Does anyone know if you do encrypt triple des on a string that can be up to 15 chars. How long is the maximum length of the encrypted string. How do you figure this out??
Tony
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googled around for a bit and I couldn't find any documentation on this...but you could test it yourself pretty easily....just create a loop that generates GUID's and then cut the GUID down to 15 chars (since you know that is your max.)..encrypt it...then do a char count on each of the encrypted strings
razzie... i'm not wanting to know the absolute max length. I just wanted to know what length to make my database field if i encrypttripledes a field that can be 15 chars. I know that I could find it out if I took 30 minutes and ran tests and all that, but I was hoping someone might just know off the top of their head.
Tony
Hi picsnet,
DES doesn't change the length of when it encrypts. Whatever the number of bits used to represent the initial value is the number of bits used to represent the encrypted value. If you have 15 characters of data or 15 * 8 bits to start with then you will end up with the same length encrypted string.
Tim Cottee
DES (and triple DES) reads data as blocks of 8 bytes (not characters). And the output has the same length. So if you try encrypt strings of length between 1 and 8 bytes, you will get 8 bytes. If you encrypt 9-16 bytes, you get 16 bytes. And so on.
If you are using UTF-8 encoding, you should get 16 bytes.
I'm not seeing what you guys are saying in the 1 password I got in my system now. I know 1 isn't much of a test, but its as far as I've gotten. I'm still working on the signup pages.
I have a password of georgia (7 chars)
it gets triple des encrypted to lvGoqugybnQ= which is 12 chars
I was expecting it to be 7 chars in the database if it didn't change length or
I was expect it to be 8 chars since it was less than 8 bytes
Here is my method:
Public Shared Function EncryptTripleDES(ByVal Value As String) As String
Dim objMemoryStream As MemoryStream = Nothing
Dim objCryptoStream As CryptoStream = Nothing
Dim objStreamWriter As StreamWriter = Nothing
Try
If Not String.IsNullOrEmpty(Value
Dim objProvider As New TripleDESCryptoServiceProv
objMemoryStream = New MemoryStream()
objCryptoStream = New CryptoStream(objMemoryStre
objStreamWriter = New StreamWriter(objCryptoStre
objStreamWriter.Write(Valu
objStreamWriter.Flush()
objCryptoStream.FlushFinal
objMemoryStream.Flush()
Return Convert.ToBase64String(obj
Else
Return String.Empty
End If
Catch Ex As Exception
Throw Ex
Finally
If objMemoryStream IsNot Nothing Then objMemoryStream.Close()
End Try
End Function
Business Accounts
Answer for Membership
by: Razzie_Posted on 2007-02-14 at 06:43:21ID: 18531479
Hi Tony,
If I unsderstand your question, you want to know what the maximum lenght of an encrypted string can be? To my knowledge, there is no maximum length of encrypted strings. The max length of a string is the max length of the string object's memory, which is 2 GB. In theory.
If you just wanted to know what the length of the encrypted string will be if you encrypt a string with a length varying from 1 to 15 chars, then I doubt you can 'predict' that. You should just call the String.Length property of the encrypted string.
HTH,
Razzie