permission.sol

pragma solidity 0.5.5;

contract TxPermission {
    /// Allowed transaction types mask
    uint32 constant None = 0;
    uint32 constant All = 0xffffffff;
    uint32 constant Basic = 0x01;
    uint32 constant Call = 0x02;
    uint32 constant Create = 0x04;
    uint32 constant Private = 0x08;
    
    /// Contract name
    function contractName() public pure returns (string memory) {
        return "TX_PERMISSION_CONTRACT";
    }
    
    /// Contract name hash
    function contractNameHash() public pure returns (bytes32) {
        return keccak256(abi.encodePacked(contractName()));
    }
    
    /// Contract version
    function contractVersion() public pure returns (uint256) {
        return 2;
    }

    /*
     * Allowed transaction types
     * 
     * Returns:
     *  - uint32 - set of allowed transactions for #'sender' depending on tx #'to' address
     *    and value in wei.
     *  - bool - if true is returned the same permissions will be applied from the same #'sender' 
     *    without calling this contract again.
     *
     * In case of contract creation #'to' address equals to zero-address
     * 
     * Result is represented as set of flags:
     *  - 0x01 - basic transaction (e.g. ether transferring to user wallet)
     *  - 0x02 - contract call
     *  - 0x04 - contract creation
     *  - 0x08 - private transaction
     *
     * @param sender Transaction sender address
     * @param to Transaction recepient address
     * @param value Value in wei for transaction
     * 
     */
    function allowedTxTypes(address sender, address to, uint value) public pure returns (uint32, bool) {
        if (sender == 0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf) return (All, true); // Secret: 0x00..01
        if (sender == 0x2B5AD5c4795c026514f8317c7a215E218DcCD6cF) return (Basic | Call, true); // Secret: 0x00..02
        if (sender == 0x6813Eb9362372EEF6200f3b1dbC3f819671cBA69) return (Basic, true); // Secret: 0x00..03
        if ((sender == 0xe1AB8145F7E55DC933d51a18c793F901A3A0b276) && (value == 0)) return (All, false); // Secret: 0x00..05
        if ((sender == 0xE57bFE9F44b819898F47BF37E5AF72a0783e1141) && (to == 0xd41c057fd1c78805AAC12B0A94a405c0461A6FBb)) return (Basic, false); // Secret: 0x00..06
        if ((sender == 0xd41c057fd1c78805AAC12B0A94a405c0461A6FBb) && (to == 0xE57bFE9F44b819898F47BF37E5AF72a0783e1141) && (value == 0)) return (All, false); // Secret: 0x00..07
        return (None, true);
    }
}