Thanks for good summary of sidechains and a clear description of the proposed design. However I’m not sure I understand how fraud reports themselves are secure. Are they just Fraud Reports or Fraud Proofs? What if CCCert(i) is legit but CCCert(i+1) (fraudulently) flags it as fraud? Should there be any proof that the main chain could verify? Section 3.3.5 of the whitepaper doesn’t seem to answer this question.