scriptSig即解锁脚本, 是交易输入里面, 用来证明自己所有权一个私钥签名scriptPubKey即锁定脚本, 即上一笔交易输出(本次交易的输入)里面用来锁定所有权的字节序列
OP_CHECKSIG is Script opcode used to verify that the signature for a tx input is valid. OP_CHECKSIG expects two values to be on the stack. These are, in order of stack depth, the public key and the signature of the script. These two values are normally obtained by running the scriptSig script of the transaction input we are attempting to validate. The scriptSig script is deleted after it is run, but the stack is left as is. Then, the scriptPubKey script from the previous transaction output that is now being spent is run, generally concluding in an OP_CHECKSIG.