Different post-quantum algorithms can have significantly different performance characteristics and implementation constraints (with respect to key sizes, signature sizes, resource requirements, etc.). Consequently, different algorithms can be more suitable than others for specific applications. For example, the signature or key size might not be a problem for some applications but can be unacceptable for others. Some widely used protocols need to be modified to handle larger signatures or key sizes (e.g., using message segmentation). Implementations of new applications will need to accommodate the demands of post-quantum cryptography (pqc) and the schemes developed that incorporate pqc for digital signatures and key establishment. In fact, pqc requirements may actually shape some future application standards. The replacement of algorithms generally requires changing or replacing cryptographic libraries, implementation validation tools, hardware that implements or accelerates algorithm performance, dependent operating system and application code, communications devices and protocols, and user and administrative procedures. Security standards, procedures, and best practice documentation are being changed or replaced, and the same will be needed for installation, configuration, and administration documentation.