AES-256 is a symmetric encryption algorithm widely used to protect data at rest by converting plaintext into ciphertext that is unreadable without the proper key. It provides strong confidentiality and is a standard for encrypting stored data.
TLS 1.2 (A) secures data in transit, not at rest. Masking (C) obscures data but typically for display or limited use and is reversible. Salting (D) is used alongside hashing to protect passwords and data integrity but does not encrypt data.
Encryption with AES-256 is recognized as a best practice for securing stored data in the Security+ Cryptography and General Security Concepts domains#6:Chapter 7 CompTIA Security+ Study Guide#.

Posting hashes allows users to verify the integrity of downloaded files. As outlined in Security+ SY0-701, a cryptographic hash (e.g., SHA-256) produces a fixed-length digest unique to the file's contents. Users can compute the hash of the downloaded file and compare it to the published value; a match confirms the file has not been altered.
Certificates (B) establish identity and trust but do not directly verify file integrity post-download unless combined with signing workflows. Algorithms (C) are general methods, not verification artifacts. Salting (D) is used with password hashing and is irrelevant here.
Therefore, A: Hashes is the correct choice.

Code signing uses digital signatures to verify software authenticity and integrity, ensuring the code has not been tampered with since it was signed by the developer. It helps detect if malware was introduced after delivery.
Static code analysis (B) inspects code for vulnerabilities during development but does not verify delivered binaries. Input validation (C) protects applications at runtime. Secure storage (A) protects stored data, unrelated to software delivery.
Code signing is an essential security control in Software Development Life Cycle and Supply Chain Security [6:Chapter 7 CompTIA Security+ Study Guide].