如何使用CommonCrypto在swift中解密

import CommonCrypto

func decrypt(data: Data, key: Data, algorithm: CCAlgorithm) -> Data? {
    let keyLength = key.count
    let dataLength = data.count
    let bufferSize = dataLength + kCCBlockSizeAES128
    
    var decryptedData = Data(count: bufferSize)
    var numBytesDecrypted: size_t = 0
    
    let cryptStatus = key.withUnsafeBytes { keyBytes in
        data.withUnsafeBytes { dataBytes in
            decryptedData.withUnsafeMutableBytes { decryptedBytes in
                CCCrypt(CCOperation(kCCDecrypt),
                        algorithm,
                        CCOptions(kCCOptionPKCS7Padding),
                        keyBytes.baseAddress, keyLength,
                        nil,
                        dataBytes.baseAddress, dataLength,
                        decryptedBytes.baseAddress, bufferSize,
                        &numBytesDecrypted)
            }
        }
    }
    
    if cryptStatus == kCCSuccess {
        decryptedData.removeSubrange(numBytesDecrypted..<decryptedData.count)
        return decryptedData
    }
    
    return nil
}

let encryptedData: Data = ...
let encryptionKey: Data = ...
let algorithm: CCAlgorithm = kCCAlgorithmAES
if let decryptedData = decrypt(data: encryptedData, key: encryptionKey, algorithm: algorithm) {
    // 解密成功，可以使用解密后的数据进行进一步操作
} else {
    // 解密失败
}