RSA signature verification in Ethereum

Please first read this blog post explaining the landscape.

Good, so you are interested how this is done in practice. The high level description is explained in this EIP proposal.

You'll need the following pieces to try this out:

• browser-solidity with rsaverify support
• the attached rsaverify.sol for the wrapper in Solidity
• and a piece of Solidity code using it

Example code

import "https://github.com/axic/ethereum-rsa/rsaverify.sol";

contract Test {
  function test(bytes msg, bytes N, uint e, bytes S) returns (bool) {
    return RSAVerify.rsaverify(msg, N, e, S, 1);
  }
}

NOTE: as much as I like using libraries, the wrapper code breaks with delegatecall. For now you must resort to using rsaverify as an inherited contracted. Or just copy the code from rsaverify.sol into your project.

And then pass one of the following sample inputs:

1. 512 bit key

• msg: 0xcd8d103034f3796038d906de40faf3c3ba118a6b
• N: 0x00890e68c2485f2c725116f259a7ac871e1de3618dfc41e1df8eacc0131b2d433de6ed6d1f36bbf5a401d5afa32eeb2d444cf02a920c81f8088ba0b99d47a0bfdf
• e: 65537
• S: 0x77c6b0c53800d37b6b946df6d91a693c25b1ba97cac16879a10b3231a5cea0932a0bc16443b2e82b33ec155a61b29572a5faaf574152bd509a248fdb8ed9d7af
• paddingScheme: 1

2. 2048 bit key

• msg: 0x70dd0c1b74d12222bc1e5257bd8c2d45b816202c
• N: 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
• e: 65537
• S: 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
• paddingScheme: 1

Building ethereumjs-vm

1. Clone https://github.com/ethereumjs/browser-builds and change the ethereumjs-vm version in package.json to: git+https://github.com/axic/ethereumjs-vm#feature/rsaverify

2. Run ./build.sh

3. Take dist/ethereumjs-vm.js

Building browser-solidity

1. Follow the instructions in https://github.com/chriseth/browser-solidity about running it locally.

2. Replace assets/js/ethereumjs-vm.js with the one created in the previous process.

3. Congratulations, you now have a working environment.

The changed sources

• https://github.com/axic/ethereumjs-vm/tree/feature/rsaverify
• https://github.com/axic/ethereumjs-util/tree/feature/rsaverify

License

MIT License

Copyright (C) 2016 Alex Beregszaszi