Add Ed25519 curve to the guest library

examples/ecc/src/main.rs

@@ -51,6 +51,8 @@ const CURVE_D: Edwards25519Coord = Edwards25519Coord::from_const_bytes([
     64, 199, 140, 115, 254, 111, 43, 238, 108, 3, 82,
 ]);
 
+// Note that we are defining the Edwards25519 curve for illustrative purposes only.
+// In practice, we would use the ed25519 module which defines the Edwards25519 curve for us.
 openvm_ecc_guest::te_setup::te_declare! {
     Edwards25519Point {
         mod_type = Edwards25519Coord,

extensions/ecc/guest/Cargo.toml

@@ -46,3 +46,4 @@ k256 = ["dep:k256"]
 halo2curves = ["dep:halo2curves-axiom", "openvm-algebra-guest/halo2curves"]
 
 p256 = []
+ed25519 = []

extensions/ecc/guest/src/ed25519.rs

@@ -0,0 +1,80 @@
+use hex_literal::hex;
+#[cfg(not(target_os = "zkvm"))]
+use lazy_static::lazy_static;
+#[cfg(not(target_os = "zkvm"))]
+use num_bigint::BigUint;
+use openvm_algebra_guest::{Field, IntMod};
+
+use super::group::{CyclicGroup, Group};
+
+#[cfg(not(target_os = "zkvm"))]
+lazy_static! {
+    pub static ref Ed25519_MODULUS: BigUint = BigUint::from_bytes_be(&hex!(
+        "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED"
+    ));
+    pub static ref Ed25519_ORDER: BigUint = BigUint::from_bytes_be(&hex!(
+        "1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED"
+    ));
+    pub static ref Ed25519_A: BigUint = BigUint::from_bytes_be(&hex!(
+        "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEC"
+    ));
+    pub static ref Ed25519_D: BigUint = BigUint::from_bytes_be(&hex!(
+        "52036CEE2B6FFE738CC740797779E89800700A4D4141D8AB75EB4DCA135978A3"
+    ));
+}
+
+openvm_algebra_moduli_setup::moduli_declare! {
+    Ed25519Coord { modulus = "0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED" },
+    Ed25519Scalar { modulus = "0x1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED" },
+}
+
+pub const ED25519_NUM_LIMBS: usize = 32;
+pub const ED25519_LIMB_BITS: usize = 8;
+pub const ED25519_BLOCK_SIZE: usize = 32;
+// from_const_bytes is little endian
+pub const CURVE_A: Ed25519Coord = Ed25519Coord::from_const_bytes(hex!(
+    "ECFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7F"
+));
+pub const CURVE_D: Ed25519Coord = Ed25519Coord::from_const_bytes(hex!(
+    "A3785913CA4DEB75ABD841414D0A700098E879777940C78C73FE6F2BEE6C0352"
+));
+
+openvm_ecc_te_setup::te_declare! {
+    Ed25519Point { mod_type = Ed25519Coord, a = CURVE_A, d = CURVE_D },
+}
+
+impl Field for Ed25519Coord {
+    const ZERO: Self = <Self as IntMod>::ZERO;
+    const ONE: Self = <Self as IntMod>::ONE;
+
+    type SelfRef<'a> = &'a Self;
+
+    fn double_assign(&mut self) {
+        IntMod::double_assign(self);
+    }
+
+    fn square_assign(&mut self) {
+        IntMod::square_assign(self);
+    }
+}
+
+impl CyclicGroup for Ed25519Point {
+    // from_const_bytes is little endian
+    const GENERATOR: Self = Ed25519Point {
+        x: Ed25519Coord::from_const_bytes(hex!(
+            "1AD5258F602D56C9B2A7259560C72C695CDCD6FD31E2A4C0FE536ECDD3366921"
+        )),
+        y: Ed25519Coord::from_const_bytes(hex!(
+            "5866666666666666666666666666666666666666666666666666666666666666"
+        )),
+    };
+    // TODO: fix
+    const NEG_GENERATOR: Self = Ed25519Point {
+        x: Ed25519Coord::from_const_bytes(hex!(
+            "1AD5258F602D56C9B2A7259560C72C695CDCD6FD31E2A4C0FE536ECDD3366921"
+        )),
+        y: Ed25519Coord::from_const_bytes(hex!(
+            "5866666666666666666666666666666666666666666666666666666666666666"
+        )),
+    };
+}

extensions/ecc/guest/src/lib.rs

@@ -32,6 +32,9 @@ pub mod k256;
 #[cfg(feature = "p256")]
 pub mod p256;
 
+#[cfg(feature = "ed25519")]
+pub mod ed25519;
+
 /// This is custom-1 defined in RISC-V spec document
 pub const SW_OPCODE: u8 = 0x2b;
 pub const SW_FUNCT3: u8 = 0b001;

extensions/ecc/tests/programs/Cargo.toml

@@ -32,6 +32,7 @@ default = ["std"]
 std = ["serde/std", "openvm/std", "openvm-ecc-guest/std"]
 k256 = ["openvm-ecc-guest/k256", "dep:k256"]
 p256 = ["openvm-ecc-guest/p256"]
+ed25519 = ["openvm-ecc-guest/ed25519"]
 
 [profile.release]
 panic = "abort"
@@ -57,3 +58,7 @@ required-features = ["k256"]
 [[example]]
 name = "ecdsa"
 required-features = ["k256"]
+
+[[example]]
+name = "edwards_ec"
+required-features = ["ed25519"]

extensions/ecc/tests/programs/examples/edwards_ec.rs

@@ -1,108 +1,54 @@
 #![cfg_attr(not(feature = "std"), no_main)]
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use core::str::FromStr;
-
-use num_bigint::BigUint;
-use openvm_algebra_guest::{
-    moduli_setup::{moduli_declare, moduli_init},
-    Field, IntMod,
-};
+use hex_literal::hex;
+use openvm_algebra_guest::{moduli_setup::moduli_init, IntMod};
 use openvm_ecc_guest::{
+    ed25519::{Ed25519Coord, Ed25519Point},
     edwards::TwistedEdwardsPoint,
-    te_setup::{te_declare, te_init},
-    Group,
+    te_setup::te_init,
+    CyclicGroup, Group,
 };
 
-moduli_declare! {
-    Edwards25519Coord { modulus = "57896044618658097711785492504343953926634992332820282019728792003956564819949" },
-}
-
 moduli_init! {
     "57896044618658097711785492504343953926634992332820282019728792003956564819949",
 }
 
-impl Field for Edwards25519Coord {
-    const ZERO: Self = <Self as IntMod>::ZERO;
-    const ONE: Self = <Self as IntMod>::ONE;
-
-    type SelfRef<'a> = &'a Self;
-
-    fn double_assign(&mut self) {
-        IntMod::double_assign(self);
-    }
-
-    fn square_assign(&mut self) {
-        IntMod::square_assign(self);
-    }
-}
-
-// a = 57896044618658097711785492504343953926634992332820282019728792003956564819948
-// d = 37095705934669439343138083508754565189542113879843219016388785533085940283555
-// encoded in little endian, 32 limbs of 8 bits each
-const CURVE_A: Edwards25519Coord = Edwards25519Coord::from_const_bytes([
-    236, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 127,
-]);
-const CURVE_D: Edwards25519Coord = Edwards25519Coord::from_const_bytes([
-    163, 120, 89, 19, 202, 77, 235, 117, 171, 216, 65, 65, 77, 10, 112, 0, 152, 232, 121, 119, 121,
-    64, 199, 140, 115, 254, 111, 43, 238, 108, 3, 82,
-]);
-
-te_declare! {
-    Edwards25519Point {
-        mod_type = Edwards25519Coord,
-        a = CURVE_A,
-        d = CURVE_D
-    }
-}
-
 te_init! {
-    Edwards25519Point,
+    Ed25519Point,
 }
 
 openvm::entry!(main);
 
-fn string_to_coord(s: &str) -> Edwards25519Coord {
-    Edwards25519Coord::from_le_bytes(&BigUint::from_str(s).unwrap().to_bytes_le())
-}
-
 pub fn main() {
     setup_all_moduli();
     setup_all_te_curves();
 
     // Base point of edwards25519
-    let x1 = string_to_coord(
-        "15112221349535400772501151409588531511454012693041857206046113283949847762202",
-    );
-    let y1 = string_to_coord(
-        "46316835694926478169428394003475163141307993866256225615783033603165251855960",
-    );
+    let mut p1 = Ed25519Point::GENERATOR;
 
     // random point on edwards25519
-    let x2 = Edwards25519Coord::from_u32(2);
-    let y2 = string_to_coord(
-        "11879831548380997166425477238087913000047176376829905612296558668626594440753",
-    );
+    let x2 = Ed25519Coord::from_u32(2);
+    let y2 = Ed25519Coord::from_be_bytes(&hex!(
+        "1A43BF127BDDC4D71FF910403C11DDB5BA2BCDD2815393924657EF111E712631"
+    ));
+    let mut p2 = Ed25519Point::from_xy(x2, y2).unwrap();
 
     // This is the sum of (x1, y1) and (x2, y2).
-    let x3 = string_to_coord(
-        "44969869612046584870714054830543834361257841801051546235130567688769346152934",
-    );
-    let y3 = string_to_coord(
-        "50796027728050908782231253190819121962159170739537197094456293084373503699602",
-    );
+    let x3 = Ed25519Coord::from_be_bytes(&hex!(
+        "636C0B519B2C5B1E0D3BFD213F45AFD5DAEE3CECC9B68CF88615101BC78329E6"
+    ));
+    let y3 = Ed25519Coord::from_be_bytes(&hex!(
+        "704D8868CB335A7B609D04B9CD619511675691A78861F1DFF7A5EBC389C7EA92"
+    ));
 
     // This is 2 * (x1, y1)
-    let x4 = string_to_coord(
-        "39226743113244985161159605482495583316761443760287217110659799046557361995496",
-    );
-    let y4 = string_to_coord(
-        "12570354238812836652656274015246690354874018829607973815551555426027032771563",
-    );
-
-    let mut p1 = Edwards25519Point::from_xy(x1.clone(), y1.clone()).unwrap();
-    let mut p2 = Edwards25519Point::from_xy(x2, y2).unwrap();
+    let x4 = Ed25519Coord::from_be_bytes(&hex!(
+        "56B98CC045559AD2BBC45CAB58D842ECEE264DB9395F6014B772501B62BB7EE8"
+    ));
+    let y4 = Ed25519Coord::from_be_bytes(&hex!(
+        "1BCA918096D89C83A15105DF343DC9F7510494407750226DAC0A7620ACE77BEB"
+    ));
 
     // Generic add can handle equal or unequal points.
     let p3 = &p1 + &p2;

extensions/ecc/tests/src/lib.rs

@@ -152,7 +152,7 @@ mod tests {
         let elf = build_example_program_at_path_with_features::<&str>(
             get_programs_dir!(),
             "edwards_ec",
-            [],
+            ["ed25519"],
         )?;
         let openvm_exe = VmExe::from_elf(
             elf,