Merge 71a1c5f into 57b25a2

docs/DeveloperGuide.adoc

@@ -318,6 +318,49 @@ image::UndoRedoActivityDiagram.png[width="650"]
 ** Cons: Requires dealing with commands that have already been undone: We must remember to skip these commands. Violates Single Responsibility Principle and Separation of Concerns as `HistoryManager` now needs to do two different things.
 // end::undoredo[]
 
+// tag::userconfirmation[]
+=== User Confirmation
+Before a loan entry can be deleted, user confirmation should be required. This ensures that only authorized users are able to delete loans. This is done through the `Password` class validating any attempts to delete loans or change password.
+
+* Current Implementation *
+There are three stages in this implementation:
+
+===== Allowing the `delete` command to accept a password
+1. To allow `delete` command to accept a password, we set a stub password of `a12345` and require all `delete` command to take in a password argument.
+* When password is wrong, we do not perform the deletion of the loans.
+* Only when password matches with stub password will the loan be deleted.
+2. Tests were edited to include and check for a valid password before deletion.
+
+The following sequence diagram shows how the new `delete` operation works.
+
+image::deleteLoanWithPass.png[width="1000"]
+
+===== Allow changing of master password
+
+This is done in the following steps:
+
+1. Create a `Password` class to store the password string.
+2. Create a `setpass` command that takes in the old password and new password.
+* We reject the command if the given old password is not equal to password
+that is stored in the database. This is to ensure only the user who has the password would be allowed to change it.
+* Set password in `UserPref` to new password if old password corresponds to current password.
+3. Write test to ensure no regression.
+
+The following sequence diagram shows how the `setpass` operation works:
+
+image::setPasswordLogic.png[width="1000"]
+
+image::setPasswordModel.png[width="1000"]
+
+===== Encrypt current password for security
+To ensure that others are unable to retrieve the app's password from the preference.json, we encrypt the password before storing. Decryption of password can only be done by Password.java.
+
+This is currently done by appending `-encrypt` to the password, and removing it when
+decrypting. For version 2.0, we plan to utilise existing libraries to encrypt and
+decrypt our stored password.
+
+// end::userconfirmation[]
+
 === Return a Loan feature
 ==== Proposed Implementation