0
$\begingroup$

How to recover plaintext, if we know public key(RSA), correctly encrypted text and text encrypted with faulty public key, where one bit is changed?

$\endgroup$
  • 2
    $\begingroup$ Do we have any information about what bit is changed, in particular if it lies in the public exponent, or the public modulus? $\endgroup$ – fgrieu Mar 10 '15 at 17:11
  • $\begingroup$ @fgrieu, if the variation holds on a single bit of exponent, letting public modulus inchanged, the recovering the input message can be simplifyed. Observe $\frac{C^{'}}{C}=m^{e^{'}-e} \; mod \; N$ gives precious informations. $\endgroup$ – Robert NACIRI Mar 10 '15 at 20:19
0
$\begingroup$

It's interesting to mention another type of faulty attack on RSA public modulus. Up to now the majority of research papers are about how to break the system after a fault attack in regular or CRT mode.

An interesting approach (among all the surveys of fault attacks on RSA), is describerd in this paper http://www.normalesup.org/~tibouchi/papers/talk-modulusfault.pdf where the authors try to exploit the CRT combination after a faulty attack on the public modulus. The obtained system is solved by using basic Lattice reduction technics to recover the RSA secret parametrers, which is more powerfull.

| improve this answer | |
$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.