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Zheng Xi’s - Project Portfolio Page

Overview

SecureNUS is a Command-Line-Interface (CLI) application that allows users to store sensitive credentials locally. Examples of such credentials include basic password, credit card details as well as CryptoWallet fields. Information submitted by users are encrypted to safeguard the interests of the user in the event the device is lost or hacked.

Summary of Contributions

[X] Code contributed

RepoSense link
***

[X] Features

1. Save Command - `$save`

All credentials submitted by users thus far will be written to the database. This function is automatically triggered when new secrets added, edited or deleted from the database.

Enter Command: $save
_____________________________________________________
Saving secrets to storage, please do not close application...
_____________________________________________________
_____________________________________________________
Save complete. All secrets saved into assets/database.txt.
If exporting to another device, save this file into the root directory's assets/database.txt before you start me again!
_____________________________________________________

2. Backend - Saving and Loading of user data

Basic reading and writing Capabilties

File paths are retrieved via $System.getProperty(Backend.USER_DIRECTORY_IDENTIFIER) so as to circumvent differences in path syntax across different operating systems. A folder and a database.txt file is generated on behalf of users.
1. Special characters $~!@#$%^&*()-=_+[]\{}|;':",./<>?can be submitted in certain fields. To ensure the veracity of the data, modifications have to be performed before they are written into the database. When reading from the database, these modifications have to be reversed accordingly.
Encryption before data is written to the database.

Sensitive fields like $username and $password are encrypted into the database when it is written to the database and decrypted again when loaded into the program
Ensuring data validity

Intentional / unintentional edits may be performed on the data in database.txt file. Therefore checks have to be performed to verify the veracity of the data when a new session starts. These checks can be divided into 4 main categories:
1. Ensuring $name and $folder name only contain alphanumeric characters
```
   if (Secret.isIllegalName(input[2]) || !SecretMaster.isLegalFolderName(input[3]))
```
2. Ensuring the other fields in a particular secret are valid with respect to the context they are used.
```
  if (!creditCardNumber.matches(CREDIT_CARD_NUMBER_FMT)) {
  throw new InvalidCreditCardNumberException();
  }
  if (!expiryDate.matches(EXPIRY_DATE_FMT)) {
  throw new InvalidExpiryDateException();
  }
  if (!isLegalCvcNumber(cvcNumber)) {
  throw new InvalidCVCNumberException();
  }
```
3. Ensuring that there are no secrets with duplicate names
```
if (secretNames.contains(secret.getUid())) {
    throw new RepeatedIdException();
}
```
4. Final checks using the hashcode of the data
  A hashcode is generated for all information written to the database. Before data is loaded into the program, this hashcode will be cross referenced. This serves as the final line of defense against any manipulation of user user data in the database
```
   public static String hash(String data) {
  int hashcode = 0;
  ...
   }
```

3. Logging Capabilities - Logging of appropriate user data to assist in debugging

Logging Architecture
All user input is logged ```java

———————————

Session began at: 2023-04-09T23:28:12.788915800Z

——————————————————————-

Session began at: 2023-04-09T23:29:18.053986200Z

———————————–

    command by user:  new pass10
    fields:  idk.com,  c/,
    >>>>user cancelled operation

    command by user:  exit
    fields:
    ------------
    | ALERT !!!|
    ------------
    Program Crashed:  unexpected exception: null
    Time: 2023-04-09T23:47:28.668632600Z

...

Within the abstract method format, all relevant information are rearranged and formatted using static methods based on the context of the information.

    if (logArray[0].equals("start")) {
        return SecureNUSLogFormatter.startOfSessionLog(record);
    }

[X] Assertions

Added assertions to the code to better safeguard the program against unexpected inputs and lapses in programming logic

    assert this.storage != null;
    assert index >= 0;
    if (index >= storage.size()) {
        throw new ArrayIndexOutOfBoundsException();
    } 

[X] Contributions to Team Based Tasks

Wrote the junit tests for various Backend Functionalities
Authored the text-ui-tests to automate testing for the core functionalities implemented in the program
Team PR reviewed [#48]

[X] Community

Contributed to forum discussions [1]
Reported bugs and suggestions for other teams in the class [1, 2, 3]

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