Checksums (New) PDF
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Summary
This document explains checksums and their role in ensuring data integrity within distributed systems. It details how cryptographic hash functions like MD5, SHA-1, SHA-256, and SHA-512 are used to calculate checksums. The document also describes how systems use checksums to verify data before storing or retrieving it.
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117 Checksum (New) Let's learn about checksum and its usage. Background In a distributed system, while moving data between components, it is possible that the data * * * * *...
117 Checksum (New) Let's learn about checksum and its usage. Background In a distributed system, while moving data between components, it is possible that the data * * * * * * fetched from a node may arrive corrupted. *** *** This corruption can occur because of faults in a storage device, network, software, etc. *** *** * How can a distributed system ensure data integrity, so that the client receives an error ** ** ** ** instead of corrupt data? * Solution * Calculate a checksum and store it with data. * *** *** * * To calculate a checksum, a cryptographic hash function like MD5, SHA-1, SHA-256, or *** *** ** ** ** ** ** ** ** SHA-512 is used. ** The hash function takes the input data and produces a string (containing letters and *** *** *** *** *** numbers) of fixed length; this string is called the checksum. *** *** *** * * * When a system is storing some data, it computes a checksum of the data and stores the * * * * * * * * * *** checksum with the data. *** * When a client retrieves data, it verifies that the data it received from the server matches the * * * * * * * *** *** * checksum stored. If not, then the client can opt to retrieve that data from another replica. * *** *** *** ***
