initial library config

lib/eth.ex

@@ -1,5 +1,5 @@
 require IEx
-# elliptic curve cryptography library for Ethereum
+# elliptic curve cryptography library for signing transactions in Ethereum
 defmodule ETH do
   @moduledoc """
   Documentation for Eth.
@@ -15,13 +15,17 @@ defmodule ETH do
 
   """
 
+  def get_private_key do
+    :crypto.strong_rand_bytes(32)
+  end
+
   def private_key_to_address(<< private_key :: binary-size(32) >>) do
     private_key
-    |> private_key_to_public_key()
+    |> get_public_key()
     |> public_key_to_address()
   end
 
-  def private_key_to_public_key(<< private_key :: binary-size(32) >>) do
+  def get_public_key(<< private_key :: binary-size(32) >>) do
     {public_key, ^private_key} = :crypto.generate_key(:ecdh, :secp256k1, private_key)
     public_key
   end
@@ -31,6 +35,24 @@ defmodule ETH do
     address
   end
 
+  def sign_transaction(
+    source_wallet, value, target_wallet, options \\ [gas_price: 100, gas_limit: 1000, data: "", chain_id: 3]
+  ) do
+    gas_price = options.gas_price |> Hexate.encode
+    gas_limit = options.gas_limit |> Hexate.encode
+    data = data |> Hexate.encode
+
+    Ethereumex.HttpClient.eth_get_transaction_count([first[:eth_address]]) |> elem(1) |> Map.get("result")
+
+    # NOTE: calc nonce
+    %{
+      to: target_wallet[:eth_address], value: Hexate.encode(value), gas_price: gas_price,
+      gas_limit: gas_limit, data: data, chain_id: 3
+    }
+    # get nonce and make a transaction map -> sign_transaction -> send it to client
+  end
+
+
   def sign_transaction(transaction, private_key) do # must have chain_id
     hash = hash_transaction(transaction)
     decoded_private_key = Base.decode16!(private_key, case: :lower)
@@ -49,7 +71,8 @@ defmodule ETH do
   def adjust_v_for_chain_id(transaction) do
     if transaction.chain_id > 0 do
       current_v_bytes = Base.decode16!(transaction.v, case: :lower) |> :binary.decode_unsigned
-      transaction |> Map.merge(%{v: encode16(<< current_v_bytes + (transaction.chain_id * 2 + 8) >>) })
+      target_v_bytes = current_v_bytes + (transaction.chain_id * 2 + 8)
+      transaction |> Map.merge(%{v: encode16(<< target_v_bytes >>) })
     else
       transaction
     end
@@ -62,6 +85,7 @@ defmodule ETH do
 
   # must have [nonce, gasPrice, gasLimit, to, value, data] # and chainId inside the transaction?
   def hash_transaction(transaction) do
+    # NOTE: if transaction is decoded no need to encode
     # EIP155 spec:
     # when computing the hash of a transaction for purposes of signing or recovering,
     # instead of hashing only the first six elements (ie. nonce, gasprice, startgas, to, value, data),

lib/eth/wallet.ex

@@ -0,0 +1,32 @@
+defmodule ETH.Wallet do
+  def create(private_key \\ :crypto.strong_rand_bytes(32)) do # pattern match on the base16 version as well
+    {public_key, _} = :crypto.generate_key(:ecdh, :secp256k1, private_key)
+    << 4 :: size(8), key :: binary-size(64) >> = public_key
+    << _ :: binary-size(12), address :: binary-size(20) >> = keccak256(key)
+
+    %{private_key: Base.encode16(private_key), public_key: Base.encode16(public_key),
+      eth_address: "0x#{Base.encode16(address)}"}
+  end
+
+  # def get_public_key(<< private_key :: binary-size(32) >>) do
+  #   {public_key, ^private_key} = :crypto.generate_key(:ecdh, :secp256k1, private_key)
+  #   public_key
+  # end
+  #
+  # def private_key_to_address(<< private_key :: binary-size(32) >>) do
+  #   private_key
+  #   |> get_public_key()
+  #   |> public_key_to_address()
+  # end
+  #
+  # def public_key_to_address(<< 4 :: size(8), key :: binary-size(64) >>) do
+  #   << _ :: binary-size(12), address :: binary-size(20) >> = keccak256(key)
+  #   address
+  # end
+
+  def balance do
+    # Ethereumex
+  end
+
+  defp keccak256(data), do: :keccakf1600.hash(:sha3_256, data)
+end

mix.exs

@@ -7,7 +7,8 @@ defmodule Eth.Mixfile do
       version: "0.1.0",
       elixir: "~> 1.5",
       start_permanent: Mix.env == :prod,
-      deps: deps()
+      deps: deps(),
+      package: package
     ]
   end
 
@@ -24,7 +25,27 @@ defmodule Eth.Mixfile do
       {:libsecp256k1, [github: "mbrix/libsecp256k1", manager: :rebar]},
       {:keccakf1600, git: "https://github.com/jur0/erlang-keccakf1600", branch: "original-keccak"},
       {:ex_rlp, "~> 0.2.1"},
-      {:hexate, "~> 0.6.1"}
+      {:hexate, "~> 0.6.1"},
+      {:ethereumex, "~> 0.1.0"}
+    ]
+  end
+
+  defp description do
+     """
+     Ethereum utilities for Elixir.
+     """
+  end
+
+  def package do
+    [
+      name: :eth,
+      files: ["lib", "mix.exs", "README*", "LICENSE*"],
+      maintainers: ["Izel Nakri"],
+      licenses: ["MIT License"],
+      links: %{
+        "GitHub" => "https://github.com/izelnakri/eth",
+        "Docs" => "https://hexdocs.pm/eth/ETH.html"
+      }
     ]
   end
 end

test/eth_test.exs

@@ -37,7 +37,7 @@ defmodule ETHTest do
     assert ETH.secp256k1_signature(hash, private_key)[:signature] |> Base.encode16(case: :lower) == target_signature
   end
 
-  test "hash_transaction\2 works" do
+  test "hash_transaction/2 works" do
     result = ETH.hash_transaction(@first_example_transaction) |> Base.encode16(case: :lower)
     target_digest = "df2a7cb6d05278504959987a144c116dbd11cbdc50d6482c5bae84a7f41e2113"
     assert result == target_digest