Robust key-evolving public key encryption schemes

Wen-Guey Tzeng, Zhi Jia Tzeng

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

7 Scopus citations


We propose a key-evolving paradigm to deal with the key exposure problem of public key encryption schemes. The key evolving paradigm is like the one used for forward-secure digital signature schemes. Let time be divided into time periods such that at time period j, the decryptor holds the secret key SKj, while the public key PK is fixed during its lifetime. At time period j, a sender encrypts a message m as 〈j, c〉, which can be decrypted only with the private key SKj. When the time makes a transit from period j to j + 1, the decryptor updates its private key from SKj to SKj+1 and deletes SKj immediately. The key-evolving paradigm assures that compromise of the private key SKj does not jeopardize the message encrypted at the other time periods. We propose two key-evolving public key encryption schemes with z-resilience such that compromise of z private keys does not affect confidentiality of messages encrypted in other time periods. Assuming that the DDH problem is hard, we show one scheme semantically secure against passive adversaries and the other scheme semantically secure against the adaptive chosen ciphertext attack under the random oracle.

Original languageEnglish
Title of host publicationInformation and Communications Security - 4th International Conference, ICICS 2002, Proceedings
EditorsSihan Qing, Robert Deng, Feng Bao, Jianying Zhou
PublisherSpringer Verlag
Number of pages12
ISBN (Print)3540001646
StatePublished - 1 Jan 2002
Event4th International Conference on Information and Communications Security, ICICS 2002 - Singapore, Singapore
Duration: 9 Dec 200212 Dec 2002

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference4th International Conference on Information and Communications Security, ICICS 2002

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