diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index 4551011f5ca9ef..190b42664c7f6a 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -380,6 +380,15 @@ def test_no_unicode_blake2(self):
         self.check_no_unicode('blake2b')
         self.check_no_unicode('blake2s')
 
+    @requires_blake2
+    @support.cpython_only
+    def test_bug_41052(self):
+        import pickle
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            s, b = _blake2.blake2s(), _blake2.blake2b()
+            self.assertRaises(TypeError, s, proto)
+            self.assertRaises(TypeError, b, proto)
+
     @requires_sha3
     def test_no_unicode_sha3(self):
         self.check_no_unicode('sha3_224')
diff --git a/Modules/_blake2/blake2b_impl.c b/Modules/_blake2/blake2b_impl.c
index 8e1acce56b1d29..69ac8757081a46 100644
--- a/Modules/_blake2/blake2b_impl.c
+++ b/Modules/_blake2/blake2b_impl.c
@@ -334,12 +334,29 @@ _blake2_blake2b_hexdigest_impl(BLAKE2bObject *self)
     return _Py_strhex((const char *)digest, self->param.digest_length);
 }
 
+/*[clinic input]
+_blake2.blake2b.__reduce__
+
+Return the digest value as a string of hexadecimal digits.
+[clinic start generated code]*/
+
+static PyObject *
+_blake2_blake2b___reduce___impl(BLAKE2bObject *self)
+/*[clinic end generated code: output=3aeb49ad77e385ca input=6155b63cd93bf62c]*/
+{
+    PyErr_Format(PyExc_TypeError,
+                 "cannot pickle %s object",
+                 Py_TYPE(self)->tp_name);
+    return NULL;
+}
+
 
 static PyMethodDef py_blake2b_methods[] = {
     _BLAKE2_BLAKE2B_COPY_METHODDEF
     _BLAKE2_BLAKE2B_DIGEST_METHODDEF
     _BLAKE2_BLAKE2B_HEXDIGEST_METHODDEF
     _BLAKE2_BLAKE2B_UPDATE_METHODDEF
+    _BLAKE2_BLAKE2B___REDUCE___METHODDEF
     {NULL, NULL}
 };
 
diff --git a/Modules/_blake2/blake2s_impl.c b/Modules/_blake2/blake2s_impl.c
index e1de5df37d0988..a1bae8dbe03c26 100644
--- a/Modules/_blake2/blake2s_impl.c
+++ b/Modules/_blake2/blake2s_impl.c
@@ -333,12 +333,29 @@ _blake2_blake2s_hexdigest_impl(BLAKE2sObject *self)
     return _Py_strhex((const char *)digest, self->param.digest_length);
 }
 
+/*[clinic input]
+_blake2.blake2s.__reduce__
+
+Return the digest value as a string of hexadecimal digits.
+[clinic start generated code]*/
+
+static PyObject *
+_blake2_blake2s___reduce___impl(BLAKE2sObject *self)
+/*[clinic end generated code: output=fb085f3da88f0c39 input=49898c2f1ef1ff74]*/
+{
+    PyErr_Format(PyExc_TypeError,
+                 "cannot pickle %s object",
+                 Py_TYPE(self)->tp_name);
+    return NULL;
+}
+
 
 static PyMethodDef py_blake2s_methods[] = {
     _BLAKE2_BLAKE2S_COPY_METHODDEF
     _BLAKE2_BLAKE2S_DIGEST_METHODDEF
     _BLAKE2_BLAKE2S_HEXDIGEST_METHODDEF
     _BLAKE2_BLAKE2S_UPDATE_METHODDEF
+    _BLAKE2_BLAKE2S___REDUCE___METHODDEF
     {NULL, NULL}
 };
 
diff --git a/Modules/_blake2/clinic/blake2b_impl.c.h b/Modules/_blake2/clinic/blake2b_impl.c.h
index 4e74e0885cf238..cbb69bb008253c 100644
--- a/Modules/_blake2/clinic/blake2b_impl.c.h
+++ b/Modules/_blake2/clinic/blake2b_impl.c.h
@@ -247,4 +247,22 @@ _blake2_blake2b_hexdigest(BLAKE2bObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _blake2_blake2b_hexdigest_impl(self);
 }
-/*[clinic end generated code: output=10eb47aba77f192d input=a9049054013a1b77]*/
+
+PyDoc_STRVAR(_blake2_blake2b___reduce____doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n"
+"Return the digest value as a string of hexadecimal digits.");
+
+#define _BLAKE2_BLAKE2B___REDUCE___METHODDEF    \
+    {"__reduce__", (PyCFunction)_blake2_blake2b___reduce__, METH_NOARGS, _blake2_blake2b___reduce____doc__},
+
+static PyObject *
+_blake2_blake2b___reduce___impl(BLAKE2bObject *self);
+
+static PyObject *
+_blake2_blake2b___reduce__(BLAKE2bObject *self, PyObject *Py_UNUSED(ignored))
+{
+    return _blake2_blake2b___reduce___impl(self);
+}
+/*[clinic end generated code: output=fb5bd684d682c259 input=a9049054013a1b77]*/
diff --git a/Modules/_blake2/clinic/blake2s_impl.c.h b/Modules/_blake2/clinic/blake2s_impl.c.h
index 0f0d9835fbfe24..c2a25ffd76510d 100644
--- a/Modules/_blake2/clinic/blake2s_impl.c.h
+++ b/Modules/_blake2/clinic/blake2s_impl.c.h
@@ -247,4 +247,22 @@ _blake2_blake2s_hexdigest(BLAKE2sObject *self, PyObject *Py_UNUSED(ignored))
 {
     return _blake2_blake2s_hexdigest_impl(self);
 }
-/*[clinic end generated code: output=f7ee8092ed67e9c7 input=a9049054013a1b77]*/
+
+PyDoc_STRVAR(_blake2_blake2s___reduce____doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n"
+"Return the digest value as a string of hexadecimal digits.");
+
+#define _BLAKE2_BLAKE2S___REDUCE___METHODDEF    \
+    {"__reduce__", (PyCFunction)_blake2_blake2s___reduce__, METH_NOARGS, _blake2_blake2s___reduce____doc__},
+
+static PyObject *
+_blake2_blake2s___reduce___impl(BLAKE2sObject *self);
+
+static PyObject *
+_blake2_blake2s___reduce__(BLAKE2sObject *self, PyObject *Py_UNUSED(ignored))
+{
+    return _blake2_blake2s___reduce___impl(self);
+}
+/*[clinic end generated code: output=c1e1e6d51762d97a input=a9049054013a1b77]*/