Hi Shaheed,
The OpenSSL error you are getting means that OpenSSL decrypted the
ciphered text but couldn't find the PKCS1 padding byte. This means that
the wrong CRT parameters were supplied. Usually this comes from the fact
that the parameters p and q (and the corresponding dmp1, dmq1) must be
swapped : p instead of q and q instead of p (same thing for dmp1 and dmq1).
In order to check this, you can use a tool I have written and that
enables you to recover e and d from these 5 parameters. You can get it
from sourceForge using the following link :
http://rsaconverter.sourceforge.net/ .
Thanks to it, you can check that these 5 parameters give you the correct
d and e. In your case, I'm sure you'll get the wrong d and e. Swap the
parameters and see if you get the correct d this time.
I hope this will help.
Cheers,
--
Mounir IDRASSI
IDRIX
http://www.idrix.fr
On 2/24/2011 4:03 AM, Shaheed Bacchus (sbacchus) wrote:
Just to be clear, below is not the actual code, but what I would
**like** to be able to do (or something close).
*From:*owner-openssl-us...@openssl.org
[mailto:owner-openssl-us...@openssl.org] *On Behalf Of *Shaheed
Bacchus (sbacchus)
*Sent:* Wednesday, February 23, 2011 9:47 PM
*To:* openssl-users@openssl.org
*Subject:* RSA_private_decrypt without e and d
Hi,
I have a situation where I have a message that has been encrypted via
RSA_public_encrypt. On the receiving end I have the n, p, q, dmp1,
dmq1, and iqmp components (I know it might sound odd that I don’t have
the e and d components but that is the case). I’m trying to do
something like:
If (!(new_key = RSA_new()))
return -1;
new_key->n = BN_bin2bn(n_data, n_data_len, NULL);
new_key->p = BN_bin2bn(p_data, p_data_len, NULL);
new_key->q = BN_bin2bn(q_data, q_data_len, NULL);
new_key->dmp1 = BN_bin2bn(dmp1_data, dmp1_data_len, NULL);
new_key->dmq1 = BN_bin2bn(dmq1_data, dmq1_data_len, NULL);
new_key->iqmp = BN_bin2bn(iqmp_data, iqmp1_data_len, NULL);
resultDecrypt = RSA_private_decrypt(encrypted_size, encrypted,
decrypted, new_key, RSA_PKCS1_PADDING);
This decrypt fails with
error:0407106B:rsa routines:RSA_padding_check_PKCS1_type_2:block type
is not 02
Supplying the correct e and d component causes it work properly, but I
will not have those under normal circumstances. Is there any way to do
this without d and e?
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