Crypto Security Architecture Exercise

Asymmetric Cryptography is a cryptography where secret key divided into two parts public key and private key. Public key is used to encrypt data and it can be given to anyone, trusted or not. Whereas private key is to decrypt the data it will be provided to only trusted ones. Public key can be provided to anyone who wants to see or encrypt a message, but private key can be given to a person for confidentiality and he only can decrypt the message. This is the difference between Asymmetric and Symmetric Cryptography. (cryptography.io, 2013-2017)

There are different ways of algorithms in Asymmetric Cryptography. Those are:

1. Diffie-Hellman key agreement: This algorithm was developed by Dr. Whitfield Diffie and Dr. Martin Hellman in 1976. This algorithm is not for encryption and decryption but it enables the communication between two parties with a secret key for exchanging information confidentially.

2. Rivest Shamir Adleman (RSA): This algorithm was released by Ron Rivest, Adi Shamir, and Len Adleman in 1978 as RSA public key algorithm. This algorithm is used to encrypt and signing data. Using series of modular multiplications this encryption and signing process will be performed.

3. Elliptic Curve Cryptography (ECC): This works like RSA and this is implemented in small devices like cell phones. This algorithm takes less computing power compared to RSA. Using the points on a curve, this ECC encryption systems will define public and private key pairs.

4. El Gamal: This is an algorithm for transmitting digital signatures and key exchanges. This method is based on calculating logarithms. As is this algorithm is to transfer digital signatures, Digital Signature Algorithm (DSA) is based in this algorithm.

5. Digital Signature Algorithm (DSA): This algorithm was developed by United States government for digital signatures. This algorithm is only for signing the data and not used for encryption.

Symmetric algorithms:

Symmetric Cryptography is a cryptography where single key may call as secret key or password is used to encrypt or decrypt the data. The two parties who is communicating will use the same key to decrypt the data. This is not as secure as Asymmetric Cryptography. But both has its own advantages and disadvantages.

These algorithms are divided into two types 1. Block algorithm – which encrypts data into blocks of electronic data using secret key. 2. Stream algorithm – in this algorithm data encrypted as streams instead of retained in the system memory. From the above-mentioned algorithms, AES, DES, IDEA, Blowfish, RC5 and RC6 uses Block algorithm. RC4 uses stream algorithm.

1. AES (Advanced Encryption Standard): This is the most commonly used algorithm which is known as Rijndael. The standards for this algorithm was set by U.S. National Institute of standards and technology (NIST) in 2001 for the encryption of electronic data announced in U.S. FIPS PUB 197. Under this NIST standard, the AES algorithm has block size of 128 bits, but this can have three different key lengths as AES-128, AES-192 and AES-256.

2. DES (Data Encryption Standard): This is the first algorithm used to secure electronic communications and is used in different variations as 2-key or 3-key 3DES. After AES algorithm developed, DES stopped using because this algorithm is considered as weak due to the high processing power usage in modern computers. 3DES are still using in EMV chip cards.

3. IDEA (International Data Encryption Algorithm): This is a block cipher algorithm designed by Xuejia and James Massey of ETH Zurich in 1991. This algorithm is similar but better than DES, so this is developed as replacement of DES. This is also called as Proposed Encryption Standard (PES).

4. Blowfish (Drop-in replacement for DES or IDEA): This is again a block cipher algorithm used as a drop-in replacement of DES or IDEA. This algorithm takes various length key from 32 bits to 448 bits. This is for both domestic and exportable use. This algorithm was designed in 1993 by Bruce Schneier as a fast and free alternative to existing algorithms. This algorithm is unpatented and license-free, and it is available for free for all uses.

5. RC4 (Rivest Cipher 4): This is stream cipher algorithm designed in 1987 by Ron Rivest and this is one of the most widely used software stream cipher and this is used in most popular protocols such as SSL (to protect Internet traffic), WEP (to secure wireless networks) and in PDF. This algorithm generates a pseudo-random stream of bits used for encryption by combining it with plaintext using bit-wise exclusive-or and decryption also performed in the same way.

6. RC5 (Rivest Cipher 5): This is a block cipher designed by Ronald Rivest in 1994. This RC5 cipher has variable block size i.e. 32, 64 and 128 bits.

7. RC6 (Rivest Cipher 6): This is another block cipher submitted by NIST AES. It was patented by RSA Security. This algorithm uses block size of 128 bits and has a key size of 128, 192, and 256 bits, and the up to 2040-bits. This algorithm is considered as simpler than the AES standard selected.

References

cryptography.io, c (2013-2017), Asymmetric algorithms