Attack implementation.

[crypto_lab3.git] / src / RsaCrt.cpp

diff --git a/src/RsaCrt.cpp b/src/RsaCrt.cpp
index ff3f21e..b078013 100644 (file)
--- a/src/RsaCrt.cpp
+++ b/src/RsaCrt.cpp
@@ -41,3 +41,17 @@ mpz_class RsaCrt::sign(const mpz_class& m, const KeyPriv& kPriv)
 
    return sq + ((kPriv.qInv * (sp - sq)) % kPriv.p) * kPriv.q;
 }
+
+mpz_class RsaCrt::signWithFaultySp(const mpz_class& m, const KeyPriv& kPriv)
+{
+   mpz_class sp, sq;
+
+   mpz_powm_sec(sp.get_mpz_t(), m.get_mpz_t(), kPriv.dp.get_mpz_t(), kPriv.p.get_mpz_t());
+   mpz_powm_sec(sq.get_mpz_t(), m.get_mpz_t(), kPriv.dq.get_mpz_t(), kPriv.q.get_mpz_t());
+
+   mpz_combit(sp.get_mpz_t(), 42); // Flip the fourty second bit.
+
+   return sq + ((kPriv.qInv * (sp - sq)) % kPriv.p) * kPriv.q;
+}
+
+