[feat] Validate relative locktime (BIP-68)

[m-kus]

Validate transaction inputs if relative locktime is enabled.

Hints:

• Introduce a new validate_input function

Reading:

• https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki
• https://learnmeabitcoin.com/technical/transaction/input/sequence/
• https://github.com/bitcoin/bitcoin/blob/master/src/consensus/tx_verify.cpp

Suggested deadline: 9 Sep

[mubarak23]

@m-kus i will like to take this,

The validate_input function checks the sequence field of a transaction's input to determine if a locktime is set. If a locktime is present, it means the transaction can't be mined until a specific block height or time is reached.

The function will then validate the locktime against the current block height or time. If the current block height or time is greater than or equal to the locktime, the input is considered valid for use in the next transaction.

since input sequence with tx_input.sequence < 0xFFFFFFFF mean the input of the transaction is not subject to locktime

for tx_input.sequence > 0xFFFFFFFF, mean the input of the transaction is subject to locktime,

having work on coinbase maturity #108 this should a continue of my work as i understand the existing transaction validation implementation.

[onlydustapp[bot]]

Hey @mubarak23! Thanks for showing interest. We've created an application for you to contribute to Raito - Bitcoin ZK Client. Go check it out on OnlyDust!

[ShantelPeters]

Please can I work on this?

[onlydustapp[bot]]

Hey @ShantelPeters! Thanks for showing interest. We've created an application for you to contribute to Raito - Bitcoin ZK Client. Go check it out on OnlyDust!

[mubarak23]

@m-kus from this function https://github.com/bitcoin/bitcoin/blob/d661e2b1b771abafb0b152842d775d3150032230/src/consensus/tx_verify.cpp#L39

if i understand the function above correctly,

if a transaction has locktime, we are to determine the minimum block height and time required to satisfy the relative lock-time constraints of a transaction

is this what the validate input function is suppose to do

as again checking to ensure the input's locktime is respected

[m-kus]

The keyword is relative

Check out https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki