2. WHAT IS ENCRYPTION :-
Encryption (Round) (cont.) :-
HISTORY OF DE :-
TYPES OF DATA ENCRYPTION :-
Security And Cryptanalysis :-
KEY OF DATA ENCRYPTION:-
3. Encryption is a technique for transforming
information on a computer in such a way that it
Encryption is the process of obscuring
information to make it unreadable without
A secure computing environment would not be
complete without consideration of encryption
6. DEs was the result of research project set up by
International Business Machines (IBM).
corporation in the late 1960’s which resulted in
a cipher know as LUCIFR in the early it was
decided to commercialise LUCIFER and a
number of significant. Changes were
Published in 1977, standardized in 1979.
Key: 64 bit quantity=8-bit parity+56-bit key
In 1971, IBM developed an algorithm, named
which operates on a block of using a key.
7. In 1971, IBM developed an algorithm, named
which operates on a block of 64 using a key
Walter Tuchman, an IBM researcher, refined
LUCIFER and reduced the key size to ,fit on a
In 1977, the results of Tuchman’s project of
IBM was adopted as the by NSA (NIST).
8. DES (and most of the other major symmetric
cipher) is based on cipher know as the festal
This was block cipher developed by the IBM
cryptography research Horst feistily in the
early 70’s. it consists of a number rounds
where each round contains bit-suffering, non-
linear substitution (s-boxe) and exclusive or
Most symmetric encryption schemes today are
based on this structure knows as a feistily
9. Once a plain-text message is received to be
it is arranged into 64 bit blocks required for
input if the number.
In this the message of bits in the message is
not evenly dividable by 64 then the last block.
will be padded multiple permutation and
substitutions are incorporated throughout in
order to increase the difficulty of performing a
cryptanalyst is on the cipher.
However it is generally accepted that the initial
and final permutation offer title or no
contribution to the security of DES and in fact
some software unit implementation then
although strictly speaking these are not DES as
10. Hashing creates a unique, fixed-length
signature for a message or data set.
Each “hash” is unique to a specific message, so
minor changes to that message would be easy
Once data is encrypted using hashing, it cannot
be reversed or deciphered.
Hashing, then, though not technically an
encryption method as such, is still useful for
proving data hasn’t been tampered with.
11. Symmetric encryption is also known as
private-key cryptography, and is called so
because the key used to encrypt and decrypt.
the message must remain secure, because
anyone with access to it can decrypt the data.
Using this method, a sender encrypts the data
with one key, sends the data (the cipher text)
and then the receiver uses the key to decrypt
12. Asymmetric encryption, or public-key
cryptography, is different than the previous method
it uses two keys for encryption or decryption (it has
the potential to sec such).
With this method, a public key is freely available to
everyone and is used to encrypt messages, and a
different, private key is used by the recipient to
Any of these methods would likely prove sufficient
for proper data security, and a quick Google search
will reveal the multitude of software available for
13. .Data encryption is a necessity (both for legal reasons
and otherwise) when transmitting information like
PHI, so no matter what method you choose, make
sure you’re doing everything you can to protect data.
Asymmetric encryption is most commonly used
to secure physically separate end points.
Web browser and web server (HTTPS).
VPN client and server.
Secure FTP (SSL encrypted connection).
14. The same algorithm as encryption. Asymmetric
encryption, or public-key cryptography,.
Is different than the previous method because it
uses two keys for encryption or decryption (it
has the potential to be more secure as such).
With this method, a public key is freely
available to everyone and is used to encrypt
messages, and a different, private key is used
by the recipient to decrypt messages.
. Data encryption is a necessity (both for legal
reasons and otherwise) when transmitting
information like PHI, so no matter what
method you choose, make sure you’re doing
everything you can to protect data.
16. Feistily cipher implements Shannon’s S-P
based on invertible product cipher
Process through multiple rounds which
partitions input block into two halves
perform a substitution on left data half
based on round function of right half & sub key
then have permutation swapping halves
Feistel cipher implements Shannon’s S-P network
Achieve diffusion and confusion
18. Although more information has been on the
Cryptanalysis of dfs than any other block
cipher while having a theoretical complicity
less than a brute force attack.
The most practical attack to date is still abrate
foree approach .the length of the key
determines the number of possible.
Differential cryptanalysis has been proposed
since 1990 to break block cipher such as DES
and while successful for breaking LUCIFER
19. A signal round DES encryption let ^x represent the
difference of the two known and chosen plaintexts
x1 and x2
^x = x1&
20. A mentioned earlier there are two main types
of cryptography in use today secret key or
Private key cryptography and public key
cryptography key cryptography
the oldest type wheres asymmetric
cryptography is only being used publicly since
the late 1970’s asymmetric.
The was major milestone in the search for a
perfect encryption scheme.
There are two types of Key Private Key &
21. Private Key also called as the secret key.
This cryptography goes back to least encryption
times and is of Concern
here it involves the use of only one key which is
used for both encryption and decryption (hence the
use of the term symmetries).
It is necessary for security purpose that the secret
key never be revaluated.
23. Private/secret/single key cryptography uses
one key .
Shared by both sender and receiver.
If this key is disclosed communications are
Also is symmetric, parties are equal .
Hence does not protect sender from receiver
forging a message & claiming is sent by sender
24. It also referred as a symmetric encryption. It
two gets in that security key private key or yes
and public key.
Sender user a security key to enciphers
message and sends to receiver when the
recipient get the message .
he uses public key of sender to descript the
message it is most secure message than
sematic one because sender need not discover
this private key .
25. A public-key, which may be known by
anybody, and can be used to encrypt
messages, and verify signatures
a private-key, known only to the recipient,
used to decrypt messages, and sign (create)
Asymmetric because those who encrypt
messages or verify signatures cannot
decrypt messages or create signatures
Probably most significant advance in the
3000 year history of cryptography
26. Public-Key algorithms rely on two keys with
the characteristics that it is:
Computationally infeasible to find decryption
key knowing only algorithm & encryption key
Computationally easy to en/decrypt messages
when the relevant (en/decrypt) key is known
Either of the two related keys can be used for
encryption, with the other used for decryption
(in some schemes)