What application can be used to verify file integrity on a server?

Using a checksum is a fundamental method for verifying file integrity on a server. A checksum is a calculated value that is derived from the contents of a file and is used to ensure that the file has not been altered or corrupted during transfer or storage. When a file is created or modified, a checksum is generated, and this value can be compared to a subsequent checksum calculated when the file is accessed later. If the two checksums match, it indicates that the file has remained unchanged.

In contrast, a port scanner is used to identify open ports and services on a networked server, helping to assess security vulnerabilities rather than file integrity. Cipher tools are generally used for encryption or decryption of files, which does not pertain to the verification of file integrity. Lastly, anti-malware applications are focused on detecting and removing malicious software but do not specifically provide checks for the integrity of standard files. Thus, the correct approach for ensuring file integrity among the options provided is indeed the use of a checksum.