crossChain-Bridge
cross chain bridge using DCRM technology
Building
git clone https://github.com/fsn-dev/crossChain-Bridge.git
cd crossChain-Bridge
make all
after building, the following files will be generated in ./build/bin
directory:
swapserver # server provide api service, and trigger swap processing
swaporacle # oracle take part in dcrm signing (can disagree illegal transaction)
config.toml
Modify config.toml
modify the example config.toml
in ./build/bin
directory
see more, please refer config file example
Identifier
Identifier should be a short string to identify the bridge (eg. BTC2ETH
, BTC2FSN
)
MongoDB
MongoDB is used by the server to store swap status and history, you should config according to your modgodb database setting.
(the swap oracle don't need it)
APIServer
APIServer is used by the server to provide API service to register swap and to provide history retrieving.
(the swap oracle don't need it)
Oracle
Oracle is needed by the swap oracle to post swap register RPC requests to swap server
(the swap server don't need Oracle
).
BtcExtra is used to customize fees when build transaction on Bitcoin blockchain
SrcToken
SrcToken is used to config the source endpoint of the cross chain bridge.
SrcGateway
SrcGateway is used to do RPC request to verify transactions on source blockchain, and to broadcast signed transaction.
DestToken
DestToken is used to config the dest endpoint of the cross chain bridge.
DestGateway
DestGateway is used to do RPC request to verify transactions on dest blockchain, and to broadcast signed transaction.
Dcrm
Dcrm is used to config DCRM node info and group info.
ServerAccount
is used to specify the server dcrm user (initiator of dcrm sign)
for the swap server, Pubkey
and SignGroups
is needed for dcrm signing.
Notice:
If in test enviroment you may run more than one program of swap servers on one machine,
Please specify different log file name
to clarify the outputs.
And please specify different config files
for each server,
and assgin KeystoreFile
, PasswordFile
and RPCAddress
etc. separatly.
Run swap server
setsid ./build/bin/swapserver --verbosity 6 --config build/bin/config.toml --log build/bin/logs/server.log
Run swap oracle
setsid ./build/bin/swaporacle --verbosity 6 --config build/bin/config.toml --log build/bin/logs/oracle.log
Others
swapserver
and swaporacle
has the following subcommands:
help - to see hep info.
version - to show the version.
license - to show the license
Preparations
Running swapserver
and swaporacle
to provide cross chain bridge service, we must prepare the following things firstly and config them rightly. Otherwise the program will not run or run rightly. To ensure this, we have add many checkings to the config items.
For the config file, please refer config file example
-
create Mongodb database (shared by all swap servers of the bridge provider)
config [MongoDB]
section accordingly (eg. DbURL
,DbName
,UserName
,Password
)
For security reason, we suggest:
- change the mongod
port
( deafults to 27017
)
- enable
auth
- create user with passord to access the database
-
create DCRM group
For example, we take creating 2/3 theshold
jonitly managed DCRM group as an example.
we have 3 users in the DCRM group, each user is running a gdcrm
node to perform DCRM functions.
user1
- build raw tx and trigger DCRM signing
user2
, user3
- verify tx and accept the DCRM signing with AGREE/DISAGREE
result
After created DCRM group,
We can get the corresponding DCRM addresses
on supported blockchains. Then we should config DcrmAddress
in [SrcToken]
and [DestToken]
section according to the blockchain of them.
We should config the [Dcrm]
section accordingly( eg. ServerAccount
, GroupID
, Pubkey
,NeededOracles
, TotalOracles
,Mode
)
And we should config the following [Dcrm]
section items sparately for each user in the DCRM group:
KeystoreFile
PasswordFile
RPCAddress
For example,
we are configing user1
now, we should config KeystoreFile
and PasswordFile
use user1
's keystore and password file (we will get user1
's private key to sign a DCRM requesting).
And we should config RPCAddress
to the RPC address of the running gdcrm
node of user1
(we will do RPC calls to this address to complete DCRM signing or accepting, etc.)
-
create DCRM sub-groups for signing
In the above step we have created a 2/3 threshold
DCRM group.
In signing we only need 2 members to agree.
So we prepared the sub-groups (2/2
) for signing. (eg. user1 + user2, user1 + user3)
please see more detail about DCRM here
After created, we should config SignGroups
in [Dcrm]
accordingly.
-
create mapping asset (eg. mBTC) contract with DCRM account
mBTC is an smart contract inherit from ERC20
and add two methods: Swapin
and Swapout
.
please see more here about mBTC
After created mBTC, we should config ContractAddress
in [DestToken]
section.
-
config [APIServer]
section
The swap server provides RPC service to query swap status and swap history. etc.
Please see more here about crossChain-Bridge-API
We should config Port
(defaults to 11556
), and AllowedOrigins
(CORS defaults to empty array. ["*"]
for allow any)
-
config [SrcToken]
,[SrcGateway]
We should config APIAddress
in [SrcGateway]
section,
to post RPC request to the running full node to get transaction, broadcat transaction etc.
Config [SrcToken]
, ref. to the following example:
BlockChain = "Bitcoin" # required
NetID = "TestNet3" # required
ID = ""
Name = "Bitcoin Coin"
Symbol = "BTC"
Decimals = 8 # required
Description = "Bitcoin Coin"
ContractAddress = ""
DcrmAddress = "mfwPnCuht2b4Lvb5XTds4Rvzy3jZ2ZWrBL" # required
Confirmations = 0 # suggest >= 6 for Mainnet # required
MaximumSwap = 1000.0 # required
MinimumSwap = 0.00001 # required
SwapFeeRate = 0.001 # required
For ERC20 token, we should config ID = "ERC20"
and ContractAddress
to the token's contract address.
-
config [DestToken]
, [DestGateway]
We should config APIAddress
in [DestGateway]
section,
to post RPC request to the running full node to get transaction, broadcat transaction etc.
Config [DestToken]
like [SrcToken]
.
Don't forget to config ContractAddress
in [DestToken]
section (see step 4)
-
config Identifier
to identify your crosschain bridge
This should be a short string to identify the bridge (eg. BTC2ETH
, BTC2FSN
)
Different DCRM group can have same Identifier.
It only matter if you want use a DCRM group to provide multiple crosschain bridge service, and config each bridge with a different identifier (Notice: This way is not suggested
)
-
config [BtcExtra]
When build and sign transaction on Bitcoin blockchain, we can customize the following items:
MinRelayFee = 400
RelayFeePerKb = 2000
UtxoAggregateMinCount = 20
UtxoAggregateMinValue = 1000000
If not configed, the default vlaue will be used (in fact, the above values are the defaults)