mimblewimble · elichai · Apr 19, 2020 · Apr 19, 2020
diff --git a/Cargo.toml b/Cargo.toml
@@ -26,6 +26,7 @@ unstable = []
 default = []
 bullet-proof-sizing = []
 dev = ["clippy"]
+lowmemory = []
 
 [dependencies]
 arrayvec = "0.3"

diff --git a/build.rs b/build.rs
@@ -21,21 +21,39 @@
 #![deny(unused_mut)]
 #![warn(missing_docs)]
 
+use std::env;
 fn main() {
+    if cfg!(feature = "external-symbols") {
+        println!("cargo:rustc-link-lib=static=secp256k1-zkp");
+        return;
+    }
+
+    // Check whether we can use 64-bit compilation
+    let use_64bit_compilation = if env::var("CARGO_CFG_TARGET_POINTER_WIDTH").unwrap() == "64" {
+        let check = cc::Build::new().file("depend/check_uint128_t.c")
+                                    .cargo_metadata(false)
+                                    .try_compile("check_uint128_t")
+                                    .is_ok();
+        if !check {
+            println!("cargo:warning=Compiling in 32-bit mode on a 64-bit architecture due to lack of uint128_t support.");
+        }
+        check
+    } else {
+        false
+    };
+
+    // Actual build
     let mut base_config = cc::Build::new();
     base_config.include("depend/secp256k1-zkp/")
                .include("depend/secp256k1-zkp/include")
                .include("depend/secp256k1-zkp/src")
-               .flag("-g")
+               .flag_if_supported("-Wno-unused-function") // some ecmult stuff is defined but not used upstream
+               .define("SECP256K1_BUILD", Some("1"))
                // TODO these three should be changed to use libgmp, at least until secp PR 290 is merged
                .define("USE_NUM_NONE", Some("1"))
                .define("USE_FIELD_INV_BUILTIN", Some("1"))
                .define("USE_SCALAR_INV_BUILTIN", Some("1"))
-               // TODO these should use 64-bit variants on 64-bit systems
-               .define("USE_FIELD_10X26", Some("1"))
-               .define("USE_SCALAR_8X32", Some("1"))
                .define("USE_ENDOMORPHISM", Some("1"))
-               // These all are OK.
                .define("ENABLE_MODULE_ECDH", Some("1"))
                .define("ENABLE_MODULE_GENERATOR", Some("1"))
                .define("ENABLE_MODULE_RECOVERY", Some("1"))
@@ -44,6 +62,27 @@ fn main() {
                .define("ENABLE_MODULE_AGGSIG", Some("1"))
                .define("ENABLE_MODULE_SCHNORRSIG", Some("1"));
 
+    if cfg!(feature = "lowmemory") {
+        base_config.define("ECMULT_WINDOW_SIZE", Some("4")); // A low-enough value to consume neglible memory
+    } else {
+        base_config.define("ECMULT_WINDOW_SIZE", Some("15")); // This is the default in the configure file (`auto`)
+    }
+
+    if let Ok(target_endian) = env::var("CARGO_CFG_TARGET_ENDIAN") {
+        if target_endian == "big" {
+            base_config.define("WORDS_BIGENDIAN", Some("1"));
+        }
+    }
+
+    if use_64bit_compilation {
+        base_config.define("USE_FIELD_5X52", Some("1"))
+                   .define("USE_SCALAR_4X64", Some("1"))
+                   .define("HAVE___INT128", Some("1"));
+    } else {
+        base_config.define("USE_FIELD_10X26", Some("1"))
+                   .define("USE_SCALAR_8X32", Some("1"));
+    }
+
     // secp256k1-zkp
     base_config.file("depend/secp256k1-zkp/contrib/lax_der_parsing.c")
                .file("depend/secp256k1-zkp/src/secp256k1.c")

diff --git a/depend/check_uint128_t.c b/depend/check_uint128_t.c
@@ -0,0 +1,16 @@
+
+#include <stdint.h>
+
+int main(void) {
+    __uint128_t var_128;
+    uint64_t var_64;
+
+    /* Try to shut up "unused variable" warnings */
+    var_64 = 100;
+    var_128 = 100;
+    if (var_64 == var_128) {
+        var_64 = 20;
+    }
+    return 0;
+}
+
diff --git a/src/ecdh.rs b/src/ecdh.rs
@@ -120,10 +120,9 @@ mod benches {
 
     #[bench]
     pub fn bench_ecdh(bh: &mut Bencher) {
-        let s = Secp256k1::with_caps(::ContextFlag::SignOnly);
+        let s = Secp256k1::new();
         let (sk, pk) = s.generate_keypair(&mut thread_rng()).unwrap();
 
-        let s = Secp256k1::new();
         bh.iter( || {
             let res = SharedSecret::new(&s, &pk, &sk);
             black_box(res);

diff --git a/src/lib.rs b/src/lib.rs
@@ -1050,20 +1050,40 @@ mod tests {
     }
 }
 
+
 #[cfg(all(test, feature = "unstable"))]
 mod benches {
-    use rand::{Rng, thread_rng};
+    use rand::{thread_rng, RngCore};
     use test::{Bencher, black_box};
 
     use super::{Secp256k1, Message};
 
     #[bench]
     pub fn generate(bh: &mut Bencher) {
-        struct CounterRng(u32);
-        impl Rng for CounterRng {
-            fn next_u32(&mut self) -> u32 { self.0 += 1; self.0 }
+        struct CounterRng(u64);
+        impl RngCore for CounterRng {
+            fn next_u32(&mut self) -> u32 {
+                self.next_u64() as u32
+            }
+
+            fn next_u64(&mut self) -> u64 {
+                self.0 += 1;
+                self.0
+            }
+
+            fn fill_bytes(&mut self, dest: &mut [u8]) {
+                for chunk in dest.chunks_mut(64/8) {
+                    let rand: [u8; 64/8] = unsafe {std::mem::transmute(self.next_u64())};
+                    chunk.copy_from_slice(&rand[..chunk.len()]);
+                }
+            }
+
+            fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand::Error> {
+                Ok(self.fill_bytes(dest))
+            }
         }
 
+
         let s = Secp256k1::new();
         let mut r = CounterRng(0);
         bh.iter( || {
@@ -1077,12 +1097,12 @@ mod benches {
     pub fn bench_sign(bh: &mut Bencher) {
         let s = Secp256k1::new();
         let mut msg = [0u8; 32];
-        thread_rng().fill(&mut msg);
+        thread_rng().fill_bytes(&mut msg);
         let msg = Message::from_slice(&msg).unwrap();
         let (sk, _) = s.generate_keypair(&mut thread_rng()).unwrap();
 
         bh.iter(|| {
-            let sig = s.sign(&msg, &sk).unwrap();
+            let sig = s.sign(&msg, &sk);
             black_box(sig);
         });
     }
@@ -1091,7 +1111,7 @@ mod benches {
     pub fn bench_verify(bh: &mut Bencher) {
         let s = Secp256k1::new();
         let mut msg = [0u8; 32];
-        thread_rng().fill(&mut msg);
+        thread_rng().fill_bytes(&mut msg);
         let msg = Message::from_slice(&msg).unwrap();
         let (sk, pk) = s.generate_keypair(&mut thread_rng()).unwrap();
         let sig = s.sign(&msg, &sk).unwrap();
@@ -1101,19 +1121,4 @@ mod benches {
             black_box(res);
         });
     }
-
-    #[bench]
-    pub fn bench_recover(bh: &mut Bencher) {
-        let s = Secp256k1::new();
-        let mut msg = [0u8; 32];
-        thread_rng().fill(&mut msg);
-        let msg = Message::from_slice(&msg).unwrap();
-        let (sk, _) = s.generate_keypair(&mut thread_rng()).unwrap();
-        let sig = s.sign_recoverable(&msg, &sk).unwrap();
-
-        bh.iter(|| {
-            let res = s.recover(&msg, &sig).unwrap();
-            black_box(res);
-        });
-    }
 }
diff --git a/src/pedersen.rs b/src/pedersen.rs
@@ -2026,3 +2026,31 @@ mod tests {
 		assert_eq!(errs, 0);
 	}
 }
+
+
+
+
+#[cfg(all(test, feature = "unstable"))]
+mod benches {
+    use rand::thread_rng;
+    use test::{Bencher, black_box};
+	use super::{ContextFlag, SecretKey, Secp256k1};
+
+    #[bench]
+    pub fn bench_bullet_proof_verification(bh: &mut Bencher) {
+		// Test Bulletproofs without message
+		let secp = Secp256k1::with_caps(ContextFlag::Commit);
+		let blinding = SecretKey::new(&secp, &mut thread_rng());
+		let value = 12345678;
+		let commit = secp.commit(value, blinding.clone()).unwrap();
+		let bullet_proof = secp.bullet_proof(value, blinding.clone(), blinding.clone(), blinding.clone(), None, None);
+        bh.iter( || {
+			let proof_range = secp.verify_bullet_proof(commit, bullet_proof, None).unwrap();
+			assert_eq!(proof_range.min, 0);
+        });
+    }
+}
+
+
+
+