bindings for EC crypto (#356)

Author: DmitriyMusatkin

Source/AwsCommonRuntimeKit/crt/EC.swift

@@ -0,0 +1,179 @@
+import AwsCCal
+
+import struct Foundation.Data
+//  Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//  SPDX-License-Identifier: Apache-2.0.
+import struct Foundation.Date
+import struct Foundation.TimeInterval
+
+public class ECKeyPair {
+
+  public enum ECAlgorithm: UInt32 {
+    case p256 = 0
+    case p384 = 1
+  }
+
+  public enum ECExportFormat: UInt32 {
+    case sec1 = 0
+    case pkcs8 = 1
+    case spki = 2
+  }
+
+  public typealias ECRawSignature = (r: Data, s: Data)
+  public typealias ECPublicCoords = (x: Data, y: Data)
+
+  public static let maxExportSize = 512
+
+  let rawValue: UnsafeMutablePointer<aws_ecc_key_pair>
+
+  private init(rawValue: UnsafeMutablePointer<aws_ecc_key_pair>) {
+    self.rawValue = rawValue
+  }
+
+  /// Generates new ECKeyPair for the specified algo
+  static func generate(algorithm: ECAlgorithm) throws -> ECKeyPair {
+    guard
+      let rawValue = aws_ecc_key_pair_new_generate_random(
+        allocator.rawValue, aws_ecc_curve_name(algorithm.rawValue))
+    else {
+      throw CommonRunTimeError.crtError(.makeFromLastError())
+    }
+    return ECKeyPair(rawValue: rawValue)
+  }
+
+  /// Load ECKeyPair from der representation.
+  /// data must be raw der bytes. i.e. strip base64 if coming from pem
+  static func fromDer(data: Data) throws -> ECKeyPair {
+    try data.withUnsafeBytes { dataPointer in
+      var dataCur = aws_byte_cursor_from_array(dataPointer.baseAddress, data.count)
+      guard
+        let rawValue = aws_ecc_key_pair_new_from_asn1(allocator.rawValue, &dataCur)
+      else {
+        throw CommonRunTimeError.crtError(.makeFromLastError())
+      }
+      return ECKeyPair(rawValue: rawValue)
+    }
+  }
+
+  /// Decode der ec signature into raw r and s components
+  static public func decodeDerEcSignature(signature: Data) throws -> ECKeyPair.ECRawSignature {
+    var rCur = aws_byte_cursor()
+    var sCur = aws_byte_cursor()
+
+    return try signature.withUnsafeBytes { signaturePointer -> ECKeyPair.ECRawSignature in
+      let signatureCur = aws_byte_cursor_from_array(
+        signaturePointer.baseAddress,
+        signature.count
+      )
+
+      guard
+        aws_ecc_decode_signature_der_to_raw(
+          allocator.rawValue,
+          signatureCur,
+          &rCur,
+          &sCur
+        ) == AWS_OP_SUCCESS
+      else {
+        throw CommonRunTimeError.crtError(.makeFromLastError())
+      }
+
+      let rData = Data(bytes: rCur.ptr, count: rCur.len)
+      let sData = Data(bytes: sCur.ptr, count: sCur.len)
+      return ECKeyPair.ECRawSignature(r: rData, s: sData)
+    }
+  }
+
+  /// Encode raw ec signature into der format
+  static public func encodeRawECSignature(signature: ECKeyPair.ECRawSignature) throws -> Data {
+    return try signature.r.withUnsafeBytes { rPointer in
+      let rCur = aws_byte_cursor_from_array(rPointer.baseAddress, signature.r.count)
+      return try signature.s.withUnsafeBytes { sPointer in
+        let sCur = aws_byte_cursor_from_array(sPointer.baseAddress, signature.s.count)
+
+        let bufferSize = signature.r.count + signature.s.count + 32
+        var outData = Data(count: bufferSize)
+        var newBufferSize = 0
+        try outData.withUnsafeMutableBytes { outPointer in
+          var outBuf = aws_byte_buf_from_empty_array(outPointer.baseAddress, bufferSize)
+          guard
+            aws_ecc_encode_signature_raw_to_der(
+              allocator.rawValue,
+              rCur, sCur, &outBuf) == AWS_OP_SUCCESS
+          else {
+            throw CommonRunTimeError.crtError(.makeFromLastError())
+          }
+          newBufferSize = outBuf.len
+        }
+        outData.count = newBufferSize
+        return outData
+      }
+    }
+  }
+
+  /// Export key pair into specified format
+  public func exportKey(format: ECKeyPair.ECExportFormat) throws -> Data {
+    var outData = Data(count: ECKeyPair.maxExportSize)
+    var newBufferSize = 0
+    try outData.withUnsafeMutableBytes { outPointer in
+      var outBuf = aws_byte_buf_from_empty_array(outPointer.baseAddress, ECKeyPair.maxExportSize)
+      guard
+        aws_ecc_key_pair_export(rawValue, aws_ecc_key_export_format(format.rawValue), &outBuf)
+          == AWS_OP_SUCCESS
+      else {
+        throw CommonRunTimeError.crtError(.makeFromLastError())
+      }
+      newBufferSize = outBuf.len
+    }
+    outData.count = newBufferSize
+    return outData
+  }
+
+  /// Get public coordinates of the key
+  public func getPublicCoords() throws -> ECKeyPair.ECPublicCoords {
+    var xCoord = aws_byte_cursor()
+    var yCoord = aws_byte_cursor()
+    aws_ecc_key_pair_get_public_key(rawValue, &xCoord, &yCoord)
+    let xData = Data(bytes: xCoord.ptr, count: xCoord.len)
+    let yData = Data(bytes: yCoord.ptr, count: yCoord.len)
+
+    return ECKeyPair.ECPublicCoords(x: xData, y: yData)
+  }
+
+  /// Sign the data.
+  /// Note: input is expected to be a digest, ex. sha256
+  public func sign(digest: Data) throws -> Data {
+    let bufferSize = aws_ecc_key_pair_signature_length(rawValue)
+    var outData = Data(count: bufferSize)
+    var newBufferSize = 0
+    try digest.withUnsafeBytes { digestPointer in
+      var digestCur = aws_byte_cursor_from_array(digestPointer.baseAddress, digest.count)
+      try outData.withUnsafeMutableBytes { outPointer in
+        var outBuf = aws_byte_buf_from_empty_array(outPointer.baseAddress, bufferSize)
+        guard aws_ecc_key_pair_sign_message(rawValue, &digestCur, &outBuf) == AWS_OP_SUCCESS else {
+          throw CommonRunTimeError.crtError(.makeFromLastError())
+        }
+        newBufferSize = outBuf.len
+      }
+    }
+    outData.count = newBufferSize
+    return outData
+  }
+
+  /// Verify signature. returns true for successful verification.
+  public func verify(digest: Data, signature: Data) -> Bool {
+    return digest.withUnsafeBytes { digestPointer -> Bool in
+      var digestCur = aws_byte_cursor_from_array(digestPointer.baseAddress, digest.count)
+
+      return signature.withUnsafeBytes { signaturePointer -> Bool in
+        var signatureCur = aws_byte_cursor_from_array(
+          signaturePointer.baseAddress, signature.count)
+        return aws_ecc_key_pair_verify_signature(rawValue, &digestCur, &signatureCur)
+          == AWS_OP_SUCCESS
+      }
+    }
+  }
+
+  deinit {
+    aws_ecc_key_pair_release(rawValue)
+  }
+}

Test/AwsCommonRuntimeKitTests/crt/ECTests.swift

@@ -0,0 +1,66 @@
+//  Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//  SPDX-License-Identifier: Apache-2.0.
+import XCTest
+import AwsCCommon
+
+@testable import AwsCommonRuntimeKit
+
+class ECTests: XCBaseTestCase {
+
+  func testP256() throws {
+    let input = "Hello"
+    let sha256 = try input.data(using: .utf8)!.computeSHA256()
+
+    let ecKey = try ECKeyPair.generate(algorithm: ECKeyPair.ECAlgorithm.p256)
+    let signature = try ecKey.sign(digest: sha256)
+
+    let raw = try ECKeyPair.decodeDerEcSignature(signature: signature)
+    XCTAssertEqual(
+      signature,
+      try ECKeyPair.encodeRawECSignature(signature: ECKeyPair.ECRawSignature(r: raw.r, s: raw.s)))
+
+    XCTAssertTrue(ecKey.verify(digest: sha256, signature: signature))
+  }
+
+  func testP384() throws {
+    let input = "Hello"
+    let sha256 = try input.data(using: .utf8)!.computeSHA256()
+
+    let ecKey = try ECKeyPair.generate(algorithm: ECKeyPair.ECAlgorithm.p384)
+    let signature = try ecKey.sign(digest: sha256)
+
+    let raw = try ECKeyPair.decodeDerEcSignature(signature: signature)
+    XCTAssertEqual(
+      signature,
+      try ECKeyPair.encodeRawECSignature(signature: ECKeyPair.ECRawSignature(r: raw.r, s: raw.s)))
+
+    XCTAssertTrue(ecKey.verify(digest: sha256, signature: signature))
+  }
+
+  func testImport() throws {
+    let input = "Hello"
+    let sha256 = try input.data(using: .utf8)!.computeSHA256()
+
+    let sec1Key = """
+      MHcCAQEEIHjt7c+VnkIkN6RW7QgZPFNLb/9AZEhqSYYMtwrlLb3WoAoGCCqGSM49AwEHoUQDQgAEv2F\
+      jRpMtADMZ4zoZxshV9chEkembgzZnXSUNe+DA8dKqXN/7qTcZjYJHKIi+Rn88zUGqCJo3DWF/X+ufVf\
+      dU2g==
+      """
+
+    guard let keyData = Data(base64Encoded: sec1Key) else {
+      XCTFail("Failed to decode base64 string")
+      return
+    }
+
+    let ecKey = try ECKeyPair.fromDer(data: keyData)
+    let signature = try ecKey.sign(digest: sha256)
+
+    let raw = try ECKeyPair.decodeDerEcSignature(signature: signature)
+    XCTAssertEqual(
+      signature,
+      try ECKeyPair.encodeRawECSignature(signature: ECKeyPair.ECRawSignature(r: raw.r, s: raw.s)))
+
+    XCTAssertTrue(ecKey.verify(digest: sha256, signature: signature))
+  }
+
+}