VB.NET Project 3
Classes and Objects, Methods and Properties
Referencing Project 2, instantiate an encryption class (see distributed class notes) to perform the character shift encryption and decryption.
Include clsSecurity.vb in your Project (see the Solution Explorer in the Visual Studio IDE)
Instantiate clsSecurity to create an Object named objShift
Use both the properties and methods of objShift to perform encryption/decryption in your VB project
The provided clsSecurity.vb class members include:
Methods
Encrypt()
Note: You will need to write the Decrypt () method in the clsSecurity.vb class
Properties
KeyNum
KeyString
CurrentChar
CharOutput
KeyDigit
CharASCII
From Project 2....
Develop a Visual Basic Windows Forms application that will ‘encrypt' (character shift)' the characters in a string based on a symmetric key (process known as symmetric-key cryptography). The application must also ‘decrypt' the message based on the symmetric key used.
General Requirements
The clear-text message (that will be ‘encrypted') is stored in a text-file.
The text-file is to be selected using an OpenFileDialog Windows control object
Text-file contents are to be displayed in a Textbox control located on the Windows form (you can also use this textbox to input clear-text characters)
Keys are contained in a ComboBox control object. Users can select a particular key resulting in alternate cipher-text output
Keys are to be a minimum of 5 digits. Each key digit is used for encoding where your program will move to the next digit for every character in the clear-text message.
Since there are a limited number of digits in a key, your program must ‘wrap-back' to the first digit
The selected key must be stored in an array
The resulting cipher-text output is to be stored in a text file and displayed in a textbox control on the Windows form
Using the same key for encryption, decrypt the cipher-text message and display it in a label on the Windows Form
Since only printable characters are used (see table), if the ASCII code becomes larger than 126, you will need to wrap around to the ASCII code 32 (space)
Use exception handling where needed...for example, FileNotFound or DirectoryNotFound.
Example: Using a sample key of 58912, the output would be as follows:
|
Clear Character
|
N
|
J
|
I
|
T
|
|
V
|
B
|
N
|
e
|
T
|
|
ASCII Code
|
78
|
74
|
73
|
84
|
32
|
86
|
66
|
78
|
101
|
84
|
|
ASCII Code + Key Value
|
83
|
82
|
82
|
85
|
34
|
91
|
74
|
87
|
102
|
86
|
|
Shifted Character
|
S
|
R
|
R
|
U
|
"
|
[
|
J
|
W
|
f
|
V
|
Clear-Text: "NJIT VBNet"
Cipher-Text: "SRRU"[JWfV"]