Cryptography Stack Exchange
Cryptography Stack Exchange

Questions tagged [checksum]

A checksum is a value created from a binary file that can be used to detect errors especially occurred in the transmission.

A checksum is a small-sized datum derived from a block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data integrity but are not relied upon to verify data authenticity.

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Checksum vs. non-cryptographic hash

What are the differences between checksums (e.g. Fletcher, Adler, CRC), non-cryptographic hashes (e.g. xxHash, MurmurHash, CityHash) and cryptographic hashes (e.g. MD5, SHA1, SHA3)? I am familiar with checksums and how they're used to detect errors…
bryc
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Blake2 vs md5 for checksum / file integrity

I'm working on something that requires computing a checksum / file integrity. I've heard MD5 was no longer recommended. Should I use Blake2 instead? Is there a specific variant of Blake2 I should use for checksums? Blake2s? Blake2sp?
aroooo
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Verify partial message given hash of full message

I need to verify partial downloads (retrieved sequentially), given a (preferably short) hash of the complete download. Given a message $m_0 \mathbin\| m_1 \mathbin\| m_2 \mathbin\| \cdots$, hash function $H$, and hash value $h = H(m_0 \mathbin\| m_1…
partialhash
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Is it feasible to get a hash collision for CRC32, MD-5 and SHA-1 on one file?

I'm aware that individually, each has its weaknesses (especially CRC32), but is it feasible that a file could be created to falsely match all three?
Hiccup
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How easy is it to fake a file hashed with three functions, CRC32, MD5 and SHA-1?

File-A is hashed with CRC32, MD5 and SHA-1. How easy is it to create a fake file-B that has the same hashes of file-A? CRC32, MD5 and SHA-1? Can an average PC with a GPU calculate a triple hash collision of file-A? And how long would it take?
user94388
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Is it possible to fake any file's SHA-256 checksum with a length extension attack?

Can a fake SHA-256 checksum be created trivially for any file by attacker after padding some data after original file i.e. using length extension attack? E.g: Alice creates fake linux installation ISO file using length extension attack by padding…
nlzzl1m
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Is CRC32C (any) better than CRC32(B)?

Is CRC32C (any) better than CRC32(B)? I read that CRC32C (alias Castagnoli) is better than CRC32 (sometimes referred as CRC32B) in detecting errors but what that exactly means and how to check it didn't mention. I know they use different polynomial…
tansy
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Why do digital signatures use a hash algorithm instead of a checksum?

Based on my knowledge, all digital signature algorithms use a hash function to sign a message, and then encrypt the hash result. So why do these algorithms not use a checksum instead of a hash algorithm? By the end, both are going to encrypted,…
Aymn Alaney
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Identifying identical files without reading them completely

Imagine the following situation: there are many "big" files (100Gb+) lying on 2 different remote servers you have no direct access to these files you can only read a small amount of each file (e.g. 10Mb) as well as it's general information (e.g.…
scable
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Suitable 16-bit checksum?

I am writing a toy1 transport protocol and I am trying to implement a feature whereby: A 16-bit checksum is included in every packet. This checksum can be extended to be 48-bit if the data is large, integrity is important, or whatever (creating…
Matt
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How to calculate a multiple-character checksum for authentication using a tabula recta?

I am not sure if this is possible to do using a tabula recta, but I would like to know how to calculate a multiple-character checksum of a text. For a single-character checksum, it's easy. You just begin on the table at the first letter of text,…
Meler Lawler
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Optimal way to get checksum digits from hash?

Let msg be some data we want to hash using an arbitrary digest size algorithm such as blake2b. From that hash, we would like to compute a checksum field with n decimal digits. If we suppose that the hash algorithm has a perfect distribution, we…
User314
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Using checksum instead of hash for authenticating ciphers

Lets assume for a specific situation we cannot use authenticated encryption like GCM ... If we were to use CTR, what would you think of using a checksum on the plaintext then encrypt the whole. The reason I don't want to use a hash is because the…
madz
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Can XTS + checksum be used for authenticated encryption?

Is it possible to use XTS + a checksum for authenticated encryption? Specifically, it seems like a good $n$ bit checksum applied before encryption should ensure that any change to the ciphertext will be detected by the plaintext checksum with a…
Demi
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Storage of Time Data in PKCS12

I have a certificate distribution script which retrieves PKCS12 binary data from a database and uses it to create a PKCS12 file locally. This is working. This script also uses SHA256 checksums to compare current and incoming certificate data so that…
pytinkerer
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