Cryptology ePrint Archive: Report 2021/1237

Hierarchical Integrated Signature and Encryption

Yu Chen and Qiang Tang and Yuyu Wang

Abstract: In this work, we introduce the notion of hierarchical integrated signature and encryption (HISE), wherein a single public key is used for both signature and encryption, and one can derive a secret key used only for decryption from the signing key, which enables secure delegation of decryption capability. HISE enjoys the benefit of key reuse, and admits individual key escrow. We present two generic constructions of HISE. One is from (constrained) identity-based encryption. The other is from uniform one-way function, public-key encryption, and general-purpose public-coin zero-knowledge proof of knowledge. To further attain global key escrow, we take a little detour to revisit global escrow PKE, an object both of independent interest and with many applications. We formalize the syntax and security model of global escrow PKE, and provide two generic constructions. The first embodies a generic approach to compile any PKE into one with global escrow property. The second establishes a connection between three-party non-interactive key exchange and global escrow PKE. Combining the results developed above, we obtain HISE schemes that support both individual and global key escrow.

We instantiate our generic constructions of (global escrow) HISE and implement all the resulting concrete schemes for 128-bit security. Our schemes have performance that is comparable to the best Cartesian product combined public-key scheme, and exhibit advantages in terms of richer functionality and public key reuse. As a byproduct, we obtain a new global escrow PKE scheme that is $12-30 \times$ faster than the best prior work, which might be of independent interest.

Category / Keywords: public-key cryptography / key reuse, key separation, individual key escrow, global key escrow, hierarchy key derivation

Original Publication (with major differences): IACR-ASIACRYPT-2021

Date: received 17 Sep 2021, last revised 20 Sep 2021

Contact author: yuchen prc at gmail com, qtang84 at gmail com, wangyuyu at uestc edu cn

Available format(s): PDF | BibTeX Citation

Version: 20210920:125510 (All versions of this report)

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