It is been use to :
1. scramble data in storage.
2. transmit data in the internet.
3. prevent from the user to understand the real message or information in the message that encrypt.
Cryptographic system is divide by 2 :
1. Cryptography : concerned with develop algorithm.
2. Cryptanalysis : obtained the meaning of encryption information.
Modern cryptography contains :
1. Mathematics to encrypt and decrypt data.
2. Concerned with principle and methods for rendering plain text unintelligible into intelligible form.
3. Used for hiding information.
Can be divide by :
1. Type of encryption operation use : substitution / transposition / product
2. number of key that been use : single key / two - key
3. way of plaintext is process : block / stream
Terms that will be use :
1. plaintext - original message
2. ciphertext - coded message
3. cipher - algorithm for transforming plaintext to ciphertext
4. key - info used in cipher known only to sender/receiver
5. encipher (encrypt) - converting plaintext to ciphertext
6. decipher (decrypt) - recovering ciphertext from plaintext
7. cryptography - study of encryption principles/methods
8. cryptanalysis (codebreaking) - study of principles/ methods of deciphering ciphertext without knowing key
9. cryptology - field of both cryptography and cryptanalysis
CRYPTANALYSIS :
It has two type : symmetric algorithm and asymmetric algorithm.
Symmetric Algorithm : sender and receiver share a common key. The encryption key is related to the decryption key. It can be divide into stream ciphers and block cipher. It need strong encryption algorithm and secret key known by sender and receiver.
2. Concerned with principle and methods for rendering plain text unintelligible into intelligible form.
3. Used for hiding information.
Can be divide by :
1. Type of encryption operation use : substitution / transposition / product
2. number of key that been use : single key / two - key
3. way of plaintext is process : block / stream
Terms that will be use :
1. plaintext - original message2. ciphertext - coded message
3. cipher - algorithm for transforming plaintext to ciphertext
4. key - info used in cipher known only to sender/receiver
5. encipher (encrypt) - converting plaintext to ciphertext
6. decipher (decrypt) - recovering ciphertext from plaintext
7. cryptography - study of encryption principles/methods
8. cryptanalysis (codebreaking) - study of principles/ methods of deciphering ciphertext without knowing key
9. cryptology - field of both cryptography and cryptanalysis
CRYPTANALYSIS :
It has two type : symmetric algorithm and asymmetric algorithm.
Symmetric Algorithm : sender and receiver share a common key. The encryption key is related to the decryption key. It can be divide into stream ciphers and block cipher. It need strong encryption algorithm and secret key known by sender and receiver.
Asymmetric Algorithm : It is use 2 key where the key that been use to encrypt the data is not the same key to decrypt the data. It contain 2 key which is private and public key. The message will be encrypt with public key and can only be decrypt with corresponding private key.
Method :
Substitution: mono - shifting the letter
polyalphabetic - using vigenere tableau (vigenere table)
Transposition : method encryption that shift the position according
to a regular system
Method :
Substitution: mono - shifting the letter
polyalphabetic - using vigenere tableau (vigenere table)
Transposition : method encryption that shift the position according
to a regular system
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