Certified Ethical Hacker (CEH v10) — Question 101

What is correct about digital signatures?

Answer options

• A. A digital signature cannot be moved from one signed document to another because it is the hash of the original document encrypted with the private key of the signing party.
• B. Digital signatures may be used in different documents of the same type.
• C. A digital signature cannot be moved from one signed document to another because it is a plain hash of the document content.
• D. Digital signatures are issued once for each user and can be used everywhere until they expire.

Correct answer: A

Explanation

Option A is correct because a digital signature is specifically tied to a document's hash and the private key of the signer, making it unique to that document. Option B is incorrect as signatures cannot be reused across different documents even if they are of the same type. Option C is wrong because a digital signature is not just a plain hash; it is the encrypted hash, which provides authenticity. Option D is misleading because digital signatures may be revoked or expire based on policies.