致命错误：“试试！”表达式意外引发错误：CryptoSwift.AES.Error.BlockSizeExceeded：

Posted 2023-02-24

【中文标题】致命错误：“试试！”表达式意外引发错误：CryptoSwift.AES.Error.BlockSizeExceeded：

【英文标题】：fatal error: 'try!' expression unexpectedly raised an error: CryptoSwift.AES.Error.BlockSizeExceeded:

【发布时间】：2015-11-06 09:51:07

【问题描述】：

错误：

我使用了这个 AES https://github.com/krzyzanowskim/CryptoSwift 和我的代码：

覆盖 func viewDidLoad() super.viewDidLoad()

let jsonString = " \"device\": \"iphone\", \"req\": \"connect\", \"deviceId\": \"device ID\" ";

let url = UrlManager()
url.setRequestData(jsonString)
url.sendRequest( (response) -> Void in
    print("Response data: \(response)")
    let bytes: [UInt8] = Converter.hexstringConvertToBytes(response)
    print("Bytes: \(bytes)")
    let dencryptedBytes: [UInt8] = try! bytes.decrypt(AES(key: UrlManager.CONNECTION_KEY, iv: UrlManager.CONNECTION_IV))
    print("Decoded Bytes: \(dencryptedBytes)")
    let jsonData: String = Converter.bytesConvertToString(dencryptedBytes)
    print("Received json: \(jsonData)")
)

UrlManager 的方法：

internal func sendRequest(responseHandler: (response: String)-> Void)

SocketManager.sharedInstance.sendMessage(self.requestData, handler: responseHandler)

SocketManager 方法：

internal func sendMessage(message: String, handler: (response: String)-> Void)

let qualityOfServiceClass = QOS_CLASS_BACKGROUND
let backgroundQueue = dispatch_get_global_queue(qualityOfServiceClass, 0)
dispatch_async(backgroundQueue, 
    // set response data to UrlManager
    let response = self.sendRequest(message, client: self.socket)
    handler(response: response!)

    dispatch_async(dispatch_get_main_queue(),  () -> Void in
        //print("This is run on the main queue")
    )

)

但它是有效的（当我测试这段代码时）：

让hexaString = “0B8F665884EE009C64A64862E26D33C42F490D6EF227709B1900D42B71FB2169802A27FACDCF2D5587A468E2AE0C14FD7FFC2D0D291A0021814A2D5EA4DC1225BE64B04C8CCA831CB1C97277040F5E36” P>

var numbers = [UInt8]()
var from = hexaString.startIndex
while from != hexaString.endIndex 
    let to = from.advancedBy(2, limit: hexaString.endIndex)
    numbers.append(UInt8(hexaString[from ..< to], radix: 16) ?? 0)
    from = to

print(numbers) // [215, 193, 122, 79]

let dencryptedBytes: [UInt8] = try! numbers.decrypt(AES(key: "be8d5ba39cde4e41", iv: "a5e5ff5dcd2a655c"))
print(dencryptedBytes)

if let str =  NSString(bytes: dencryptedBytes, length: dencryptedBytes.count, encoding: NSUTF8StringEncoding) as? String 
    print(str)
 else 
    print("not a valid UTF-8 sequence")

为什么会这样？ 请给我建议。谢谢！

【参考方案1】：

struct Error: ErrorType 



func f() throws -> Void 
    throw Error()


/*
try! f()    // expression unexpectedly raised an error: Error()
*/

let a = try? f()
a == nil    // true
do 
    try f()
 catch 
    print("ERROR")

// print "ERROR"

在你的情况下 CryptoSwift.AES.Error.BlockSizeExceeded 并且结果为零