Combining Hashing and Enciphering Algorithms for Epidemiological Analysis of Gathered Data

Summary

Objectives: Compiling individual records coming from different sources is necessary for multi-center studies. Legal aspects can be satisfied by implementing anonymization procedures. When using these procedures with a different key for each study it becomes almost impossible to link records from separate data collections.

Methods: The originality of the method relies on the way the combination of hashing and enciphering techniques is performed: like in asymmetric encryption, two keys are used but the private key depends on the patient’s identity.

Results: The combination of hashing and enciphering techniques provides a great improvement in the overall security of the proposed scheme.

Conclusion: This methodology makes stored data available for use in the field of public health, while respecting legal security requirements.

Keywords

Security - patient identification - encryption - hashing

• References

• 1 Couris CM, Gutknecht C, Ecochard R, Gelas-Dore B, Hajri T, Colin C, Schott AM. Estimates of the number of cancer patients hospitalized in a geographic area using claims data without a unique personal identifier. Methods Inf Med 2006; 45: 515-522.
• 2 Blakely T, Woodward A, Salmond C. Anonymous linkage of New Zealand mortality and Census data. Aust N Z J Public Health 2000; 24: 92-95.
• 3 Quantin C, Bouzelat H, Allaert FA, Benhamiche AM, Faivre J, Dusserre L. Automatic record hash coding and linkage for epidemiological follow-up data confidentiality. Methods Inf Med 1998; 37: 271-277.
• 4 Churches T, Christen P. Some methods for blindfolded record linkage. BMC Med Inform Decis Mak 2004; 28: 4-9.
• 5 Bellare M, Canetti R, Krawczyck H. Message authentication using hash functions. The HMAC construction. RSA laboratories’ CyrptoBytes 1996; 2: 1-5. Available at http://www.cs.ucsd.edu/users/mihir/papers/hmac.html/
• 6 Armstrong BK, Kricker A. Record linkage – a vision renewed. Aust N Z J Public Health 1999; 23: 451-452.
• 7 Quantin C, Binquet C, Allaert FA, Cornet B, Pattisina R, Le Teuff G, Ferdynus C, Gouyon JB. Decision analysis for the assessment of a record linkage procedure : application to a perinatal network. Methods Inf Med 2005; 44: 72-79.
• 8 Quantin C, Allaert FA, Gouyon B, Cohen O. Proposal for the creation of a European healthcare identifier. Stud Health Technol Inform 2005; 116: 949-954.
• 9 Quantin C, Cohen O, Riandey B, Allaert FA. Unique patient concept: a key choice for European epidemiology. International Journal of Medical Informatics 2007; 76: 419-426.
• 10 Quantin C, Allaert FA, Fassa M, Riandey B, Fieschi M, Cohen O. How to manage a secure direct access of European patients to their computerised medical record and personal medical record?. Technology and Informatics 2007; 127: 246-255.
• 11 Vuillet-Tavernier S. Réflexion autour de l’anonymat dans le traitement des données de santé. Med et Droit 2000; 40: 1-4.
• 12 Roger France FH, De Clercq E, Bangels M. Purposes of Health Identification Cards in Belgium. In: Engelbrecht R, Geissbuhler A, Clovis C, Mihalas G. (eds). Connecting Medical Informatics and Bio-Informatics. Proceedings of MIE 2005. Amsterdam: IOS Press; 2005
• 13 Borst F, Allaert FA, Quantin C. The Swiss solution for anonymously chaining patient files. Proc MEDINFO 2001; IMIA: 1239-1241.
• 14 http//en.wikipedia.org/wiki/SHA_hash_funtions
• 15 Ethridge Y. PKI (public key infrastructure): how and why it works. Health Manag Technol 2001; 22: 20-21.
• 16 Trouessin G. Tierces Parties de Confiance interopérables (TPCi) – interoperable Trusted Third Parties (iTTP). Colloque InfoSec’99 (Securicom’ 99). La Défense, Paris, June 1-3, 1999
• 17 Schneier B. Applied Cryptography. Paris, France: International Thomson Publishing; 1994