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Here all you want to know symmetric encryption and asymmetric encryption, the fundamental types of encryption schemes. This article also features stream ciphers, blocks ciphers and, for instance, sheds a light on Public Key Cryptography.

An encryption algorithm is mathematical operation where plaintext is transformed to so called ciphertext, unintelligible to anyone who doesn’t know the secret key to decrypt it. Encryption algorithms have their roots in the Greek history, and until the advent of computing have encrypted messages been the domain of the military and erudites. These days encryption is also used for secure online banking, digital rights management, protecting health data and email exchange such as by PGP for example.

Encryption algorithms are called symmetric when the same secret, password or key is used to encrypt and to decrypt. Shared secret algorithms either operate on a bit bases (stream ciphers) or encrypt chunk of bites (block ciphers). Encryption algorithms which use a different key for decryption and encryption are called asymmetric and have some functional advantages over symmetric encryption which if fast, and can be secured by on-the-fly key generation and frequent key changes.

The downside of symmetric encryption is that anyone who knows the secret key or password can transform the secret cipher text to plaintext. This makes symmetric encryption vulnerable to leaking, and spying out passwords. A famous example of symmetric encryption used to be DES (Data Encryption Standard) which is no longer in wide use. DES and its variants have now largely been replaced with Advanced Encryption Standard (AES) which uses a 128, 192, or 256 bit key. The longer the key the more secure the message is in general (“theoretically stronger”).

Asymmetric encryption on the other hand employs a different key for decryption and encryptions by so called public key encryption in which anyone can get the public key of the recipient to encrypt files or messages so that only the holder of the private key of the public-private key pair can open the item. In a similar operation can the holder of the private key sign messages so that anyone can check message authenticity. RSA ( Rivest, Shamir and Adleman) is the de-facto standard algorithm public key encryption algorithm. The downside of public key encryption is that asymmetric encryption usually is much slower and needs more computing power than shared secret encryption.

When have been discussing types of encryption in terms of symmetry, which is common. Another way to classify encryption algorithms is differentiating in secure and non-secure encryption. Secure encryption algorithms are those whose inner workings have been made known to the public such as, for example AES whilst until recently perhaps no-one has discovered a flaw in the algorithm or was able to break it (In contrast are secret encryption schemes usually considered not to be secure. Rather, people speak of security through obscurity). save money at fast cash

Apart from social engineering exist two ways to break an encryption key like AES, brute force and cryptanalysis. Find out here whether AES encryption can be cracked any time soon, along with the latest AES development and recommendations from IT security evangelist Bruce Schneier.

Besides social engineering exist two ways to break any encryption key, brute force and cryptanalysis. After the introduction we look at why AES and similar encryption schemes are secure against brute-force attacks using computer power to crack a key. Then you will find the latest development from the studies of AES by means of cryptanalysis. If you are not familiar with encryption it is recommended reading Bright Hub’s article What is AES Encryption? and Types of Encryption.

Brute Force

Mathematicians have discovered that any positive integer greater than one can be expressed as the product of its prime factors; the prime decomposition of the number 22 for instance is 2 x 11. There are a number of algorithms for integer factorization, but the difficulty and complexity to find the prime factor increases at the last sub-exponentially with the size of the integer.

This essentially means that the prime decomposition of large numbers is computationally infeasible with traditional computers. As the strongest encryption algorithms in use today, such as, for instance, Rijndael, which has become the Advanced Encryption Standard (AES), employ large integer factorization, AES in unbreakable – again with the premise of traditional computers in mind.

A quantum computer operating on qubits instead of bits offer polynomial speed for some computing problems including Integer factorization, so that taking into account Cobham’s thesis we know that the traditional encryption algorithm keys can be feasibly computed. Therefore, when quantum computing gets out of the lab will ciphertext produced by traditional cryptography no longer be secure.

Cryptanalysis

The Advanced Encryption Standard can be used with 256-bit keys, immune against Moore’s Law for the years to come. However, cryptanalysts studying the inner working of an algorithm are constantly trying to find a weakness in the encryptions algorithms or to break it. Most “vulnerabilities” are usually of rather theoretical nature, so there is nothing to worry about for an ordinary computer user as the subject is being watched and followed by the IT security community which has been trying to crack publicly documented encryption schemes including AES for years.

Yet, it was only recently when Bruce Schneier, the inventor of Twofish and Blowfish AES competitors stipulated “that the safety margin of AES is much less than previously believed [1].” Schneier demands that AES implements more round of Rijndael for any key length “and for new applications I suggest that people don’t use AES-256. AES-128 provides more than enough security margin for the foreseeable future