Time-Lock Encrypted Storage for Blockchains

Amit Agarwal; Kushal Babel; Sourav Das; Babak Poorebrahim Gilkalaye

Paper 2025/2048 Original: eprint.iacr.org/2025/2048 ↗

Time-Lock Encrypted Storage for Blockchains

Amit Agarwal

Kushal Babel

Sourav Das

Babak Poorebrahim Gilkalaye

Abstract

We introduce time-lock encrypted storage (tTLES), a storage service provided by blockchains. In tTLES, clients store encrypted values towards a future decryption time $\tau_{tgt}$ (measured in block height). The security of tTLES requires that a value is decrypted only if (i) the encrypted value is included in the blockchain, and (ii) the time $\tau_{tgt}$ has passed. This is crucially different from existing schemes, which only enforce either of these conditions but not both. We formalize tTLES, and present an efficient protocol that relies on (in a black-box manner) a threshold identity-based encryption scheme, and a recent batch threshold decryption scheme. Finally, we discuss various applications that will benefit from tTLES.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
History: 2025-11-06: last updated; 2025-11-06: published
Short URL: https://ia.cr/2025/2048
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2025/2048,
      author = {Amit Agarwal and Kushal Babel and Sourav Das and Babak Poorebrahim Gilkalaye},
      title = {Time-Lock Encrypted Storage for Blockchains},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/2048},
      year = {2025},
      url = {https://eprint.iacr.org/2025/2048}
}