Remove unused rijndael encryption implementation (#465)

* Remove unused rijndael encryption

* Add current PR link to CHANGELOG.md

* Update CHANGELOG.md

Co-authored-by: Pieter Marsman <pietermarsman@gmail.com>

CHANGELOG.md

@@ -3,6 +3,12 @@ All notable changes in pdfminer.six will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
+### Removed
+
+- Remove unused rijndael encryption implementation ([#465](https://github.com/pdfminer/pdfminer.six/pull/465))
+
 ## [20200726]
 
 ### Fixed

tests/test_pdfminer_crypto.py

@@ -6,7 +6,6 @@ from nose.tools import assert_equal
 from pdfminer.arcfour import Arcfour
 from pdfminer.ascii85 import asciihexdecode, ascii85decode
 from pdfminer.lzw import lzwdecode
-from pdfminer.rijndael import RijndaelEncryptor
 from pdfminer.runlength import rldecode
 
 
@@ -58,11 +57,3 @@ class TestRunlength():
     def test_rldecode(self):
         assert_equal(rldecode(b'\x05123456\xfa7\x04abcde\x80junk'),
                      b'1234567777777abcde')
-
-
-class TestRijndaelEncryptor():
-    def test_RijndaelEncryptor(self):
-        key = dehex(b'00010203050607080a0b0c0d0f101112')
-        plaintext = dehex(b'506812a45f08c889b97f5980038b8359')
-        assert_equal(hex(RijndaelEncryptor(key, 128).encrypt(plaintext)),
-                     b'd8f532538289ef7d06b506a4fd5be9c9')

tox.ini

@@ -1,10 +1,6 @@
 [tox]
 envlist = py{34,35,36,37,38}
 
-[flake8]
-per-file-ignores =
-    pdfminer/rijndael.py:E202,E222
-
 [testenv]
 extras =
     dev