A safe way to remove objectionable content from the blockchain

The proposal introduces a novel mechanism to prevent the embedding of arbitrary data within public keys by leveraging the unique hash-to-curve output of a publicly verifiable BLS root signature, moving away from the traditional user-selected points on the secp256k1 curve. This approach ensures that each public key is deterministically generated from the root certificate, eliminating the possibility of using the key as a covert channel for steganography. The process involves establishing a fixed BLS12-381 public key (PK_root) and generating a one-time BLS signature (σ = Sign_root(S)). Subsequent secp256k1 keys are derived through a standardized hash-to-curve map (e.g., IETF RFC 9380), applying the signature and an arbitrary index (i) as inputs. This method allows verifiers to confirm the legitimacy of a public key by checking if its curve point matches the expected hash-to-curve output for any given index, thus ensuring the key's integrity without the need for continuous verification.

This system aligns with existing cryptographic research aimed at thwarting steganographic misuse in public-key infrastructures, drawing parallels with concepts of forced randomness and extractable commitments previously discussed in academic literature. By removing the sender's ability to choose specific curve points, and by utilizing hash-to-curve techniques to limit the available entropy, the proposed method addresses the concerns of non-malleability and covert information storage highlighted in works by Hopper–Langford–von Ahn on secure steganography and Bellare–Ristenpart–Tessaro on channel indistinguishability. This ensures that public keys cannot be exploited as hidden channels for unauthorized data transmission, reinforcing the security and integrity of cryptographic communications systems.