A digital certificate contains the subject's identity and their public key.

A digital certificate contains the subject's identity and their public key.

• A. Private key
• B. Public key
• C. Password
• D. Digital signature

Answer: (B)

Digital certificates in PKI are used to bind an entity’s identity to a cryptographic key. The certificate includes the subject’s public key so others can encrypt data for the holder or verify their signatures, and it also carries identity information and metadata. This binding is attested by a trusted authority that signs the certificate, ensuring the key indeed belongs to that identity. The private key never leaves the subject and is not stored in the certificate; passwords are not part of certificates. While a digital signature is present, that signature is the issuer’s verification of the certificate, not the subject’s public key itself. Hence, the element that the certificate contains, and that the statement highlights, is the public key.

Digital certificates in PKI are used to bind an entity’s identity to a cryptographic key. The certificate includes the subject’s public key so others can encrypt data for the holder or verify their signatures, and it also carries identity information and metadata. This binding is attested by a trusted authority that signs the certificate, ensuring the key indeed belongs to that identity. The private key never leaves the subject and is not stored in the certificate; passwords are not part of certificates. While a digital signature is present, that signature is the issuer’s verification of the certificate, not the subject’s public key itself. Hence, the element that the certificate contains, and that the statement highlights, is the public key.