---
title: Quantum Key Distribution with Classical Bob
url: https://www.emergentmind.com/papers/0703107
type: paper
arxiv_id: '0703107'
arxiv_url: https://arxiv.org/abs/0703107
published: '2007-03-13'
categories:
- quant-ph
- cs.CR
---

# Quantum Key Distribution with Classical Bob

## Abstract

Secure key distribution among two remote parties is impossible when both are classical, unless some unproven (and arguably unrealistic) computation-complexity assumptions are made, such as the difficulty of factorizing large numbers. On the other hand, a secure key distribution is possible when both parties are quantum. What is possible when only one party (Alice) is quantum, yet the other (Bob) has only classical capabilities? We present a protocol with this constraint, and prove its robustness against attacks: we prove that any attempt of an adversary to obtain information (and even a tiny amount of information) necessarily induces some errors that the legitimate users could notice.