Quick Index

• Smart Contract: Core practices, ownership, safe patterns and minimal examples.
• DeFi: Simple lending pool & share model — deposit/withdraw maths and security notes.
• Blockchain VM & Concepts: Telemetry anchoring (IPFS + on-chain CID anchoring), verification and provenance notes for telemetry.

Smart Contracts — Basics & Best Practices (Overview & PoC)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract SimpleOwnable {
    address public owner;
    event OwnershipTransferred(address indexed oldOwner, address indexed newOwner);
    constructor() { owner = msg.sender; }
    modifier onlyOwner() { require(msg.sender == owner, "owner only"); _; }
    function transferOwnership(address newOwner) external onlyOwner {
        require(newOwner != address(0), "zero");
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }
}

contract SafeDeposit is SimpleOwnable {
    mapping(address => uint) public balances;
    event Deposited(address indexed who, uint amount);
    function deposit() external payable {
        require(msg.value > 0, "zero");
        balances[msg.sender] += msg.value;
        emit Deposited(msg.sender, msg.value);
    }
    function withdraw(uint amount) external {
        require(balances[msg.sender] >= amount, "insufficient");
        balances[msg.sender] -= amount;
        (bool ok, ) = msg.sender.call{value: amount}("");
        require(ok, "transfer failed");
    }
}
          

Decentralized Election Voting — Vote Hash Anchoring (Proof of Concept)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract VoteHashAnchor {
    address public admin;
    mapping(address => bool) public registered;
    mapping(bytes32 => bool) public voteSeen;
    mapping(address => bool) public hasVoted;
    bool public closed;

    constructor() { admin = msg.sender; }

    modifier onlyAdmin { require(msg.sender == admin, "admin only"); _; }
    modifier open { require(!closed, "poll closed"); _; }

    function registerVoter(address v) external onlyAdmin { registered[v] = true; }
    function closePoll() external onlyAdmin { closed = true; }

    // submit hash of (pollId || voterSalt || choice)
    function submitVote(bytes32 h) external open {
        require(registered[msg.sender], "not registered");
        require(!hasVoted[msg.sender], "already voted");
        require(!voteSeen[h], "duplicate vote");
        voteSeen[h] = true;
        hasVoted[msg.sender] = true;
    }
}
          

Decentralized Finance — Simple Lending Pool & Share Model (Proof of Concept)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IERC20 { function transferFrom(address from, address to, uint amount) external returns(bool); function transfer(address to, uint amount) external returns(bool); function balanceOf(address owner) external view returns(uint); }

contract SimpleLendingPool {
    IERC20 public immutable token;
    uint public totalShares;
    uint public totalAssets;
    mapping(address => uint) public shares;

    constructor(address _token) { token = IERC20(_token); }

    function deposit(uint amount) external {
        require(amount>0, "zero");
        uint minted;
        if (totalShares == 0) {
            minted = amount;
        } else {
            minted = amount * totalShares / totalAssets;
        }
        token.transferFrom(msg.sender, address(this), amount);
        totalAssets += amount;
        totalShares += minted;
        shares[msg.sender] += minted;
    }

    function withdraw(uint shareAmount) external {
        require(shareAmount>0 && shares[msg.sender]>=shareAmount, "invalid");
        uint value = shareAmount * totalAssets / totalShares;
        shares[msg.sender] -= shareAmount;
        totalShares -= shareAmount;
        totalAssets -= value;
        token.transfer(msg.sender, value);
    }
}
          

Blockchain Virtual Machine & Concepts — Telemetry Anchoring (IPFS + On-chain CID)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract TelemetryAnchor {
    struct Entry { string cid; uint256 ts; address submitter; }
    Entry[] public entries;
    event Anchored(uint indexed id, string cid, uint256 ts, address indexed submitter);

    function anchorCID(string calldata cid) external {
        entries.push( Entry({ cid: cid, ts: block.timestamp, submitter: msg.sender }) );
        emit Anchored(entries.length-1, cid, block.timestamp, msg.sender);
    }

    function getEntry(uint id) external view returns(string memory, uint256, address) {
        Entry storage e = entries[id];
        return (e.cid, e.ts, e.submitter);
    }
}
          

Blockchain For Space Research

// pseudo-code (off-chain uploader)
// 1) sign snapshot, 2) upload to IPFS, 3) submit CID to TelemetryAnchor
// NOTE: this is illustrative; real integrations need secure key storage and relay nodes.

const signed = signSnapshot(privateKey, snapshot);
const cid = await ipfs.add(snapshot);
await telemetryAnchorContract.anchorCID(cid);