How to Encrypt a String

[Anonymous]

Hi, I'm wondering how to encrypt a string. Anybody has a clue, please help. thanks.

[arcticad]

http://www.vbforums.com/showthread.php?t=345183

Public Function encrypt(strInput As String)
Dim n As Integer, i As Integer
n = 13
For i = 1 To Len(strInput)
Mid(strInput, i, 1) = Chr(Asc(Mid(strInput, i, 1)) + n)
Next i
encrypt = strInput
End Function


Public Function decrypt(strInput As String)
Dim n As Integer, i As Integer
n = 13
For i = 1 To Len(strInput)
Mid(strInput, i, 1) = Chr(Asc(Mid(strInput, i, 1)) - n)
Next i
decrypt = strInput
End Function

[Ed__Jobe]

It depends on how secure you need it, but basically you apply an algorithm to the text, chaning it into some other string. You need to reverse the process to decrypt it. Here's a sample. http://vbnet.mvps.org/code/algorithms/rot39.htm

The main consideration becomes, which algorithm to use. You could check msdn for more info.

[Ed__Jobe]

That looks like ROT-13.

[Anonymous]

Hi, Everybody, Thank you for your replies, and Sorry I didn't reply promptly. I'm just curious, why use Rot-13, not Rot-14 or something, is there any limitation on the number?

[arcticad]

There are 26 letters. So half of them is 13. It's so you can always easily convert them back.

[Ed__Jobe]

You are only limited by your imagination as to what algorithm you apply to encrypt something. As I said earlier, what level of security you need would determine to what level of encryption you need. If you are just trying to discourage a fellow employee, then you could get away with low security. But if your information is exposed to the internet where there are people with nothing better to do than to hack into things, then you need more security. As to ROT-13, some patterns are easily recognizable.