VERSION                |  2 +-
 doc/install.rst        | 12 ++++++------
 doc/news.rst           |  7 +++++++
 pyderasn.py            | 10 +++++-----
 tests/test_pyderasn.py | 15 +++++++++++++++

diff --git a/VERSION b/VERSION
index 411d89de8ca9a3f1a2c3eed1f563347fc4c8c3551fa525e2aeebf6877c2c5d14..3d470a9594054246df442ffe935077895e0ba5f47a676885080b08e949d4f0ed 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-6.1
+6.2
diff --git a/doc/install.rst b/doc/install.rst
index 54bb5db9e9c3e6f79449b67736aa185c4197f48e086787d4edb679f04e463052..964fd4ef811418cd5ce642345e271e3bcec0e8e32e28df14b0c82c45b9c8a48f 100644
--- a/doc/install.rst
+++ b/doc/install.rst
@@ -4,11 +4,11 @@
 Preferable way is to :ref:`download <download>` tarball with the
 signature from `official website <http://pyderasn.cypherpunks.ru/>`__::
 
-    $ [fetch|wget] http://pyderasn.cypherpunks.ru/pyderasn-6.1.tar.xz
-    $ [fetch|wget] http://pyderasn.cypherpunks.ru/pyderasn-6.1.tar.xz.sig
-    $ gpg --verify pyderasn-6.1.tar.xz.sig pyderasn-6.1.tar.xz
-    $ xz --decompress --stdout pyderasn-6.1.tar.xz | tar xf -
-    $ cd pyderasn-6.1
+    $ [fetch|wget] http://pyderasn.cypherpunks.ru/pyderasn-6.2.tar.xz
+    $ [fetch|wget] http://pyderasn.cypherpunks.ru/pyderasn-6.2.tar.xz.sig
+    $ gpg --verify pyderasn-6.2.tar.xz.sig pyderasn-6.2.tar.xz
+    $ xz --decompress --stdout pyderasn-6.2.tar.xz | tar xf -
+    $ cd pyderasn-6.2
     $ python setup.py install
     # or copy pyderasn.py (+six.py, possibly termcolor.py) to your PYTHONPATH
 
@@ -19,7 +19,7 @@
 You could use pip (**no** OpenPGP authentication is performed!) with PyPI::
 
     $ cat > requirements.txt <<EOF
-    pyderasn==6.1 --hash=sha256:TO-BE-FILLED
+    pyderasn==6.2 --hash=sha256:TO-BE-FILLED
     six==1.14.0 --hash=sha256:236bdbdce46e6e6a3d61a337c0f8b763ca1e8717c03b369e87a7ec7ce1319c0a
     EOF
     $ pip install --requirement requirements.txt
diff --git a/doc/news.rst b/doc/news.rst
index 9ba02b00bf4e3cb2278f88535ca390490a2f430421fa6fa1d611490799deeb84..ef8c4870b69c9003bcbb99a94067c31d8752802a3d803db5207a9b1263266279 100644
--- a/doc/news.rst
+++ b/doc/news.rst
@@ -1,6 +1,13 @@
 News
 ====
 
+.. _release6.2:
+
+6.2
+---
+* Python ``int()``'s accepts even more various non-decimal characters
+  than expected. Make validation fully strict, without relying in ``int()``
+
 .. _release6.1:
 
 6.1
diff --git a/pyderasn.py b/pyderasn.py
index d7e574f8c960f26a21e43c80c4691120ab74bbd9d3661e3e035fa0c7733e9373..57bd5d60224358707ad7fe73986cfaf5871be17031f01d155b5f1dea82bb6c7f 100755
--- a/pyderasn.py
+++ b/pyderasn.py
@@ -690,7 +690,7 @@ except ImportError:  # pragma: no cover
     def colored(what, *args, **kwargs):
         return what
 
-__version__ = "6.1"
+__version__ = "6.2"
 
 __all__ = (
     "Any",
@@ -765,15 +765,15 @@ EOC_LEN = len(EOC)
 LENINDEF = b"\x80"  # length indefinite mark
 LENINDEF_PP_CHAR = "I" if PY2 else "∞"
 NAMEDTUPLE_KWARGS = {} if PY2 else {"module": __name__}
-SET01 = frozenset(("0", "1"))
+SET01 = frozenset("01")
+DECIMALS = frozenset("0123456789")
 DECIMAL_SIGNS = ".,"
 
 
 def pureint(value):
-    i = int(value)
-    if (value[0] in "+- ") or (value[-1] == " "):
+    if not set(value) <= DECIMALS:
         raise ValueError("non-pure integer")
-    return i
+    return int(value)
 
 def fractions2float(fractions_raw):
     pureint(fractions_raw)
diff --git a/tests/test_pyderasn.py b/tests/test_pyderasn.py
index 85855460c49e467cc09b3e3773b1f73cb82655261194a8863388cbec53db5114..310f857957a1001ed2581d350b79a2113df7e49b62b58b1c601b7911ff411554 100644
--- a/tests/test_pyderasn.py
+++ b/tests/test_pyderasn.py
@@ -4305,6 +4305,14 @@                 b"2000010203+405Z",
                 b"200001020304+5Z",
                 b"20000102030405.+6Z",
                 b"20000102030405.-6Z",
+                b"_2000102030405Z",
+                b"2000_102030405Z",
+                b"200001_2030405Z",
+                b"20000102_30405Z",
+                b"2000010203_405Z",
+                b"200001020304_5Z",
+                b"20000102030405._6Z",
+                b"20000102030405.6_Z",
                 b" 2000102030405Z",
                 b"2000 102030405Z",
                 b"200001 2030405Z",
@@ -4406,6 +4414,13 @@                 b"0001+2030405Z",
                 b"000102+30405Z",
                 b"00010203+405Z",
                 b"0001020304+5Z",
+                b"_10102030405Z",
+                b"00_102030405Z",
+                b"0001_2030405Z",
+                b"000102_30405Z",
+                b"00010203_405Z",
+                b"0001020304_5Z",
+                b"00010203045_Z",
                 b" 10102030405Z",
                 b"00 102030405Z",
                 b"0001 2030405Z",