fake multisig

"Multisig" One-time-use Cold Storage

Useful to prevent theft due to a compromised computer during generation ("computer A,B"). Can be used with two (or more, any N-of-N, or even N-1 of N with some extra params) separate parties for long term escrow or custodial storage.
The spending/redemption process MUST be secure and the account never reused afterwards.

1. User A OR B choose random viewkey d. Keeping it secret is only a privacy consideration.
2. D = dG;

3. User/computer A randomly choose factor a.
4. A = aG;

5. User/computer B randomly choose factor b.
6. B = bG;

Spend pubkey C = A + B;

Public Address = C || D;

User/computer A stores a,d,Public Address.
User/computer B stores b,d,Public Address.

At the time of account recovery (for spending), generate c = a + b. Restore non-deterministic c,d in simplewallet (etc).