Utilizing code signing by a trusted third party and making the DACL (discretionary access control list) read-only are actions that the developer can perform to maintain integrity to each module of a program and ensure the code cannot be altered by malicious users. Code signing is a technique that uses digital signatures to verify the authenticity and integrity of code, preventing unauthorized modifications or tampering. A trusted third party, such as a certificate authority, can issue and validate digital certificates for code signing. A DACL is an attribute of an object that defines the permissions granted or denied to users or groups for accessing or modifying the object. Making the DACL read-only can prevent unauthorized users or groups from changing the permissions or accessing the code. Implementing certificate-based authentication is not an action that the developer can perform to maintain integrity to each module of a program and ensure the code cannot be altered by malicious users, but a method for verifying the identity of users or devices based on digital certificates, preventing unauthorized access or impersonation. Verifying MD5 hashes is not an action that the developer can perform to maintain integrity to each module of a program and ensure the code cannot be altered by malicious users, but a method for checking the integrity of files based on cryptographic hash functions, detecting accidental or intentional changes or corruption. Compressing the program with a password is not an action that the developer can perform to maintain integrity to each module of a program and ensure the code cannot be altered by malicious users, but a method for reducing the size of files and protecting them with a password, preventing unauthorized access or extraction. Encrypting with 3DES is not an action that the developer can perform to maintain integrity to each module of a program and ensure the code cannot be altered by malicious users, but a method for protecting the confidentiality of data based on symmetric-key encryption algorithms, preventing unauthorized disclosure or interception. Verified References: https://www.comptia.org/blog/what-is-code-signing https://partners.comptia.org/docs/default-source/resources/casp-content-guide