Hashing is best described as?

• A. A technique for digitally signing data.
• B. A method of data compression.
• C. A form of encrypting data where the data cannot be decrypted.
• D. A protocol for routing web traffic.

Answer: (C)

Hashing is a one-way function that maps input data to a fixed-length digest. It’s easy to compute a hash for any given data, but very hard to reverse the process or find two different inputs that produce the same hash. This makes hashes useful for verifying data integrity and creating compact fingerprints of large data. Importantly, hashing is not encryption: there is no key involved, and you cannot recover the original data from the hash. Encryption is designed to protect confidentiality and is reversible with the correct key. While hashing can be a step in creating digital signatures, the act of hashing itself does not hide or decrypt information. Data compression aims to reduce size, but a hash output is a fixed length regardless of input size, so hashing is not compression. A routing protocol handles how data moves across a network, which is unrelated to hashing.