diff --git a/extmod/moduhashlib.c b/extmod/moduhashlib.c
index bdc2529c19..8c6b34a4ca 100644
--- a/extmod/moduhashlib.c
+++ b/extmod/moduhashlib.c
@@ -36,6 +36,8 @@
 
 #if MICROPY_PY_UHASHLIB
 
+#include "crypto-algorithms/sha256.h"
+
 typedef struct _mp_obj_hash_t {
     mp_obj_base_t base;
     char state[0];
@@ -45,8 +47,9 @@ STATIC mp_obj_t hash_update(mp_obj_t self_in, mp_obj_t arg);
 
 STATIC mp_obj_t hash_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
-    mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, 0);
+    mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(SHA256_CTX));
     o->base.type = type_in;
+    sha256_init((SHA256_CTX*)o->state);
     if (n_args == 1) {
         hash_update(o, args[0]);
     }
@@ -54,17 +57,31 @@ STATIC mp_obj_t hash_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw
 }
 
 STATIC mp_obj_t hash_update(mp_obj_t self_in, mp_obj_t arg) {
+    mp_obj_hash_t *self = self_in;
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
+    sha256_update((SHA256_CTX*)self->state, bufinfo.buf, bufinfo.len);
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_2(hash_update_obj, hash_update);
 
 STATIC mp_obj_t hash_digest(mp_obj_t self_in) {
-    return mp_obj_new_bytes((const byte*)"\0\0\0\0", 4);
+    mp_obj_hash_t *self = self_in;
+    byte *hash;
+    mp_obj_t o = mp_obj_str_builder_start(&mp_type_bytes, SHA256_BLOCK_SIZE, &hash);
+    sha256_final((SHA256_CTX*)self->state, hash);
+    return mp_obj_str_builder_end(o);
 }
 MP_DEFINE_CONST_FUN_OBJ_1(hash_digest_obj, hash_digest);
 
 STATIC mp_obj_t hash_hexdigest(mp_obj_t self_in) {
-    return mp_obj_new_str("00000000", 8, false);
+    mp_not_implemented("");
+#if 0
+    mp_obj_hash_t *self = self_in;
+    byte hash[SHA256_BLOCK_SIZE];
+    sha256_final((SHA256_CTX*)self->state, hash);
+    return mp_obj_new_str((char*)hash, SHA256_BLOCK_SIZE, false);
+#endif
 }
 MP_DEFINE_CONST_FUN_OBJ_1(hash_hexdigest_obj, hash_hexdigest);
 
@@ -105,4 +122,6 @@ const mp_obj_module_t mp_module_uhashlib = {
     .globals = (mp_obj_dict_t*)&mp_module_hashlib_globals,
 };
 
+#include "crypto-algorithms/sha256.c"
+
 #endif //MICROPY_PY_UHASHLIB