Abstract
In this work, we propose generic and novel side-channel assisted chosen-ciphertext attacks on NTRU-based key encapsulation mechanisms (KEMs). These KEMs are IND-CCA secure, that is, they are secure in the chosen-ciphertext model. Our attacks involve the construction of malformed ciphertexts. When decapsulated by the target device, these ciphertexts ensure that a targeted intermediate variable becomes very closely related to the secret key. An attacker, who can obtain information about the secret-dependent variable through side-channels, can subsequently recover the full secret key. We propose several novel CCAs which can be carried through by using side-channel leakage from the decapsulation procedure. The attacks instantiate three different types of oracles, namely a plaintext-checking oracle, a decryption-failure oracle, and a full-decryption oracle, and are applicable to two NTRU-based schemes, which are NTRU and NTRU Prime. The two schemes are candidates in the ongoing NIST standardization process for post-quantum cryptography. We perform experimental validation of the attacks on optimized and unprotected implementations of NTRU-based schemes, taken from the open-source pqm4 library, using the EM-based side-channel on the 32-bit ARM Cortex-M4 microcontroller. All of our proposed attacks are capable of recovering the full secret key in only a few thousand chosen ciphertext queries on all parameter sets of NTRU and NTRU Prime. Our attacks, therefore, stress on the need for concrete side-channel protection strategies for NTRU-based KEMs.
Original language | English |
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Pages (from-to) | 722–761 |
Number of pages | 40 |
Journal | IACR Transactions on Cryptographic Hardware and Embedded Systems |
Volume | 2022 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2022 |
Keywords
- lattice based cryptography
- Side channel attacks
- Post-quantum cryptography
- learning with error
- chosen ciphertext attack
- key encapsulation mechanism
- public key encryption
- learning with rounding
- lattice-based cryptography
- electromagnetic-based side-channel attack
ASJC Scopus subject areas
- Software
- Artificial Intelligence
- Signal Processing
- Hardware and Architecture
- Computer Networks and Communications
- Computer Graphics and Computer-Aided Design