The timeline of communication systems presents a chronological overview of the most important events in the history of communication systems from the 4th millennium B.C. to the present.
It shows that from the very beginning - the first Sumerian pictographs on clay tablets to today's state-of-the-art technologies - broadband communication via
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The U.S. Data Encryption Standard (= DES) is the most widely used encryption algorithm, especially used for protection of financial transactions. It was developed by IBM in 1971. It is a symmetric-key cryptosystem. The DES algorithm uses a 56-bit encryption key, meaning that there are 72,057,594,037,927,936 possible keys.
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The Clipper Chip is a cryptographic device proposed by the U.S. government that purportedly intended to protect private communications while at the same time permitting government agents to obtain the "keys" upon presentation of what has been vaguely characterized as "legal authorization." The "keys" are held by two government "escrow agents" and would enable the government to access the encrypted private communication. While Clipper would be used to encrypt voice transmissions, a similar chip known as Capstone
would be used to encrypt data. The underlying cryptographic algorithm, known as Skipjack, was developed by the National Security Agency (NSA).