Solidity provides special variables and functions which always exist in the global namespace and are mainly used to provide information about the blockchain or are general-use utility functions. The following is a list of properties related to the block and transactions:

• block.blockhash (uint blockNumber) returns (bytes32): Hash of the given block, works for only the 256 most recent blocks
• block.coinbase (address): Current block miner’s address
• block.difficult (uint): Current block difficulty
• block.gaslimit (uint): Current block gas limit
• block.number (uint): Current block number
• block.timestamp (uint): Current block timestamp
• msg.data (bytes): Complete call data
• msg.gas (uint): Remaining gas
• msg.sender (address): Sender of the message (current call)
• msg.sig (bytes4): First 4 bytes of the call data (function identifier)
• msg.value (uint): Number of wei sent with the message
• now (uint): Current block timestamp (alias for block.timestamp)
• tx.gasprice (uint): Gas price of the transaction
• tx.origin (address): Sender of the transaction (full call chain)