Which of the following techniques is NOT appropriate for preventing or detecting tampering with data?

The choice of filtering as a technique that is not appropriate for preventing or detecting data tampering is accurate because filtering primarily focuses on controlling the flow of data, such as identifying and blocking unwanted traffic rather than ensuring data integrity. Filtering can be useful in contexts like network security, where it helps prevent unauthorized access, but it does not directly address the issue of whether the data itself has been altered.

In contrast, hashing, encryption, and digital signatures all play critical roles in protecting data from tampering. Hashing creates a fixed-size representation of data that can be checked for integrity; if even a single bit of the data changes, the hash will not match, thus detecting tampering. Encryption secures data against unauthorized access, but it also prevents tampering, as any changes to an encrypted message would make it undecipherable. Digital signatures provide both authentication of the sender and integrity of the message, verifying that the message has not been altered in transit.

Thus, filtering does not provide the mechanisms necessary to ensure the integrity of data or detect its tampering, making it the correct answer in this context.