Cryptology ePrint Archive: Report 2000/065

How to Encrypt Long Messages without Large Size Symmetric/Asymmetric Encryption Schemes

Masashi Mitomo and Kaoru Kurosawa

Abstract: Suppose that we wish to encrypt long messages with small overhead by a public key encryption scheme which is secure against adaptive chosen ciphertext attack (IND-CCA2). Then the previous schemes require either a large size one-way trapdoor permutation (OAEP) or both a large size symmetric encryption scheme and a small size asymmetric encryption scheme (hybrid encryption). In this paper, we show a scheme which requires only a small size asymmetric encryption scheme satisfying IND-CCA2 for our purpose. Therefore, the proposed scheme is very efficient. A hash function and a psuedorandom bit generator are used as random oracles.

Category / Keywords: public-key cryptography / public-key cryptography, chosen ciphertext attack, provable security, long message, efficient encryption/decryption

Date: received 18 Dec 2000, revised 21 Dec 2000

Contact author: kurosawa at ss titech ac jp

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | BibTeX Citation

Version: 20001222:004304 (All versions of this report)

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