Fix a bug in correlation_immunity function

src/sage/crypto/boolean_function.pyx

@@ -847,15 +847,26 @@ cdef class BooleanFunction(SageObject):
             sage: B = BooleanFunction("7969817CC5893BA6AC326E47619F5AD0")
             sage: B.correlation_immunity()
             2
+
+        TESTS:
+
+        Check if :trac:`28001` is fixed::
+
+            sage: from sage.crypto.boolean_function import BooleanFunction
+            sage: f = [False, False, True, False, False, True, False, False]
+            sage: f = BooleanFunction(f)
+            sage: f.correlation_immunity()
+            1
         """
         cdef long c, i
         if self._correlation_immunity is None:
             c = self._nvariables
             W = self.walsh_hadamard_transform()
-            for i in range(len(W)):
+            for i in range(1, len(W)):
                 sig_check()
                 if W[i]:
-                    c = min(c, hamming_weight(i))
+                    c = hamming_weight(i)
+                    break
             self._correlation_immunity = ZZ(c-1)
         return self._correlation_immunity
 

src/sage/groups/libgap_wrapper.pyx

@@ -347,7 +347,7 @@ class ParentLibGAP(SageObject):
 
     def minimal_normal_subgroups(self):
         """
-        Return the nontrivial minimal normal subgroups ``self``.
+        Return the nontrivial minimal normal subgroups of ``self``.
 
         EXAMPLES::
 

src/sage/groups/perm_gps/permgroup.py

@@ -4118,7 +4118,7 @@ def isomorphism_type_info_simple_group(self):
 
     def minimal_normal_subgroups(self):
         """
-        Return the nontrivial minimal normal subgroups ``self``.
+        Return the nontrivial minimal normal subgroups of ``self``.
 
         EXAMPLES::