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Symmetric Key Encryption

The most basic form of encryption is symmetric key encryption, so named because both the sender and the receiver of the data use the same key to encrypt and decrypt the data. The problem with symmetric key encryption is that you must have a secure way to transport the encryption key to individuals you wish to exchange data with. If you do not use a secure method to send the key to a recipient, someone may intercept the key. This makes encryption useless, because now the interceptor
can decrypt the data knowing the key. In addition, if you are using encryption techniques for multiple recipients, you may not want one person to have access to another’s data. Now you must keep multiple single keys per person, which can become extremely cumbersome.

Stream Cipher

Stream cipher algorithms encrypt data one bit at a time. Plain text bits are converted into encrypted cipher text. This method is usually not as secure as block cipher techniques, but it generally executes faster. In addition, the cipher text is always the same size as the original plain text and is less prone to errors. If an error occurs during the encryption process, usually this affects only a single bit instead of the whole string. In contrast, when block ciphers contain errors, the entire block becomes unintelligible.

block cipher

Instead of encrypting a bit at a time, block cipher algorithms encrypt data in blocks. Block ciphers also have more overhead than stream ciphers, which is provided separately depending on the implementation and the block size that can be modified (the most common size being 64 bits). Because it handles encryption at a higher level, it is generally more secure. The downside is that the execution takes longer. Numerous block cipher options are available, such as Electronic Codebook (ECB), Cipher Block Chaining (CBC), Cipher Feedback (CFB), and Output Feedback Mode (OFB).

D.E.S

The Data Encryption Standard (DES) was created and standardized by IBM in 1977. It is a 64-bit block symmetric algorithm and is specified in the ANSI X3.92 and X3.106 standards for both enciphering and deciphering operations, which are based on a binary number. In addition, the National Security Agency (NSA) uses it as the standard for all government organizations. There currently exist 72 quadrillion (72,000,000,000,000,000) encryption keys for DES, in which a key is chosen at random. DES uses a block cipher methodology to apply a 56-bit symmetric key to each 64-bit block. An additional form of DES, known as triple DES, applies three keys in succession to each block.

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