This seems interesting, using file size to check integrity of transfer and file is valid. <\/p>\n\n\n\n
from Wiki <\/p>\n\n\n\n
A checksum<\/strong> is a small-sized block<\/a> of data derived from another block of digital data<\/a> for the purpose of detecting errors<\/a> that may have been introduced during its transmission<\/a> or storage<\/a>. By themselves, checksums are often used to verify data integrity<\/a> but are not relied upon to verify data authenticity<\/a>.[1]<\/a><\/sup><\/p>
The procedure<\/a> which generates this checksum is called a checksum function<\/strong> or checksum algorithm<\/a><\/strong>. Depending on its design goals, a good checksum algorithm usually outputs a significantly different value, even for small changes made to the input.[2]<\/a><\/sup> This is especially true of cryptographic hash functions<\/a>, which may be used to detect many data corruption errors and verify overall data integrity<\/a>; if the computed checksum for the current data input matches the stored value of a previously computed checksum, there is a very high probability the data has not been accidentally altered or corrupted.<\/p>
Checksum functions are related to hash functions<\/a>, fingerprints<\/a>, randomization functions<\/a>, and cryptographic hash functions<\/a>. However, each of those concepts has different applications and therefore different design goals. For instance, a function returning the start of a string can provide a hash appropriate for some applications but will never be a suitable checksum. Checksums are used as cryptographic primitives<\/a> in larger authentication algorithms. For cryptographic systems with these two specific design goals, see HMAC<\/a>.<\/p>
Check digits<\/a> and parity bits<\/a> are special cases of checksums, appropriate for small blocks of data (such as Social Security numbers<\/a>, bank account<\/a> numbers, computer words<\/a>, single bytes<\/a>, etc.). Some error-correcting codes<\/a> are based on special checksums which not only detect common errors but also allow the original data to be recovered in certain cases.<\/p><\/blockquote>\n\n\n\n
wiki<\/p>\n\n\n\n
https:\/\/en.wikipedia.org\/wiki\/Checksum<\/a><\/p>\n\n\n\n
https:\/\/www.lifewire.com\/what-does-checksum-mean-2625825<\/a><\/p>\n\n\n\n
Linux <\/p>\n\n\n\n