Version 3.0.0

.github/workflows/Build.yml

@@ -1,9 +1,14 @@
 name: Build
 
-on: [push]
+on:
+  push:
+    branches:
+      - '*'
+      - '!master'
 
 jobs:
   build:
+    name: Release
     runs-on: ubuntu-latest
 
     steps:

.github/workflows/Checks.yml

@@ -1,30 +1,49 @@
 name: Checks
 
-on: [push]
+on:
+  push:
+    branches:
+      - '*'
+      - '!master'
 
 jobs:
-  build:
+  documentation:
+    name: Documentation
     runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup
+        run: sudo apt-get install -y doxygen
+
+      - name: Documentation
+        shell: bash
+        run: ./scripts/build_documentation.sh
 
+  headers:
+    name: Header files
+    runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+      - uses: actions/checkout@v2
 
-    - name: Setup
-      run: sudo apt-get install -y doxygen clang-format-12
+      - name: Copyright
+        run: ./scripts/check_copyright_headers.py
 
-    - name: Documentation
-      shell: bash
-      run: ./scripts/build_documentation.sh
+      - name: Header Guards
+        run: ./scripts/check_header_guards.py
 
-    - name: Copyright
-      run: ./scripts/check_copyright_headers.py
+  style:
+    name: Code style
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
 
-    - name: Header Guards
-      run: ./scripts/check_header_guards.py
+      - name: Setup
+        run: sudo apt-get install -y clang-format-12
 
-    - name: Style
-      shell: bash
-      run: |
-        find . -type f \( -iname "*.h" -o -iname "*.cc" \) -exec clang-format -n --style=Google {} \; &> checks.txt
-        cat checks.txt
-        test ! -s checks.txt
+      - name: Check
+        shell: bash
+        run: |
+          find . -type f \( -iname "*.h" -o -iname "*.cc" \) -exec clang-format -n --style=Google {} \; &> checks.txt
+          cat checks.txt
+          test ! -s checks.txt

.github/workflows/Test.yml

@@ -1,51 +1,57 @@
 name: Test
 
-on: [push]
+on:
+  push:
+    branches:
+      - '*'
+      - '!master'
 
 env:
   BUILD_TYPE: Debug
 
 jobs:
   build:
+    name: Coverage and Linting
     runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v2
 
-    - name: Setup catch2
+    - name: Setup
       run: |
-        sudo apt-get install -y lcov
+        sudo apt-get install -y lcov bear
         curl -L https://github.com/catchorg/Catch2/archive/v2.13.0.tar.gz -o c.tar.gz
         tar xvf c.tar.gz
         cd Catch2-2.13.0/
-        cmake -Bbuild -H. -DBUILD_TESTING=OFF
-        sudo cmake --build build/ --target install
+        cmake -B catch -DBUILD_TESTING=OFF
+        cmake --build catch
+        sudo cmake --install catch
 
-    - name: Create build directory
-      run: cmake -E make_directory ${{runner.workspace}}/build
-
-    - name: Configure CMake
-      shell: bash
-      working-directory: ${{runner.workspace}}/build
-      run: cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+    - name: CMake
+      run: cmake -B ${{runner.workspace}}/build -DCMAKE_BUILD_TYPE=$BUILD_TYPE .
 
     - name: Build
       working-directory: ${{runner.workspace}}/build
       shell: bash
-      run: cmake --build . --config $BUILD_TYPE
+      run: bear make -s -j4
 
     - name: Test
       working-directory: ${{runner.workspace}}/build
       shell: bash
       run: ctest -C $BUILD_TYPE
 
     - name: Coverage
-      working-directory: ${{runner.workspace}}/build
       shell: bash
       run: |
-        make coverage
-        lcov --summary coverage.info >> summary.txt
+        cmake --build ${{runner.workspace}}/build --target coverage
+        lcov --summary ${{runner.workspace}}/build/coverage.info >> ${{runner.workspace}}/summary.txt
+        ./scripts/check_coverage.py ${{runner.workspace}}/summary.txt
 
-    - name: Check
+    - name: Lint
       shell: bash
-      run: ./scripts/check_coverage.py ${{runner.workspace}}/build/summary.txt
+      run: |
+        find include/ src/ test/ -type f \( -iname "*.h" -o -iname "*.cc" \) \
+        -exec clang-tidy -p ${{runner.workspace}}/build/compile_commands.json --quiet {} \; 1>> lint.txt 2>/dev/null
+        cat lint.txt
+        test ! -s lint.txt
+

CMakeLists.txt

@@ -16,7 +16,7 @@
 
 cmake_minimum_required( VERSION 3.14 )
 
-project( scl VERSION 2.1.0 DESCRIPTION "Secure Computation Library" )
+project( scl VERSION 3.0.0 DESCRIPTION "Secure Computation Library" )
 
 if(NOT CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE Release)
@@ -120,7 +120,7 @@ if(CMAKE_BUILD_TYPE MATCHES "Debug")
     add_compile_definitions(SCL_ENABLE_EC_TESTS)
   endif()
 
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0 -fsanitize=address")
   find_package(Catch2 REQUIRED)
   include(CTest)
   include(Catch)
@@ -150,3 +150,5 @@ if(CMAKE_BUILD_TYPE MATCHES "Debug")
     EXCLUDE "/usr/include/*" "test/*" "/usr/lib/*" "/usr/local/*")
 
 endif()
+
+message(STATUS "CXX_FLAGS=" ${CMAKE_CXX_FLAGS})

RELEASE.txt

@@ -1,3 +1,17 @@
+3.0: More features, build changes
+- Add method for returning a point as a pair of affine coordinates
+- Add method to check if a channel has data available
+- Allow sending and receiving STL vectors without specifying the size
+- Extend Vec with a SubVector, operator== and operator!= methods
+- Begin Shamir code refactor and move all of it into details namespace
+- bugs:
+  - fix scalar multiplication for secp256k1_order
+  - fix compilation error on g++12
+- build:
+  - build tests with -fsanitize=address
+  - disable actions for master branch
+  - add clang-tidy action
+
 2.1: More Finite Fields
 - Provide a FF implementation for computations modulo the order of Secp256k1
 - Extend EC with support for scalar multiplications with scalars from a finite

examples/03_secret_sharing.cc

@@ -46,30 +46,36 @@ int main() {
    * correction. Lets see error detection at work first
    */
 
+  scl::details::ShamirSSFactory<Fp> factory(
+      1, prg, scl::details::SecurityLevel::CORRECT);
   /* We create 4 shamir shares with a threshold of 1.
    */
-  auto shamir_shares = scl::CreateShamirShares(secret, 4, 1, prg);
+  auto shamir_shares = factory.Share(secret);
   std::cout << shamir_shares << "\n";
 
   /* Of course, these can be reconstructed. The second parameter is the
    * threshold. This performs reconstruction with error detection.
    */
-  auto shamir_reconstructed = scl::ReconstructShamir(shamir_shares, 1);
+  auto recon = factory.GetInterpolator();
+  auto shamir_reconstructed =
+      recon.Reconstruct(shamir_shares, scl::details::SecurityLevel::DETECT);
   std::cout << shamir_reconstructed << "\n";
 
   /* If we introduce an error, then reconstruction fails
    */
   shamir_shares[2] = Fp(123);
   try {
-    std::cout << scl::ReconstructShamir(shamir_shares, 1) << "\n";
+    std::cout << recon.Reconstruct(shamir_shares,
+                                   scl::details::SecurityLevel::DETECT)
+              << "\n";
   } catch (std::logic_error& e) {
     std::cout << e.what() << "\n";
   }
 
   /* On the other hand, we can use the robust reconstruction since the threshold
    * is low enough. I.e., because 4 >= 3*1 + 1.
    */
-  auto r = scl::ReconstructShamirRobust(shamir_shares, 1);
+  auto r = recon.Reconstruct(shamir_shares);
   std::cout << r << "\n";
 
   /* With a bit of extra work, we can even learn which share had the error.
@@ -79,26 +85,26 @@ int main() {
    * default these are just the field elements 1 through 4.
    */
   Vec alphas = {Fp(1), Fp(2), Fp(3), Fp(4)};
-  auto pe = scl::ReconstructShamirRobust(shamir_shares, alphas, 1);
+  auto pe = scl::details::ReconstructShamirRobust(shamir_shares, alphas, 1);
 
   /* pe is a pair of polynomials. The first is the original polynomial used for
    * generating the shares and the second is a polynomial whose roots tell which
    * share had errors.
    *
    * The secret is embedded in the constant term.
    */
-  std::cout << pe[0].Evaluate(Fp(0)) << "\n";
+  std::cout << std::get<0>(pe).Evaluate(Fp(0)) << "\n";
 
   /* This will be 0, indicating that the share corresponding to party 3 had an
    * error.
    */
-  std::cout << pe[1].Evaluate(Fp(3)) << "\n";
+  std::cout << std::get<1>(pe).Evaluate(Fp(3)) << "\n";
 
   /* Lastly, if there's too many errors, then correction is not possible
    */
   shamir_shares[1] = Fp(22);
   try {
-    scl::ReconstructShamirRobust(shamir_shares, 1);
+    recon.Reconstruct(shamir_shares);
   } catch (std::logic_error& e) {
     std::cout << e.what() << "\n";
   }

include/scl/hash.h

@@ -130,13 +130,17 @@ Hash<B> &Hash<B>::Update(const unsigned char *bytes, std::size_t nbytes) {
   const unsigned char *p = bytes;
 
   if (nbytes < old_tail) {
-    while (nbytes--) mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+    while (nbytes-- > 0) {
+      mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+    }
     return *this;
   }
 
-  if (old_tail) {
+  if (old_tail != 0) {
     nbytes -= old_tail;
-    while (old_tail--) mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+    while (old_tail-- != 0) {
+      mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+    }
 
     mState[mWordIndex] ^= mSaved;
     mByteIndex = 0;
@@ -167,7 +171,9 @@ Hash<B> &Hash<B>::Update(const unsigned char *bytes, std::size_t nbytes) {
     p += sizeof(uint64_t);
   }
 
-  while (tail--) mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+  while (tail-- > 0) {
+    mSaved |= (uint64_t)(*(p++)) << ((mByteIndex++) * 8);
+  }
 
   return *this;
 }
@@ -194,7 +200,9 @@ auto Hash<B>::Finalize() -> DigestType {
 
   // truncate
   DigestType digest = {0};
-  for (std::size_t i = 0; i < digest.size(); ++i) digest[i] = mStateBytes[i];
+  for (std::size_t i = 0; i < digest.size(); ++i) {
+    digest[i] = mStateBytes[i];
+  }
 
   return digest;
 }
@@ -208,7 +216,9 @@ template <typename D>
 std::string DigestToString(const D &digest) {
   std::stringstream ss;
   ss << std::setw(2) << std::setfill('0') << std::hex;
-  for (const auto &c : digest) ss << (int)c;
+  for (const auto &c : digest) {
+    ss << (int)c;
+  }
   return ss.str();
 }
 

include/scl/math/ec.h

@@ -271,6 +271,14 @@ class EC {
     return details::CurveIsPointAtInfinity<Curve>(mValue);
   };
 
+  /**
+   * @brief Return this point as a pair of affine coordinates.
+   * @return this point as a pair of affine coordinates.
+   */
+  std::array<Field, 2> ToAffine() const {
+    return details::CurveToAffine<Curve>(mValue);
+  };
+
   /**
    * @brief Output this point as a string.
    */

include/scl/math/ec_ops.h

@@ -59,6 +59,15 @@ template <typename C>
 void CurveSetAffine(typename C::ValueType& out, const FF<typename C::Field>& x,
                     const FF<typename C::Field>& y);
 
+/**
+ * @brief Convert a point to a pair of affine coordinates.
+ * @param point the point to convert.
+ * @return a set of affine coordinates.
+ */
+template <typename C>
+std::array<scl::FF<typename C::Field>, 2> CurveToAffine(
+    const typename C::ValueType& point);
+
 /**
  * @brief Add two elliptic curve points in-place.
  * @param out the first point and output
@@ -135,11 +144,11 @@ void CurveToBytes(unsigned char* dest, const typename C::ValueType& in,
 
 /**
  * @brief Convert an elliptic curve point to a string
- * @param in the point
+ * @param point the point
  * @return an STL string representation of \p in.
  */
 template <typename C>
-std::string CurveToString(const typename C::ValueType& in);
+std::string CurveToString(const typename C::ValueType& point);
 
 }  // namespace details
 }  // namespace scl

include/scl/math/ff_ops.h

@@ -37,7 +37,7 @@ namespace details {
  * @param value the integer to convert
  */
 template <typename F>
-void FieldConvertIn(typename F::ValueType& out, const int value);
+void FieldConvertIn(typename F::ValueType& out, int value);
 
 /**
  * @brief Add two field elements in-place.