triam-base/src/signing.js

Low level triam network support library

//  This module provides the signing functionality used by the stellar network
//  The code below may look a little strange... this is because we try to provide
//  the most efficient signing method possible.  First, we try to load the 
//  native ed25519 package for node.js environments, and if that fails we
//  fallback to tweetnacl.js


var actualMethods = {};

/**
 * Use this flag to check if fast signing (provided by `ed25519` package) is available.
 * If your app is signing a large number of transaction or verifying a large number
 * of signatures make sure `ed25519` package is installed.
 */
export const FastSigning = checkFastSigning();

export function sign(data, secretKey) {
  return actualMethods.sign(data, secretKey);
}

export function verify(data, signature, publicKey) {
  return actualMethods.verify(data, signature, publicKey);
}

function checkFastSigning() {
  var ed25519Used;
  // if in node
  if (typeof window === 'undefined') {
    // NOTE: we use commonjs style require here because es6 imports
    // can only occur at the top level.  thanks, obama.
    let ed25519;
    try {
      ed25519 = require("ed25519");
      ed25519Used = true;
    } catch (err) {
      ed25519Used = false;
    }

    if (ed25519Used) {
      actualMethods.sign = function(data, secretKey) {
        data = new Buffer(data);
        return ed25519.Sign(data, secretKey);
      };

      actualMethods.verify = function(data, signature, publicKey) {
        data = new Buffer(data);
        try {
          return ed25519.Verify(data, signature, publicKey);
        } catch(e) {
          return false;
        }
      };
    }
  } else {
    ed25519Used = false;
  }

  if (!ed25519Used) {
    // fallback to tweetnacl.js if we're in the browser or
    // if there was a failure installing ed25519
    let nacl = require("tweetnacl");

    actualMethods.sign = function(data, secretKey) {
      data      = new Buffer(data);
      data      = new Uint8Array(data.toJSON().data);
      secretKey = new Uint8Array(secretKey.toJSON().data);

      let signature = nacl.sign.detached(data, secretKey);

      return new Buffer(signature);
    };

    actualMethods.verify = function(data, signature, publicKey) {
      data      = new Buffer(data);
      data      = new Uint8Array(data.toJSON().data);
      signature = new Uint8Array(signature.toJSON().data);
      publicKey = new Uint8Array(publicKey.toJSON().data);

      return nacl.sign.detached.verify(data, signature, publicKey);
    };
  }

  return ed25519Used;
}