RHEL 6 Security Guide - 7.2. Federal Information Processing Standard (FIPS)

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7.2. Federal Information Processing Standard (FIPS)

The Federal Information Processing Standard (FIPS) Publicaton 140-2, is a computer security standard, developed by a U.S. Government and industry working group to validate the quality of cryptographic modules. FIPS publications (including 140-2) can be found at the following URL: https://csrc.nist.gov/publications/PubsFIPS.html. Note that at the time of writing, Publication 140-3 is at Draft status, and may not represent the completed standard. The FIPS standard provides four (4) security levels, to ensure adequate coverage of different industries, implementations of cryptographic modules and organizational sizes and requirements. These levels are described below:

Level 1 - Security Level 1 provides the lowest level of security. Basic security requirements are specified for a cryptographic module (e.g., at least one Approved algorithm or Approved security function shall be used). No specific physical security mechanisms are required in a Security Level 1 cryptographic module beyond the basic requirement for production-grade components. An example of a Security Level 1 cryptographic module is a personal computer (PC) encryption board.
Level 2 - Security Level 2 enhances the physical security mechanisms of a Security Level 1 cryptographic module by adding the requirement for tamper-evidence, which includes the use of tamper-evident coatings or seals or for pick-resistant locks on removable covers or doors of the module. Tamper-evident coatings or seals are placed on a cryptographic module so that the coating or seal must be broken to attain physical access to the plaintext cryptographic keys and critical security parameters (CSPs) within the module. Tamper-evident seals or pick-resistant locks are placed on covers or doors to protect against unauthorized physical access.
Level 3 - In addition to the tamper-evident physical security mechanisms required at Security Level 2, Security Level 3 attempts to prevent the intruder from gaining access to CSPs held within the cryptographic module. Physical security mechanisms required at Security Level 3 are intended to have a high probability of detecting and responding to attempts at physical access, use or modification of the cryptographic module. The physical security mechanisms may include the use of strong enclosures and tamper detection/response circuitry that zeroizes all plaintext CSPs when the removable covers/doors of the cryptographic module are opened.
Level 4 - Security Level 4 provides the highest level of security defined in this standard. At this security level, the physical security mechanisms provide a complete envelope of protection around the cryptographic module with the intent of detecting and responding to all unauthorized attempts at physical access. Penetration of the cryptographic module enclosure from any direction has a very high probability of being detected, resulting in the immediate zeroization of all plaintext CSPs. Security Level 4 cryptographic modules are useful for operation in physically unprotected environments.

Refer to the full FIPS 140-2 standard at https://csrc.nist.gov/publications/fips/fips140-2/fips1402.pdf for further details on these levels and the other specifications of the FIPS standard.