NIST FIPS 140-2

Security requirements for cryptographic modules used in US government, defining four security levels.

NIST FIPS 140-2 specifies the security requirements that cryptographic modules must meet for use in U.S. and Canadian government systems, spanning four levels from basic algorithm correctness to tamper-responsive hardware. Smart cards and hardware security modules are validated against it to demonstrate approved algorithms, key management, and physical protection. It is being superseded by FIPS 140-3, which aligns the U.S. scheme with the international ISO/IEC 19790 standard.