Which of the following is a characteristic of Public Key Infrastructure (PKI)?

Asymmetric (public-key) cryptosystems are significantly slower than symmetric-key cryptosystems because of the mathematical complexity of operations such as RSA modular exponentiation.

In PKI, public keys are embedded within digital certificates that are themselves signed by a Certificate Authority (CA), meaning public keys are distributed as part of a digital signature construct. The CA's signature over the certificate validates the authenticity of the enclosed public key, making signed certificate distribution the core mechanism of PKI public key propagation.

While public keys can travel over untrusted channels, PKI still requires a trusted distribution mechanism - Certificate Authorities and a chain of trust - to prevent key substitution and man-in-the-middle attacks.

PKI explicitly provides technical non-repudiation through digital signatures, because only the holder of the corresponding private key could have produced a valid signature, constituting strong evidence of origin.