did:key generation

.gitignore

@@ -24,3 +24,4 @@ hexpds-*.tar
 
 # Temporary files, for example, from tests.
 /tmp/
+priv/native/libhexpds_k256.so

lib/hexpds/didgenerator.ex

@@ -1,20 +1,33 @@
 defmodule Hexpds.DidGenerator do
   require Logger
   alias :crypto, as: Crypto
-  alias ExSecp256k1, as: Secp256k1
+  alias Hexpds.K256, as: K256
 
   def generate_private_key(), do: Crypto.strong_rand_bytes(32)
 
   @spec get_public_key(binary()) :: binary() | {:error, String.t()}
   def get_public_key(privkey) when is_binary(privkey) and byte_size(privkey) == 32 do
-    case(Secp256k1.create_public_key(privkey)) do
+    case(K256.create_public_key(privkey)) do
       {:ok, pubkey} -> pubkey
-      _ -> {:error, "Invalid private key"}
+      _ -> raise "Error generating public key"
     end
   end
 
-  def create_did_web_pubkey(pubkey) do
-    # Convert public key to the required format and encode
+  @spec multicodec_encode(binary(), :"secp256k1-pub") :: <<_::16, _::_*8>>
+  def multicodec_encode(pubkey, :"secp256k1-pub") do
+    <<0xE7, 0x01, pubkey::binary>>
+  end
+
+  @spec create_public_did_key(binary()) :: String.t()
+  def create_public_did_key(pubkey) do
+    "did:key:" <>
+      (case pubkey |> K256.compress_public_key() do
+         {:ok, pubkey} -> pubkey
+         _ -> raise "Error compressing public key"
+       end
+       |> Base.decode16!(case: :lower)
+       |> multicodec_encode(:"secp256k1-pub")
+       |> Multibase.encode!(:base58_btc))
   end
 
   def sign_genesis(genesis, privkey) do

lib/hexpds/k256.ex

@@ -0,0 +1,5 @@
+defmodule Hexpds.K256 do
+  use Rustler, otp_app: :hexpds, crate: "hexpds_k256"
+    def create_public_key(private_key), do: :erlang.nif_error(:nif_not_loaded)
+    def compress_public_key(public_key), do: :erlang.nif_error(:nif_not_loaded)
+end

mix.exs

@@ -27,9 +27,10 @@ defmodule Hexpds.MixProject do
       {:cbor, "~> 1.0.0"},
       {:jason, "~> 1.4"},
       {:ex_doc, "~> 0.28.0", only: :dev, runtime: false},
-      {:ex_secp256k1, "~> 0.7.2"},
       {:multibase, "~> 0.0.1"},
       {:ex_multihash, "~> 2.0.0"},
+      {:rustler, "~> 0.30.0"},
+      {:toml, "~> 0.7.0"}
     ]
   end
 end

mix.lock

@@ -2,13 +2,19 @@
   "base1": {:hex, :base1, "0.1.0", "493a46bb5b34bf38d3b69ea6eaff33416d222f1621231cb1a04af42a351117ea", [:mix], [], "hexpm", "57cb13fe05f3dc4174c7fbca147b94dcfdceea1ce87fdd5f803a29d3ca75fc96"},
   "base2": {:hex, :base2, "0.1.0", "bc9e19f1578e1439010d26b1bee456f3ac980481a46c3643b24e15c40e1db0ed", [:mix], [], "hexpm", "a25eb2892e03f609fd5634aaf9a7795fb90f98dc9a7a495ed8c03b2844bbb647"},
   "basefiftyeight": {:hex, :basefiftyeight, "0.1.0", "3d48544743bf9aab7ab02aed803ac42af77acf268c7d8c71d4f39e7fa85ee8d3", [:mix], [], "hexpm", "af12f551429528c711e98628c029ad48d1e5ba5a284f40b2d91029a65381837a"},
+  "bitcoinex": {:hex, :bitcoinex, "0.1.7", "2357049df10ba79e701138481692326863553476fd902c1c5a6e918d7f93b721", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}], "hexpm", "06f2d2c84b98ada2cf87106e54b7cc309497281f2bbf601e86b8528cfbd6e9fd"},
   "castore": {:hex, :castore, "1.0.5", "9eeebb394cc9a0f3ae56b813459f990abb0a3dedee1be6b27fdb50301930502f", [:mix], [], "hexpm", "8d7c597c3e4a64c395980882d4bca3cebb8d74197c590dc272cfd3b6a6310578"},
   "cbor": {:hex, :cbor, "1.0.1", "39511158e8ea5a57c1fcb9639aaa7efde67129678fee49ebbda780f6f24959b0", [:mix], [], "hexpm", "5431acbe7a7908f17f6a9cd43311002836a34a8ab01876918d8cfb709cd8b6a2"},
   "certifi": {:hex, :certifi, "2.12.0", "2d1cca2ec95f59643862af91f001478c9863c2ac9cb6e2f89780bfd8de987329", [:rebar3], [], "hexpm", "ee68d85df22e554040cdb4be100f33873ac6051387baf6a8f6ce82272340ff1c"},
+  "combine": {:hex, :combine, "0.10.0", "eff8224eeb56498a2af13011d142c5e7997a80c8f5b97c499f84c841032e429f", [:mix], [], "hexpm", "1b1dbc1790073076580d0d1d64e42eae2366583e7aecd455d1215b0d16f2451b"},
+  "csv": {:hex, :csv, "2.5.0", "c47b5a5221bf2e56d6e8eb79e77884046d7fd516280dc7d9b674251e0ae46246", [:mix], [{:parallel_stream, "~> 1.0.4 or ~> 1.1.0", [hex: :parallel_stream, repo: "hexpm", optional: false]}], "hexpm", "e821f541487045c7591a1963eeb42afff0dfa99bdcdbeb3410795a2f59c77d34"},
+  "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.39", "424642f8335b05bb9eb611aa1564c148a8ee35c9c8a8bba6e129d51a3e3c6769", [:mix], [], "hexpm", "06553a88d1f1846da9ef066b87b57c6f605552cfbe40d20bd8d59cc6bde41944"},
   "ex_doc": {:hex, :ex_doc, "0.28.6", "2bbd7a143d3014fc26de9056793e97600ae8978af2ced82c2575f130b7c0d7d7", [:mix], [{:earmark_parser, "~> 1.4.19", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "bca1441614654710ba37a0e173079273d619f9160cbcc8cd04e6bd59f1ad0e29"},
   "ex_multihash": {:hex, :ex_multihash, "2.0.0", "7fb36f842a2ec1c6bbba550f28fcd16d3c62981781b9466c9c1975c43d7db43c", [:mix], [], "hexpm", "66a08a86a1ba00d95736c595d7975696e5691308cdf7770c50b0f84a2a1172b0"},
   "ex_secp256k1": {:hex, :ex_secp256k1, "0.7.2", "33398c172813b90fab9ab75c12b98d16cfab472c6dcbde832b13c45ce1c01947", [:mix], [{:rustler, ">= 0.0.0", [hex: :rustler, repo: "hexpm", optional: true]}, {:rustler_precompiled, "~> 0.6", [hex: :rustler_precompiled, repo: "hexpm", optional: false]}], "hexpm", "f3b1bf56e6992e28b9d86e3bf741a4aca3e641052eb47d13ae4f5f4d4944bdaf"},
+  "expo": {:hex, :expo, "0.5.1", "249e826a897cac48f591deba863b26c16682b43711dd15ee86b92f25eafd96d9", [:mix], [], "hexpm", "68a4233b0658a3d12ee00d27d37d856b1ba48607e7ce20fd376958d0ba6ce92b"},
+  "gettext": {:hex, :gettext, "0.24.0", "6f4d90ac5f3111673cbefc4ebee96fe5f37a114861ab8c7b7d5b30a1108ce6d8", [:mix], [{:expo, "~> 0.5.1", [hex: :expo, repo: "hexpm", optional: false]}], "hexpm", "bdf75cdfcbe9e4622dd18e034b227d77dd17f0f133853a1c73b97b3d6c770e8b"},
   "hackney": {:hex, :hackney, "1.20.1", "8d97aec62ddddd757d128bfd1df6c5861093419f8f7a4223823537bad5d064e2", [:rebar3], [{:certifi, "~> 2.12.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~> 6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~> 1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~> 1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.4.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~> 1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "fe9094e5f1a2a2c0a7d10918fee36bfec0ec2a979994cff8cfe8058cd9af38e3"},
   "httpoison": {:hex, :httpoison, "1.8.2", "9eb9c63ae289296a544842ef816a85d881d4a31f518a0fec089aaa744beae290", [:mix], [{:hackney, "~> 1.17", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm", "2bb350d26972e30c96e2ca74a1aaf8293d61d0742ff17f01e0279fef11599921"},
   "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},
@@ -20,10 +26,17 @@
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "monad": {:hex, :monad, "1.0.5", "bd02263a8dad0894433ca3283ebb6f71a55799e1cd17bda1e8b2ea9e14eeb9c5", [:mix], [], "hexpm", "d8ebe20971160e96bd6cdf11b5e8b5c24b70fddde3d198e5f7c3b5ebfbc78d6e"},
   "multibase": {:hex, :multibase, "0.0.1", "9243bebe6f7f0f9f873c770ddcddab285cc554a8dd2374b8de6b2add087eccbc", [:mix], [{:base1, "~> 0.1.0", [hex: :base1, repo: "hexpm", optional: false]}, {:base2, "~> 0.1.0", [hex: :base2, repo: "hexpm", optional: false]}, {:basefiftyeight, "~> 0.1.0", [hex: :basefiftyeight, repo: "hexpm", optional: false]}, {:zbase32, "~> 2.0.0", [hex: :zbase32, repo: "hexpm", optional: false]}], "hexpm", "6ea13a19e47da727c2def81b241ad10a39440c5705a4abed18e8310b46f45f51"},
+  "multicodec": {:git, "https://github.com/ShreyanJain9/ex-multicodec.git", "7570cd559691e414a67223e9e8a7fd4ad2d7549b", [branch: "master"]},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
+  "parallel_stream": {:hex, :parallel_stream, "1.1.0", "f52f73eb344bc22de335992377413138405796e0d0ad99d995d9977ac29f1ca9", [:mix], [], "hexpm", "684fd19191aedfaf387bbabbeb8ff3c752f0220c8112eb907d797f4592d6e871"},
   "parse_trans": {:hex, :parse_trans, "3.4.1", "6e6aa8167cb44cc8f39441d05193be6e6f4e7c2946cb2759f015f8c56b76e5ff", [:rebar3], [], "hexpm", "620a406ce75dada827b82e453c19cf06776be266f5a67cff34e1ef2cbb60e49a"},
+  "rustler": {:hex, :rustler, "0.30.0", "cefc49922132b072853fa9b0ca4dc2ffcb452f68fb73b779042b02d545e097fb", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:toml, "~> 0.6", [hex: :toml, repo: "hexpm", optional: false]}], "hexpm", "9ef1abb6a7dda35c47cfc649e6a5a61663af6cf842a55814a554a84607dee389"},
   "rustler_precompiled": {:hex, :rustler_precompiled, "0.7.1", "ecadf02cc59a0eccbaed6c1937303a5827fbcf60010c541595e6d3747d3d0f9f", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:rustler, "~> 0.23", [hex: :rustler, repo: "hexpm", optional: true]}], "hexpm", "b9e4657b99a1483ea31502e1d58c464bedebe9028808eda45c3a429af4550c66"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.7", "354c321cf377240c7b8716899e182ce4890c5938111a1296add3ec74cf1715df", [:make, :mix, :rebar3], [], "hexpm", "fe4c190e8f37401d30167c8c405eda19469f34577987c76dde613e838bbc67f8"},
+  "timex": {:hex, :timex, "3.7.11", "bb95cb4eb1d06e27346325de506bcc6c30f9c6dea40d1ebe390b262fad1862d1", [:mix], [{:combine, "~> 0.10", [hex: :combine, repo: "hexpm", optional: false]}, {:gettext, "~> 0.20", [hex: :gettext, repo: "hexpm", optional: false]}, {:tzdata, "~> 1.1", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm", "8b9024f7efbabaf9bd7aa04f65cf8dcd7c9818ca5737677c7b76acbc6a94d1aa"},
+  "toml": {:hex, :toml, "0.7.0", "fbcd773caa937d0c7a02c301a1feea25612720ac3fa1ccb8bfd9d30d822911de", [:mix], [], "hexpm", "0690246a2478c1defd100b0c9b89b4ea280a22be9a7b313a8a058a2408a2fa70"},
+  "tzdata": {:hex, :tzdata, "1.1.1", "20c8043476dfda8504952d00adac41c6eda23912278add38edc140ae0c5bcc46", [:mix], [{:hackney, "~> 1.17", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm", "a69cec8352eafcd2e198dea28a34113b60fdc6cb57eb5ad65c10292a6ba89787"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
+  "varint": {:hex, :varint, "1.4.0", "b7405c8a99db7b95d4341fa9cb15e7c3af6c8dda43e21bbe1c4a9cdff50b6502", [:mix], [], "hexpm", "0fd461901b7120c03467530dff3c58fa3475328fd75ba72c7d3cbf13bce6b0d2"},
   "zbase32": {:hex, :zbase32, "2.0.0", "5a61d5ee8f39092d4a243da2a42b5b4339ef226d9b182603f63d5a3f16d192ee", [:mix], [], "hexpm", "798f81895658f9773e1dcf30ba3c118547f482502c5e1e19e72752f9a6f23e44"},
 }

native/hexpds_k256/.cargo/config.toml

@@ -0,0 +1,5 @@
+[target.'cfg(target_os = "macos")']
+rustflags = [
+    "-C", "link-arg=-undefined",
+    "-C", "link-arg=dynamic_lookup",
+]

native/hexpds_k256/.gitignore

@@ -0,0 +1,14 @@
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb

native/hexpds_k256/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "hexpds_k256"
+version = "0.1.0"
+authors = [ "NetWatchInc" ]
+edition = "2021"
+
+[lib]
+name = "hexpds_k256"
+path = "src/lib.rs"
+crate-type = ["cdylib"]
+
+[dependencies]
+atoms = "2.2.3"
+elliptic-curve = "0.13.8"
+hex = "0.4.3"
+k256 = "0.13.3"
+rustler = "0.30.0"

native/hexpds_k256/README.md

@@ -0,0 +1,20 @@
+# NIF for Elixir.Hexpds.k256
+
+## To build the NIF module:
+
+- Your NIF will now build along with your project.
+
+## To load the NIF:
+
+```elixir
+defmodule Hexpds.K256 do
+  use Rustler, otp_app: :hexpds, crate: "hexpds_k256"
+
+  # When your NIF is loaded, it will override this function.
+  def create_public_key(private_key), do: :erlang.nif_error(:nif_not_loaded)
+end
+```
+
+## Examples
+
+[This](https://github.com/rusterlium/NifIo) is a complete example of a NIF written in Rust.

native/hexpds_k256/src/lib.rs

@@ -0,0 +1,44 @@
+use rustler::{Binary, Encoder, Env, Term};
+use k256::{elliptic_curve::sec1::ToEncodedPoint, PublicKey, SecretKey};
+use hex;
+
+mod atoms {
+    rustler::atoms! {
+        ok,
+        error,
+    }
+}
+
+#[rustler::nif]
+fn create_public_key<'a>(env: Env<'a>, private_key: Binary<'a>) -> Term<'a> {
+
+    let secret_key = match SecretKey::from_slice(&private_key) {
+        Ok(key) => key,
+        Err(e) => return (atoms::error(), format!("Failed to create secret key: {}", e)).encode(env),
+    };
+
+    let public_key = secret_key.public_key();
+
+    let public_key_hex = hex::encode(public_key.to_encoded_point(false).as_bytes());
+
+    (atoms::ok(), public_key_hex).encode(env)
+}
+
+#[rustler::nif]
+fn compress_public_key<'a>(env: Env<'a>, public_key: Binary<'a>) -> Term<'a> {
+    let public_key = match hex::decode(public_key.as_slice()) {
+        Ok(key) => key,
+        Err(e) => return (atoms::error(), format!("Failed to decode hex string: {}", e)).encode(env),
+    };
+
+    let public_key = match PublicKey::from_sec1_bytes(&public_key) {
+        Ok(key) => key,
+        Err(e) => return (atoms::error(), format!("Failed to parse public key: {}", e)).encode(env),
+    };
+
+    let compressed_key = hex::encode(public_key.to_encoded_point(true).as_bytes());
+    (atoms::ok(), compressed_key).encode(env)
+}
+
+rustler::init!("Elixir.Hexpds.K256", [create_public_key, compress_public_key]);
+

test/hexpds_didgenerator_test.exs

@@ -0,0 +1,28 @@
+defmodule HexpdsDidGeneratorTest do
+  use ExUnit.Case
+  doctest Hexpds.DidGenerator
+
+  defp test_cases do
+    %{
+      "9085d2bef69286a6cbb51623c8fa258629945cd55ca705cc4e66700396894e0c" =>
+        "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme",
+      "f0f4df55a2b3ff13051ea814a8f24ad00f2e469af73c363ac7e9fb999a9072ed" =>
+        "did:key:zQ3shtxV1FrJfhqE1dvxYRcCknWNjHc3c5X1y3ZSoPDi2aur2",
+      "6b0b91287ae3348f8c2f2552d766f30e3604867e34adc37ccbb74a8e6b893e02" =>
+        "did:key:zQ3shZc2QzApp2oymGvQbzP8eKheVshBHbU4ZYjeXqwSKEn6N",
+      "c0a6a7c560d37d7ba81ecee9543721ff48fea3e0fb827d42c1868226540fac15" =>
+        "did:key:zQ3shadCps5JLAHcZiuX5YUtWHHL8ysBJqFLWvjZDKAWUBGzy",
+      "175a232d440be1e0788f25488a73d9416c04b6f924bea6354bf05dd2f1a75133" =>
+        "did:key:zQ3shptjE6JwdkeKN4fcpnYQY3m9Cet3NiHdAfpvSUZBFoKBj"
+    }
+  end
+
+  test "derives correct did:key" do
+    for {privkey_hex, expected_did} <- test_cases() do
+      assert privkey_hex
+             |> Base.decode16!(case: :lower)
+             |> Hexpds.DidGenerator.get_public_key()
+             |> Hexpds.DidGenerator.create_public_did_key() == expected_did
+    end
+  end
+end