Every current encryption scheme is based upon an algorithm, a step-by-step, recursive computational procedure for solving a problem in a finite number of steps. The cryptographic algorithm—what is commonly called the encryption algorithm or cipher—is made up of mathematical steps for encrypting and decrypting information. Figure 4-1 shows a diagram of the encryption and decryption process and its parts. There are three types of encryption algorithms commonly used, the symmetric, asymmetric, and hashing algorithms. Symmetric algorithms are also known as shared secret algorithms, as the same key is used for encryption and decryption. Asymmetric algorithms use a very different process using two keys, a public key and a private key, making ...

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