Replace bincode with borsh (#452)

* Add SignalsConfig to chain_spec

* Correct multiexp feature flagging for rand_core std

* Remove bincode for borsh

Replaces a non-canonical encoding with a canonical encoding which additionally
should be faster.

Also fixes an issue where we used bincode in transcripts where it cannot be
trusted.

This ended up fixing a myriad of other bugs observed, unfortunately.
Accordingly, it either has to be merged or the bug fixes from it must be ported
to a new PR.

* Make serde optional, minimize usage

* Make borsh an optional dependency of substrate/ crates

* Remove unused dependencies

* Use [u8; 64] where possible in the processor messages

* Correct borsh feature flagging

crypto/dkg/Cargo.toml

@@ -22,7 +22,8 @@ zeroize = { version = "^1.5", default-features = false, features = ["zeroize_der
 
 std-shims = { version = "0.1", path = "../../common/std-shims", default-features = false }
 
-serde = { version = "1", features = ["derive"], optional = true }
+borsh = { version = "1", default-features = false, features = ["derive", "de_strict_order"], optional = true }
+serde = { version = "1", default-features = false, features = ["derive"], optional = true }
 
 transcript = { package = "flexible-transcript", path = "../transcript", version = "^0.3.2", default-features = false, features = ["recommended"] }
 chacha20 = { version = "0.9", default-features = false, features = ["zeroize"] }
@@ -45,7 +46,8 @@ std = [
 
   "std-shims/std",
 
-  "serde/std",
+  "borsh?/std",
+  "serde?/std",
 
   "transcript/std",
   "chacha20/std",
@@ -58,6 +60,7 @@ std = [
   "dleq/std",
   "dleq/serialize"
 ]
+borsh = ["dep:borsh"]
 serde = ["dep:serde"]
 tests = ["rand_core/getrandom"]
 default = ["std"]

crypto/dkg/src/lib.rs

@@ -31,6 +31,7 @@ pub mod tests;
 
 /// The ID of a participant, defined as a non-zero u16.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Zeroize)]
+#[cfg_attr(feature = "borsh", derive(borsh::BorshSerialize, borsh::BorshDeserialize))]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Participant(pub(crate) u16);
 impl Participant {
@@ -146,6 +147,7 @@ mod lib {
   /// Parameters for a multisig.
   // These fields should not be made public as they should be static
   #[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
+  #[cfg_attr(feature = "borsh", derive(borsh::BorshSerialize, borsh::BorshDeserialize))]
   #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
   pub struct ThresholdParams {
     /// Participants needed to sign on behalf of the group.

crypto/multiexp/Cargo.toml

@@ -32,7 +32,7 @@ k256 = { version = "^0.13.1", default-features = false, features = ["arithmetic"
 dalek-ff-group = { path = "../dalek-ff-group" }
 
 [features]
-std = ["std-shims/std", "zeroize/std", "ff/std", "rand_core/std"]
+std = ["std-shims/std", "zeroize/std", "ff/std", "rand_core?/std"]
 
 batch = ["rand_core"]