Is this Visual Basic encryption algorithm secure for real-world use?

No. This algorithm is intended for educational purposes only. For production systems, standardized cryptographic solutions such as the Web Crypto API should be used.

Why does this tutorial use BigInteger?

BigInteger is used to handle large numbers generated by the key-dependent recurrent sequence, avoiding numeric overflow and improving accuracy.

What is key-dependent encoding?

Key-dependent encoding is an encryption approach where the transformation of data depends directly on a secret key, ensuring that the same key is required to reverse the process.

Single Key Encryption in VB.Net | Symmetric Cryptography Tutorial

Q: What is single key encryption in Visual Basic?

Single key encryption, also known as symmetric encryption, uses the same secret key for both encryption and decryption. In Visual Basic, this means the same key is required to encode and decode data.

Visual Basic Secret Key Encryption Using a Single Key

This page presents a Visual Basic secret key encryption tutorial based on a key-dependent encoding algorithm. The method demonstrates how a single secret key can be used to both encrypt and decrypt textual data using a mathematical recurrent sequence. The implementation is intended for educational purposes, helping students and developers understand the fundamentals of custom encryption algorithms in Visual Basic.

Secret Key Encryption in Visual Basic Explained

Encryption, or Encoding, simply is the art of leaving data in obfuscated form in order to keep it secure.

It could be as simple as replacing all characters in a text file with those from a predetermined set in a manner that has the original text having a direct correlation with the encrypted / encoded version.
An example of this is seen in the Base-64 Encoding System.

Encryption could also mean adding junk data to an original data in such a way that the original data is completely defaced but can still be comfortably extracted from the encrypted version.

Encryption processes must always be consistent: i.e. the same type of encryption, or encoding, carried out on the same data or file must always produce exactly the same obfuscated output.

What Is Single Key Encryption in Visual Basic?

Single key encryption, also known as symmetric encryption, is a cryptographic approach in which the same secret key is used for both encryption and decryption. In a Visual Basic context, this means that any party wishing to decode an encrypted message must possess the same key that was used to encode it.

In this tutorial, the secret key influences the encoding process directly. Each character in the message is transformed according to a mathematically generated sequence that depends on the key, making this a clear example of key-dependent encoding in Visual Basic.

How Single Key Encryption Works | Explanation for Visual Basic Kids

In secret key cryptography, both parties rely on the same key for encryption and decryption. We'll explore how Visual Basic cryptography algorithms apply recurrent series to strengthen security, ensuring that sensitive information remains protected.

With key dependent encryption, every unique key produces a completely different encoded set or obfuscated data.
This ensures better security of data since brute-forcing becomes very difficult without knowledge of the secret key used.
Also, the longer the key used, the more useless brute-forcing becomes.

This means that different individuals or firms can employ the same encryption process, but have their own unique secret key (Private Key) to encrypt data with.
Such encrypted data cannot be comfortably decrypted by a second firm using the same encryption process if the first firm can keep its key secret enough.

Overview of the Visual Basic Encryption Algorithm

The Visual Basic encryption algorithm used here is not based on standard cryptographic libraries or industry encryption standards. Instead, it illustrates how encryption can be constructed from first principles using mathematics and programming logic.

Key characteristics of the Visual Basic algorithm include:

A single secret key shared between encryption and decryption
A recurrent mathematical series generated from the key
Character-by-character transformation of plaintext
Reversible encoding that allows accurate decryption

This makes the approach well suited for learning how Visual Basic encryption and decryption mechanisms work internally, rather than for securing sensitive production data.

Key-Dependent Encoding Process | Explanation for Visual Basic Kids

At the core of this implementation is a key-dependent encoding algorithm in Visual Basic. The secret key is first converted into a numerical form, which then seeds a recurrent series. This series determines how each character's numeric representation is modified during encryption.

Because the same sequence can be regenerated using the same key, the process is fully reversible. During decryption, the algorithm applies the inverse operations to recover the original text.

This approach demonstrates an important principle in cryptography: the strength of an encryption system depends heavily on the secrecy and handling of the key.

Use of BigInteger for Large Number Arithmetic

Visual Basic's native number type has limitations when working with very large integers. To overcome this, the algorithm uses the BigInteger library, allowing calculations to be performed beyond standard numeric bounds.

Using BigInteger enables:

Reliable handling of large values generated by the recurrent sequence
Accurate encryption and decryption without numeric overflow
A clearer demonstration of mathematical encryption with Visual Basic

This makes the example particularly useful for educational settings where precision and transparency are important.

Visual Basic Encryption and Decryption Example | Explanation for Visual Basic Kids

The following implementation shows how to encrypt text in Visual Basic using a single secret key, and how to decode the encrypted output using the same key. The example illustrates a complete **encode and decode workflow with a secret key**, highlighting the symmetry of the algorithm.

By studying the code, readers can observe how:

Plaintext characters are converted to numeric form
The key-generated sequence modifies each value
The encrypted output is produced and later reversed

This reinforces understanding of custom cryptography implementations in Visual Basic.

Geometric Sequences or Series | Maths Explanation for Visual Basic Kids

Remember Geometric Sequences and Series from Ordinary Level Mathematics; Recurrent Series to be precise? They become as useful as they can be here!

Recurrent Series has the unique characteristic that all succeeding terms in a progression are totally dependent on all preceding terms - i.e. for any Recurrent Series, any n+1^th term cannot be determined unless the value of the n^th term and its predecessors are known;
and even more true is the fact that every other term in the progression is absolutely dependent on the 1^st term of the series.

So given the carefully selected recurrent series

$$ T_n = \frac{3^{n-1}(2t_1 + 1) - 1}{2} $$ where $t_1$ is the first term,

We can exploit the core property of recurrent series and use the above sequence for encrypting data in Visual Basic with reference to single secret keys.

Create a new VB.Net class file;
Call it SoleKeyEncryption.
Type out the adjoining VB.Net algorithm for encrypting a chunk of data with a secret key.

Important: BigInteger is inbuilt in VB.Net.
You only need to import the System.Numerics library.

You might have to add the above library in the reference section - Project >> Add Reference...; tick off System.Numerics - to be able to use it.

Educational Use and Limitations | Explanation for Visual Basic Kids

While this example demonstrates core ideas behind encryption, it should not be used as a replacement for established cryptographic standards such as those provided by the Web Crypto API.

This tutorial is best suited for:

Learning how encryption algorithms work internally
Teaching cryptography concepts with Visual Basic
Exploring key-dependent encoding methods
Understanding the relationship between mathematics and data security

For real-world applications, standardized and peer-reviewed cryptographic libraries should always be used.

Applications of Secret Key Encryption Algorithm in Visual Basic

Securing user authentication systems
Protecting sensitive data in web applications
Implementing data security with Visual Basic for client-side operations

Summary: Visual Basic Secret Key Encryption Algorithm

This tutorial provides a clear and practical introduction to single key encryption in Visual Basic using a mathematical, key-dependent encoding algorithm. By combining recurrent sequences with BigInteger arithmetic, it demonstrates how encryption and decryption can be implemented from first principles.

The example serves as a foundation for further study in Visual Basic cryptography, algorithm design, and data security concepts. Mastering Visual Basic secret key encryption equips developers with essential skills for building secure applications.

VB.Net Code for Sole Key Encryption - Class File

Imports System.Numerics
Imports System.Globalization

Public Class SoleKeyEncryption

    Public Function encodeWord(msg As Char(), key As Char()) As String()
        ' encoding eqn { Tn = 3^n-1(2t1 + 1) - 1 } - please use your own eqn
        '                        2
        Dim encryption(msg.Length - 1) As String
        Dim n As Integer
        Dim t1 As Integer
        Dim Tn As BigInteger
        For i As Integer = 0 To msg.Length - 1
            ' get unicode of this character as t1
            t1 = AscW(msg(i))
            ' get next key digit as n
            n = Convert.ToInt32(key(i Mod (key.Length - 1)).ToString(), 16)
            ' use recurrence series equation to encrypt & save in base 16
            Tn = BigInteger.Divide(BigInteger.Subtract(BigInteger.Multiply(BigInteger.Pow(3, n - 1), 2 * t1 + 1), 1), 2)
            encryption(i) = Tn.ToString("X")
        Next i

        Return encryption
    End Function

    Public Function decodeWord(code As String(), key As Char()) As String
        ' decoding eqn { t1 = 3^1-n(2Tn + 1) - 1 }
        '                        2
        Dim decryption As String = ""
        Dim n As Integer
        Dim t1 As BigInteger
        Dim Tn As BigInteger
        For i As Integer = 0 To code.Length - 1
            Tn = BigInteger.Parse(code(i), NumberStyles.HexNumber)
            ' get next key digit as n
            n = Convert.ToInt32(key(i Mod (key.Length - 1)).ToString(), 16)
            ' use recurrence series equation to decrypt
            t1 = BigInteger.Divide(BigInteger.Subtract(BigInteger.Divide(2 * Tn + 1, BigInteger.Pow(3, n - 1)), 1), 2)
            decryption &= ChrW(CInt(t1))
        Next i

        Return decryption
    End Function

End Class

VB.Net Code for Sole Key Encryption - Main Class

Module Miscellaneous_SoleKeyEncryption

    Sub Main()

        Dim message As Char() = "merry xmas".ToCharArray()
        Dim key As Char() = "A5FB17C4D8".ToCharArray() ' you might want To avoid zeroes
        Dim go_secure As SoleKeyEncryption = New SoleKeyEncryption()

        Dim encrypted As String() = go_secure.encodeWord(message, key)
        Console.WriteLine("Message is '" & String.Join("", message) & "';" &
                          Environment.NewLine & "Encrypted version is " & String.Join(", ", encrypted))

        Dim decrypted As String = go_secure.decodeWord(encrypted, key)
        Console.WriteLine(Environment.NewLine & "Decrypted version is '" & decrypted & "'.")

    End Sub

End Module

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