Function crypto_sign_ed25519_sk_to_curve25519, from_string are not implemented

[kaladivo]

The function is exported by the library but it is not implemented. This is very confusing since the error is thrown when calling that function (even though it's exported)....

Might be a good idea to either not export it, or actually implement it.

I found a workaround, that can be used in the meantime:

function privateKeyToCurve25519Fallback(
  ed25519PrivateKey: Uint8Array
): Uint8Array {
  if (ed25519PrivateKey.length < 32) {
    throw new Error('Invalid Ed25519 private key length')
  }

  const hash = sha512(ed25519PrivateKey.subarray(0, 32))
  const curve25519PrivateKey = new Uint8Array(hash.subarray(0, 32))

  curve25519PrivateKey[0] &= 248
  curve25519PrivateKey[31] &= 127
  curve25519PrivateKey[31] |= 64

  return curve25519PrivateKey
}

The same is true for from_string functions.

again the workaround might simply be:

sodium.from_string(message) // THIS DOES NOT WORK
Buffer.from(message, 'utf-8') // THIS WORKS

[kaladivo]

This is problematic since I am using this library in monorepo where I share the same functions in node and react-native and I am switching libsodium-wrappers for react-native-libsodium in my metro config like so:

config.resolver.resolveRequest = (context, moduleName, platform) => {
  // Alias libsodium-wrappers to react-native-libsodium for shared packages
  if (moduleName === 'libsodium-wrappers') {
    return context.resolveRequest(context, 'react-native-libsodium', platform)
  }

  return context.resolveRequest(context, moduleName, platform)
}

[kaladivo]

I was using an old version. to_string function seems to work fine in react-native.

[nikgraf]

@kaladivo only a sub-set of functions is exported atm. The full list can be found in the readme here: https://github.com/serenity-kit/react-native-libsodium?tab=readme-ov-file#usage

That said I'm def open to PRs adding new function in case it also has a test (our tests run in app and by running them on web and mobile we can ensure they lead to correct results)