I want to do all this on chain

Response
Doing zk-SNARKs fully on-chain on BSV is extremely ambitious, but not impossible with clever design—though it will face major limitations due to:

The lack of built-in zk cryptographic primitives in Bitcoin Script

Script size and opcode limits

Performance/memory constraints (verifying zk-SNARKs is expensive)



---

🧠 Here's what "fully on-chain zk-SNARK token on BSV" would require:

✅ GOAL:

All logic and proof generation + verification of zk-SNARKs occurs entirely inside BSV’s UTXO model, with no off-chain logic.


---

⚙️ 1. Use Precomputed Proofs + On-chain Verification

Since BSV doesn't natively support zk-SNARK verification like Ethereum does (with pairing opcodes), you need to simulate the verifier logic inside Bitcoin Script, which is minimal.

→ This means:

Embed proof data and verifier parameters inside the transaction

Build a custom zk verifier script using raw opcodes (like OP_ADD, OP_CHECKSIG, etc.)

Or, encode the zk verifier circuit as a Merkleized script and reveal paths via OP_IF branches


⚠️ Problem: zk verifiers require elliptic curve pairings, which are not supported natively in Bitcoin Script.
So this is basically not viable unless:

You redefine the zk circuit to use crypto primitives supported by Bitcoin (e.g., hash-based zk proofs like Bulletproofs, zk-STARKs over hashes)

Or build a custom SNARK circuit that outputs a commitment that Bitcoin can validate using existing ops (like SHA256 preimage or signature check)



---

🛠️ 2. Alternative Approach: SNARK-proof-as-script

One clever way:
Build your token protocol so that the zk-proof output becomes the unlocking script of the next token UTXO.

Flow:

1. You create a zk-proof that proves a valid token transfer


2. You embed the proof in the unlocking script


3. The locking script of the token enforces:

That the zk-proof is valid

That it commits to the right inputs/outputs




This approach turns the BSV UTXO model into a programmable privacy layer, where spending a token = p…