Paper 2011/109 Original: eprint.iacr.org/2011/109 ↗

Secure Blind Decryption

Matthew Green
Abstract

In this work we construct public key encryption schemes that admit a protocol for /blindly/ decrypting ciphertexts. In a blind decryption protocol, a user with a ciphertext interacts with a secret keyholder such that the user obtains the decryption of the ciphertext and the keyholder learns nothing about what it decrypted. While we are not the first to consider this problem, previous works provided only weak security guarantees against malicious users. We provide, to our knowledge, the first practical blind decryption schemes that are secure under a strong CCA security definition. We prove our construction secure in the standard model under simple, well-studied assumptions in bilinear groups. To motivate the usefulness of this primitive we discuss several applications including privacy-preserving distributed file systems and Oblivious Transfer schemes that admit /public/ contribution.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2011-03-05: last updated
2011-03-05: published
Short URL
https://ia.cr/2011/109
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2011/109,
      author = {Matthew Green},
      title = {Secure Blind Decryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2011/109},
      year = {2011},
      url = {https://eprint.iacr.org/2011/109}
}
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