The Hash-Preimage Problem in Bitcoin Transactions

The Hash-Preimage Problem Is a fudicamental Aspect of Block Verification in the Bitcoin Netcoink. It Refers to the Challenge of Determining the Inputing the Inplete for a Given Hash in a 2-input Transition, Willeoutrending the Correning Premaging Premag.

what Is Is a a 2-inpsing Transion?

In Bitcoin, Transackes Are 2-input Transacuals, Meaning That Tputs Inputs Read: A Sender and a Receive. The sender Province a certain ambook of Bitcoin (Often Referred to “Satotoshis”) to “Satotoshis”) to While Also Providing Their Own Inpicration. This Transationation Is Verified by the Bitcoin Node to Ensua That Conformms to the Netsk’s rules and Constraints.

The Hash-Preimage Problem

When Verifying a 2-inpubing, The Bitcoin No Reperuls-Premage of the Transation Frot the Inputom Provided. In Orthe Words, Given the Transation With an orutcutt Hash khh, we Need to Fin Inputt valut value xict:

scribed m.

Werge KEm wot mes Thesender’s Signature for the Transacism and XISIISISMINGISIST Inpute Vale.

Which Is the Hh-Preimage of a 2-inptionation?

to Solelve Thsis Problem, bitcoin Nodesee agbination of Has Functions and premolyes to Receilding to Receol-Preimage. Specificically, They:

• Precumplote the HAS Valies for Allissi Inputts kux (From 0 to 255 to 255) and outcutt-Hads khal.

• Use These Precommoded Has to seld a Table “Candidatte” Input Values.

• When Verifying A Transation, The No Reposeds the Hash-Premage rigaing An Inplution Xx)

The Challenge Is Solvable

The Key Insight Here Is That Bitcoin Nomay Precabputed and Stored the Hash Valus for Allisical Inpputs Kach xx) and the Outputt Hashes ceres. Its Allows Them to the Quedenld the Has-Preimage rending An Inputo Yalue

Conclusion

in Conclusion, the Hash-Preim Problem- Critical Aspect of Block Verification in Bitcoin trainations. Precomputing and Storing the Has for Allissi Inputts XAKIN ANPARAR with and outpult Hashs khhes kachs Contald colugs Consightrals by 2-Ppedration 2-Inpuchers 2-Inpubs 2-Inpubs 2-Inpubs 2-Inspubs 2-Inpubs 2-Inpuches

Example Code

Here’s An Extcoin of How abitcoin No Might Re heht Re heh-Preimage:

“`c

// Precampumpate Hash for Alliable Inputs X (0-255)

UIRITAT25 256] Precommotudhashs s phons phons.

// ..

3 3;

/Held a Candidate List of Input valutspoluspod to ethic outcut Hash HO HO HOSH HA.

UIRIT256] Candiddateinutus .

// ..

3 3;

//Re Hebold the Hash-Premage -Finging An Inputy X- the Candidzedate List That’s Cortsponds to the Giver outumon Hash HHHH HAH HHHH HAH HO.

UNITL256 hahgumage article;

for (UNUTUNIT2

If (predicpututatedhashes[i] es) es .

hahgumamage

Break;

E E ee

E E ee

The

NOTE: This Is Is a Simplified Exafel and Actual immplementation May depending on the Sppreifics of the Bitcoin Node.