encrypt and decrypt more than 132 char in Swift - swift

Question

I have this Rsa swift code and it's work good and encrypt or decrepit data but when string.count is more than 132 char error decrepit and encrypt data , how can I decrepit and encrypt data for more than 132 char
my Rsa class is, I don't want separate my data
class RSAWrapper {
private var publicKey : SecKey?
private var privateKey : SecKey?
func generateKeyPair(keySize: UInt, privateTag: String, publicTag: String) -> Bool {
self.publicKey = nil
self.privateKey = nil
if (keySize != 512 && keySize != 1024 && keySize != 2048) {
// Failed
print("kelid kharab ast")
return false
}
let publicKeyParameters: [NSString: AnyObject] = [
kSecAttrIsPermanent: true as AnyObject,
kSecAttrApplicationTag: publicTag as AnyObject
]
let privateKeyParameters: [NSString: AnyObject] = [
kSecAttrIsPermanent: true as AnyObject,
kSecAttrApplicationTag: publicTag as AnyObject
]
let parameters: [String: AnyObject] = [
kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
kSecAttrKeySizeInBits as String: keySize as AnyObject,
kSecPrivateKeyAttrs as String: privateKeyParameters as AnyObject,
kSecPublicKeyAttrs as String: publicKeyParameters as AnyObject
];
let status : OSStatus = SecKeyGeneratePair(parameters as CFDictionary, &(self.publicKey), &(self.privateKey))
return (status == errSecSuccess && self.publicKey != nil && self.privateKey != nil)
}
func encrypt(text: String) -> [UInt8] {
let plainBuffer = [UInt8](text.utf8)
var cipherBufferSize : Int = Int(SecKeyGetBlockSize((self.publicKey)!))
var cipherBuffer = [UInt8](repeating:0, count:Int(cipherBufferSize))
// Encrypto should less than key length
let status = SecKeyEncrypt((self.publicKey)!, SecPadding.PKCS1, plainBuffer, plainBuffer.count, &cipherBuffer, &cipherBufferSize)
if (status != errSecSuccess) {
print("Failed Encryption")
}
return cipherBuffer
}
func decprypt(encrpted: [UInt8]) -> String? {
var plaintextBufferSize = Int(SecKeyGetBlockSize((self.privateKey)!))
var plaintextBuffer = [UInt8](repeating:0, count:Int(plaintextBufferSize))
let status = SecKeyDecrypt((self.privateKey)!, SecPadding.PKCS1, encrpted, plaintextBufferSize, &plaintextBuffer, &plaintextBufferSize)
if (status != errSecSuccess) {
print("Failed Decrypt")
return nil
}
return NSString(bytes: &plaintextBuffer, length: plaintextBufferSize, encoding: String.Encoding.utf8.rawValue)! as String
}
func encryptBase64(text: String) -> String {
let plainBuffer = [UInt8](text.utf8)
var cipherBufferSize : Int = Int(SecKeyGetBlockSize((self.publicKey)!))
var cipherBuffer = [UInt8](repeating:0, count:Int(cipherBufferSize))
// Encrypto should less than key length
let status = SecKeyEncrypt((self.publicKey)!, SecPadding.PKCS1, plainBuffer, plainBuffer.count, &cipherBuffer, &cipherBufferSize)
if (status != errSecSuccess) {
print("Failed Encryption")
}
let mudata = NSData(bytes: &cipherBuffer, length: cipherBufferSize)
return mudata.base64EncodedString(options: NSData.Base64EncodingOptions.lineLength64Characters)
}
func decpryptBase64(encrpted: String) -> String? {
let data : NSData = NSData(base64Encoded: encrpted, options: .ignoreUnknownCharacters)!
let count = data.length / MemoryLayout<UInt8>.size
var array = [UInt8](repeating: 0, count: count)
data.getBytes(&array, length:count * MemoryLayout<UInt8>.size)
var plaintextBufferSize = Int(SecKeyGetBlockSize((self.privateKey)!))
var plaintextBuffer = [UInt8](repeating:0, count:Int(plaintextBufferSize))
let status = SecKeyDecrypt((self.privateKey)!, SecPadding.PKCS1, array, plaintextBufferSize, &plaintextBuffer, &plaintextBufferSize)
if (status != errSecSuccess) {
print("Failed Decrypt")
return nil
}
return NSString(bytes: &plaintextBuffer, length: plaintextBufferSize, encoding: String.Encoding.utf8.rawValue)! as String
}
func getPublicKey() -> SecKey? {
return self.publicKey
}
func getPrivateKey() -> SecKey? {
return self.privateKey
}
I try to change UInt8 but when I do that error, what I must to do?

Answer 1

For encryption data use symmetric encryption such as AES, it is fast and does not have a size limitation.
If you really need to use an RSA (asymmetric) key pair use hybrid encryption where the data is encrypted with symmetric encryption and the symmetric is encrypted with asymmetric encryption, this is called hybrid encryption.
But as Luke states, just use HTTPS for encryption of data in transit.

Answer 2

only way Is that split string
this class for split.
extension String {
func splitByLength(_ length: Int) -> [String] {
var result = [String]()
var collectedCharacters = [Character]()
collectedCharacters.reserveCapacity(length)
var count = 0
for character in self.characters {
collectedCharacters.append(character)
count += 1
if (count == length) {
// Reached the desired length
count = 0
result.append(String(collectedCharacters))
collectedCharacters.removeAll(keepingCapacity: true)
}
}
// Append the remainder
if !collectedCharacters.isEmpty {
result.append(String(collectedCharacters))
}
return result
}
}
and then
let rsa : RSAWrapper? = RSAWrapper()
let success : Bool = (rsa?.generateKeyPair(keySize: 2048, privateTag: "com.atarmkplant", publicTag: "com.atarmkplant"))!
if (!success) {
print("Failed")
return
}
let test : String = "string more than 132 char "
let test2=test.splitByLength(132)
let tedadarrray = test2.count
var i = 0
var encryptionstring = ""
repeat {
let test3 = test2[i]
let encryption = rsa?.encryptBase64(text: test3)
encryptionstring = encryptionstring + encryption!
i = i + 1
} while i < tedadarrray
let decripArray = encryptionstring.splitByLength(349)
let tedadarrray2 = decripArray.count
var i2 = 0
var decripttionstring = ""
repeat {
print(i2 as Any)
let test3 : String = decripArray[i2]
let decription = rsa?.decpryptBase64(encrpted: test3)
decripttionstring = decripttionstring + decription!
i2 = i2 + 1
} while i2 < tedadarrray2