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PFS still involves asymmetric cryptography. And in fact in essentially every modern cryptography stack (ie. (EC)DLP-based) the "PFS primitive" (Diffie-Hellman,
by dfox 6y ago
PFS still involves asymmetric cryptography. And in fact in essentially every modern cryptography stack (ie. (EC)DLP-based) the "PFS primitive" (Diffie-Hellman, ie. scalar multiplication/exponentiation) is the one thing that everything else is derived from.
RSA is in fact somewhat notable for being the only widely used asymmetric cryptosystem where the underlying operation is block cipher-ish encryption primitive and not key agreement primitive.
- SAI_Peregrinus 6y ago> RSA is in fact somewhat notable for being the only widely used asymmetric cryptosystem where the underlying operation is block cipher-ish encryption primitive and not key agreement primitive. Debatable. It's sort of true of RSA-OAEP. That's not true of RSA-PSS (signatures), nor of RSA-KEM (key encapsulation). Really it's the OAEP that's block-cipher like, and the fundamental RSA operation (modular exponentiation) isn't "encryption" or "signing" or "decryption" or "encapsulation" or anything else cryptographic on its own.