PKI is most commonly used for:

• A. Signing and/or encrypting data
• B. Data compression
• C. Audio streaming
• D. File deletion

Answer: (A)

Public Key Infrastructure provides a framework for trust in digital interactions by using paired keys and certificates to enable authentication, integrity, and confidentiality. The most common use is signing data to verify who created it and that it hasn’t been altered, and encrypting data so only the intended recipient can read it. With PKI, you use a private key to sign or decrypt, and a public key distributed via a certificate to others, backed by a certificate authority that vouches for identities. Digital signatures give authenticity and non-repudiation, while encryption protects confidentiality. This combination underpins many security protocols and practices, such as TLS for websites, email signing, and document signing. Data compression, audio streaming, and file deletion aren’t functions PKI provides.