Your Compute-Usage Receipt Can Be Cryptographically Signed and Still Be Forged. Here's the One Field That Actually Prevents It, From the Command Line.

Cryptographic signatures on compute-usage receipts do not guarantee the receipt's authenticity. If the signer's public key is included alongside the signed data, an attacker can replace that key with a different one, re-sign the receipt, and the verification will still pass. The key to preventing this forgery lies in including the public key as part of the signed payload itself, rather than providing it separately.

This ensures that any tampering with the public key would result in a mismatched hash, causing the verification to fail before the signature check even occurs. In the ComputeLedger project, they addressed this issue by hashing the entire payload, including the public key, before signing it. This design decision ensures that any attempt to alter the public key would invalidate the signature, thus preventing forgery.

The audit conducted on the ComputeLedger project revealed two minor bugs that had not been caught during development. The first bug was related to the ledger's ability to handle invalid JSON input, which could cause the entire system to crash. The second bug was a failure to validate certain input fields properly, leading to unexpected stack traces.

Both issues were addressed during a security-focused audit of the finished implementation, highlighting the importance of thorough testing and review in software development.