Paper 2026/165 Original: eprint.iacr.org/2026/165 ↗

Secure Montgomery Curves over TMVP-Friendly Primes for High-Performance ECC

Abstract

We propose Curve5453 and Curve6071, two Montgomery curves over the Crandall prime $2^{545}-3$ and Mersenne prime $2^{607}-1$, respectively, providing 271 and 302 bits of classical security. Comprehensive security analysis shows Curve6071 passes all verifiable SafeCurves criteria, while Curve5453 passes all except completeness. We develop TMVP-optimized field multiplication tailored to the arithmetic structure of these primes for 10-limb representations on 64-bit architectures, achieving $12.0\%$ and $20.4\%$ speedups over the closest alternative. ARM64 benchmarks show scalar multiplication completing in 871,898 and 895,028 cycles, respectively, competitive with existing lower-security alternatives such as E-521 (259-bit security) while delivering higher security levels. These curves address a critical gap for hybrid post-quantum constructions requiring classical security commensurate with quantum-resistant components, blockchain systems with decades-long security requirements, and specialized deployments where implementation robustness and enhanced classical security are essential---providing the first SafeCurves-compliant alternatives beyond 260 bits with demonstrated practical performance on modern architectures.