Make Curve25519 PublicKeys conform to Equatable

Sources/Crypto/Keys/EC/Ed25519.swift

@@ -57,7 +57,7 @@ extension Curve25519 {
             }
         }
 
-        public struct PublicKey {
+		public struct PublicKey: Equatable {
             private var baseKey: Curve25519.Signing.Curve25519PublicKeyImpl
 
             public init<D: ContiguousBytes>(rawRepresentation: D) throws {
@@ -75,6 +75,10 @@ extension Curve25519 {
             var keyBytes: [UInt8] {
                 return self.baseKey.keyBytes
             }
+
+			public static func ==(lhs: Self, rhs: Self) -> Bool {
+				lhs.rawRepresentation == rhs.rawRepresentation
+			}
         }
     }
 }

Sources/Crypto/Keys/EC/X25519Keys.swift

@@ -26,7 +26,7 @@ extension Curve25519 {
         typealias Curve25519PublicKeyImpl = Curve25519.KeyAgreement.OpenSSLCurve25519PublicKeyImpl
         #endif
 
-        public struct PublicKey: ECPublicKey {
+        public struct PublicKey: ECPublicKey, Equatable {
             fileprivate var baseKey: Curve25519PublicKeyImpl
 
             /// Initializes a Curve25519 Key for Key Agreement.
@@ -54,6 +54,10 @@ extension Curve25519 {
             private func withUnsafeBytes<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R {
                 return try self.baseKey.keyBytes.withUnsafeBytes(body)
             }
+
+			public static func ==(lhs: Self, rhs: Self) -> Bool {
+				lhs.rawRepresentation == rhs.rawRepresentation
+			}
         }
 
         public struct PrivateKey: ECPrivateKey, DiffieHellmanKeyAgreement {

Tests/CryptoTests/Signatures/EdDSA/EdDSATests.swift

@@ -75,4 +75,39 @@ class EdDSATests: XCTestCase {
         // This signature should be invalid
         XCTAssertFalse(privateKey.publicKey.isValidSignature(DispatchData.empty, for: DispatchData.empty))
     }
+
+	func testCurve25519SigningPublicKeyEquatable() throws {
+		// Equality
+		let publicKey = Curve25519.Signing.PrivateKey().publicKey
+		XCTAssertEqual(publicKey, publicKey)
+
+		// Inequality
+
+		// The probability of this inequality check loop
+		// accidentally failing is... 1/2^246, i.e. low.
+		for _ in 0..<1024 {
+			XCTAssertNotEqual(
+				publicKey,
+				Curve25519.Signing.PrivateKey().publicKey
+			)
+		}
+
+	}
+
+	func testCurve25519KeyAgreementPublicKeyEquatable() throws {
+		// Equality
+		let publicKey = Curve25519.KeyAgreement.PrivateKey().publicKey
+		XCTAssertEqual(publicKey, publicKey)
+
+		// Inequality
+
+		// The probability of this inequality check loop
+		// accidentally failing is... 1/2^246, i.e. low.
+		for _ in 0..<1024 {
+			XCTAssertNotEqual(
+				publicKey,
+				Curve25519.KeyAgreement.PrivateKey().publicKey
+			)
+		}
+	}
 }