From dd529f9871bb6a6220ba1f011ea9c09f17efa2cf Mon Sep 17 00:00:00 2001
From: "J. Ayo Akinyele" <ayo@boltlabs.io>
Date: Fri, 6 Dec 2019 22:46:45 -0500
Subject: [PATCH] reduce deps by not using rand pkg in secp256k1

---
 Cargo.toml                  |  5 ++---
 examples/bolt_test_bls12.rs |  1 -
 examples/bolt_test_bn256.rs |  1 -
 src/channels.rs             | 39 ++++++++++++++++++++++++++-----------
 src/lib.rs                  |  2 +-
 5 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index f516256..e6bd8e1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,8 +10,7 @@ repository = "https://github.com/ZcashFoundation/libbolt"
 license = "MIT License"
 
 [dependencies]
-rand = "0.6"
-rand_core = "0.4.0"
+rand = "0.7"
 ff_bl = { git = "https://github.com/boltlabs-inc/ff", branch = "master" }
 pairing_bl = { git = "https://github.com/boltlabs-inc/pairing", branch = "master", features = ["serde"] }
 libc = "*"
@@ -20,7 +19,7 @@ serde_json = "1.0"
 serde_with = "1.0"
 serde_bytes = "0.11.2"
 time = "*"
-secp256k1 = { version = "0.16.0", features = ["rand", "serde"] }
+secp256k1 = { version = "0.16.0", features = ["serde"] }
 sha2 = { version = "0.8", default-features = false }
 hex = "0.3.2"
 
diff --git a/examples/bolt_test_bls12.rs b/examples/bolt_test_bls12.rs
index 409e5c2..bcd85ee 100644
--- a/examples/bolt_test_bls12.rs
+++ b/examples/bolt_test_bls12.rs
@@ -1,5 +1,4 @@
 extern crate rand;
-extern crate rand_core;
 extern crate bolt;
 extern crate ff_bl as ff;
 extern crate pairing_bl as pairing;
diff --git a/examples/bolt_test_bn256.rs b/examples/bolt_test_bn256.rs
index 107e6ae..6ce065c 100644
--- a/examples/bolt_test_bn256.rs
+++ b/examples/bolt_test_bn256.rs
@@ -1,5 +1,4 @@
 extern crate rand;
-extern crate rand_core;
 extern crate bolt;
 extern crate ff_bl as ff;
 extern crate pairing_bl as pairing;
diff --git a/src/channels.rs b/src/channels.rs
index 83107a1..5f32a98 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -210,13 +210,20 @@ impl<E: Engine> CustomerState<E> {
               <E as pairing::Engine>::G2: serde::Serialize,
               <E as ff::ScalarEngine>::Fr: serde::Serialize
     {
-        let mut kp = secp256k1::Secp256k1::new();
-        kp.randomize(csprng);
+        let secp = secp256k1::Secp256k1::new();
 
-        // generate the keypair for the channel
-        let (sk_c, pk_c) = kp.generate_keypair(csprng);
+        let mut seckey = [0u8; 32];
+        csprng.fill_bytes(&mut seckey);
+
+        // generate the signing keypair for the channel        
+        let sk_c = secp256k1::SecretKey::from_slice(&seckey).unwrap();
+        let pk_c = secp256k1::PublicKey::from_secret_key(&secp, &sk_c);
+        
+        let mut seckey1 = [0u8; 32];
+        csprng.fill_bytes(&mut seckey1);
         // generate the keypair for the initial wallet
-        let (wsk, wpk) = kp.generate_keypair(csprng);
+        let wsk = secp256k1::SecretKey::from_slice(&seckey1).unwrap();
+        let wpk = secp256k1::PublicKey::from_secret_key(&secp, &wsk);
         // hash the wallet pub key
         let wpk_h = hash_pubkey_to_fr::<E>(&wpk);
         channel_token.set_customer_pk(&pk_c);
@@ -333,9 +340,14 @@ impl<E: Engine> CustomerState<E> {
     // for channel pay
     pub fn generate_payment<R: Rng>(&self, csprng: &mut R, channel: &ChannelState<E>, amount: i64) -> (NIZKProof<E>, Commitment<E>, secp256k1::PublicKey, CustomerState<E>) {
         // 1 - chooose new wpk/wsk pair
-        let mut kp = secp256k1::Secp256k1::new();
-        kp.randomize(csprng);
-        let (new_wsk, new_wpk) = kp.generate_keypair(csprng);
+        let secp = secp256k1::Secp256k1::new();
+
+        let mut seckey = [0u8; 32];
+        csprng.fill_bytes(&mut seckey);
+        
+        let new_wsk = secp256k1::SecretKey::from_slice(&seckey).unwrap();
+        let new_wpk = secp256k1::PublicKey::from_secret_key(&secp, &new_wsk);
+        // compute hash of the pubkey
         let wpk_h = hash_pubkey_to_fr::<E>(&new_wpk);
 
         // 2 - form new wallet and commitment
@@ -476,9 +488,14 @@ impl<E: Engine> MerchantState<E> {
     pub fn new<R: Rng>(csprng: &mut R, channel: &mut ChannelState<E>, id: String) -> (Self, ChannelState<E>) {
         let l = 5;
         // generate keys here
-        let mut tx_kp = secp256k1::Secp256k1::new();
-        tx_kp.randomize(csprng);
-        let (wsk, wpk) = tx_kp.generate_keypair(csprng);
+        let secp = secp256k1::Secp256k1::new();
+        // tx_kp.randomize(csprng);
+        // let (wsk, wpk) = tx_kp.generate_keypair(csprng);
+        let mut seckey = [0u8; 32];
+        csprng.fill_bytes(&mut seckey);
+        let wsk = secp256k1::SecretKey::from_slice(&seckey).unwrap();
+        let wpk = secp256k1::PublicKey::from_secret_key(&secp, &wsk);
+
         let mut ch = channel.clone();
         let nizkParams = NIZKSecretParams::<E>::setup(csprng, l);
         ch.cp = Some(ChannelParams::<E> { pub_params: nizkParams.pubParams.clone(), l, extra_verify: true });
diff --git a/src/lib.rs b/src/lib.rs
index c384dde..9532a0c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -21,7 +21,7 @@ extern crate test;
 extern crate ff_bl as ff;
 extern crate pairing_bl as pairing;
 extern crate rand;
-extern crate rand_core;
+// extern crate rand_core;
 
 extern crate secp256k1;
 extern crate time;