Oblivious Transfer from Diffie-Hellman
Stub. Two further public-key encryption applications (key escrow, encrypting to a group) and a concrete classical (non-quantum) construction of oblivious transfer from Diffie-Hellman/ElGamal encryption, extended to the adaptive setting via oblivious pseudorandom functions.
Corresponds to Chapter 11 (sections beyond RSA/ElGamal encryption itself, already covered in public-key-encryption-schemes). Covers two further example applications of public-key encryption (sharing encrypted files among a group, and key escrow), then a concrete classical construction of oblivious transfer from ElGamal encryption — compare quantum-oblivious-transfer‘s information-theoretic, no-cloning-based approach to the same primitive, here instead built from a standard computational assumption. Extends the basic (one-shot) construction to adaptive oblivious transfer, where the receiver can make a sequence of choices depending on earlier outcomes, via oblivious pseudorandom functions (letting the receiver learn for a PRF key the sender holds, without the sender learning or the receiver learning ).
Outline (TODO — flesh out each)
- Further applications of public-key encryption: sharing encrypted files, key escrow
- Oblivious transfer based on Diffie-Hellman
- A secure OT construction from ElGamal encryption
- Adaptive oblivious transfer
- Oblivious pseudorandom functions
- A simple adaptive OT from an oblivious PRF