From the course: Learning Cryptography and Network Security

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Compare block and stream ciphers

Compare block and stream ciphers

From the course: Learning Cryptography and Network Security

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Compare block and stream ciphers

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- [Instructor] Symmetric encryption algorithms are one of two types, either a block cipher, such as DES or AES or a stream cipher such as RC4 or SEAL. Let's compare the differences between a block and a stream cipher. A block cipher processes plain text in fixed size blocks that are either 64 or 128 bits. They then produce a block of cipher text of equal size. In some cases, padding might be required to create a complete block. For example, if the block is 126 bits, you'll need to add two bits to create a 128 bit block A block cipher can only encrypt a single block of data at a time. If you need to encrypt a variable length message the data must first be split into separate blocks. However, a better option is to use a stream cipher. If we add memory to a block cipher this results in a stream cipher. In most cases we're going to use a stream cipher because many times we're transmitting a large amount of data or the size…

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