How is the previous transaction hash calculated?

Question

Can anyone provide a clear example on how to calculate a previous transaction hash?

Say I want to create a new transaction, I get that the hash is calculated by doubling sha256 a message m, but I'm having a hard time understanding the structure of m.

score 2 · Answer 1 · edited Apr 13 '17 at 12:47

2

You do not need to calculate previous transaction hash, because it is already known. To spend the previous output you just have to know

tx hash
output index in this tx
output value
output script

plus you should choose

fee
new address

then create some byte data and sign it with appropriate private key

Good manual you can find here: How to redeem a basic Tx?

edited Apr 13 '17 at 12:47

Community

1

answered Jul 31 '14 at 15:26

amaclin

6,760
1
21
32

score 0 · Answer 2 · answered Jul 31 '14 at 15:12

0

You hash the header. Format is here: https://en.bitcoin.it/wiki/Block_hashing_algorithm The body contains the transactions. Here's the Bitcoin transaction format: https://en.bitcoin.it/wiki/Transactions

answered Jul 31 '14 at 15:12

juhraffe

156
1

How is the previous transaction hash calculated?

2 Answers2