init

2026-08-30 10:36:52 +02:00
commit fdcc644828
30 changed files with 4152 additions and 0 deletions
@@ -0,0 +1,46 @@
+import CommonCrypto
+import Foundation
+
+/// AES-128 im Counter-Modus. CryptoKit bietet CTR nicht an, deshalb CommonCrypto.
+enum AESCounterMode {
+    /// - Parameters:
+    ///   - data: Der verschlüsselte Nutzteil des Advertisements.
+    ///   - key: 16 Byte Geräteschlüssel aus VictronConnect.
+    ///   - nonce: Der 16-Byte-Zählerblock (Victron: Nonce little-endian in den
+    ///            ersten beiden Bytes, Rest 0).
+    static func crypt(_ data: [UInt8], key: [UInt8], nonce: [UInt8]) -> [UInt8]? {
+        guard key.count == kCCKeySizeAES128, nonce.count == kCCBlockSizeAES128 else { return nil }
+
+        var cryptor: CCCryptorRef?
+        let createStatus = key.withUnsafeBytes { keyBuffer in
+            nonce.withUnsafeBytes { ivBuffer in
+                CCCryptorCreateWithMode(
+                    CCOperation(kCCEncrypt),          // CTR ist symmetrisch
+                    CCMode(kCCModeCTR),
+                    CCAlgorithm(kCCAlgorithmAES),
+                    CCPadding(ccNoPadding),
+                    ivBuffer.baseAddress,
+                    keyBuffer.baseAddress, key.count,
+                    nil, 0, 0,
+                    CCModeOptions(kCCModeOptionCTR_BE),
+                    &cryptor
+                )
+            }
+        }
+        guard createStatus == kCCSuccess, let cryptor else { return nil }
+        defer { CCCryptorRelease(cryptor) }
+
+        var output = [UInt8](repeating: 0, count: data.count)
+        var moved = 0
+        let updateStatus = data.withUnsafeBytes { input in
+            output.withUnsafeMutableBytes { out in
+                CCCryptorUpdate(cryptor,
+                                input.baseAddress, data.count,
+                                out.baseAddress, data.count,
+                                &moved)
+            }
+        }
+        guard updateStatus == kCCSuccess else { return nil }
+        return Array(output.prefix(moved))
+    }
+}