/usr/lib/python2.7/dist-packages/sage/crypto/ is in sagemath-common 8.1-7ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/sage/crypto/__init__.py
/usr/lib/python2.7/dist-packages/sage/crypto/all.py
/usr/lib/python2.7/dist-packages/sage/crypto/block_cipher/
/usr/lib/python2.7/dist-packages/sage/crypto/block_cipher/__init__.py
/usr/lib/python2.7/dist-packages/sage/crypto/block_cipher/all.py
/usr/lib/python2.7/dist-packages/sage/crypto/block_cipher/miniaes.py
/usr/lib/python2.7/dist-packages/sage/crypto/block_cipher/sdes.py
/usr/lib/python2.7/dist-packages/sage/crypto/cipher.py
/usr/lib/python2.7/dist-packages/sage/crypto/classical.py
/usr/lib/python2.7/dist-packages/sage/crypto/classical_cipher.py
/usr/lib/python2.7/dist-packages/sage/crypto/cryptosystem.py
/usr/lib/python2.7/dist-packages/sage/crypto/lattice.py
/usr/lib/python2.7/dist-packages/sage/crypto/lfsr.py
/usr/lib/python2.7/dist-packages/sage/crypto/lwe.py
/usr/lib/python2.7/dist-packages/sage/crypto/mq/
/usr/lib/python2.7/dist-packages/sage/crypto/mq/__init__.py
/usr/lib/python2.7/dist-packages/sage/crypto/mq/mpolynomialsystemgenerator.py
/usr/lib/python2.7/dist-packages/sage/crypto/mq/rijndael_gf.py
/usr/lib/python2.7/dist-packages/sage/crypto/mq/sbox.py
/usr/lib/python2.7/dist-packages/sage/crypto/mq/sr.py
/usr/lib/python2.7/dist-packages/sage/crypto/public_key/
/usr/lib/python2.7/dist-packages/sage/crypto/public_key/__init__.py
/usr/lib/python2.7/dist-packages/sage/crypto/public_key/all.py
/usr/lib/python2.7/dist-packages/sage/crypto/public_key/blum_goldwasser.py
/usr/lib/python2.7/dist-packages/sage/crypto/sbox.py
/usr/lib/python2.7/dist-packages/sage/crypto/sboxes.py
/usr/lib/python2.7/dist-packages/sage/crypto/stream.py
/usr/lib/python2.7/dist-packages/sage/crypto/stream_cipher.py
/usr/lib/python2.7/dist-packages/sage/crypto/util.py