Merge pull request #15 from dekentz/dekentz

Add VrfOracleContract verify vrf proof

Author: klembee

2-oracles/vrf-oracle-dekentz/.env

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+tokenXRD=030000000000000000000000000000000000000000000000000004
+act=020d3869346218a5e8deaaf2001216dc00fcacb79fb43e30ded79a
+package=0159481154fa6bb76f5eb4fefc5f2d89b0f696e4376cd3236d30bc
+vrf=02085265d2d8592f199f25c9293e4b00acc6e04906e2151ff410ef
+r1=037be68f1cb8b2ec3bd934c5468063b610e5a459e958aafb396187
+r2=032897ddec0cb69de990a1d1de0062e1c40aa409fe498f068c3b91
+receiptaddr=03accb60143e35c60880d56ef19a27e1be5e24557433c2133e1e7d

2-oracles/vrf-oracle-dekentz/Cargo.toml

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+[package]
+name = "vrf-oracle-dekentz"
+version = "0.1.0"
+edition = "2021"
+authors = ["dekentz"]
+
+[dependencies]
+sbor = { git = "https://github.com/radixdlt/radixdlt-scrypto", tag = "v0.4.0" }
+scrypto = { git = "https://github.com/radixdlt/radixdlt-scrypto", tag = "v0.4.0" }
+p256 = { git = "https://github.com/radixdlt/elliptic-curves", branch = "alloc", default-features = false, features = ["hash2curve", "arithmetic"] }
+thiserror = "1.0.31"
+sha2 = "^0.10"
+hex = "0.4.3"
+
+[dev-dependencies]
+radix-engine = { git = "https://github.com/radixdlt/radixdlt-scrypto", tag = "v0.4.0" }
+
+[profile.release]
+opt-level = 's'     # Optimize for size.
+lto = true          # Enable Link Time Optimization.
+codegen-units = 1   # Reduce number of codegen units to increase optimizations.
+panic = 'abort'     # Abort on panic.
+strip = "debuginfo" # Strip debug info.
+
+[lib]
+crate-type = ["cdylib", "lib"]

2-oracles/vrf-oracle-dekentz/README.md

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+# VRF Oracle
+
+- This implementation of VRF follows the [draft-irtf-cfrg-vrf-11](https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-vrf-11) publication. This publication is an updated version of the VRF implementation that the [Chainlink VRF v1](https://github.com/smartcontractkit/chainlink/blob/ff56c1657a48bb7f9782e407412b4e5aa10ff2fc/contracts/src/v0.6/VRF.sol#L6) uses. Version 12 was released on May 26th, 2022, right before the deadline of the Scrypto Oracle submissions challenge, and the implementation in this repo has not yet been updated to use the most current draft publication.
+- This implementation uses the NistP256 curve as this is the curve that the publication has the most details regarding the VRF implementation, specifically encoding random input seeds to points on the P256 curve, a required step in generating proofs. This curve is also the the curve with the most support for the required VRF ECC math in the Rust elliptic-curves [p256](https://docs.rs/p256/latest/p256/#) crate.
+- This model follows the the architecture where a random number requestor will request a random number from a VrfOracleContract component, which returns a receipt badge. The requestor will then need to fetch the result of the random number generation from the VrfOracleContract component at a later time. The VrfOracle internally verifies the proof that it receives from the off-chain oracle VRF prover, so the random number requestor may directly use the returned random bytes.
+
+# Usage
+
+For a VRF oracle operator, the process is as follows:
+
+1. Generate Nist P256 elliptical curve public/private key pair that you will be using in the off-chain oracle VRF prover.
+2. Instantiate your on-chain component using the VrfOracleContract::new() method, providing it the public key from above as a string of hex characters.
+3. Have the off-chain oracle node subscribe random number requests made by consumers to the VrfOracleContract::request_randomness() method.
+4. In the off-chain oracle, generate VRF proofs for the requested input seeds and submit the VRF proof on-chain using the VrfOracleContract::fullfill_randomness_request() method.
+
+For a random number requestor/consumer, the process is as follows:
+
+1. Identify a VRF Oracle Contract component that an oracle operator is running.
+2. Call the request_randomness method with a payment of (TBD) XRD. (For the sake of the challenge submission, the amount is anything you want, there are no checks.) The method will return a receipt badge of your random number request.
+3. At a later point in time, call the fetch_randomness method with your receipt badge. If the off-chain oracle correctly serviced your request with a valid proof, then the method will return a vector of random bytes. The badge will be burnt, as all random numbers are one time use.
+
+Example usage can be seen in the vrf_verify.rev revup script. 
+
+# Verification of implementation
+
+The implementation is verified with unit tests using the [provided test vectors and examples](https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-vrf-11#appendix-A.2) in the publication.