Ethereum: How to create the part in “scriptSig”?
Creation of the play Sig 'and" Pubkey ": unlocking of Ethereum transactions
When you receive an Ethereum transaction, it is divided into several components, including script data ("scriptsig") and public keys. Understanding how to extract these parts can help you decipher and check transactions.
In this article, we will focus on creating a part ofSig 'and "Pubkey" in the "Scriptsig" section of a transaction.
The Scriptsig section
The “Scriptsig” section is the first part of the script data in an Ethereum transaction. It contains the unlocking script, which determines how to derive the private key from the public keys used by the sender and the recipient.
A typical “scriptsig” section begins with the following format:
`Hex
0x
...
'
In your case, assuming that you have a private key in a paper portfolio and want to receive a transaction from someone, the "Scriptsig" section would look like this:
Hex
0x
'
Here:
is the public address of the sender.
- The part
unlocking_Scriptis the place where we will create our signature.
Creation of the signature
To create a “GIS”, you must calculate the signature using your private key. In Ethereum, the signature process consists in calculating the digestion of your private key, then comparing it to the expected signature.
Here is an example of how you can create a “GIS” in Solide, a popular programming language for smart contracts:
`Solidity
Pragma Solidity ^ 0.8,0;
UnlockingScript contract {
Createsignature function () Returns public to pay (bytes32) {
// Calculate the digest of the private key using Keccak-256 hash
bytes32 PrivateKeydigest = Keccak256 (abi.encode_packed (
4, // 4 bytes for the address and the key identifier
msg.sender.address,
msg.value // msg.value is not directly available in solidity, but we can use it as a space reserved for the moment.
));
// Create the signature using the digest of the private key
bytes32 Sig = Keccak256 (abi.encode_packed (
1, // 1 byte for nonce (we will define it at 0 initially)
PrivateKeydigest
));
Return Sig;
}
}
'
In this example:
- We calculate aprivate_key_digest ‘using the Hachage
Keccak-256' '' algorithm with the address and value of the sender.
- We create a signature by calculating an empty digest (using 1 byte for nonce) and comparing it to the digest of the expected private key.
Verification of the signature
To check the signature, you can compare it to the expected signature used in the transaction. In this case, we will use the sameunlocking_Scriptthat before:
Hex
0x
'
We will create a new signature using the private digest key and compare it to the expected signature:
Hex
bytes32 sig = 0x ...
Bool isvalidsignature () Returns of public view (Bool) {
Return Keccak256 (Abi.Ecode_Packed (
1, // 1 byte for nonce
sig
)) == bytes32 ("..." // digest of private key expected
));
}
` ‘
If the two signatures correspond, we can believe that the signature has been generated properly.
Conclusion
Solana When Wallet