The hash of a transaction ‘s data .

A TXID ( Transaction ID ) is basically an recognition number for a bitcoin transaction .


  • f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16 – First ever Bitcoin transaction to Hal Finney in 2010.
  • a1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d – Pizza transaction for 10,000 BTC in 2010.
  • 4ce18f49ba153a51bcda9bb80d7f978e3de6e81b5fc326f00465464530c052f4 – The transaction containing the first donation I received for making this website.

A TXID is constantly 32 bytes ( 64 characters ) and hexadecimal .

Creating a TXID

You get a TXID by hashing transaction data through SHA256 doubly.

Reading: TXID


169e1e83e930853391bc6f35f605c6754cfead57cf8387639d3b4096c54f18f4   (Note: reverse the byte order first if you want to find this transaction in the blockchain…)

Searching for TXIDs in the blockchain.

If you ’ ve just hashed some transaction data and want to search for a TXID in the blockchain, you have to search for it in reverse byte order .

txid (original):  169e1e83e930853391bc6f35f605c6754cfead57cf8387639d3b4096c54f18f4
txid (searching): f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16


Because welcome to Bitcoin .

due to historical accident, the texas and block hashes that bitcoin congress of racial equality uses are byte-reversed. I ’ meter not entirely certain why. May be something like using openssl bignum to store hashes or something like that, then printing them as a count. – Wladimir van five hundred Laan ( Bitcoin Core developer )

In early words, this was a little oversight in the early development of Bitcoin that has now become a standard .

Where are TXIDs used?

1. Searching the blockchain.

If you ’ ve just made a transaction, you can use the TXID to find it in the blockchain. For case :

 bitcoin-cli getrawtransaction 0e3e2357e806b6cdb1f70b54c3a3a17b6714ee1f0e68bebb44a74b1efd512098 getrawtransaction 0e3e2357e806b6cdb1f70b54c3a3a17b6714ee1f0e68bebb44a74b1efd512098

The console window in the Bitcoin Core Wallet
If you have been given a TXID by your bitcoin wallet, it ’ second credibly already in its “ searchable ” format ( reverse byte order ) .

2. Spending outputs.

You use a TXID when you want to use an existing output as an remark in a new transaction .
To refer to an existing output, you use the txid it was created in, along with the vout number for that transaction.

Because after all, a TXID is a alone identifier 1 for a transaction.


Why hash twice? Why not once?

Things frequently get hashed twice in bitcoin for super-extra security .

SHA-256 ( SHA-256 ( x ) ) was proposed by Ferguson and Schneier in their excellent book “ Practical Cryptography ” ( by and by updated by Ferguson, Schneier, and Kohno and renamed “ Cryptography Engineering ” ) as a way to make SHA-256 invulnerable to “ length-extension ” attack. They called it “ SHA-256d ”. –

hypertext transfer protocol : //crypto.stackexchange.com/questions/779/hashing-or-encrypting-twice-to-increase-security/884 # 884

Hash functions like SHA256 are great for creating recognition numbers, because they will take in any string of data and constantly spit out a brusque so far unique result .

generator : https://www.peterswar.net
Category : Finance

Related Posts

How to Calculate Credit Card Interest Rates

interest rates are one of the ways to work out how much it will cost you to use your credit card, along with other charges and fees….

What debt collectors can & cannot do

If you are dealing with a debt collector, you have protections under the law. A debt collector must not mislead, harass, coerce or act unconscionably towards you….

Can You Afford a New Home? How to Determine Your Homebuying Budget

Can You Afford a New Home? How to Determine Your Homebuying Budget As with any major purchase, determining what you can afford before you look for a…

Why Did My Credit Score Drop?

Why Did My Credit Score Go Down When Nothing Changed? sometimes your mark does change based on factors outside of your control, but most times your behavior…

Why Do I Owe Taxes To The IRS & How To Avoid Them

Are you wondering why you owe indeed much in taxes this year ? Want to make certain you never owe a big tax bill – or any…

The 5 reasons why your credit score might suddenly drop

Select ’ s editorial team works independently to review fiscal products and write articles we think our readers will find useful. We earn a perpetration from affiliate…