Live Demo

metamask turn on is required (done this way for easy check, "nostyle"-style)

https://block-soft.github.io/hiddenContracts/index.html

Created Example

Main

https://ropsten.etherscan.io/address/0x647f22069adf3bf00e8ec4ca4c8eb5dfd92783a1

MainContract.pay was changed to default function but all other logic the same

Matching Hidden

https://ropsten.etherscan.io/address/0xc10c925654ad2b9a0a0e37808f61cdbf7d2fcf4b

Not Matching Hidden

without optimization

https://ropsten.etherscan.io/address/0xbf24f06ca6710e35ec7555d40a5069ebdc016257

with optimization

https://ropsten.etherscan.io/address/0xb44e681a645cbeb0e38c944d138f455fdccd2e67