lovesh / cp-snark-bbs

Proof of concept of using Groth16 (LegoGroth16) with BBS+ using CP-SNARK construction

PoC of using LegoSNARK with BBS+

Using LegoGroth16, the cc-SNARK specified in the LegoSNARK paper, appendix H.5, to prove properties of messages signed in a BBS+ signature.

The cc-SNARK is here

Examples

Following tests demonstrate some potential use cases. Run the tests in release mode with --nocapture to see the time taken by proof generation and verification.

1. See test bound_check_message where a specific signed message is proven in some range, i.e. for public min and max, min < message < max. This will be useful in doing proof of age in a range.
2. See test bound_check_messages_sum where sum of specific signed messages is proven in some range, i.e. for public min and max, min < sum < max. This can be useful in proving that the sum of income sources is in a range.
3. See test compare_messages_sum where sum of certain signed messages from the 1st signature is proven less than the sum of certain signed messages from 2nd signature. This can be useful in proving sum of liabilities < sum of assets where liabilities and assets are signed under different signatures.