As stated, telecommunication is seen as an unreliable media for transporting secret messages. Therefore today, cryptography is needed more than ever before, especially for e-commerce.
Key cryptosystems try to provide more privacy.
symmetric-key cryptosystems:
The same key is used for both encryption and decryption. In this case the encipherer and the recipient of the message/text have to agree on a common key before the enciphering-process can start. And most of all they should trust each other. And exactly this is the main problem of this system: how to exchange the key without offering an opportunity for stealing it?
In former times messengers or pigeons were doing the exchange of those keys.
Symmetric-key systems make sense in small entities. If a lot of people are spread over a wide area and belong to the same network, distributing the keys starts getting complicated.
Today, those cryptosystems get controlled by other keys, based on highly complex mathematical algorithms.
some symmetric-key systems are:
- DES (Data Encryption Standard), the standard for credit cards
- Triple-DES, which is a variation of DES, encrypting the plaintext three times.
- IDEA (International Data Encryption Standard)
- blowfish encryption algorithm, which is said to be faster than DES and IDEA
Security and confidence are the key-words for a popular key-system: As DES and its successors have been used for so many years and by many people without having been broken, they are considered safe - safer than others, not used that frequently, no matter whether they are actually safer or not.
For further information see:
TEXTBLOCK 1/1 // URL: http://world-information.org/wio/infostructure/100437611776/100438659090
b. June 12, 1924
41st President of the United States. In 1954, George Bush co-founded and became the president of Zapata Offshore Company. By 1964, he became chairman of the Republican Party of Harris County. That same year, he ran for the U.S. Senate, but was defeated in the Democratic landslide. Bush had better luck in the election of 1966, when he became the first Republican ever to represent Houston in Texas. Presidents Nixon and Ford selected Bush for a series of high-profile appointments: Ambassador to the United Nations in 1971, Chairman of the Republican National Committee in 1973, envoy to China in 1974 and Director of Central Intelligence in 1976. When Jimmy Carter was elected President in 1976, he appointed a new Director and George Bush returned to private life. In 1980, Bush made his own run for the Presidency. George Bush sought the Presidency again in 1988, and won the Republican nomination over a large field of candidates. His election that November was a decisive one, though not the landslide he and Reagan had enjoyed in 1984.