diff --git a/IDNACocoaTouch copy-Info.plist b/IDNACocoaTouch copy-Info.plist
new file mode 100644
index 0000000..9bcb244
--- /dev/null
+++ b/IDNACocoaTouch copy-Info.plist	
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>$(PRODUCT_BUNDLE_PACKAGE_TYPE)</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
+</dict>
+</plist>
diff --git a/Sources/IDNA/Data+Extensions.swift b/Sources/IDNA/Data+Extensions.swift
index 140b649..50d6995 100644
--- a/Sources/IDNA/Data+Extensions.swift
+++ b/Sources/IDNA/Data+Extensions.swift
@@ -10,11 +10,21 @@ import zlib
 
 extension Data {
 
+	/// Compute the CRC-32 of the data.
+	///
+	/// Does not handle data with a `count` larger than `UInt32.max` on macOS
+	/// < 10.13 or on iOS < 11.0.
 	var crc32: UInt32 {
 		return self.withUnsafeBytes {
 			let buffer = $0.bindMemory(to: UInt8.self)
-			let initial = zlib.crc32(0, nil, 0)
-			return UInt32(zlib.crc32(initial, buffer.baseAddress, numericCast(buffer.count)))
+
+			if #available(macOS 10.13, iOS 11.0, tvOS 9999.0, watchOS 9999.0, *) {
+				let initial = zlib.crc32_z(0, nil, 0)
+				return UInt32(zlib.crc32_z(initial, buffer.baseAddress, buffer.count))
+			} else {
+				let initial = zlib.crc32(0, nil, 0)
+				return UInt32(zlib.crc32(initial, buffer.baseAddress, UInt32(buffer.count)))
+			}
 		}
 	}