Contents
1 Summary 2
2 Findings 3
2.1 KZENC-F-001: Biased Ed25519Scalar Random Generation . . . . . . . . . . 3
2.2 KZENC-F-002: Secret Data Variables Not Zeroized After Use . . . . . . . . 4
2.3 KZENC-F-003: Potential Side-Channel Timing Attack Due to Use of GMP . 5
2.4 KZENC-F-004: Potential Length Extension Attack with SHA-256 . . . . . . . 5
2.5 KZENC-F-005: Loss of Security Bits by Unnecessary Multiplication . . . . . 6
2.6 KZENC-F-006: Lack of Control on Feldman VSS Parameters . . . . . . . . . 6
2.7 KZENC-F-007: Possible Timing Leak in Mpz::Modulo::mod_sub . . . . . . . 7
2.8 KZENC-F-008: Possible Timing Attack in ECScalar::from() . . . . . . . . . . 8
3 Observations 9
3.1 KZENC-O-001: Add SHA Testing . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 KZENC-O-002: Non-Standard Diffie-Hellman Protocol Implementation . . 9
3.3 KZENC-O-003: Deleting Source Code File Causes Issues . . . . . . . . . . . 10
3.4 KZENC-O-004: Out-of-Date Comments . . . . . . . . . . . . . . . . . . . . 10
3.5 KZENC-O-005: Document Use of Magic Numbers . . . . . . . . . . . . . . 11
3.6 KZENC-O-006: Outdated Ring Library . . . . . . . . . . . . . . . . . . . . . 11
3.7 KZENC-O-007: Mismatched
Purpose
Attribute . . . . . . . . . . . . . . . . 12
3.8 KZENC-O-008: Missing
x_coor
Code . . . . . . . . . . . . . . . . . . . . . . 12
1
