1. Definition
1.1. Cryptopgraphy
1.1.1. art of encrypting and decrypting information
1.2. Cryptographic
1.2.1. act of relating or using cryptography, such as cryptographic system, or cryptographic protocol
1.3. Cryptoanalysis
1.3.1. act of decrypting a ciphertext without the secret key
1.4. Cryptographer
1.4.1. someone who studies all aspect of cryptosystems
1.5. Cryptosystem
1.5.1. all the aspects of a particular encryption system, so includes the information about the message and ciphertext alphabets, the encryption and decryption algorithms, the method of blocking and the allowable keys.
1.6. Public Key
1.6.1. keys used to encrypt and decrypt data. can be generated by software, and is available through a publicly accessible repository or directory.
1.7. Private Key
1.7.1. keys that are linked to the public key, where only the key's generator know the key, which make it secure.
1.8. Encryption
1.8.1. Transforming a message (plaintext) into an ciphertext (encrypted) form
1.9. Decryption
1.9.1. transforming a cyphertext into plaintext.
1.10. Substitution function
1.11. Permutation function
1.12. Link Encryption
1.12.1. encrypting data on the network such as IPSEC
1.13. End-to-End Encryption
1.13.1. Encryption from source to system (client to server)
1.14. Traffic Analysis
1.14.1. Inference of information from analysis of traffic
1.15. Work Factor
1.15.1. Effort/ Time need to overcome a protective measure
2. Information Protection
2.1. Confidentiality
2.1.1. Only authorized use can view the data through decrypting it.
2.1.2. Assymmetric, Symmetric
2.2. Data Integrity
2.2.1. Information is correct, as encrypted data cannot be change
2.2.2. Assymmetric, Symmetric, Hash Function
2.3. Availability
2.3.1. Data is available to authorized user with key
2.3.2. Assymmetric, Symmetric
2.4. Authentication
2.4.1. Proof as assurance that sender is legitimate
2.4.2. Assymmetric
2.5. Non-repudiation
2.5.1. Proof that user performed the action or sent the information.
2.5.2. Assymmetric
3. Encryption Mode
3.1. Hardware
3.1.1. USB Drive
3.1.2. Hard Disk
3.1.3. TPM (Trusted Platform Module)
3.1.4. HSM (Hardware Security Module)
3.2. Software
3.2.1. FIle and File System
3.2.2. Whole Disk
3.2.3. PGP (Pretty Good Privacy)
3.2.4. GPG (GNU Privacy Guard)
3.2.5. EFS (Microsoft Windows Encrypting File System
3.2.6. EFS (Microsoft Windows Encrypting File System
4. Type of Attack
4.1. Ciphertext only
4.2. Known message
4.3. Probably known message
4.4. Chosen message
4.5. chosen ciphertext
4.6. chosen message and ciphertext
5. Crypto System
5.1. Symmetry
5.1.1. Original Cryptographic algorithm with usage of private key. A practical cipher is use short key to generate a long keystream
5.1.2. Block Algorithm
5.1.2.1. plaintext is divided into block before encryption. use entire block of plaintext at one time. and more secure as input is random, yet slower with increasing plaintext length.
5.1.2.2. DES (Data Encryption Standard)
5.1.2.2.1. divide plaintext into 64bit blocks and execute algorithms 16 times.
5.1.2.2.2. ciphertext is 64 bit block and key is 56 bits
5.1.2.2.3. Weakness: Not really secure nowadays for key space 2^56. As linear and differential analysis can be use
5.1.2.3. 3DES ( Triple Data Encryption Standard)
5.1.2.3.1. 3 rounds of encryption instead of 1. (3 x 16 = 48 iteration). some encryption use 2 keys alternately each time. Better in hardware than software.
5.1.2.4. AES (Advanced Encryption Standard)
5.1.2.4.1. known as Rinjdael
5.1.2.4.2. do 3 steps on each block of plaintext (128 bits)
5.1.2.4.3. Strength: Flexible, Efficient, Small memory
5.1.2.4.4. Weakness: not many details study as it is new.
5.1.2.5. RC (Reverse Cipher)
5.1.2.5.1. By Ron Rivest. Used by European Nations in 1990s
5.1.2.5.2. RC2
5.1.2.5.3. RC5
5.1.2.5.4. RC6
5.1.2.6. IDEA (International Data Encryption Algorithm)
5.1.2.6.1. process 64 bits with 128 key on 8 round
5.1.2.7. Blowfish
5.1.2.7.1. operate 64bits blocks and key length vary (32 bits - 448 bits)
5.1.2.7.2. Twofish
5.1.2.8. Operation Mode
5.1.2.9. Feistel Block Cipher
5.1.2.10. Modes of Operation
5.1.2.11. Iterated Block Cipher
5.1.3. Stream Algorithm
5.1.3.1. Keystream
5.1.3.1.1. One Time Pad
5.1.3.1.2. Pseudo-random key
5.1.3.2. SEAL
5.1.3.3. RC (Reverse Cipher)
5.1.3.3.1. RC4
5.2. Assymmetry
5.2.1. has both public and private key, where each decrypted the other.
5.2.2. RSA
5.2.2.1. Developed by MIT
5.2.2.2. Use Prime Number. by factoring 2 large prime number.
5.2.2.3. Uses points on sloping curved lines. and slower.
5.2.3. ECC (Elliptic Curve Cryptography)
5.2.3.1. alternative to prime numbers for mobile and wireless devcies.
5.2.3.2. smaller key size.
5.2.4. Quantum Cryptography
5.2.4.1. uses microscopic object such as photons.
5.2.4.2. share keys to detect eavesdropping.
5.2.5. DSA
5.2.6. NTRUEncrypt
5.2.6.1. Lattice-based that relies on sets of points in space.
5.2.6.2. Used at petrol station to send credit card data using satellite.
5.2.7. Digital Signature
5.2.7.1. Verify the sender and not allow sender to disown the message to keeps the integrity.
5.3. Hash Function
5.3.1. HMAC
5.3.1.1. Start with a shared secret key that both party have.
5.3.1.2. use widely in data transmission. as the hash value posted on websites.
5.3.2. MD (Message Digest)
5.3.2.1. MD 2
5.3.2.1.1. 16 bit length and padded as needed
5.3.2.2. MD4
5.3.2.2.1. 512 bit length and padded as needed
5.3.2.3. MD5
5.3.2.3.1. 512 bit length and padded as needed
5.3.2.3.2. use by Linux
5.3.3. SHA (Secure Hash Algorithm)
5.3.3.1. SHA-2 much secure has with no vulnerability found
5.3.3.2. SHA-1 use by MAC OS
5.3.4. Whirlpool