Pegs CC
Pegs CC is a complex module using several other CCs. It allows creating a coin that is pegged (bound) to some other currency. In essence a mechanism for creating a decentralized stable coin. Using Tokens CC and Gateways CC other crypto currencies can be deposited on chain in form of tokens and locked in an account so it can back a coin with existing value. With Prices CC that locked deposit can be calculated in any other currency like fiat (USD, EUR ...) or crypto (BTC, ETH ...) and coins can be issued in correspondent ratio. For the sake of further explanation of Pegs in this article, I will use the term USDK that is a chain in Komodo ecosystem in which the USDK coin is pegged to US Dollar and backed by KMD.
These CCs won't be explained here as it assumed that you are familiar with other CC, but we'll cover just some basic explanation of what is each one for so that you can better understand Pegs CC if you have not yet read about these CCs. Tokens CC allows you to create a token from the coins on chain up to the satoshi. So each satoshi can represent one token or you can choose whatever scaling you like by the amount of tokens you create for you need. Gateways CC will give you tokens upon deposits on external chain. For example create BTCT token on Komodo asset chain, lock all tokens in gateways CC and deposit funds in BTC chain to get BTCT. Last but not least is the Prices CC which is a decentralized oracle for getting crypto prices. It has some native prices submitted like BTC/USD, BTC/EUR, EUR/USD, ETH/BTC, KMD/BTC, and for every other a synthetic can be created from these prices.
Core functionality is based on accounts that track deposited value vs. issued coins on that deposit. It is not easy to grasp the essence on how it works from the beginning but if you think of it as a model of "deposit and debt" it will be much easier. You deposit the value on chain and take a "loan" on that deposit in form of USDK coins. Initially the USDK chain will start with 0 coins and they will be issued for account holders on request. To get yourself an account you must deposit some KMD first through the gateway and get KMDT tokens. With this tokens you can fund your account with pegsfund command and issue USDK coins up to 80% of the deposited value with pegsget. Now you are equipped with USDK coins and you can do with them like with every other coin. At any point, the pegsredeem command can be done to basically close your account by repaying the whole "debt" (burning coins) and get the deposited KMDT back. If you are a holder of USDK without an account, got them on exchange or sent by someone, you can exchange them with pegsexchange and you will get KMDT for the coins you gave. This kind of exchange is done by taking an account that is in bad shape, so called "yellow zone" - the debt on the deposit is pretty high and in this way the account ratio is improved by repaying the part of debt and taking that amount of deposit. The example would be an account: deposit 100KMDT, debt 80USDK (at KMD price 1$) - debt ratio 80%, so by exchanging 40USDK you are getting account: deposit 60KMDT, debt 40USDK - debt ratio 66.66%.
So how does Pegs CC manage to maintain a coin to be stable and pegged to some other currency? When looking at the problems of maintaining a stable coin there are two aspects. When the price of backed assets goes up and when price goes down. As the coin is backed by crypto which can have its price very volatile it will be necessary to solve these problems very often. The first case is pretty easy to solve, you can issue more coins to reach the value of the deposit (but not necessary needed as the backed value stays there). The problem comes when price goes down. One way would be to burn coins and in that way maintain the ratio with the deposited value. But as this is decentralized stable coin, no body has the control of the supply of the coins. So to address this problem there is a method of liquidating worst accounts. The whole pegs CC system tracks all accounts and calculates the global ratio of the system by summing all deposits and debts. When the ratio of the system reaches some high value (let's say 60%) then it is possible that other users liquidate accounts that have account ratio very high that we will call "red zone" (for example over 90%). They can repay the whole debt of that account to get 5% gain and what is left will go to the system to improve the global ratio. By liquidating worst accounts you are lowering the overall debt of the system and prevent getting in the situation that you have more coins than backed assets - so the system keeps every satoshi of the coin backed with some existing value.
Let's now see how this works on a proper example. Initial state of the system is normal - global ratio is 35% and price of KMD is 1$, and one of the accounts is: 100KMDT, 46USDK - ratio 46%. Now let's see what happens if price of KMD suddenly drops to 0.5$. The global ratio now is 70% and account is: 100KMDT, 46USDK - ratio 92%. Liquidator will now give 46USDK to get 46$+5% worth of KMDT that equals to 96.6KMDT and 3.4KMDT what is left will go to pegs CC global reserve. In this way, the account holder that did not maintain good ratio lost 10%, liquidator gained 5% on his funds and the rest went to the system.
History of all transactions for account.
komodo-cli -ac_name=KUSDTEST pegsaccounthistory a130861d422655cb28ffbf788c3b4a07748ba67eb7c413c9440b7cbbfcb9d296
{ "result": "success", "name": "pegsaccounthistory", "account history": [ { "action": "fund", "amount": 1000000, "accounttxid": "11de1dfdd5a061be45072b758feb5d1ef34b698b609a758ca1c6b45b87cf2492", "token": "KMD", "deposit": 1000000, "debt": 0 }, { "action": "get", "amount": 1100000, "accounttxid": "193c90bb479a70c7a0d56f18ab2ea004aaa64ad53c410fe45761e431e09fe959", "token": "KMD", "deposit": 1000000, "debt": 1100000 } ] }
Current info for account.
komodo-cli -ac_name=KUSDTEST pegsaccountinfo a130861d422655cb28ffbf788c3b4a07748ba67eb7c413c9440b7cbbfcb9d296
{ "result": "success", "name": "pegsaccountinfo", "account info": [ { "token": "KMD", "deposit": 0.01, "debt": 0.013, "ratio": "93.85%" } ] }
Addresses of Pegs CC contract.
komodo-cli -ac_name=KUSDTEST pegsaddress
{ "result": "success", "PegsCCAddress": "RHnkVb7vHuHnjEjhkCF1bS6xxLLNZPv5fd", "PegsCCBalance": 9.99920000, "PegsNormalAddress": "RMcCZtX6dHf1fz3gpLQhUEMQ8cVZ6Rzaro", "PegsNormalBalance": 0.00000000, "PegsCCTokensAddress": "RHG4K84bPP9h9KKqvpYbUzocaZ3LSUHxLa", "myCCAddress(Pegs)": "RWvHzZy4caP1jv3yVoa7Pps6Wsqm8TsM7q", "myCCbalance(Pegs)": 0.00000000, "myaddress": "RLMV9iDe8iPLf82xEniz2R8rr9EKEHTmiP", "mybalance": 0.00060000 }
Create peg contract for given gateways. Amount parameter is for funds that will be added to pegs CC global address for tx fees and markers of pegs transactions. N is for number of following gateways bind transactions. This tx is done once per chain and put in -ac_earlytxid parameter so that after block height 100 it cannot be changed and only one pegs txid is the trusted one.
Exchange given amount of coins for deposited token (tokenid). This rpc is used when user does not have an account and wants to exchange coins for other crypto.
Funds the account with given token and amount. If user does not have an account yet it will open a new one.
Issues coins for given amount on account of given token.
Info about total deposit and debt per token and global ratio of whole pegs CC.
komodo-cli -ac_name=KUSDTEST pegsinfo a130861d422655cb28ffbf788c3b4a07748ba67eb7c413c9440b7cbbfcb9d296
{ "result": "success", "name": "pegsinfo", "info": [ { "token": "KMD", "total deposit": 1022885, "total debt": 1300000, "total ratio": "86.63%" } ], "global ratio": "86.63%" }
Liquidate account for given txid if the account ratio is over defined "red zone" threshold.
Withdraw deposited tokens on account by covering the whole debt in coins.
Get info on accounts that can be liquidated (ratio in red zone).
komodo-cli -ac_name=KUSDTEST pegsworstaccounts a130861d422655cb28ffbf788c3b4a07748ba67eb7c413c9440b7cbbfcb9d296
{ "result": "success", "name": "pegsworstaccounts", "KMD": [ { "accounttxid": "a9f6d273e916b74831d7ee5822bd47f32e5e2f6c6c6f97a7f8ebcd25cab747a6", "deposit": 1000000, "debt": 1300000, "ratio": "91.18%" } ] }