As I understand, we can generate a TXID by hashing transaction data through SHA256 twice, and as you know probably, A bitcoin transaction is just a bunch of data that describes the movement of bitcoins.

after that, to search a TXID in the blockchain, we should search for it in reverse byte order.

I tried this instruction to generate a TXID for some sample tx messages, but i didn't find it in blockchain explorers.

  • The most common mistake many people do is hashing the serialized transaction as an encoded text rather than using the bytes that the hexadecimal represents.
    – Ugam Kamat
    Jun 22, 2019 at 8:27
  • @Ugam I open my pcap file with wireshark and copy tx message structure as hex stream. and then hash it twice.
    – Saeed
    Jun 22, 2019 at 11:33
  • follow the process that is mentioned in the question I have linked.
    – Ugam Kamat
    Jun 23, 2019 at 8:51
  • It will be easier to help you if you share the steps you took and the data you are hashing so it can be reproduced.
    – JBaczuk
    Jun 24, 2019 at 13:41
  • @Ugam Finally I completed my C++ program to calculate TXID with double hashing of TX data and after that reverse it. but sometimes generated TXID is not in some bitcoin explorers like blockchain.com. why some TXID's are found and some others not found?
    – Saeed
    Jul 1, 2019 at 6:18


Browse other questions tagged or ask your own question.