Symmetric Key Algorithms
Symmetric algorithms use the same shared secret key value that will both encrypt plaintext and decrypt the resulting ciphertext. Both parties share the exact same key.
Common symmetric algorithms include DES, 3DES, and AES.
Other, less common symmetric algorithms include International Data Encryption Algorithm (IDEA), Blowfish, and Carlisle Adams/Stafford Tavares (CAST).
DES
DES was originally developed in 1977 by IBM. It is a 56-bit encryption algorithm, meaning the number of possible keys “key space” is 2^56 or 72,057,594,037,927,936. Seventy-two quadrillion was a very large number in 1977 and would have taken computers hundreds of years to search the DES key space. It was considered so secure the U.S. Department of ...
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