How shall i implement encryption

Question

Hello,

i am using vb.net 2008

this is the code

Dim str1(100) As Char

        str1 = "`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./?><MNBVCXZ:LKJHGFDSA}{POIUYTREWQ+_)(*&^%$#@!~| "

        Dim STR2(100) As Char

        STR2 = " /.,MNBVCXZ';LKJHGFDSA\][POIUYTREWQ=-0987654321?><mnbvcxz:lkjhgfdsa|}{poiuytrewq~!@#$%^&*()_+"

        Dim STR3(20) As Char

        STR3 = "peter parker"

        Dim str4(20) As Char

        Dim i, j As Integer

        For j = 0 To STR3.Length

            For i = 0 To str1.Length - 1

                If (STR3(j) = str1(i)) Then

                    str4.Concat("213")

                    'str4 = STR2(i)

                End If

            Next

        Next

        MsgBox(str4)

    End Sub

it gives me index array out of range exception

through this code i am trying to do is that

i want to encrypt text in str3

i am getting an character frm str3 then searching it in str1 if found then putting an character frm str2 using the same index of str1 at which character was found in str4   

kindly help me

Answer 1

fireblade123 said:

Hello,

i am using vb.net 2008

this is the code

Dim str1(100) As Char

        str1 = "`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./?><MNBVCXZ:LKJHGFDSA}{POIUYTREWQ+_)(*&^%$#@!~| "

        Dim STR2(100) As Char

        STR2 = " /.,MNBVCXZ';LKJHGFDSA\][POIUYTREWQ=-0987654321?><mnbvcxz:lkjhgfdsa|}{poiuytrewq~!@#$%^&*()_+"

        Dim STR3(20) As Char

        STR3 = "peter parker"

        Dim str4(20) As Char

        Dim i, j As Integer

        For j = 0 To STR3.Length -1

            For i = 0 To str1.Length - 1

                If (STR3(j) = str1(i)) Then

                    str4.Concat("213")

                    'str4 = STR2(i)

                End If

            Next

        Next

        MsgBox(str4)

    End Sub

it gives me index array out of range exception

through this code i am trying to do is that

i want to encrypt text in str3

i am getting an character frm str3 then searching it in str1 if found then putting an character frm str2 using the same index of str1 at which character was found in str4   

kindly help me

Look at the marker !

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Answer 2

if i remove -1 then error comes

Answer 3

Hi,

not remove ! add it !

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Answer 4

Hello fireblade123!,

Heslacher,

I was thinking the same thing that it was probably the "STR3.Length - 1", but if we look closer we find that "str1" is 94 chars long while "STR2" is 93.  This will cause an error because the char " " is at the very end of "str1" and tries to find it in STR2 at an index which again is not there.  I went ahead and just made this a Function to make things a-bit organized, here is what I came up with:

Public Class Form1

Private encryptKey As Char() = "`1234567890-=qwertyuiop[]\asdfghjkl;'zxcvbnm,./?><MNBVCXZ:LKJHGFDSA}{POIUYTREWQ+_)(*&^%$#@!~| "

Private decryptKey As Char() = " /.,MNBVCXZ';LKJHGFDSA\][POIUYTREWQ=-0987654321?><mnbvcxz:lkjhgfdsa|}{poiuytrewq~!@#$%^&*()_+~"

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

MessageBox.Show(encrypt("peter parker"))

End Sub

Private Function encrypt(ByVal str3() As Char) As Char()

Dim str4(str3.Length - 1) As Char

Dim i As Integer = 0

For Each str03 As Char In str3

For Each str01 As Char In encryptKey

If str01 = str03 Then

str4(i) = decryptKey(Array.IndexOf(encryptKey, str01))

End If

Next

i += 1

Next

Return str4

End Function

End Class

Basically this is a cipher, in which the program looks for a Char in a Char array and replaces that Char with a new Char from a different Key.  You could actually make more functions like this and use different decrypt Keys.

NOTE: I added the "~" in the "decryptKey" to make both Keys the same Length.

I hope this helps you.  Any questions, feel free to post.

Best Regards,

Adjutor

Answer 5

Hello Adjutor, fireblade123,

yes you are right, almost. If the str3().length > 21 then there is also an indexoutofrange.

You need to change Dim str4(20) As Char  in Dim str4(str3.Length-1) As Char 

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Answer 6

Hello,

Ah, yes, trying to keep the code the same, I left out that detail.

Regards,

Adjutor

Answer 7

in the code which u have posted

u used 

Private Function encrypt(ByVal str3() As Char) As Char()

Dim str4(str3.Length - 1) As Char

Dim i As Integer = 0

For Each str03 As Char In str3

For Each str01 As Char In encryptKey

If str01 = str03 Then

str4(i) = decryptKey(Array.IndexOf(encryptKey, str01))

End If

Next

i += 1

Next

Return str4

End Function  would u plz explain to me what is str03 and str01 here........

Answer 8

I would also like to tell u that there is nothing like decrypt key here

this is only encryption algorithm program.....

u should take a look at this algorithm

1. get a character from str1

2. search for that character in str2.

3. if found then note the index of that character in temp

4. go to the index stored in temp in str3 and read the character on that index.

5. copy that character in str4

6. repeat the above procedure for all characters in str1

7. final encrypted text will be in str4

 

Answer 9

Hello fireblade123,

The str03 and str01 are like temporary variables used to store the Char that was found in the encryptKey Char array.  The program I wrote was modified based off of what you were trying to do.  The program is an encryption algorithm, based off the idea of the cipher.

The algorithm that you posted is the same algorithm that the code I posted will do, just using a different approach to keep things more orderly.  Check the output of the program, it should be what you desire, if not explain what output you expect.

Best Regards,

Adjutor

Answer 10

Hello,

Thanks. I tried u r code. It works........

Thank you very much sir for solving my problem....