Extract curve25519 crate from zk-token-sdk (solana-labs#951)

* extract curve25519 crate

* remove obsolete comment

* fix Cargo.toml files

* fix imports

* update lock file

* remove unused deps from zk-token-sdk

* fmt

* add solana-curve25519 patch

* add missing override to programs/sbf/Cargo.toml

* copy over an allow()

* move new crate to curves dir

* use workspace version

* add back missing dev dep

* add missing dependencies to programs/sbf

* fmt

* move dep to the correct dependency table

* remove #[cfg(not(target_os = "solana"))] above errors mod

Cargo.toml

@@ -31,6 +31,7 @@ members = [
     "connection-cache",
     "core",
     "cost-model",
+    "curves/*",
     "dos",
     "download-utils",
     "entry",
@@ -340,6 +341,7 @@ solana-config-program = { path = "programs/config", version = "=2.0.0" }
 solana-connection-cache = { path = "connection-cache", version = "=2.0.0", default-features = false }
 solana-core = { path = "core", version = "=2.0.0" }
 solana-cost-model = { path = "cost-model", version = "=2.0.0" }
+solana-curve25519 = { path = "curves/curve25519", version = "=2.0.0" }
 solana-download-utils = { path = "download-utils", version = "=2.0.0" }
 solana-entry = { path = "entry", version = "=2.0.0" }
 solana-faucet = { path = "faucet", version = "=2.0.0" }
@@ -490,6 +492,7 @@ crossbeam-epoch = { git = "https://github.com/anza-xyz/crossbeam", rev = "fd279d
 #
 # There is a similar override in `programs/sbf/Cargo.toml`.  Please keep both
 # comments and the overrides in sync.
+solana-curve25519 = { path = "curves/curve25519" }
 solana-program = { path = "sdk/program" }
 solana-zk-sdk = { path = "zk-sdk" }
 solana-zk-token-sdk = { path = "zk-token-sdk" }

curves/curve25519/.gitignore

@@ -0,0 +1 @@
+/farf/

curves/curve25519/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "solana-curve25519"
+description = "Solana Curve25519 Syscalls"
+documentation = "https://docs.rs/solana-curve25519"
+version = { workspace = true }
+authors = { workspace = true }
+repository = { workspace = true }
+homepage = { workspace = true }
+license = { workspace = true }
+edition = { workspace = true }
+
+[dependencies]
+bytemuck = { workspace = true, features = ["derive"] }
+solana-program = { workspace = true }
+thiserror = { workspace = true }
+
+[target.'cfg(not(target_os = "solana"))'.dependencies]
+curve25519-dalek = { workspace = true, features = ["serde"] }

zk-token-sdk/src/curve25519/edwards.rs → curves/curve25519/src/edwards.rs

@@ -9,7 +9,7 @@ pub struct PodEdwardsPoint(pub [u8; 32]);
 mod target_arch {
     use {
         super::*,
-        crate::curve25519::{
+        crate::{
             curve_syscall_traits::{GroupOperations, MultiScalarMultiplication, PointValidation},
             errors::Curve25519Error,
             scalar::PodScalar,
@@ -134,7 +134,7 @@ mod target_arch {
 mod target_arch {
     use {
         super::*,
-        crate::curve25519::{
+        crate::{
             curve_syscall_traits::{ADD, CURVE25519_EDWARDS, MUL, SUB},
             scalar::PodScalar,
         },
@@ -245,7 +245,7 @@ mod target_arch {
 mod tests {
     use {
         super::*,
-        crate::curve25519::scalar::PodScalar,
+        crate::scalar::PodScalar,
         curve25519_dalek::{
             constants::ED25519_BASEPOINT_POINT as G, edwards::EdwardsPoint, traits::Identity,
         },

curves/curve25519/src/errors.rs

@@ -0,0 +1,25 @@
+use thiserror::Error;
+
+#[derive(Error, Clone, Debug, Eq, PartialEq)]
+pub enum Curve25519Error {
+    #[error("pod conversion failed")]
+    PodConversion,
+}
+
+#[derive(Error, Clone, Debug, Eq, PartialEq)]
+pub enum ElGamalError {
+    #[error("key derivation method not supported")]
+    DerivationMethodNotSupported,
+    #[error("seed length too short for derivation")]
+    SeedLengthTooShort,
+    #[error("seed length too long for derivation")]
+    SeedLengthTooLong,
+    #[error("failed to deserialize ciphertext")]
+    CiphertextDeserialization,
+    #[error("failed to deserialize public key")]
+    PubkeyDeserialization,
+    #[error("failed to deserialize keypair")]
+    KeypairDeserialization,
+    #[error("failed to deserialize secret key")]
+    SecretKeyDeserialization,
+}

curves/curve25519/src/lib.rs

@@ -0,0 +1,8 @@
+#![allow(clippy::arithmetic_side_effects, clippy::op_ref)]
+//! Syscall operations for curve25519
+
+pub mod curve_syscall_traits;
+pub mod edwards;
+pub mod errors;
+pub mod ristretto;
+pub mod scalar;

zk-token-sdk/src/curve25519/ristretto.rs → curves/curve25519/src/ristretto.rs

@@ -9,7 +9,7 @@ pub struct PodRistrettoPoint(pub [u8; 32]);
 mod target_arch {
     use {
         super::*,
-        crate::curve25519::{
+        crate::{
             curve_syscall_traits::{GroupOperations, MultiScalarMultiplication, PointValidation},
             errors::Curve25519Error,
             scalar::PodScalar,
@@ -135,7 +135,7 @@ mod target_arch {
 mod target_arch {
     use {
         super::*,
-        crate::curve25519::{
+        crate::{
             curve_syscall_traits::{ADD, CURVE25519_RISTRETTO, MUL, SUB},
             scalar::PodScalar,
         },
@@ -247,7 +247,7 @@ mod target_arch {
 mod tests {
     use {
         super::*,
-        crate::curve25519::scalar::PodScalar,
+        crate::scalar::PodScalar,
         curve25519_dalek::{
             constants::RISTRETTO_BASEPOINT_POINT as G, ristretto::RistrettoPoint, traits::Identity,
         },

zk-token-sdk/src/curve25519/scalar.rs → curves/curve25519/src/scalar.rs

@@ -6,7 +6,11 @@ pub struct PodScalar(pub [u8; 32]);
 
 #[cfg(not(target_os = "solana"))]
 mod target_arch {
-    use {super::*, crate::curve25519::errors::Curve25519Error, curve25519_dalek::scalar::Scalar};
+    use {
+        super::*,
+        crate::errors::{Curve25519Error, ElGamalError},
+        curve25519_dalek::scalar::Scalar,
+    };
 
     impl From<&Scalar> for PodScalar {
         fn from(scalar: &Scalar) -> Self {
@@ -21,4 +25,18 @@ mod target_arch {
             Scalar::from_canonical_bytes(pod.0).ok_or(Curve25519Error::PodConversion)
         }
     }
+
+    impl From<Scalar> for PodScalar {
+        fn from(scalar: Scalar) -> Self {
+            Self(scalar.to_bytes())
+        }
+    }
+
+    impl TryFrom<PodScalar> for Scalar {
+        type Error = ElGamalError;
+
+        fn try_from(pod: PodScalar) -> Result<Self, Self::Error> {
+            Scalar::from_canonical_bytes(pod.0).ok_or(ElGamalError::CiphertextDeserialization)
+        }
+    }
 }

programs/bpf_loader/Cargo.toml

@@ -16,12 +16,12 @@ libsecp256k1 = { workspace = true }
 log = { workspace = true }
 scopeguard = { workspace = true }
 solana-compute-budget = { workspace = true }
+solana-curve25519 = { workspace = true }
 solana-measure = { workspace = true }
 solana-poseidon = { workspace = true }
 solana-program-runtime = { workspace = true }
 solana-sdk = { workspace = true }
 solana-type-overrides = { workspace = true }
-solana-zk-token-sdk = { workspace = true }
 solana_rbpf = { workspace = true }
 thiserror = { workspace = true }
 

programs/bpf_loader/src/syscalls/mod.rs

@@ -901,7 +901,7 @@ declare_builtin_function!(
         _arg5: u64,
         memory_mapping: &mut MemoryMapping,
     ) -> Result<u64, Error> {
-        use solana_zk_token_sdk::curve25519::{curve_syscall_traits::*, edwards, ristretto};
+        use solana_curve25519::{curve_syscall_traits::*, edwards, ristretto};
         match curve_id {
             CURVE25519_EDWARDS => {
                 let cost = invoke_context
@@ -967,9 +967,7 @@ declare_builtin_function!(
         result_point_addr: u64,
         memory_mapping: &mut MemoryMapping,
     ) -> Result<u64, Error> {
-        use solana_zk_token_sdk::curve25519::{
-            curve_syscall_traits::*, edwards, ristretto, scalar,
-        };
+        use solana_curve25519::{curve_syscall_traits::*, edwards, ristretto, scalar};
         match curve_id {
             CURVE25519_EDWARDS => match group_op {
                 ADD => {
@@ -1195,9 +1193,7 @@ declare_builtin_function!(
         result_point_addr: u64,
         memory_mapping: &mut MemoryMapping,
     ) -> Result<u64, Error> {
-        use solana_zk_token_sdk::curve25519::{
-            curve_syscall_traits::*, edwards, ristretto, scalar,
-        };
+        use solana_curve25519::{curve_syscall_traits::*, edwards, ristretto, scalar};
 
         if points_len > 512 {
             return Err(Box::new(SyscallError::InvalidLength));
@@ -2765,7 +2761,7 @@ mod tests {
 
     #[test]
     fn test_syscall_edwards_curve_point_validation() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::CURVE25519_EDWARDS;
+        use solana_curve25519::curve_syscall_traits::CURVE25519_EDWARDS;
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());
@@ -2838,7 +2834,7 @@ mod tests {
 
     #[test]
     fn test_syscall_ristretto_curve_point_validation() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::CURVE25519_RISTRETTO;
+        use solana_curve25519::curve_syscall_traits::CURVE25519_RISTRETTO;
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());
@@ -2911,9 +2907,7 @@ mod tests {
 
     #[test]
     fn test_syscall_edwards_curve_group_ops() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::{
-            ADD, CURVE25519_EDWARDS, MUL, SUB,
-        };
+        use solana_curve25519::curve_syscall_traits::{ADD, CURVE25519_EDWARDS, MUL, SUB};
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());
@@ -3068,9 +3062,7 @@ mod tests {
 
     #[test]
     fn test_syscall_ristretto_curve_group_ops() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::{
-            ADD, CURVE25519_RISTRETTO, MUL, SUB,
-        };
+        use solana_curve25519::curve_syscall_traits::{ADD, CURVE25519_RISTRETTO, MUL, SUB};
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());
@@ -3227,9 +3219,7 @@ mod tests {
 
     #[test]
     fn test_syscall_multiscalar_multiplication() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::{
-            CURVE25519_EDWARDS, CURVE25519_RISTRETTO,
-        };
+        use solana_curve25519::curve_syscall_traits::{CURVE25519_EDWARDS, CURVE25519_RISTRETTO};
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());
@@ -3335,9 +3325,7 @@ mod tests {
 
     #[test]
     fn test_syscall_multiscalar_multiplication_maximum_length_exceeded() {
-        use solana_zk_token_sdk::curve25519::curve_syscall_traits::{
-            CURVE25519_EDWARDS, CURVE25519_RISTRETTO,
-        };
+        use solana_curve25519::curve_syscall_traits::{CURVE25519_EDWARDS, CURVE25519_RISTRETTO};
 
         let config = Config::default();
         prepare_mockup!(invoke_context, program_id, bpf_loader::id());