) or Rijndael • IDEA (Internal Data Encryption Algorithm) – Europe • FEAL (Fast Data Encryption Algorithm) - Japan • Seed, Aria - Korea • GOST - Russia • CAST, Blowfish, Skipjack, many more… (c.f. Schneier)

12. Cryptography • DES (Data encryption Standard) • Designed by IBM • Published in 1977 by NIST (FIPS-46) • Adopted also by ISO an standard of ANSI • Used by many private enterprise, bank • Susceptible to Brute-Force (try all 256 keys) • 1998: machine Deep Crack breaks it in hours • Subsequently been able to break even faster

13. Cryptography • DES (Data encryption Standard) • Input: 64-bit plaintext(block), 56-bit key (64 w/ parity) • Output: 64-bit ciphertext

14. Cryptography • Triple DES • Made part of DES in 1999 • Uses 3 keys and 3 DES executions • using 3 keys 3DES has an effective key length of 168 bits (3*56) • follows encrypt-decrypt-encrypt (EDE) • 3x slower than DES • FIPS algorithm of choice • using DES are encouraged to convert to 3DES

15. Cryptography • AES (Advanced Encryption Standard - Rijndael) • Designed by Rijmen-Daemen in Belgium • US National Institute of Standards and Technology (NIST) in 2001 in response to the shortcoming of DES • Selected by NIST from 15 competitors after three years of conferences vetting proposals • Selection Criteria: • Security, Cost (Speed/Memory) • Implementation Considerations (Hardware/Software) • Key size & Block size: 128, 192, or 256 bits (much larger than DES) • Rely on algorithmic properties for security, not obscurity

16. Cryptography • AES (Advanced Encryption Standard - Rijndael) • Key size & Block size: 128, 192, or 256 bits (much larger than DES)

17. Cryptography • Stream Cipher • Much faster than block ciphers and used in hardware and network cipher • Encrypts one byte of plaintext at a time • Keystream: infinite sequence (never reused) of random bits used as key • Approximates theoretical scheme: one-time pad, trying to make it practical with finite keys

18. Cryptography • RC4 • The most widely used software Stream cipher and is used in popular protocols such as SSL and WEP (to secure wireless networks). • 10x faster than DES • Fixed-size key “seed” to generate infinite stream • State Table S that changes to create stream • Ex: 256-bit key used to seed table (fill it)

19. Cryptography • Asymmetric Key Encryption • Unlike symmetric-key cryptography, there are distinctive keys(private, public key) in asymmetric-key cryptography • Encryption performed with one asymmetric key decrypted only with corresponding key

20. Cryptography • Asymmetric Key Encryption • Diffie and Hellman in 1976 invented asymmetric public key cryptography (revolutionary!) - Sender’s key differs from receiver’s key - Simplifies key distribution – just protect Private key - Useful for authentication as well as encryption • Asymmetric key encryption are incredibly complex, Asymmetric key encryption is up to 1000 times slower than symmetric key encryption. • Examples of several algorithms: • RSA • ECC (Elliptic Curve Cryptography)

21. Cryptography • RSA • Invented by Rivest/Shamir/Adelman (1978) • First asymmetric encryption algorithm • Most widely known public key cryptosystem • Used in many protocols (e.g.., SSL, PGP, …) • Number theoretic algorithm: security based on difficulty of factoring large prime numbers • 1024, 2048, 4096-bit keys common

22. Cryptography • ECC (Elliptical Curve Crytography) • ECC was invented by Neil Koblitz and Victor Miller in 1985, eight years after the RSA algorithm • ECC has been studied extensively for 20+ years and is well recognized and accepted world-wide for its strong number-theoretic foundation. • ECC has been standardized internationally by ISO and the IETF and within the US by ANSI and NIST • Elliptical Curve Cryptography is much stronger per bit than RSA and is less computationally intensive

23. Cryptography • Hybrid Encryption (Symmetric + Asymmetric) • Use symmetric algorithm in encrypting original message • Use asymmetric algorithm for protecting symmetric encryption keys for protecting key distribution • Just don’t let the secret key travel unless it was asymmetrically encrypted • Uses best advantages of each approach • It’s widely used in SSL , Enveloped-Data and many commercial software

24. Cryptography • Hybrid Encryption (Symmetric + Asymmetric) Sender Receiver (1) Encrypted CEK with recipient public Key (1) Message (decrypted by CEK) Decrypt CEK with recipient Private Key(1) Generate a random symmetric encryption key (CEK) Encrypted CEK with recipient public Key (2) Receiver (2) Message (encrypted by CEK) Message (decrypted by CEK) Decrypt CEK with recipient Private Key(2) • Use symmetric key in message encryption/decryption • Use asymmetric key in key distribution (key encryption/decryption)

25. Cryptography • Message digest • A hash function H is a transformation that takes an input m and returns a fixed-size string, which is called the hash value h (that is, h = H(m)). • A hash function H is said to be one-way becauseit is hard to invert, where “hard to invert'' means that given a hash value h, it is computationally infeasible to find some input x such that H(x) = h. • Examples of well known hash functions are MD-x and SHA-x

26. Cryptography • Message digest algorithm • MD5 (Message Digest Algorithm 5) - Produces a 128 bits hash value - In 2004, flaws were discovered and its usage was discouraged. • SHA (Secure Hash Algorithm) - Ranges from 160 bits to 512 bits, depending on the chosen flavor. - One of the most secure algorithms. • CRC-32 (Cyclic Redundancy Check) - Used for data integrity in networks - Not suitable for security (very poor randomness).

27. Cryptography • Algorithm Strength Not Recommend Recommend

28. Cryptography • NIST Recommendation • NIST recommends phasing out 80-bit crypto by 2010 • Agencies need to initiate policies and architectures now for eventual migration to stronger cryptography • NIST recommends phasing out 112-bit crypto by 2030

29. Digital Signature • Digital Signature • Digital signature can provide authentication, integrity, and nonrepudiation for a message. • Digital signature does not provide privacy(confidentiality). If there is a need for privacy, another layer of encryption/decryption must be applied. • There is still a problem linked to the “Real Identity” of the Signer. • So the need to PKI (public key infrastructure)

30. Digital Signature • sign and verify Sign process verify process Message Message Hash Hash • Cert validation Public Key Digest Real signer’s key Private Key Decryption Encryption Expected Digest Actual Digest Signature Public Key (certificate) Compare transfer

31. Digital Certificate • Digital Certificate • A Digital Certificate is a binding between an entity’s public Key and one or more attributes relating its identity • The entity can be a Person, an Hardware Component, a Service, etc. • A Digital Certificate is issued (and signed) by someone • A self-signed certificate usually is not very trustworthy (Issuer = subject) • X.509 – “the certificate standard” today • v.1 (1988) – not extendable • v.2 – not much better • v.3 (1997) is much better – optional extensionsToday, X.509=v.3 • Many other standards extend X.509

32. Digital Certificate • X.509 v3 Certificate

33. PKI • PKI (public Key Infrastructure) “A public-key infrastructure(PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke Digital Certificate”

34. PKI • PKI Component • Certificate Authority (CA) • - Issuer/Signer of the certificate • - Manage for Lifecycle of Certificate (create, store, revoke) • Registration Authority (RA) • - Also called LRA – Local RA • - Support Identification of entity • - Interface to CA • Certificate Distribution System (CDS) • Digital certificates issued by CAs need to be made available to other network users. • A CDS is normally implemented as an ITU-T X.500 directory database or a Lightweight Directory Access Protocol (LDAP) • stores certificates and maintains a list of revoked certificates • PKI applications • Applications that use the PKI technology

35. PKI • Certificate Validation • Integrity: signature is valid • Signed by a trusted CA • or certification path is rooted in a trusted CA • Certificate is valid now: • We are between Not Valid Before and Not Valid After time points in the certificate • Not Revoked (by CRL check or OCSP) • Use is consistent with the policy (CPS , CP)

36. PKI • Certificate Polices • Certificate Policy (CP) - A document that sets out the rights, duties and obligations of each party in a Public Key Infrastructure - “high level what is supported” document - usually has legal effect - A CP is usually publicly exposed by CAs, for example on a Web Site (VeriSign, etc.) • Certification Practice Statement (CPS) - A document that sets out what happens in practice to support the policy statements made in the CP in a PKI - “detailed, comprehensive, technical how policy is supported” document

37. PKI • PKI Trust Model - CA Hierarchy • The root CA’s certificate is self signed and each sub-CA is signed by its parent CA. • Each CA may also issue CRLs. In particular the lowest level CAs issue CRLs frequently. • End entities need to “find” a certificate path to a CA that they trust. Root CA CA _A CA _B E_1 E_2 E_3 E_4

38. PKI • PKI Trust Model – Cross-Certificate (Mesh) • CAs deal with each other as peers and choose whether or not to trust each other. • the CAs issue cross-certificates to each other and need policy mapping and agreement • A user can then trace a certificate from an unknown CA back to a local trusted CA • achieving interoperability through a mesh of certifications is technically and logistically challenging • It’s not an ideal approach to establishing a broad, multi-national PKI • cross certification is most suited where two or three related CAs CA _B CA _A CA _C CA _D

39. PKI • PKI Trust Model – Bridge CA • bridge CA model is based on a central (bridging) CA which cross-certifies with each CA. • combines aspects of both the root model and the cross-certification model • bridge model allows for PKIs built using different models to be joined together in a single, interoperable network • bridge must set certain minimum standards for CAs to participate. CA _B Cross-certificate Bridge CA CA _C CA _A CA _D

40. PKI • PKI Trust Model – Cross-recognition • Cross recognition is where an individual CA or an entire PKI domain agrees to recognize another CA or domain • requires close co-operation among either the CAs at an administrative level or accreditation agencies • (and governments) at a higher level • trust model that is being pursued by the Asia Pacific Economic Cooperation • (APEC) Telecommunications (TEL) Working Group Coordinating authority Agreement CA _A CA _B CA _C

41. PKI • PKI Trust Model – Certificate Trust List model • The Certificate Trust List (CTL) is a list of CAs’ certificates from a trusted authority • Trust lists have also given rise to the ‘browser’ model - the most widespread interoperable PKI by virtue of web browser applications (such as Internet Explorer, Netscape or Firefox) Publishing authority Certificate Trust List CA _A CA _B CA _C

42. PKI • CA Trust model comparison

43. PKI • PKI Trust Model in Korea Ministry of public Administration and security Foreign Government Mutual Recognition GPKI NPKI Government Root CA (GCMA) Foreign CA National Root CA (KISA) Cross Certification CTL Accredite CA Accredite CA Accredite CA Accredite CA Accredite CA Accredite CA User User User User User User User User

44. PKI • NPKI vs. PKI

45. CMS • CMS (cryptographic message syntax) • cryptographic Message Syntax describes an encapsulation syntax for data protection. It supports digital signatures, encryption and message authentication codes • there are six content types defined in the RFC 3852, data, signed-data, enveloped-data, digested-data, encrypted-data, and authenticated-data • CMS is derived from PKCS #7 version 1.5 (it was originally published as an RSA Laboratories Technical Note in November 1993)

46. CMS • General Syntax (ASN.1 structure) ContentInfo ::= SEQUENCE { contentTypeContentType, content [0] EXPLICIT ANY DEFINED BY contentType } ContentType::= OBJECT IDENTIFIER Content Type Content

47. CMS • Signed-data • used to cryptographically sign the content, can have more then one signer • Data can be encapsulated in signed-data or can be detached. • Any number of signers in parallel can sign any type of content. • The typical application of the signed-data represents one signer's digital signature on content of the data content type. • Another typical application disseminates certificates and certificate revocation lists (CRLs).

48. CMS • Signed-data Version Content type (Set of) Digest Algorithms EncapContentInfo Content Set of certificates Version Set of CRLs Signer ID (issuer and ser. no.) Digest Algorithm Signer Info Authenticated Attributes Digest Encryption Alg. Encrypted digest (signature)

49. CMS • Enveloped-data • The enveloped-data content type consists of an encrypted content of any type • encrypted content-encryption keys for one or more recipients. • The combination of the encrypted content and one encrypted content-encryption key for a recipient is a "digital envelope" for that recipient. • Any type of content can be enveloped for an arbitrary number of recipients using any of the three key management techniques for each recipient.

50. CMS • Enveloped-data Version Originator Info Version Recipient ID (issuer and s.no.) Recipient Info Key Encryption Algorithm Encrypted Key Encrypted Content Info Content type Content Encryption Alg. Encrypted Content