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JFRobertoAsked on December 1, 2018 at 6:31 PM
Hi
I try to decrypt the data of a form using c # RSACryptoServiceProvider.
I get the error "the data to be decrypted exceeds the maximum for this modulus of 128 bytes"
You can provide an example c # code for decoding the values retrieved from a form.
Thanks in advance
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MikeReplied on December 2, 2018 at 12:39 AM
At this time we have only a PHP code example to decrypt the data:
class Decryption
{
private $privateKey = '{yourPrivateKey}';
public
function decryptSegment($data)
{
if (openssl_private_decrypt(base64_decode($data) , $decryptedData, $this->privateKey)) return $decryptedData;
return "ERROR 1000: Decryption failed!";
}
function decrypt($data)
{
$decrypted_string = '';
$string_parts = preg_split("/#Jot#/", $data);
}
foreach($string_parts as $str)
{
$decrypted_string.= $this->decryptSegment($str);
}
return $decrypted_string;
}
}I have escalated a ticket to see if we can create a C# example. Althrough, we cannot provide a ETA for when this will be addressed.
We will get back to you via this thread if we have any updates.
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JFRobertoReplied on December 2, 2018 at 4:15 AM
Hi Mike
thank you for the sample, but I can't use PHP in my project.
So I have another question,
I read at this link
https://www.jotform.com/help/344-Encrypted-Forms-and-How-to-Use-Them
that I can create my Public and Private Key and post it.
The question is :
Can generate the Key with another tool (dll) that is not openssl, for c# there is System.Security.Cryptography.RijndaelManaged then generate XML file (not PEM) ?
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MikeReplied on December 2, 2018 at 9:28 AM
Looks like that Rijndael algorithm is similar to AES, so I think that the RijndaelManaged Class will not work since we use RSA based encryption.
We use RSA 2048-bit keys. In theory, you can upload your own RSA 2048 key generated with some library other than OpenSSL. However, we recommend using the OpenSSL.