File, data, and link encryption as well as VPNs are described. File encryption encrypts files to protect them from being read or altered without a key. Data encryption hides data from other users by encoding it using a key into a pseudorandom stream. Link encryption encrypts all traffic at each end of a communications line. A VPN allows communication between systems using an existing shared network infrastructure.

1. How Encryption for Strong
Security Works
● File Encryption
● Data Encryption
● Link Encryption
● VPN ● s1170087 Shingo Watanabe
● s1170069 Ryohei Suda
● s1170067 Takahiro Shinkai
● s1170070 Shuhei Takahashi

2. File Encryption
File encryption is
encrypting files to
protect the files from
being read or changing
without an encryption
key.
There are many
algorithm.

3. Data Encrypion
– Hidding data to other users,
an encryption program uses Hidding data to other users,
a key witch is a string of
numbers. The real data is
encorded to stream using the
key. It stream conbine
pseudorandom stream. The
ral data is bured in the
pseudorandom “noise.”
– This is Data Encrypion. It is
used for UNIX passward.

4. Link Encryption
Link encryption is an approach to
communications security that encrypts and
decrypts all traffic at each end of a
communications line.

5. VPN
● The purpose of a VPN
is to allow
communications
between systems
connected to the VPN
using an existing
shared network
network infrastructure
as the transport.

6. References
● @IT
http://www.atmarkit.co.jp/fsecurity/dictionary/indexpa
● Wikipedia
– http://en.wikipedia.org/wiki/Main_Page