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# Encryption technology

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Basic guide for understanding symmetric and asymmetric encryption. It's one of my another college time presentation.

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• thanks mam u provide a such good information. ur info i use i really thank ful to u

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### Encryption technology

1. 1. Encryption Technology By: Neha Bhambu Preeti Chawla 1
2. 2. Introduction In the era of www and portable pc’s ,electronic data security is under great threat from prowling hackers and information stealers. Information has become so important that it has achieved the achieved the status of currency. Encryption is a main tool used by IT geeks to protect terabytes of data criss – crossing the information highway . 2
3. 3. Information Security Requirements : Confidentiality – accessibility of data only to authorized users.  Authentication – verification of the identity of communicating user at the other end.  Integrity control – allowing the modification of data only by authorized personnel. 3
4. 4. TERMINOLOGY  Cryptography : science of encrypting information to form a scrambled or randomized text by using mathematical transformations such that it becomes indecipherable until it is decrypted.  Cryptanalysis : process aimed at cracking the encrypted text either by breaking the algorithm or by guessing or inferencing the decryption key.  Brute force attack : process of key spacing the algorithm by inducing trial of every possible key in succession until text is deciphered. If the key length is k bits , then key space is 2^k bits, and for large keys, even the fastest computer is unable to try out all the possible combinations in key space . 4
5. 5. Encryption Model :ENCRYPTION KEY , K PLAINTEXT ENCRYPTION DECRYPTION KEY DECRYPTION PLAINTEXT CIPHERTEXT, C = E k ( PLAINTEXT )     Plaintext : original data or message fed as input. Ciphertext : scrambled message produced as output. Encryption : conversion of plaintext to ciphertext. Decryption : conversion of ciphertext to plaintext. 5
6. 6. TYPES OF ENCRYPTION ALGORITHMS :  Symmetric Key Algorithm : is implemented using a secret key shared by both sender & reciever for encryption & decryption respectively . Shared secret key PLAINTEXT ENCRYPTION CIPHERTEXT DECRYPTION PLAINTEXT 6
7. 7. Asymmetric Key Algorithm  It implies use of two different keys ,one for encryption which is made public & the other private key which serves as the unique decryption key. PUBLIC KEY PLAINTEXT ENCRYPTION PRIVATE CIPHERTEXT KEY DECRYPTION 7 PLAINTEXT
8. 8. PREVALENT ENCRYPTION ALGORITHMS Symmetric Key algorithms – DES : (DATA ENCRYPTION STANDARD ). IDEA : (INTERNATIONAL DATA ENCRYPTION ALGORITHM). BLOWFISH: (LATEST & MOST SECURE). Asymmetric Key algorithms – RSA :(RIVEST,SHAMIR,ADLEMAN). PGP : (PRETTY GOOD PRIVACY). 8
9. 9. - Relative Strength Comparisons of Encryption Algorithms - Type Security Level Implementation Speed Idea Military Grade 128 bit Shared Secret Fast Blowfish Military Grade 256 to 448 bit Shared Secret Fastest DES Low 40 to 56 bit Shared Secret Fast RSA Military Grade 2048 bit Public Key Very Slow 9
10. 10. DES Encryption Algorithm :L ( i-1) LEFT 32 BIT INPUT R ( i-1) RIGHT 32 BIT INPUT L (i-1) EX-OR f (R (i-1) ,Ki ) LEFT 32 BIT OUTPUT LEFT32 BIT OUTPUT L ( i ) RIGHT 32 BIT OUTPUT R ( i ) Plaintext encrypted in blocks of 64 bits ,using 56 bit key and 16 iterations. Initial permutation of 64 bit plaintext block is followed by iterations .Each iteration involves production of two 32 bit outputs from two 32 bit inputs.. Left output is a copy of right output and right output is bitwise EX-OR of left input , a function of right input and key for this iteration Ki. After each iteration the two 32 bit halves are swapped. After final iteration a final permutation or transposition is applied to get ciphertext block. decryption is done with 10 same key by the running steps in reverse order.
11. 11. RSA ALGORITHM : It is based on a concept of number theory which implies computational infeasibility of the factorization of large numbers in real time which increases exponentially with the geometric growth of numbers.  Formulation of method by Rivest, Shamir, Adleman :  Choose two large primes, p and q (greater than 10 ^ 100).  Compute n = p * q and z = (p – 1 ) * (q – 1).  Choose a number relatively prime to z, and denote it by d.  Compute e such that e = (1 mod z) / d .  C = P ^ e (mod n) P = C ^ d (mod n) where C and P are ciphertext and plaintext 11 blocks of k bits where k is largest integer such that 2 ^ k < n.
12. 12. DIGITAL SIGNATURES A digital signature does not refer to a digitized image of paper signature, but is created using asymmetric cryptography in which private key is known only to signer and is used to create digital signature while public key is used to verify the signature. Message digest is calculated by putting the data through one way hash function .then the digital signature is created by encrypting this message digest with sender’s private key. Receiver will be able to ensure that this document has been signed by that particular person if message digest can be obtained by using sender’s public key and it matches message digest of Message sent message sent along with it. Message sent Hash function Message digest Private key of sender Digital signature Received message Digital signature Hash function Message digest Digital signature Digital signature Sender’s public key 12 Message digest
13. 13. LATEST ENCRYPTION TECHNOLOGIES  Virtual matrix algorithm: The basis of VME is a Virtual Matrix, a matrix of random binary values which is, in theory, is infinite in size and therefore contains no redundant values. The data to be encrypted is compared to the data in the Virtual Matrix. Once a match is found, a set of pointers that indicate how to navigate inside the Virtual Matrix is created. That set of pointers is then further encrypted using dozens of other algorithms using key. The data sent consists of pointers to locations of the content of the message within a virtual matrix .  The key size which can reach up to 1 million bits is not sent , but recreated at a remote location from an electronic file available at both sender and receiver computer .VME . encryption results in a statistically even distribution of 13 characters .
14. 14. QUANTUM CRYPTOGRAPHY Quantum cryptography is based on the fundamental physical law that observation by eavesdroppers inevitably affects the quantum system and the information of the system , making the information incomplete. That is, once communication content is tapped on the channel, the content itself changes irreversibly. The eavesdropped content, then, becomes meaningless and the legitimate recipient can detect the eavesdropper by the change in content. . 14
15. 15. CONCLUSION  Better and more secure algorithms are being developed with a very large key space so that no computer can bruteforce some encrypted text.  Encryption applications range from providing secure email ,authenticating users by digital signatures and providing credibility through digital certificates.  Thus as we can see encryption technology which has great utility in transferring information securely over networks is an emerging field of research and new progress is being made day by day. 15
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