(E)mail Client for Blocked Internet Access

A protocol for transacting with Ergo (and other blockchains) via email or other low-bandwidth channels when the Internet is restricted or unavailable. Enables secure asset transfers and blockchain access even under censorship or outages.

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Why It Matters

In countries like China and Belarus, Tor is already restricted. During civil unrest, governments often shut down the Internet, as seen in Egypt, Ethiopia, Sudan, Iran, and Turkey. Regardless, individuals should have the ability to secure their assets, especially when threatened by monetary policies, political instability, or warfare.

The combination of digital communication and digital currency can provide a solution to this issue, allowing users to transact and protect their funds even under severe network restrictions.

How It Works

  1. Deal Creation: Bob initiates a transaction from his box, creating a new box (the "deal box") with X ERG, secured by a smart contract: Before deadline: Bob's signature + output to Alice; After deadline: Bob's signature.
  2. Offline Transmission: Bob transmits the transaction via (e)mail to a gateway. The gateway returns a compact NiPoPoW proof for a header with sufficient confirmations + proof of box membership. For enhanced security, Bob may request a proof from another gateway.
  3. Verification: Bob presents the proof to Alice. Alice verifies the proofs and ensures the deadline will not likely be met before her transaction is included.
  4. Finalization: Bob signs the new transaction (spending the deal box, creating Alice's output). Alice sends the signed transaction to the gateway and receives a proof of inclusion.

Given the small size of these proofs (tens of kilobytes), communication methods like email, fax, ADSL modem, or even paperwork are viable for communication between users and gateways.

Scenario: Cash-for-ERG in a Blackout

Alice wants to purchase X ERGs from Bob (paying with cash), but their area has limited or no Internet access. Using this protocol, they can securely complete the transaction using only email or other low-bandwidth channels, with all steps verifiable via cryptographic proofs.

Technical Details & Alternatives

  • Blockstream Satellite: For Bitcoin, the Blockstream Satellite network can broadcast the blockchain globally, but is susceptible to jamming.
  • Email as a fallback: Email is often the last service to be blocked and can be used to transmit compact blockchain proofs and transactions.
  • Other methods: Fax, modem calls, or even physical mail can be used to exchange proofs and transactions, thanks to the small size of NiPoPoW proofs.

References & Further Reading