Paper 2012/154

The Joint Signature and Encryption Revisited

Laila El Aimani

Abstract

We study the Sign_then_Encrypt, Commit_then_Encrypt_and_Sign, and Encrypt_then_Sign paradigms in the context of two cryptographic primitives, namely designated confirmer signatures and signcryption. Our study identifies weaknesses in those paradigms which impose the use of expensive encryption (as a building block) in order to meet a reasonable security level. Next, we propose some optimizations which annihilate the found weaknesses and allow consequently cheap encryption without compromising the overall security. Our optimizations further enjoy verifiability, a property profoundly needed in many real-life applications of the studied primitives.

Metadata
Available format(s)
-- withdrawn --
Category
Public-key cryptography
Publication info
Published elsewhere. Unknown status
Keywords
Sign_then_EncryptCommit_then_Encrypt_and_SignEncrypt_then_Sign(public) verifiabilitydesignated confirmer signaturessigncryptionzero knowledge proofs.
Contact author(s)
laila elaimani @ yahoo fr
History
2017-06-14: withdrawn
2012-03-23: received
See all versions
Short URL
https://ia.cr/2012/154
License
Creative Commons Attribution
CC BY
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