Here you will get program for vigenere cipher in Java for both encryption and decryption. Vigenere Cipher is a polyalphabetic substitution technique that is used for encrypting and decrypting a message text. In this technique we use a table of alphabets A to Z which are written in 26 rows which is also known as Vigenere Table.
He is known as the father of Strategic management. Igor Ansoff (December 12, 1918 – July 14, 2002) was a Russian American, applied mathematician and business manager.
Also Read: Also Read: Encryption Lets understand encryption by one example. Bluesuite download csr bluetooth. Plain Text: THEJAVAPROGRAMMER Key: NEERAJ We have to generate a new key by repeating above key in cyclic order until its length becomes equal to length of plain text. New Key: NEERAJNEERAJNEERAJ Now take first letter of plain text and key, i.e. See row T and column N in vigenere table, take the letter where row T and column N coincides i.e. Here G is the first letter of encrypted or cipher text. Now take second letter of plain text and key i.e. Again analyze the table to find second letter of encrypted text.
Vigenere Cipher Examples
This process is repeated for all the letters in plain text. So finally we get the encrypted text as. Cipher Text: GLIAAENTVFGANQQVR Algebraic Form We can express above process in algebraic equation in following way.
For plain text (P) and key (K), the cipher text can be obtained as. E i = (P i + K i) mod 26 Decryption Let’s understand decryption process with another example. Cipher Text: GLIAAENTVFGANQQVR Key: NEERAJ New Key: NEERAJNEERAJNEERAJ Take first letter in cipher text and key, i.e. Now take column N and look for letter G in it, the corrosponding row to letter G is T which is the first letter of plain text after decryption. Repeate the same process for all the letters in cipher text. Thus the plain text is obtained as. Plain Text: THEJAVAPROGRAMMER Algebraic Form We can express above decryption process in algebraic equation in following way.
For cipher text (E) and key (K), the plain text can be obtained as. P i = (E i – K i + 26) mod 26 Java Vigenere Cipher Program (Encryption and Decryption) Below is the implementation of vigenere cipher in java.
Earlier we talked about and its implementation both in C and C, it was a kind of encryption where each letter was replaced by a letter corresponding to a certain number of alphabets after or before it. Vigenere Cipher is a way of encryption where different series of were used. In simple words it was a type of poly-alphabetical encryption where a key decided by the person who encrypted the text, was used for decryption.
It also applied that a same alphabet in the same string can have a different code alphabet which made the decryption more and more complex. Talking about the table which was used for encryption and decryption was basically a kind of mapping table.
So Looking at this table I ll give you an Example. Just suppose 'RAKSHIT' was to be encrypted and the key decided was 'KEY' So the key decided was written below the string this way: Now Each alphabet was mapped so as to get the encrypted alphabet. For Example R would be written as B when we consider the top row as out string and column as the key and so on for the rest of the string. And so RAKSHIT would be encrypted as BEICLGD. Now converting into computer logic i came across 2 formulas: For Encryption E 1 = (S 1 + K 1)% 26 (% means remainder) For Decryption D 1 = (E 1 - K 1 + 26)% 26 (% means remainder).