data encryption, description, des
DESCRIPTION
Telecommuncations Primer Signals, Building Blocks and Networks.Data Encryption & Description, DES, Single and Two key ConceptTRANSCRIPT
Data Encryption
Tayyab ArifAllama Iqbal Open Unviersity PakistanBook: Telecommunication PrimerBS(cs) 7th SemsterMob: 00923445064252
Encryption Definition: The action of disguising information so that
it can be recovered easily by the persons who have the key, but is highly resistant to recovery by persons who do not have the key.
Tayyab Arif 00923445064252, Allama Iqbal Open University
A message is cleartext (plaintext) is encrypted (disguised) through the use of an encryption key to create a Ciphertext.
Tayyab Arif 00923445064252, Allama Iqbal Open University
The encryption key may be changed from time to time to make an intruder’s task more difficult.
Restoration of a ciphertext to cleartext is achieved by the action of decryption using a decryption key.
Tayyab Arif 00923445064252, Allama Iqbal Open University
In symmetric (Single key):The encryption and decryption keys are the
same.
In asymmetric (two keys):The encryption and decryption keys are
different.
Tayyab Arif 00923445064252, Allama Iqbal Open University
Encryption Methods: Encryption is accomplished by scrambling
the bits, characters, words, or phrases in the original message. Scrambling involves two activities:
Transposition Substitution
Tayyab Arif 00923445064252, Allama Iqbal Open University
Transposition: In which the order of the bits patterns,
characters, words or phrases is rearranged.
Substitution: In which new bit patterns, characters, words,
or phrases are substituted for the originals without changing their order.
Tayyab Arif 00923445064252, Allama Iqbal Open University
Data Encryption Standard (DES):Most widely used algorithmPioneered by IBM It is symmetric cryptosystemDeveloped to protect sensitive, unclassified,
US government, Computer data.Used to provide authentication of electronic
funds transfer messages.
Tayyab Arif 00923445064252, Allama Iqbal Open University
DES Algorithm:
The algorithm accepts plaintext, P, and performs an initial permutation, IP, on P producing P0, The block is then broken into left and right halves, the Left (L0) being the first 32 bits of P0 and the right (R0) being the last 32 bits of P0.
With L0 and R0, 16 rounds are performed until L16 and R16 are generated.
The inverse permutation, IP-1, is applied to L16R16 to produce ciphertext C.
Tayyab Arif 00923445064252, Allama Iqbal Open University
Public Key Cryptosystem It is an asymmetric cryptosystem. First announced in 1976. Offer a radically different approach to
encryption. The idea depends on the use of a pair of keys
that differ in a complementary way. Several algorithms are proposed RSA algorithm is considered to be highly
secure.
Tayyab Arif 00923445064252, Allama Iqbal Open University
Public key encryption can achieved:
PrivacyAuthentication
Tayyab Arif
Allama Iqbal Open Unviersity PakistanBook: Telecommunication Primer
BS(cs) 7th SemsterMob: [email protected]
www.youtube.com/tayyab8632