TY  - THES
N1  - Sumarsono S.T, M.Kom,
ID  - digilib34046
UR  - https://digilib.uin-suka.ac.id/id/eprint/34046/
A1  - AMIROH MUJAHIDAH, NIM. 14650031
Y1  - 2018/06/08/
N2  - Cryptography is techniques to hide messages can be a solution to avoid this crime. Playfair Cipher is one of the cryptographic algorithms that can hide the message well because it forms a message key in matrix form. Playfair ciphers form a 5x5 square-shaped key matrix to hold up to 25 characters of capital letters by omitting the letter J and replace it with the letter I. Then make the plaintext message into the bigram pairs to do the encryption process with some rules and conditions in this algorithm. Thus formed ciphertext which has the same character length as its plaintext.
This mechanism of the playfair cipher algorithm is the weakness of the playfair cipher, the limitations in holding the characters, the removal of the letter J that causes ambiguity and the length of plaintext characters and the same ciphertext making it easy to solve with the frequency of occurrence bigram. The modification of the playfair cipher algorithm by extending the 5x19 key matrix with 95 characters to hold many characters (capital letters, small, numbers, symbols) and eliminating ambiguity and cryptographic expansion techniques to form different ciphertext results with its plaintext can be a solution to the weakness of playfair cipher. The purpose of this study was to produce a playfair cipher modification algorithm that could cover the weakness of playfair cipher and result in differences in character length on plaintext and ciphertext implementation results from playfair cipher modification.
PB  - UIN SUNAN KALIJAGA YOGYAKARTA
KW  - Playfair Cipher
KW  -  Matriks Kunci
KW  -  Teknik Ekspansi Kriptografi
M1  - skripsi
TI  - MODIFIKASI ALGORITMA PLAYFAIR CIPHER DENGAN MATRIKS 5X19 DAN TEKNIK EKSPANSI KRIPTOGRAFI PADA PESAN PLAINTEXT
AV  - restricted
EP  - 91
ER  -