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Intro

In order to lower the risk of creditor account granting delegatebw permission to Bank of Staked, we have built a smart contract called SafeDelegatebw.

As we know it, there is a 5th parameter in system contract's delegatebw action called transfer, which can be specified as true meaning transfer the ownership of the EOS you staked to the beneficiary account, which is pretty risky. Bank of Staked set transfer to false while it calls creditors delegatebw action, but still, there is a single point failure risk here. Thats why we built SafeDelegatebw.

Design of SafeDelegatebw

SafeDelegatebw wraps up a new customized interface also named delegatebw with only 3 parameters(without from and transfer as in system contract) and hardcodes transfer to false while it calls system contract. creditor account deployed SafeDelegatebw can just grant this customized delegatebw action to Bank of Staked instead of the one from system contract.

Code is open source: https://github.com/EOSLaoMao/safedelegatebw

The only cost we see here is an additional 60K RAM. We will have detailed guide for creditors to set it up later.

setup safe creditor for Bank of Staked using SafeDelegatebw

First, deploy SafeDelegatebw contract to creditor account

0. clone SafeDelegatebw repo

git clone https://github.com/EOSLaoMao/SafeDelegatebw

1. Verify wasm hash before deply:

First, check the hash of build wasm:

cat SafeDelegatebw/safedelegatebw.wasm | shasum -a 256
3da535cdb8e47384e3af6e9583f4ec7a82cc2f9f4a188c2c477130fe21b2cfc3  -

cat SafeDelegatebw/safedelegatebw.wasm | md5
0c780517f8e9154423606f9cf8c1f0f4

Deploy:

cleos -u https://api.eoslaomao.com set contract <your_creditor_account> safedelegatebw/

2. grant system contract's delegatebw action permission to a new permission delegateperm, which will be used only for SafeDelegatebw:

./delegate_perm.sh <your_creditor_account> https://api.eoslaomao.com

now the permission structure of creditor account would be like:

cleos -u https://api.eoslaomao.com get account <your_creditor_account>

permissions:
     owner     1:    1 OWNER_KEY
        active     1:    1 ACTIVE_KEY
           delegateperm     1:    1 <your_creditor_account>@eosio.code

Grant creditor delegate/undelegate permission to Bank of Staked

There is a script called creditor_perm.sh to facilicate this process, which do the following 2 things.

1. Create creditorperm permission and grant it to bankofstaked@eosio

2. Grant these two actions permission to creditorperm:

   delegatebw action from <your_creditor_account>(SafeDelegatebw)

   undelegatebw action from eosio (System Contract)

./creditor_perm.sh <your_creditor_account> https://api.eoslaomao.com

Finally the permission structure of creditor account would like:

cleos -u https://api.eoslaomao.com get account <your_creditor_account>

permissions:
     owner     1:    1 OWNER_KEY
        active     1:    1 ACTIVE_KEY
           delegateperm     1:    1 <your_creditor_account>@eosio.code
           creditorperm     1:    1 bankofstaked@eosio.code

Now it's all set, contact Bank of Staked to add it to creditor table to start leasing your EOS(which is only aval to BPs for now)https://t.me/BOSCreditor