4. CAMO BANANO - Private Coins on BANANO using ECDH

4.1. Blockchain Stenography and ECDH

4.2. A Private Reversible Transaction

1- Assume Part A (Alice) and B (Bob) have an existing seed and wallet.

2- Alice and Bob achieve a shared secret using Elliptic-curve Diffie-Hellman (ECDH) [4].

3- Alice and Bob must agree on a third neutral location to use to mix the funds and obfuscate records of their transactions to any eavesdropper (Eve).

4- Alice sends three transactions to herself to store the seed of a third party on the blockchain. To do this, she leverages the fact the BANANO balance field has a precision of 29 places after the decimal point, i.e. you can store 11 bytes of data in the balance field 2. Alice splits the 32 byte public key into three chunks of 11, 11, and 10 bytes and sends three transactions to herself encoding these bytes in the balance field.

5- Bob looks through Alice's transactions history and finds three where the representative is the hash of the shared secret. Bob combines theses to obtain the seed Alice hid in the blockchain. This seed is now neutral to both participating parties, and only both parties have access to it. At this point, if Alice sends funds to this neutral location the transaction can be considered reversible.

6- Alice sends funds to the first N addresses contained in the neutral seed, starting at the zeroth address. She uses multiple transactions where the total number N is determined by the total amount of funds to be sent. In the Camo Phase 1 release this is orders of 10 BANANO: 10, 100, 1000 .... In production it is intended to be split according to how transactions in the blockchain look at that point in time.

7- Bob moves funds from each used address in the neutral seed to N separate addresses under a seed in his control. To Eve, it appears Alice simply sent out many random low payments, which then each went onto a second address. However, if Bob consolidated into his wallet at only its zeroth address, Eve could then collapse the graph and see all the transactions went from Alice to Bob.