diff --git a/include/lwehe.h b/include/lwehe.h
index abb7d6e..c4d6f6f 100644
--- a/include/lwehe.h
+++ b/include/lwehe.h
@@ -151,6 +151,14 @@ class SchemeLWE
          * @param[in] ct_2 encryption of the second input bit
          */
         void xor_gate(Ctxt_LWE& ct_res, const Ctxt_LWE& ct1, const Ctxt_LWE& ct2) const;
+
+
+        /**
+         * Computes the NOT gate of a given ciphertext ct
+         * @param[out] ct_res encryption of the outuput of the NOT gate
+         * @param[in] ct encryption of the input bit
+         */
+        void not_gate(Ctxt_LWE& ct_res, const Ctxt_LWE& ct) const;
 };
 
     
diff --git a/src/lwehe.cpp b/src/lwehe.cpp
index 025b716..d9b04a2 100644
--- a/src/lwehe.cpp
+++ b/src/lwehe.cpp
@@ -484,4 +484,13 @@ void SchemeLWE::xor_gate(Ctxt_LWE& ct_res, const Ctxt_LWE& ct1, const Ctxt_LWE&
     bootstrap(ct_res);
 }
 
+void SchemeLWE::not_gate(Ctxt_LWE& ct_res, const Ctxt_LWE& ct) const
+{
+    if (ct_res.a.size() != parLWE.n)
+        ct_res.a = vector<int>(parLWE.n);
+    for (size_t i = 0; i < parLWE.n; i++)
+        ct_res.a[i] = -ct.a[i];
+    ct_res.b = parLWE.delta_base - ct.b;
+    ct_res.b = parLWE.mod_q_base(ct_res.b);
+}