CRYPTOGRAPHY:
Cryptography is the practice and study of techniques for secure communication in the presence of third parties
communication in the presence of third parties.Cryptology prior to the modern age was almost synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The sender retained the ability to decrypt the information and therefore avoid unwanted persons being able to read it.
Applications of cryptography include ATM cards, computer passwords, and electronic commerce.
There are many tools available online to encrypt or decrypt data like Cryptool.
Even our social communities use the method of encryption to save passwords.
Encryption is also done in several ways to avoid any chance of leakage of data.It includes:
a.Ciphers
b.Coding Methods
c.Analysis Tool
CIPHER:
A cipher is an algorithm for performing encryption or decryption -- a series of well-defined steps that can be followed as a procedure.
For example "GOOD DOG" can be encrypted as "PLLX XLP" where "L" substitutes for "O", "P" for "G", and "X" for "D" in the message. Transposition of the letters "GOOD DOG" can result in "DGOGDOO". These simple ciphers and examples are easy to crack, even without plaintext-ciphertext pairs.
Modern encryption methods can be divided by two criteria: by type of key used, and by type of input data.
By type of key used ciphers are divided into:
Symmetric key algorithms (Private-key cryptography), where the same key is used for encryption and decryption, and
Asymmetric key algorithms (Public-key cryptography), where two different keys are used for encryption and decryption.
CODING METHODS:
Codes are used to transform data into a format, which is more convenient for the target application. One of the most common codes is the bar code, which can be optically scanned.
It includes:
ASCII
Bacon
Barcode generator
Base64
Code39
Huffman
Morse code
ANALYSIS TOOL OR CRYPTANALYSIS:
The goal of cryptanalysis is gaining knowledge of the encrypted text without the key.
A distinction is made for different attack scenarios:
Ciphertext-Only:
Only the encrypted text is known.
Probable Plaintext:
The encrypted text is known and one can assume that the message contained follows a certain pattern.
Known Plaintext:
An encrypted text and its plaintext is known. The goal is to determine the key from the text.
Chosen Plaintext:
One can freely choose a text that is to be encrypted and subsequently has access to the resulting encrypted text.
Chosen Ciphertext:
One can temporarily generate the decrypted text from an assortment of corresponding encrypted text of one's own choice.
EXAMPLE:
Try a ciphertext-only attack against this cipher by performing a frequency analysis.
URKAG QZODK BFMPA OGYQZ FFTQD QEGXF IUXXN QETAI ZUZMZ QIEGN IUZPA IFTQF UFXQA RFTQD QEGXF UZSIU ZPAIO AZFMU ZENAF TFTQZ MYQAR FTQAD USUZM XPAOG YQZFM ZPFTQ QZODK BFUAZ WQKGE QPFTQ GEMSQ ARWQK EUEEG BBADF QPNKF IAEBQ OUMXU OAZEO XUOWU ZSFTQ UOAZE TAIWQ KMXXA IEKAG FAEFA DQMOA BKARF TQWQK GEQPR DAYMD QEGXF UZSIU ZPAIU ZFAMZ UZFQD ZMXEF ADMSQ URKAG FTQZQ ZODKB FMZAF TQDPA OGYQZ FIUFT FTQEM YQQZO DKBFU AZYQF TAPFT QUOAZ UZEQD FWQKU EMOFU HQIUF TUZFT QWQKQ ZFDKP UMXAS NAJFT UEUET QXBRG XQEBQ OUMXX KIUFT YADQO AYBXQ JWQKE
Hint: The most frequently used character in English is "E". Determine the offset of the most frequently reoccurring character and "E".
For example, the character "G" is the most frequently used character in a text. "G" is the 7th character of the alphabet, "E" the 5th. 7 - 5 = 2. The key is 2.
OTHERS:
AES(Advanced Encrpytion Standard)
Password Check
Password Generator
Matrix Screensaver
Taxman
Hashes
SALONI BHATIA
CS II YR