Adopt swift 6

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        swift: ["5.10", "6.0"]
+        swift: ["6.0"]
     name: swift ${{ matrix.swift }} tests
     steps:
     - uses: slashmo/[email protected]

Benchmarks/PolyBenchmark/PolyBenchmark.swift

@@ -13,7 +13,8 @@
 // limitations under the License.
 
 // Benchmarks for PolyRq functions.
-// These benchmarks can be triggered with `swift package benchmark --target PolyBenchmark`
+// These benchmarks can be triggered with
+// swift package benchmark --target PolyBenchmark
 
 import Benchmark
 import HomomorphicEncryption

Benchmarks/PrivateInformationRetrievalBenchmark/PrivateInformationRetrievalBenchmark.swift

@@ -13,7 +13,8 @@
 // limitations under the License.
 
 // Benchmarks for Pir functions.
-// These benchmarks can be triggered with `swift package benchmark --target PIRBenchmark`
+// These benchmarks can be triggered with
+// swift package benchmark --target PIRBenchmark
 
 import Benchmark
 import Foundation

Benchmarks/PrivateNearestNeighborSearchBenchmark/PrivateNearestNeighborSearchBenchmark.swift

@@ -13,7 +13,8 @@
 // limitations under the License.
 
 // Benchmarks for Pnns functions.
-// These benchmarks can be triggered with `swift package benchmark --target PNNSBenchmark`
+// These benchmarks can be triggered with
+// swift package benchmark --target PNNSBenchmark
 
 import Benchmark
 import Foundation

Benchmarks/RlweBenchmark/RlweBenchmark.swift

@@ -13,7 +13,8 @@
 // limitations under the License.
 
 // Benchmarks for Rlwe functions.
-// These benchmarks can be triggered with `swift package benchmark --target RlweBenchmark`
+// These benchmarks can be triggered with
+// swift package benchmark --target RlweBenchmark
 
 import Benchmark
 import HomomorphicEncryption

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.10
+// swift-tools-version: 6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 // Remember to update CI if changing
 
@@ -17,9 +17,7 @@
 // limitations under the License.
 import PackageDescription
 
-let librarySettings: [SwiftSetting] = [
-    .enableExperimentalFeature("StrictConcurrency"),
-]
+let librarySettings: [SwiftSetting] = []
 
 let executableSettings: [SwiftSetting] =
     librarySettings +
@@ -282,6 +280,8 @@ package.targets += [
 ]
 
 // Set the minimum macOS version for the package
+#if canImport(Darwin)
 package.platforms = [
-    .macOS(.v14), // Constrained by Swift 5.10 support for Xcode (https://developer.apple.com/support/xcode/)
+    .macOS(.v15), // Constrained by UInt128 support
 ]
+#endif

README.md

@@ -79,7 +79,7 @@ The PNNS implementation in Swift Homomorphic Encryption uses homomorphic encrypt
 Swift Homomorphic Encryption requires:
 * 64-bit processor with little-endian memory representation
 * macOS or Linux operating system
-* [Swift](https://www.swift.org/) version 5.10 or later
+* [Swift](https://www.swift.org/) version 6.0 or later
 
 > [!NOTE]
 > Swift Homomorphic Encryption relies on [SystemRandomNumberGenerator](https://developer.apple.com/documentation/swift/systemrandomnumbergenerator) as a cryptographically secure random number generator, which may have platform-dependent behavior.

Sources/HomomorphicEncryption/DoubleWidthUInt.swift

@@ -717,6 +717,5 @@ extension DoubleWidthUInt: UnsignedInteger where Base: FixedWidthInteger & Unsig
     }
 }
 
-@usableFromInline typealias DWUInt128 = DoubleWidthUInt<UInt64>
 @usableFromInline typealias QuadWidth<T: FixedWidthInteger & UnsignedInteger> = DoubleWidthUInt<DoubleWidthUInt<T>>
 @usableFromInline typealias OctoWidth<T: FixedWidthInteger & UnsignedInteger> = DoubleWidthUInt<QuadWidth<T>>

Sources/HomomorphicEncryption/HomomorphicEncryption.docc/UsingSwiftHomomorphicEncryption.md

@@ -6,7 +6,7 @@ Get started using Swift Homomorphic Encryption.
 Swift Homomorphic Encryption requires:
 * 64-bit processor with little-endian memory representation
 * macOS or Linux operating system
-* [Swift](https://www.swift.org/) version 5.10 or later
+* [Swift](https://www.swift.org/) version 6.0 or later
 
 > Note: Swift Homomorphic Encryption relies on [SystemRandomNumberGenerator](https://developer.apple.com/documentation/swift/systemrandomnumbergenerator) as a cryptographically secure random number generator, which may have platform-dependent behavior.
 

Sources/HomomorphicEncryption/PolyRq/PolyRq+Randomize.swift

@@ -55,7 +55,7 @@ extension PolyRq {
     @inlinable
     public mutating func randomizeUniform(using rng: inout some PseudoRandomNumberGenerator) {
         let chunkCount = min(degree, 1024)
-        let uint128ByteCount = MemoryLayout<DWUInt128>.size
+        let uint128ByteCount = MemoryLayout<UInt128>.size
         var randomBytes: [UInt8] = .init(repeating: 0, count: chunkCount * uint128ByteCount)
         // We can sample directly in Coeff or Eval domain
         for (rnsIndex, reduceModulus) in context.reduceModuliUInt64.enumerated() {
@@ -65,7 +65,7 @@ extension PolyRq {
                 for index in 0..<chunkCount {
                     // NOTE: for interoperability always ask rng for a UInt128 and reduces it
                     let u128 =
-                        DWUInt128(littleEndianBytes: randomBytes[index * uint128ByteCount..<(index + 1) *
+                        UInt128(littleEndianBytes: randomBytes[index * uint128ByteCount..<(index + 1) *
                                 uint128ByteCount])
                     let u64 = reduceModulus.reduce(u128)
                     self[offset + index] = T(u64)
@@ -94,7 +94,7 @@ extension PolyRq {
             // consumed for each coefficient.
             let u64: UInt64 = rng.next()
             let u32: UInt32 = rng.next()
-            let u128 = DWUInt128(u64) &<< 32 | DWUInt128(u32)
+            let u128 = UInt128(u64) &<< 32 | UInt128(u32)
 
             let val = T(reductionModulus.reduce(u128))
             for (index, modulus) in zip(rnsIndices(coeffIndex: coeffIndex), moduli) {

Sources/HomomorphicEncryption/Random/NistCtrDrbg.swift

@@ -24,17 +24,23 @@ import Foundation
 @usableFromInline
 package struct NistCtrDrbg {
     @usableFromInline static let ReseedInterval: Int64 = 1 << 48
+
     @usableFromInline static let MaxByteCountPerRequest: Int = 1 << 16
+
     /// Size of AES block.
     @usableFromInline static let BlockCount: Int = 16
+
     /// Size of AES key.
     @usableFromInline static let KeyCount: Int = 16
+
     /// Size of the seed.
     @usableFromInline static let SeedCount: Int = KeyCount + BlockCount
 
     @usableFromInline var key: SymmetricKey
+
     /// This is called `V` in the NIST specification.
-    @usableFromInline var nonce: DWUInt128
+    @usableFromInline var nonce: UInt128
+
     @usableFromInline var reseedCounter: Int64
 
     @usableFromInline var nonceBytes: [UInt8] {
@@ -70,7 +76,7 @@ package struct NistCtrDrbg {
 
         let zeroes = [UInt8](repeating: 0, count: requestedByteCount)
         let output = try AES._CTR.encrypt(zeroes, using: key, nonce: .init(nonceBytes: nonceBytes))
-        nonce &+= DWUInt128(requestedByteCount.dividingCeil(Self.BlockCount, variableTime: true))
+        nonce &+= UInt128(requestedByteCount.dividingCeil(Self.BlockCount, variableTime: true))
 
         let additionalInput = [UInt8](repeating: 0, count: Self.SeedCount)
         try ctrDrbgUpdate(providedData: additionalInput)

Sources/HomomorphicEncryption/Scalar.swift

@@ -22,31 +22,8 @@ public protocol SignedScalarType: ModularArithmetic.CoreSignedScalarType, Codabl
 extension UInt32: ScalarType {}
 extension Int32: SignedScalarType {}
 
-extension Int64: CoreSignedScalarType {}
-extension Int64: SignedScalarType {
-    public typealias UnsignedScalar = UInt64
-}
-
-extension UInt64: CoreScalarType {}
-extension UInt64: ScalarType {
-    public typealias DoubleWidth = DoubleWidthUInt<UInt64>
-    public typealias SignedScalar = Int64
-
-    public static var rnsCorrectionFactor: UInt64 {
-        // ~1000'th largest prime less than 2**62,
-        // but also NTT-unfriendly for all N
-        (Self(1) << 62) - 40797
-    }
-
-    public static var mTilde: UInt64 {
-        Self(1) << 32
-    }
-}
-
-extension DWUInt128: DoubleWidthType {
-    /// Single-width scalar, with bit-width half that of the ``DoubleWidthType``.
-    public typealias Scalar = UInt64
-}
+extension Int64: SignedScalarType {}
+extension UInt64: ScalarType {}
 
 extension FixedWidthInteger {
     /// Big endian byte representation of this value.

Sources/HomomorphicEncryption/Util.swift

@@ -25,21 +25,6 @@ extension Sequence where Element: Hashable {
     }
 }
 
-// https://github.com/swiftlang/swift-evolution/blob/main/proposals/0220-count-where.md
-// introduced in swift 6
-#if swift(<6.0)
-extension Sequence {
-    @inlinable
-    package func count(where predicate: (Element) throws -> Bool) rethrows -> Int {
-        var count = 0
-        for element in self where try predicate(element) {
-            count += 1
-        }
-        return count
-    }
-}
-#endif
-
 extension FixedWidthInteger {
     // not a constant time operation
     @inlinable

Sources/HomomorphicEncryptionProtobuf/MessageExtensions.swift

@@ -24,7 +24,7 @@ extension Message {
     /// - Throws: Error upon failure to initialize message.
     public init(from path: String) throws {
         if path.hasSuffix(".txtpb") {
-            try self.init(textFormatString: String(contentsOfFile: path))
+            try self.init(textFormatString: String(contentsOfFile: path, encoding: .utf8))
         } else {
             let serializedData = try Data(contentsOf: URL(fileURLWithPath: path))
             try self.init(serializedBytes: serializedData)

Sources/ModularArithmetic/Scalar.swift

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/// Scalar type for ``PolyRq`` polynomial coefficients.
+/// Scalar type.
 public protocol CoreScalarType: FixedWidthInteger, UnsignedInteger, Sendable
     where Self.Magnitude: Sendable
 {
@@ -93,31 +93,7 @@ extension CoreSignedScalarType {
     }
 }
 
-extension Int32: CoreSignedScalarType {
-    public typealias UnsignedScalar = UInt32
-}
-
-extension UInt64: DoubleWidthType {
-    /// Single-width scalar, with bit-width half that of the ``DoubleWidthType``.
-    public typealias Scalar = UInt32
-}
-
-extension UInt32: CoreScalarType {
-    public typealias DoubleWidth = UInt64
-    public typealias SignedScalar = Int32
-
-    public static var rnsCorrectionFactor: UInt32 {
-        // ~1000'th largest prime less than 2**30,
-        // but also NTT-unfriendly for N > 8
-        (Self(1) << 30) - 20405
-    }
-
-    public static var mTilde: UInt32 {
-        Self(1) << 16
-    }
-}
-
-/// Double-width scalar type which can hold a product of two ``ScalarType`` multiplicands.
+/// Double-width scalar type which can hold a product of two ``CoreScalarType`` multiplicands.
 public protocol DoubleWidthType: FixedWidthInteger, UnsignedInteger {
     /// Single-width scalar, with bit-width half that of the ``DoubleWidthType``.
     associatedtype Scalar: CoreScalarType
@@ -499,3 +475,51 @@ extension FixedWidthInteger {
         return result
     }
 }
+
+// MARK: Conformances
+
+extension Int32: CoreSignedScalarType {
+    public typealias UnsignedScalar = UInt32
+}
+
+extension Int64: CoreSignedScalarType {
+    public typealias UnsignedScalar = UInt64
+}
+
+extension UInt64: DoubleWidthType {
+    public typealias Scalar = UInt32
+}
+
+extension UInt128: DoubleWidthType {
+    public typealias Scalar = UInt64
+}
+
+extension UInt32: CoreScalarType {
+    public typealias DoubleWidth = UInt64
+    public typealias SignedScalar = Int32
+
+    public static var rnsCorrectionFactor: UInt32 {
+        // ~1000'th largest prime less than 2**30,
+        // but also NTT-unfriendly for N > 8
+        (Self(1) << 30) - 20405
+    }
+
+    public static var mTilde: UInt32 {
+        Self(1) << 16
+    }
+}
+
+extension UInt64: CoreScalarType {
+    public typealias DoubleWidth = UInt128
+    public typealias SignedScalar = Int64
+
+    public static var rnsCorrectionFactor: UInt64 {
+        // ~1000'th largest prime less than 2**62,
+        // but also NTT-unfriendly for all N
+        (Self(1) << 62) - 40797
+    }
+
+    public static var mTilde: UInt64 {
+        Self(1) << 32
+    }
+}

Tests/HomomorphicEncryptionTests/Array2dTests.swift

@@ -33,7 +33,7 @@ class Array2dTests: XCTestCase {
         runTest(Int32.self)
         runTest(Int64.self)
         runTest(UInt64.self)
-        runTest(DWUInt128.self)
+        runTest(UInt128.self)
     }
 
     func testZeroAndZeroize() {
@@ -54,7 +54,7 @@ class Array2dTests: XCTestCase {
         runTest(Int32.self)
         runTest(Int64.self)
         runTest(UInt64.self)
-        runTest(DWUInt128.self)
+        runTest(UInt128.self)
     }
 
     func testShape() {