## Introduction

BigRich provides its users many financial benefits and advantages. One of them is that BigRich offers deals on a regular basis where users can buy things at discounted prices. Besides that, there are other in-app services that charge real money from users before using.

While directly charging users for the bought things/services with real money seems natural, it is not convenient and flexible enough due to some reasons:

- Transactions usually take days to be settled.
- Managing ledger of transactions for reckoning/auditing is challenge and error-prone
- Being tied to specific types of funding sources (bank/card)

Such issues cause negative impacts on users experience. They need to wait for days before their orders could be confirmed.

Bigrich coin (BRC) has been introduced to solve such issues. It is planned to be the currency in BigRich system. Based on Solana blockchain, using BRC as BigRich currency has some advantages over traditional currency:

- Transactions take seconds or minutes to be settled.
- No trust-related friction since ledger is public and verifiable and can be verified by anyone.
- Proven reliablity and availability since Solana is one of the most powerful operational blockchains.
- Total control over the funding sources.
- Unlike other blockchains, transaction fee is much lower on Solana blockchain which results in better scability.

## Account management

- Our treasury account is cold wallet from which the coins are distributed to the hot wallet. This account is managed by a legal entity using a Solana wallet app, for example, Phantom or SolFlare. The person who holds treasurry account likely takes responsibiilty to keep it safe.

- Our intermediate account is hot wallet which receives coins from our cold wallet on a regular basis. Server uses this account to distribute coins to users. Wallet keys are encrypted and stored safe in AWS Secret Manager. Other than distributing coins to user wallets, hot wallet is also used for paying transaction fee in Solana
+ Hot wallet must have enough balance of BRC to distribute BRC to user wallets when needed
+ Hot wallet must have enough balance of Solana to pay for transaction fee, given the current fee is about 0.000005 SOL = 0.00096 USD for each transaction

## Moving coins from cold wallet to hot wallet

Unlike cold wallet, hot wallet is where BigRich's outgoing and incoming transactions is likely to happen. To serve the purpose, the hot wallet must be funded properly from the cold wallet.

- On a regular basis (depends on our business decision)
- Via a wallet mobile app: Phantom or Solflare
- Transactions can be verified and audited directly anytime on chain but it is better that account holder should also keep tracks of transactions
- Transaction fee (Solana) should be taken into consideration

## Example

devnet: sends **12** tokens from **8faJtmpFTpLeFz8TfCJyjJyaTo92Sw1Q913VRnCLzavi**
to **8tJcS4PUZdw6W4M8m1oSGpwqL1ajgDHQWNEFaXGVfbd9** with fee 0.000005 SOL

Example token is https://solscan.io/token/5PwyUHoJgNzx7UgtBEKfHEf7mbxYjSbtJSFaysDVUA5E?cluster=devnet
the token does not have friendly name due to not being registered to Solana. We will proceed that right before going live.


Transaction:
https://solscan.io/tx/3Jrrymo9VAQ36er6midczxpanJe7yy9LE39kwCaNoAf9MzXYJUE3ZTnvArN3Tu9AbEW3rKP4nDyHDaybgehtpUJW?cluster=devnet