I want to sign a message using the private key of my physical RSA digital certificate and I want to validate this signature onchain.

Does anyone know a lib that can sign messages offchain using the same version of ECDSA of Ethereum? The private key used to sign this message will be from my digital certificate.

It would be nicer if there is one in Javascript.

1 Answer 1


If you are using web3, you could easily sign any transactions or just messages: https://web3js.readthedocs.io/en/1.0/web3-eth-accounts.html#sign

If you don't want to use web3 (for example because you dont want to initialize with an ethereum endpoint), you can find some alternatives:

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