A ”Final” Security Bug

Nguyen Thoi Minh Quan

Paper 2020/384

A ”Final” Security Bug

Nguyen Thoi Minh Quan

Abstract

This article discusses a fixed critical security bug in Google Tink's Ed25519 Java implementation. The bug allows remote attackers to extract the private key with only two Ed25519 signatures. The vulnerability comes from the misunderstanding of what "final" in Java programming language means. The bug was discovered during security review before Google Tink was officially released. It reinforces the challenge in writing safe cryptographic code and the importance of the security review process even for the code written by professional cryptographers.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: Ed25519 security bugs remote attackers
Contact author(s): msuntmquan @ gmail com
History: 2020-04-09: received
Short URL: https://ia.cr/2020/384
License: CC BY

BibTeX

@misc{cryptoeprint:2020/384,
      author = {Nguyen Thoi Minh Quan},
      title = {A ”Final” Security Bug},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/384},
      year = {2020},
      url = {https://eprint.iacr.org/2020/384}
}