2009 | OriginalPaper | Buchkapitel
Key-Private Proxy Re-encryption
verfasst von : Giuseppe Ateniese, Karyn Benson, Susan Hohenberger
Erschienen in: Topics in Cryptology – CT-RSA 2009
Verlag: Springer Berlin Heidelberg
Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.
Wählen Sie Textabschnitte aus um mit Künstlicher Intelligenz passenden Patente zu finden. powered by
Markieren Sie Textabschnitte, um KI-gestützt weitere passende Inhalte zu finden. powered by
Proxy re-encryption (PRE) allows a proxy to convert a ciphertext encrypted under one key into an encryption of the same message under another key. The main idea is to place as little trust and reveal as little information to the proxy as necessary to allow it to perform its translations. At the very least, the proxy should not be able to learn the keys of the participants or the content of the messages it re-encrypts. However, in all prior PRE schemes, it is easy for the proxy to determine between which participants a re-encryption key can transform ciphertexts. This can be a problem in practice. For example, in a secure distributed file system, content owners may want to use the proxy to help re-encrypt sensitive information
without
revealing to the proxy the
identity
of the recipients.
In this work, we propose key-private (or anonymous) re-encryption keys as an additional useful property of PRE schemes. We formulate a definition of what it means for a PRE scheme to be secure and key-private. Surprisingly, we show that this property is not captured by prior definitions or achieved by prior schemes, including even the secure obfuscation of PRE by Hohenberger et al. (TCC 2007). Finally, we propose the first key-private PRE construction and prove its CPA-security under a simple extension of Decisional Bilinear Diffie Hellman assumption and its key-privacy under the Decision Linear assumption in the standard model.