I am using cryptoSwift library for encryption and decryption. But it's working with only string 16 bytes. If i am passing small string or less than 16 bytes then getting nil result.
I am using Incremental operations use instance of Cryptor and encrypt/decrypt one part at a time.
Please help me here, is there anything which i am doing wrong.
Thanks in advance.
				do {
						// Encryption start
						let data =	Data.init(base64Encoded: "12345678901234567890123456789012".base64Encoded()!)
						let iv : Array<UInt8> = [0,0,0,0,0,0,0,0,0,0,0,0]
						let nIv = Data(iv)
						let gcmEnc = GCM(iv: nIv.bytes, mode: .detached)
						var enc = try? AES(key: data!.bytes, blockMode: gcmEnc, padding: .noPadding).makeEncryptor()
						let arrStr = ["My name is tarun"] // Working
						//let arrStr = ["tarun"] // Not working for this string
						var ciphertext = Array<UInt8>()
						for txt in arrStr{
								 let ciperText = try? enc?.update(withBytes: Array(txt.utf8)) // Getting nil for small string.
								 ciphertext.append(contentsOf: ciperText!)
						}
						var res = try? enc?.finish()
						gcmEnc.authenticationTag = self.randomGenerateBytes(count: 16)?.bytes
						res?.append(contentsOf: (gcmEnc.authenticationTag)!)
						let cipherData = Data(ciphertext) + Data(res!)
						let strEnc = String(decoding: cipherData, as: UTF8.self)
						print(strEnc)
				
						// Decryption start from here
						do {
								let gcmDec = GCM.init(iv: nIv.bytes, additionalAuthenticatedData: nil, tagLength: 16, mode: .detached)
								var aesDec = try! AES(key: data!.bytes, blockMode: gcmDec, padding: .noPadding).makeDecryptor()
								let tag_length = 16
								let encData = cipherData.subdata(in: 0..<cipherData.count - tag_length)
								let tag = cipherData.subdata(in: encData.count ..< cipherData.count)
								
								let decData = try? aesDec.update(withBytes: encData.bytes) //Getting nil here for small string
								let strData = String(decoding: decData!, as: UTF8.self)
								print(strData)
								
								do{
										var res = try? aesDec.finish(withBytes: tag.bytes)
										res?.append(contentsOf: tag)
										
								}catch{
										
								}
								
						} catch {
								// failed
						}
		}
		}
		func randomGenerateBytes(count: Int) -> Data? {
				let bytes = UnsafeMutableRawPointer.allocate(byteCount: count, alignment: 1)
				defer { bytes.deallocate() }
				let status = CCRandomGenerateBytes(bytes, count)
				guard status == kCCSuccess else { return nil }
				return Data(bytes: bytes, count: count)
		}
Prashant Aggarwal
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for