Suppose that you want to send an e-mail to someone and you want to ensure that no one else can read the message. You must change the message in some way so that anonymous intruders cannot read its content.

In cryptographic terminology, the unaltered message is called plaintext. If the contents of a message is altered in such a way that the meaning is hidden from others, the file is considered to be encrypted. The process of encrypting information or converting information to an unreadable form is called encryption. The encrypted message is called the ciphertext.

The process of retrieving the plaintext from the ciphertext is called decryption. Encryption and decryption usually make use of a key. It is hoped that a message cannot be decrypted unless the recipient of the message has the proper key and knows the method by which the message was encrypted. The method used to encrypt or decrypt the message is sometimes referred to as the coding method or simply the encoding.

Cryptography is the art or science of keeping communications secret. Cryptanalysis is the art of breaking encrypted messages, i.e. retrieving the plaintext by analyzing the ciphertext without knowledge of the key. People who practice cryptography are called cryptographers; cryptanalysts being individuals who practice cryptanalysis.

Cryptography deals with all aspects of making information secure (secure messaging); verifying that the correct people have permission to use, send, encrypt, or decrypt a message (authentication); veryfying that the sender of a message is not an imposter (digital signatures); making sure that web enabled transactions are secure so that electronic money is properly exchanged; and other applications like smart cards and securing files. Cryptology is the branch of mathematics that studies the mathematical foundations of cryptographic methods.

Cryptographic Algorithms

The algorithm used in encryption and decryption is called a cipher. No method is better than the cipher or algorithm it uses to encrypt messages or files. Cryptographic methods rely on the secrecy of the algorithms, the ability of the algorithm to scramble the plaintext sufficiently to resist cryptanalysis, and a secret key to protect the encrypted message in case the algorithm is discovered. All modern algorithms use a key to control encryption and decryption. Ideally, it is hoped that a message can be decrypted only with the proper key.

There are two classes of key-based encryption algorithms, symmetric (or secret key) and asymmetric (or public key) algorithms. The difference is that symmetric algorithms use the same key for encryption and decryption (or the decryption key is easily derived from the encryption key), whereas asymmetric algorithms use a different key for encryption and decryption, and the decryption key cannot be derived from the encryption key.

Symmetric algorithms can be divided into stream ciphers and block ciphers. Stream ciphers can encrypt a single bit of plaintext at a time, whereas block ciphers take a number of bits (typically 128 bits in modern ciphers), and operate on them as a single unit to encrypt a block of text.

Asymmetric ciphers also called public-key algorithms or generally public-key cryptography, permit the encryption key to be public, that is, it can even be published in a newspaper or in a web dictionary. This allows anyone to send an encrypted message to a targeted recipent by encrypting the message with the recipients key. Supposedly, only the proper recipient who knows the decryption key can decrypt the message. The encryption key is also called the public key and the decryption key is called the private (or secret) key.

Modern cryptographic algorithms are no longer pencil-and-paper ciphers. Strong cryptographic algorithms are designed to be executed by computers or specialized hardware devices. In most applications, cryptography is done in computer software like Dynacrypt® Version 4.0.

Generally, symmetric algorithms are much faster to execute on a computer than asymmetric ones. In practice they are often used together, so that a public-key algorithm is used to encrypt a randomly generated encryption key, and the random key is used to encrypt the actual message using a symmetric algorithm. This is sometimes called hybrid encryption.

Descriptions of many good cryptographic algorithms are widely and publicly available from any major bookstore, scientific library, patent office, or on the Internet. The most studied and probably the most widely used symmetric cipher is the Data Encryption Standard or DES; the upcoming Advanced Encryption Standard or AES will replace it as the most widely used encryption algorithm. RSA is probably the best known asymmetric encryption algorithm.

DES and AES are sponsored by the Federal Government (National Institute for Standards Testing (NIST)) as standards to be used for encryption and decryption. DES was replaced by AES in the first quarter of 2001. AES is an algorithm proposed by Joan Daemen and Vincent Rijmen and adopted by the Federal Government on October 2, 2000 as the new standard for encrypting sensitive but unclassified information. The Algorithm is called Rijndael, pronounced "rain doll". But can you trust the Federal Government and the National Security Agency (NSA) to propose a standard to you that is secure, meaning they cannot break it whenever they want to?

The most important questions to ask are:

Secure communications is an issue of paramount concern to public and private America. The Federal Bureau of Investigations (FBI) along with the NSA and CIA are monitoring all communications in this country whether they are Internet, cellular telephone, regular telephone, books, newspapers, television, or any kind of communication broadcasts. The FBI has the Carnivore program to monitor and listen in on all Internet communications. This is why you need a secure encryption method that they cannot break like Dynacrypt® Version 4.0.

Many encryption schemes have been proposed with the intent of securing communications over the Internet. Some of these methods are:

These methods with the exception of RSA and Elliptic Curve are secret key, symmetric cryptographic methods. Secret key, symmetric systems are faster data execution methods than the public key, private key, asymmetric method of RSA. However, RSA and especially the Elliptic Curve CryptoSystem may offer the advantage of increased security, if very large prime numbers or a very large bit modulus is used.

The algorithms used in all of these systems are public information. They rely upon the assumption that it will take a long time before computers can break the code using a brute force method or that the necessary computing power is too expensive to build. In the case of RSA, it is assumed that it is very difficult to factor two large prime numbers that is necessary to break the public key, private key method of RSA. Although it is not necessary to factor two large primes to decrypt RSA, a judicious choice of public and private keys will make it virtually impossible to break by brute force.

While these methods may offer some security with the current state of computers, they are not without security risks. The authors of RSA issued a $10,000 challenge to anyone who could break the DES 56-bit encryption scheme. On June 18, 1997, thousands of Internet users and computer hackers combined their efforts and in only four months cracked the DES 56-bit encryption scheme. RSA's next DES challenge (RSA DES-II-1) began on Tuesday, January 13, 1998. Distributed Net discovered the key about 39 days later. RSA's most recent challenge (RSA DES-II-2) began on Monday, July 13, 1998. The key was discovered on Wednesday, July 15! The Electronic Frontier Foundation using a homemade DES Cracker machine costing about $250,000 found the key.

Other encryption schemes have not been attacked like DES. This is because many computer experts felt that the government had purposely crippled IBM's 112-bit encryption scheme to a breakable 56-bit Data Encryption Standard (DES). The government thought that with a 56-bit scheme producing 7.205759403793 x 10e16 (72 quadrillion) possible keys, it could convince the public that DES would be difficult to break.

A message encrypted with RC5 using a 64-bit key was broken by Distributed.net.

Because these schemes and their algorithms are all public information and have such small key sizes compared to Dynacrypt®, it is just a matter of time before computers are capable of breaking any of these schemes in a short period of time. With modern computers, the 40-bit DES encryption scheme suitable for export can be broken in only 26 minutes or less by brute force. In 2007, IBM, Cray Computers, Inc. and Silicon Graphics, Inc. produced 100 TFLOPS (Tera-Flops) supercomputers. These computers are able to do 100 trillion floating-point operations per second or 100 x 10e12 operations per second. With a 100 TFLOP machine, DES can be broken by brute force in approximately 6 minutes. Modern classical computers are approaching 500 TFLOPS using clusters of single core dual processor computers. What is most interesting is that these same computers in 2007 can be 4 times faster with quad core technology. It is quite likely that by the end of 2007, supercomputers will reach the speed of 2 PFLOPS (Peta-Flops) or 2 x 10e15. Using a 2 PFLOPS machine, DES can be broken in approximately 18 seconds.

It is generally thought that brute force attacks are impractical and a waste of time. Most so-called experts believe that computers will not be fast enough to search through the required number of keys to break the cryptographic system. These ideas are backed up by theoretical physicists making predictions on how much energy it will take for a computer to break say a 128-bit cryptographic system. The so-called Von Neumann-Landauer Limit implied by the laws of physics sets a lower limit on the energy required to perform a computation. according to the Von Neumann-Landauer Limit theory, to search through the possible values for a 128-bit key (ignoring any computing energy to check the results), one would need at a minimum a 10 gigawatts device running continuously for 100 years. Ten (10)gigawatts is approximately eight (8) large, dedicated nuclear reactors. This theory and its calculations are based on old computer technology with no forethought for modern computing. It is a ridiculous proposition but one that people who are using inferior schemes love to hear.

What these experts are doing are showing off their ignorance. Today we have computers with Central Processing Units (CPUs) that have multiple cores and operating speeds in the GHz range. On the horizon are Quantum computers. It is widely believed that if large-scale quantum computers can be built, they will be able to solve certain problems like doing cryptanalysis exponentially faster than any classical computer. This would make the modern day cryptographic systems obsolete. Hence, the need for Dynacrypt® Version 4.0.

Another important issue of interest is that security thieves have learned that instead of trying to break an encryption scheme by brute force, it is better to find out what the receiver of an encrypted message is trying to do to the message. These thieves send a message to a receiver using the appropriate authentication, digital signature, and public key. Next, they monitor what the receiver is trying to do to the cipher text to decrypt it. Monitoring the computer operations of the receiver gives the thief important information about the receiver's private key or encryption scheme.

There are several important facts that have been learned about modern day cryptography that are of interest for developing new encryption schemes for securing data transmissions over the Internet: