FRP256v1 is a 256-bit prime curve published by the French government (ANSSI) in 2011.
FRP256v1 is a short Weierstrass curve y² = x³ + ax + b over a 256-bit prime field with a 256-bit prime-order subgroup and cofactor 1; its estimated security level is 128 bits. Status: secure, but regional or niche.
FRP256v1 is a short Weierstrass curve y² = x³ − 3x + b over a 256-bit prime, with prime order. ANSSI published it in 2011 in a notice in the Journal officiel, and its OID is 1.2.250.1.223.101.256.1.
The notice gives the parameters without a verifiable generation procedure. Bouncy Castle ships the curve (as FRP256v1), but TLS, JOSE, COSE and the Web PKI have not adopted it.