noir-rsa
This library contains an implementation of a RSA signature verify for the Noir language. RSA is one of the most widely used digital signature schemes in Web2 applications, such as DKIM email verification, TLS, message encryption etc
The repo contains 2 crates and 1 example circuit:
- rsa-biguint - Fork of shuklaayush's Noir BigInt v0.1.0 with additional functionality
- rsa - RSA signature verification library
- dkim - DKIM email verification circuit
RSA BigUint
Fork of v0.1.0 of Noir BigInt with the following updates:
- Updated constants for a max 2048 bit RSA. The BigInt lib only supports 5 limbs
- Added mulmod and powmod functions
- Use unconstrained division for powmod
RSA
Currently, Noir RSA supports pkcs1v15, sha256, max RSA modulus of 2048 bits and a max exponent value of 17 bits. Typical RSA modulus sizes are 512, 1024 and 2048 bits. And typically, 65537 is used as the public exponent (which is <2^17).
DKIM Verification
Verifies a email DKIM signature which signs an email header. The email header comprises of fields such as From, To, Subject and bh (hash of the email body encoded in base64). The circuit does the following:
- Decodes the base64 body hash
- Hash email body (in bytes) using sha256
- Compares the hash of the email body with the decoded base64 body hash
- Hash email header (in bytes) using sha256
- Verifies the RSA signature matches the public key and the hash of the email header
Installation
In your Nargo.toml file, add the following dependency:
[dependencies]
noir-rsa = { tag = "v0.1.0", git = "https://github.com/SetProtocol/noir-rsa" }
Usage
Running tests
For the RSA crate:
cd crates/rsa
nargo test --show-output
For the RSA biguint crate:
cd crates/rsa-biguint
nargo test --show-output
For the DKIM example
cd examples/dkim
nargo test --show-output
nargo compile
nargo execute
NOTE: The main branch only allows RSA bits up to 1024. This is due to proving time being significantly slower if you increase the BigInt limbs to support 2048 bit RSA. Currently proving time for 1024 bits takes ~45 min for the DKIM example. If you need to use a 2048 bit RSA, we support it in the richard/2048-rsa branch
Benchmarks
TODO
Ref
Disclaimer
This is experimental software and is provided on an "as is" and "as available" basis. We do not give any warranties and will not be liable for any losses incurred through any use of this code base.