Invalid length for a Base-64 char array.

Question

2.00/5 (1 vote)

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SQL-Server-2005

, +

Hi all,

When i try to decrypt my password which is stored in binary(16),null datatype in DB, it gives me error like 'Invalid length for a Base-64 char array.'.

i try the below code from one of the asp.net forum.

C#

public string DecryptPassowrd(object obj)
{
    string password = obj.ToString();
    System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
    System.Text.Decoder utf8Decode = encoder.GetDecoder();
    byte[] todecode_byte = Convert.FromBase64String(password);
    int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
    char[] decoded_char = new char[charCount];
    utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
    string result = new String(decoded_char);
    return result;
}

I got the error at byte[] todecode_byte = Convert.FromBase64String(password); line.

when i googled for that error many of site says to replace " " to "+". but when i did this it gives me another error.

String cannot be of zero length.
Parameter name: oldValue

i am trying to decode "0xA02B92F62E209BC4058E08CF4F6C9689".

so what sould i do to overcome this error?

thanks,
krunal

Posted 16-Jul-12 20:58pm

kk2014

Updated 16-Jul-12 21:00pm

StianSandberg

v2

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Comments

ssd_coolguy 17-Jul-12 3:11am

hei.. i am not sure but this error comes when your string contains any blank space.. that's why you need to replace youre sting with " " to "+".

kk2014 17-Jul-12 4:25am

i think there is no blank space in my string i have provided but solution like this given on net. 0x indicating it is hex string.

OriginalGriff 17-Jul-12 4:52am

"so can u give/suggest me code to decrypt the string in normal plain text which i had provided?"

Sorry, but no - I have absolutely no idea how you encrypted it.
Start with the code you used to that - it should be fairly clear.

3 solutions

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OriginalGriff · Answer 1 · 2012-07-16T21:04:00

Solution 2

That doesn't look like a base64 string - it looks like a normal hex number - albeit a bit hex number - and the "0x" prefix does sort of hint at that as well.

I would go back to where you stored the information, and look at the process you used to convert it from binary to a format you can store in a DB - then reverse it.

BTW: You do realize that Base64 is not an encryption algorithm in nay way, don't you? And that it provides the same security level as printing your data on a T shirt and selling them on Ebay?

Posted 16-Jul-12 21:04pm

OriginalGriff

Comments

Sandeep Mewara 17-Jul-12 4:44am

Comment from OP:

ok nop.

so can u give/suggest me code to decrypt the string in normal plain text which i had provided?

thanks.

OriginalGriff 17-Jul-12 4:51am

Sorry, but no - I have absolutely no idea how you encrypted it.
Start with the code you used to that - it should be fairly clear.

OriginalGriff 17-Jul-12 4:52am

Sorry Sandeep - I didn't notice it was from you!

Sandeep Mewara 17-Jul-12 5:37am

No problemo! :)

Phanindra Baddula · Answer 2 · 2014-05-27T02:50:00

try this it will work

public string Decryptdata(string encryptpwd)
{
string decryptpwd = string.Empty;
UTF8Encoding encodepwd = new UTF8Encoding();
Decoder Decode = encodepwd.GetDecoder();
byte[] todecode_byte = Convert.FromBase64String(encryptpwd);
int charCount = Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
char[] decoded_char = new char[charCount];
Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
decryptpwd = new String(decoded_char);
return decryptpwd;
}

sachin tank · Answer 3 · 2013-04-19T01:46:00

Solution 4

add an space between ""

"" should be " "

Posted 19-Apr-13 1:46am

sachin tank