secp192k1 is a 192-bit SEC 2 Koblitz curve (y² = x³ + 3) with about 96 bits of security.
secp192k1 is a short Weierstrass curve y² = x³ + ax + b over a 192-bit prime field with a 192-bit prime-order subgroup and cofactor 1; its estimated security level is 96 bits. Status: deprecated, do not use for new keys.
The 'k' curves of SEC 2 have a = 0 and a small b — here y² = x³ + 3. Because a = 0 and p ≡ 1 (mod 3), the curve has an efficiently computable endomorphism that speeds up scalar multiplication (the GLV method). secp192k1 has a prime-order group of about 2^192 elements.
At about 96 bits of security it falls short of the 112-bit minimum of NIST SP 800-57, and RFC 8422 deprecated it for TLS (code point 18). It survives only in legacy systems.