An estimate of the largest security strength that can be attained by a cryptographic mechanism given the explicit and implicit assumptions that are made regarding its implementation and supporting infrastructure (e.g., the algorithms employed, the selection of associated primitives and/or auxiliary functions, the choices for various parameters, the methods of generation and/or protection for any required keys, etc.). The estimated maximum security strengths of various approved cryptographic mechanisms are provided in [SP 800-57].
Source(s):
NIST SP 800-56C Rev. 2