Decrypting the Secret of ScriptSig Signatures
In cryptography, a script is a sequence of transactions that are transmitted and signed by the parties involved. One type of script used by Ethereum, known as a “ScriptSig”, contains a signature for each transaction it contains. However, when decrypted, the intent of these signatures can be unclear.
What makes ScriptSig signatures complicated?
A ScriptSig signature is constructed using the following components:
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Transaction hash: A hexadecimal representation of the input transaction.
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Data bytes: A variable-length array of 0x01 byte values used to create a hash (a sum of digits) of the script and append the transaction data to it.
Multiple signatures secret
A ScriptSig may appear to have more than one signature, which may appear to be a mistake or an error. However, this is not always the case. The reason for these “multiple” signatures is the way Ethereum stores and processes transactions.
When you create a transaction, its inputs (the data that will be used to create the script hash) are signed. These signature values are then combined with the transaction’s input data and stored as a ScriptSig value on the blockchain. In most cases, a single transaction can only have one signature.
Why do we need multiple signatures?
Multiple signatures are allowed for several reasons:
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Transaction verification: By using a signature from each of its inputs, Ethereum ensures that at least one transaction has been verified and accepted within a single transaction (i.e., within a single ScriptSig).
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Double-spend prevention
: If a transaction were to be spent twice on the same input data, two identical transactions would be created. Multiple signatures prevent this by ensuring that each transaction is verified independently.
What does it mean if a script has multiple signatures?
Typically, when you see “multiple signatures” or “more than one signature” in relation to ScriptSig values, it usually means that they are part of a larger transaction where two separate transactions share the same input but require independent verification.
To decrypt and verify the following transactions on Ethereum:
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Check the transaction hash
: Verify that it is correct.
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Check the script base: Verify that each signature value matches its corresponding input.
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Check multiple signatures: If you see more than one signature, make sure they are from different inputs and are properly combined.
Conclusion
In summary, while it may seem complicated at first glance, ScriptSig signatures on Ethereum serve a specific purpose. Multiple signatures are a result of the blockchain architecture, which ensures that transactions are independently verified by multiple parties. Understanding these complexities can help you better understand Ethereum transactions and scripts, even if they seem cryptic at first.
Additional Resources
To learn more, please explore the [Ethereum documentation on ScriptSig] (