The hash function supports data in transit by ensuring:

A cryptographic hash function supports data in transit primarily by providingintegrity assurance. When a sender computes a hash (digest) of a message and the receiver recomputes the hash after receipt, the two digests should match if the message arrived unchanged. If the message is altered in any way while traveling across the network—whether by an attacker, a faulty intermediary device, or transmission errors—the recomputed digest will differ from the original. This difference is the key signal that the messagewas modified in transit, which is what option B expresses. In practical secure-transport designs, hashes are typically combined with a secret key or digital signature so an attacker cannot simply modify the message and generate a new valid digest. Examples include HMAC for message authentication and digital signatures that hash the content and then sign the hash with a private key. These mechanisms provide integrity and, when keyed or signed, also provide authentication and non-repudiation properties.

Option A is more specifically about authentication of origin, which requires a keyed construction such as HMAC or a signature scheme; a plain hash alone cannot prove who sent the message. Option C is incorrect because keys are not “converted” from public to private. Option D relates to confidentiality, which is provided by encryption, not hashing. Therefore, the best answer is B because hashing enables detection of message modification during transit.