 WHAT IS ENCRYPTION :-  Encryption (Round) (cont.) :-  HISTORY OF DE :-  TYPES OF DATA ENCRYPTION :-  Decryption :-  Security And Cryptanalysis :-  KEY OF DATA ENCRYPTION:-

 Encryption is a technique for transforming information on a computer in such a way that it becomes unreadable.  Encryption is the process of obscuring information to make it unreadable without special knowledge.  A secure computing environment would not be complete without consideration of encryption technology.

 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 introduced.  Published in 1977, standardized in  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.

 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 chip.  In 1977, the results of Tuchman’s project of IBM was adopted as the by NSA (NIST).

 DES (and most of the other major symmetric cipher) is based on cipher know as the festal block cipher.  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 operation.  Most symmetric encryption schemes today are based on this structure knows as a feistily network.

 Once a plain-text message is received to be encrypt.  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 they do not adhere to.

 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 to track.  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.

 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 the data.

 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 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 decrypt messages.  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 data encryption.

.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. Examples include:  Web browser and web server (HTTPS).  VPN client and server.  Secure FTP (SSL encrypted connection).

 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.

 Feistily cipher implements Shannon’s S-P network concept. 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 concept  Achieve diffusion and confusion

 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

 A signal round DES encryption let ^x represent the difference of the two known and chosen plaintexts x1 and x2  ^x = x1&

 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 & public key.

 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.

SECRE T KEY E{p.k} D{C,K} CIPHERTEXT(C) SECRET KEY

 Private/secret/single key cryptography uses one key.  Shared by both sender and receiver.  If this key is disclosed communications are compromised.  Also is symmetric, parties are equal.  Hence does not protect sender from receiver forging a message & claiming is sent by sender

 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.

 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) signatures  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

 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)

FIG : public key

 William Stallings, Cryptography and Network Security,  THANKE YOU