Checksum collision probability. the range for binary_checksum ()) to be 54563.

Checksum collision probability. Sep 30, 2016 · Their names change randomly. CRC Collision A CRC collision occurs when two different data blocks, when encoded, produce the same CRC checksum value. 18 Probability in Hashing A popular method for storing a collection of items to sup-port fast look-up is hashing them into a table. In this way, a 128 bit algorithm doesn't care if you feed it 1 The collision probability because significant around 2^64 values, but the clash rate for two arbitrary values is only 2^-128. So: given a good hash function and a set of values, what is the probability of there being a collision? What is the chance you will have a hash collision if you use 32 bit hashes for a thousand items? And how many items could you have if you switched to a 64-bit hash without the risk of collisions going above one-in-a-million? Jun 28, 2023 · Collision Resistant: The MD5 hash function is considered collision-resistant, meaning it is computationally infeasible to find two different input messages that produce the same hash value. The main improvement of Jan 20, 2017 · Even though the probability of a collision is very low, it is prudent in the FOOBAR case, say if there is an issue and the hashes accumulate for more than 15 minutes, to at least confirm what would happen in the event of a collision. So, the probability of collision between the hashes of two given files is 1 / 2^32. Just don't go with MD5 as it's not properly designed and have structual weakness. substantially smaller than 2n/2). Thus: SHA256 {100} = 256-bits (hash Size of the hash function's output space You can use also mathematical expressions in your input such as 2^26, (19*7+5)^2, etc. Why hasn't' this happened? Oct 27, 2017 · The popularity of SHA-256 as a hashing algorithm, along with the fact that it has 2 256 buckets to choose from leads me to believe that collisions do exist but are quite rare. Apr 25, 2019 · 1) Do I need to worry about checksum collisions? I'm planning on using MD5 to calculate the has There is a difference between a checksum (e. At this scale, you'd probably beat Google in terms of storage capacity. This collision can lead to data corruption Dec 1, 2024 · Choose a Good Hash Function: A well-designed hash function distributes keys uniformly across the table. al Suppose we use a hash function h h to hash n n distinct keys into an array T T of length m m. If the output of the hash function is discernibly different from random, the probability of collisions may be higher. The exact probability depends on what "8 characters" means. We showed that the probability of a collision is inversely proportional Apr 4, 2025 · 1. It’s important that each individual be assigned a unique value. See the first table at Wikipedia: Birthday Attack for exact probabilities. The former is the probability that the hash of two items will collide, and follows the formula above (although, as noted by Kamel, the distribution is not perfectly uniform and thus the probability is likely higher). C) You store 8 bytes, encoded in some single-byte charset/ or hacked in some broken way into a character ~5 million years (or 1. To put that in perspective, there are about 10^23 stars in the entire known universe. For all we know, SHA Jan 5, 2019 · What are the odds of a hash collision for the MD5 hash? MD5: The fastest and shortest generated hash (16 bytes). In general the mathematical expression that gives you the probability of hash function is : p (k) = 1 - exp (-k (k-1)/2N, k (number of hashes) randomly generated values, where each value is a non-negative integer less than N (number of possible hashes): N = 2^ (number of bit), example for md5 it is 2^128, or 2^32 for 32 bit-hash If you Feb 24, 2023 · A pair of 16-bit registers makes a checksum comparable to CRC32 with much less coding complexity. The probability that a key will not collide with any of J keys already in the table is just the probability that it will land in one of the remaining M-J locations. For MD5, this means different data sets can generate the same 32-character hash, a serious vulnerability for any cryptographic hash function. 44e+14 seconds) needed, in order to have a 1 % probability of at least one collision if 1000 ID's are generated every hour. For example, if there are 1,000 available hash values and only 5 individuals, it doesn't seem likely that you'll get a collision if you just pick a random sequence of 5 values for the 5 individuals. Given today’s computing power, an MD5 collision can be generated in a matter of seconds. Aug 28, 2016 · Birthday problem for cryptographic hashing, 101. Oct 25, 2010 · If we have a "perfect" hash function with output size n, and we have p messages to hash (individual message length is not important), then probability of collision is about p2/2n+1 (this is an approximation which is valid for "small" p, i. For even SHA256, you must generate 4. Hash Collision Probabilities A hash function takes an item of a given type and generates an integer hash value within a given range. Nov 22, 2020 · I am trying to show that the probability of a hash collision with a simple uniform 32-bit hash function is at least 50% if the number of keys is at least 77164. 5, how many times should the said "attacker" have to search to find identical hash values? I've come across a series of solutions from searching, but none that thoroughly walk me through the process and explain it in a way that makes sense Dec 17, 2013 · To summarize, the probability of producing a hash collision on a Git repository is so small that it's extremely unlikely to happen during our lifetimes. For a 16-bit only checksum, the two 16-bit registers can be added. The exponential approximation appears to be robust. Nov 13, 2011 · If I also calculate the (e. In this case n = 2^64 so the Birthday Paradox formula tells you that as long as Depending on the hash function there exist algorithms to calculate a hash collision (If I remember correctly the game I exploited used CRC32, so it was very easy to calculate the collision). Published in Paul L. However, because the MD5 hash To begin with, one could calculate the probability of collision for random numbers where the first 6 digits are random dates in reasonble time (1950-2010) and digit 7 and 8 are random, and then try to understand what probability was discussed. Since each index should ideally store only one value, collisions can lead to incorrect data retrieval or overwriting. That probability is lower than the number of water drops contained in all the oceans of the earth together. Assuming simple uniform hashing, what is the expected number of collisions? More precisely, what is the expected cardinality of {{k, l}: k ≠ l and h(k) = h(l)} {{k, l}: k ≠ l and h (k) = h (l)} ? Jul 9, 2017 · If we take every possible hash (1664 16 64) and rehash it, the amount of possible outcomes for any given rehash is 1 out of 1664 16 64. The possibility of your input having a collision is of course much higher (assuming that it is randomly generated Feb 5, 2012 · The probability of a random collision is highly dependent on the size of the data that you're working with; the more strings you're hashing, the more likely a collision is to occur. In fact, it's equal to exactly 1 - sPn/s^n, where s is the size of the search space (2^128 in this case), and n is the number of items hashed. The collision probability Sep 20, 2019 · A properly designed n n -bit hash function has collision probability 2−n/2 2 n / 2 due to birthday paradox. Considering the birthday paradox, given a set of 2^64 (or 18,446,744,073,709,551,616) assets, the probability of a single MD5 collision within this set is 50%. I'm Nov 11, 2022 · In the case you cite, at least one collision is essentially guaranteed. So, all possible rehashes is equal to all possible unique hashes. Nov 25, 2020 · Regardless of the algorithm, if the result is 8 bytes then you have created a 64-bit hash, and even if it is perfectly collision resistant, it still only takes about 2^32 operations to find a collision by brute force, which is practically nothing for security purposes. SHA-256 is a cryptographic one-way function, compressing a byte sequence of arbitrary length to a 256-bit sequence. The other two are convenient for back of the envelope calculations, but may lose their nerve as you add more books to your collection. Assume, I am using SHA256 to hash 100-bits. close to zero. Jan 10, 2017 · This means that with a 64-bit hash function, there’s about a 40% chance of collisions when hashing 2 32 or about 4 billion items. Apr 22, 2025 · A hash collision occurs when two distinct inputs produce the same hash value as output from a hash function. The efficiency of all hashing algorithms de-pends on how often this happens. What about non integer keys? Hash function definition A hash function is any function that can be used to map data of arbitrary size to fixed-size values. We would like to show you a description here but the site won’t allow us. And if you draw a million numbers, the probability that all numbers are unique is in the range 1E-50. The probability of just two hashes accidentally colliding is approximately: 1. 8*10^37 hashes before the probability of collision reaches even one percent. Finding a collision would require generating 2^64 hashes by brute force, which is computationally infeasible with current technology. Jan 22, 2008 · Assuming random input, the probability of any of these values appearing is equal. Let pn p n be the probability of collision for a number n n of random distinct inputs hashed to k k possible values (that is, probability that at least two hashes are identical), on the assumption that the hash is perfect. com In this article, we present the Mathematical Analysis of the Probability of Collision in a Hash Function. Dec 15, 2015 · The likelihood of MD5 collisions is pretty low (needing 609 million records before a 1% chance of collision), SHA1 even lower (1. 7 Since the only relevant property of hash algorithms in your case is the collision probability, you should estimate it and choose the fastest algorithm which fulfills your requirements. I find that showing collisions to people I'm explaining hashing to is a great way to show them what non The probability of hash collisions is based partially on the number of bits, but also the number of distinct data elements hashed. 5 log (2) or when n is around 4. This is at around Sqrt[n] where n is the total number of possible hash values. for an available time of t=13. We present a collision attack on 28 steps of the hash function with practical complexity. Bennett, Mathematics in Cyber Research, 2022 Cheyne Homberger Hashes are used as building blocks for more complex security mechanisms, and the collision resistance—the inability to easily find hash collisions—is a major factor in the level of security provided. A longer bit length increases the number of possible hash outputs (2^n). Using a two-block approach we are able to turn a semi-free-start collision into a collision for 31 steps with a complexity of at most 265:5. 2E19 strings. MD5 uses 128 bits, so to achieve a 50% collision probability, you'll need 2. The same input always generates the same hash value, and a good hash function tends to generate different hash values when given different inputs. If two individuals are assigned the same value, there is a collision, and this causes trouble in identification. But even if that analysis shows your application isn May 27, 2020 · 2 If MD5 was a perfect hash function (it isn't) then each of the characters in its hex string would be a random number from 0 to 15. While hash functions are designed to map data of arbitrary size into a fixed-size output (hash values), they are not immune to collisions due to mathematical constraints on the size of their output space. That pn p n is also the minimum probability of collision with no hypothesis on the hash. From what I understood so far (from this forum and also from Wikipedia) that SHA-2 algorithms are not collision-free. What is CRC Collision? CRC (Cyclic Redundancy Check) collision is a phenomenon that occurs when two different sets of data produce the same CRC value. Due to the pigeonhole principle (where we're mapping an infinite input space to a finite output space), collisions are mathematically inevitable - the question is not if they exist, but how hard they are Therefore, the probability of a hash collision for MD5 (where w = 64) exceeds 1 2 when n ≈ 2 32. B) You store 8 characters of BASE-64? That would store 48 bits. Let's make some assumptions about randomness and find the probability that there is no collision. For SHA512, that number increases to 1. I'm well aware of the birthday paradox and used an estimation from the linked article to compute the probability. input given in bits number of possible outputs MD5 SHA-1 32 bit 64 bit 128 bit 256 bit 384 bit 512 bit Number of elements that are hashed You can use also mathematical expressions in your input such as 2^26, (19*7+5)^2, etc. Yet it is cumbersome to keep track of which hash values have and have not been Jan 15, 2022 · Conclusions We have seen how to calculate the probability of a hash collision, as well as 3 different ways to approximate this probability. Aug 16, 2023 · CRC x + 1 is appended to data. input given in bits number of hash 2 16 2 Hash Collisions: Understanding the Fundamentals What is a Hash Collision? A hash collision occurs when two different inputs produce the same hash output when processed through a hash function. In how do you solve a hash collision?, it helps keep databases and caches working well. Aug 12, 2024 · Real-World Applications Hash collision probability is used in many areas. Jun 24, 2017 · How has a collision never been found? If I decide to find the hash for a random input of increasing length I should find a collision eventually, even if it takes years. Are there any well-documented SHA-256 collisions? Or any well-known collisions at all? I am curious to know. Apr 12, 2024 · A collision in cryptographic terms occurs when two distinct inputs produce the same output hash. I imagine this can also be done where the input is a large file and you just change one byte and calculate the hashes until you find a collision. Jul 1, 2024 · We scrutinize the probability of root collisions in Merkle Trees, considering various factors such as hash length and path length within the tree. 4×10 38, much less likely. Dec 18, 2021 · For a formal problem statement, I quote from the text Introduction to Algorithms by Cormen et. Whether this is a risk in your application would require a detailed analysis of how your application uses the hash, what the relevant threat models are, etc. As such the 16 character hash has a collision probability of 16 -16 = 1 in 1. Feb 7, 2018 · Also is it not possible to append some kind of additional checksum or digest as an additional part of the final hash to prevent collisions? For example by adding a couple checksum bytes onto the output which may reduce the probability of collisions producing the same hash output coupled with the checksum? Feb 27, 2022 · The probability of an accidental collision will be the same, but there are known (non-accidental) ways to find collisions in SHA-1, which will also apply to any truncated version of it. In general, the average number of collisions in k samples, each a random choice among n possible values is: The probability of at least one Dec 8, 2009 · @Djarid It's important not to confound accidental hash collision and adversarial collision hunting. Dec 7, 2023 · As to why hashbytes over binary_checksum () comes down to math. I have figured out how to plot a gra May 25, 2025 · Explanation Collision Probability Estimation: The bit length of a hash value directly impacts the security of a cryptographic algorithm. 47*10-29. How long will you need to hash 6 million files before a MD5 hash collision occurs? To have a 50% chance of any hash colliding with any other hash you need 264 hashes. Our findings reveal a direct correlation between the increase in path length and the heightened probability of root collisions, thereby underscoring potential security vulnerabilities. Using a hash function for that purpose - no matter whether security is a concern Oct 14, 2015 · Alright, so I know that SHA-1 produces a hash of 160 bits. Is there a known probability function f: N -> [0,1], that computes the probability of a sha256 collision for a certain amount of values to be hashed? The values might fulfill some simplicity characteristics to reduce the complexity of the problem e. Goethals, Natalie M. The probability of CRC collisions depends on: Length of CRC code - Longer CRCs have lower collision chance. If you specify the units of N to be bits, the number of buckets will be 2 N. Feb 25, 2014 · Say I have a hash algorithm, and it's nice and smooth (The odds of any one hash value coming up are the same as any other value). Oct 27, 2010 · For practical purposes, the hash created might be suitably random, but theoretically there is always a probability of a collision, due to the Pigeonhole principle. crc32) and cryptographic hash. If I assume I have no more than 100 000 files the probability of two files having the same MD5 (128 bit) is about 1,47x10 -29. The probability of collision is dependent on the number of items already hashed, it's not a fixed number. Jan 27, 2018 · It must mean that many different inputs exist that produce the same checksum. Running the same calculation for SHA2-256 gives me something in the range of 2e38. That's even true for MD5, which is a broken secure hash. Verhoeff Algorithm Damm Algorithm Nov 20, 2018 · The thing to remember is that, unlike a CRC where certain types of input are more or less likely to result in a collision (with certain types of input having a 0% chance of causing a collision), the actual probability of collisions for input to a cryptographic hash is a function of only the length of the hash. Even with a very large input (think 2^64) of hashes, the chances of generating a collision is still about 1/ (2^64). ) MD-5 hash of the block, and use the combination (SHA-256, MD-5) as the key, is the chance of a collision about the same as some 384-bit hash function, or is it a little bit better because I'm using different hash functions? Thanks for the info! If we have a "perfect" hash function with output size n, and we have p messages to hash (individual message length is not important), then probability of collision is about p2/2n+1 (this is an approximation which is valid for "small" p, i. This means that to get a Feb 16, 2014 · Yes, there is a collision probability & it's probably somewhat too high. The relevant principle here is the birthday attack. Jul 1, 2020 · The exact formula for the probability of getting a collision with an n-bit hash function and k strings hashed is 1 - 2 n! / (2 kn (2 n - k)!) This is a fairly tricky quantity to work with directly, but we can get a decent approximation of this quantity using the expression 1 - e -k2/2n+1 1. A 64-bit hash function cannot be secure since an attacker could easily hash 4 billion items. Considering I am using CRC32, is there any way I can shorten the list of possible messages I have to try when Dec 22, 2017 · The probability of a collision depends on the length of the hash function in bits and the number of configurations that you compute the CRC on. The probability of collision is very low, maybe negligible, mathematically still higher than zero. When hash functions and fingerprints are used to identify similar data, such as homologous DNA sequences or similar audio files, the functions are designed so as to maximize the probability of collision between distinct but similar data, using techniques like locality-sensitive hashing. Now say that I know that the odds of picking 2 hashes and there being a collision are (For arguments sake) 50000:1. The overall idea would be to take the general 267 2 67 idea found in the answer to How hard is it to generate a simultaneous MD5 and SHA1 collision? and perform the attack 33 successive times (generating 33 places in the hash image where we can take either Xi X Nov 20, 2024 · The probability of such an event largely depends on the length of the hash key generated by the specific type of hash function used. There was a table with a number of attributes. By "safe" do you mean "unlikely to happen by pure chance" or "unlikely for an attacker to be able to cause"? Mar 21, 2024 · Demonstrating an MD5 hash, how to compute hash functions in Python, and how to diff strings. Comparing with Other Hash Sizes 64-bit hash - Collision chance of 1 in 2^32, unsafe for cryptography. This makes it exponentially more difficult to find collisions (two different inputs producing the same hash). This leads to misdetection of errors since the wrong data may appear valid. I had a case once where I used checksum with some success. 71 x 10^23 records before a 1% chance of collision), and SHA2 256 or 512 ridiculously low. If these functions are indeed not collision-free, how to make them collision-free? Mar 12, 2016 · Consider the situation that since the beginning of the universe the bitcoin network's current hashing capacity would have been available for the sole purpose of finding a collision for a specific hash value, i. Between two messages and the probability of 0. The data content doesn't matter, so long as it's more than 32 bits, which it is in this case, since a CRC does a very good job mixing the bits. Feb 3, 2016 · For a set of even billions of assets, the chances of random collisions are negligibly small -- nothing that you should worry about. Does "8 characters" mean: A) You store 8 hex characters of the hash? That would store 32 bits. Feb 26, 2014 · Is there a formula to estimate the probability of collisions taking into account the so-called Birthday Paradox? Using the Birthday Paradox formula simply tells you at what point you need to start worrying about a collision happening. 9k 41 185 267 Apr 22, 2021 · The user inputs a lengthy URL and the system computes the hash and encodes it binary64 and sends it back to the user. g. This reduces the likelihood of collisions and helps keep operations fast. I am trying to find a collision between two messages that will lead to the same CRC hash. Hash collisions The hash of a Condensation object is calculated by applying the SHA-256 hash function on the object's content. Assuming each rehash provided a unique hash, with no collisions, doesn't this imply any input larger or smaller than 64 bytes would collide with one of these values? What is the "best" generator polynom for my use case? How to cacluate the error-detection-feasability or collision probability if more then 32 consecutive bits change? How to cacluate the error-detection-feasability or collision probability if x x not consecutive (different locations in the complete input stream) bits change? Aug 16, 2023 · Excerpt Checksum collisions can occur when two different files have the same checksum. the range for binary_checksum ()) to be 54563. Apr 17, 2020 · With only 128 bits for the size of its hash value, the probability of having two MD5 hash values accidentally colliding is approximately 1. e. 8 Attackers can take advantage of this vulnerability by writing two separate programs, and having both program files hash to the same digest. $ Hi 1 6 jRj Construction: Any 2-wise independent hash function family is also universal (we proved this result). Dec 8, 2018 · Please give help! how can I calculate the probability of collision? I need a mathematical equation for my studying. So as n grows, the chance of a collision grows accordingly. In this paper, we focus on the construction of semi-free-start collisions for SHA-256, and show how to turn them into collisions. Moreover, the collision probability is pretty high as there are only 4 bytes for a checksum in SQL Server. The latter is used to intentionally try to find collisions, and relies on Aug 12, 2019 · Finding a simultaneous collision for all three would take the effort of approximately 272 2 72 SHA-1 compression function evaluations. If we suppose your algorithm has absolute uniformity, the probability of a hash collision among n files using hashes with d possible values will be: Aug 19, 2010 · This can be interpreted as "if you double the number of records, and calculate a checksum value, the likelyness of getting a collision (false positive) is quadrupled. The input items can be anything: strings, compiled shader programs, files, even directories. The longer the hash key, the lower the risk of collision. But, as you can imagine, the probability of collision of hashes even for MD5 is terribly low. In any case, if you're wondering what would happen to a repository in the event of a hash collision, you can find the answer in this page. Cryptographic hash is designed to be collision resistant. If you put 'k' items in 'N' buckets, what's the probability that at least 2 items will end up in the same bucket? In other words, what's the probability of a hash collision? See here for an explanation. Using the Birthday Problem, I calculate the number of elements that you'd need to have a 50% probability of a collision in a 32-bit space (i. Dec 24, 2018 · MD5 suffers from a collision vulnerability,reducing it’s collision resistance from requiring 264 hash invocations, to now only218. A lifetime of Dec 12, 2017 · The probability of a hash collision does not depend on the length of the message, so long as the entropy (number of significant bits) of the message is greater than or equal to the number of bits in the hash, and that it is a good hash that well mixes the bits of the input into each hash. 8×10 19, and the 32 character has has a collision probability of 16 -32 = 1 in 3. It means using a hash may be the best option you have. CRC32, Adler32, Rollsum, Murmur, whatever C# uses for strings, etc, those are not designed for hash collision resistance, they are designed to "hash" the data very quickly, and check for unintended errors. Mar 13, 2017 · With the announcement that Google has developed a technique to generate SHA-1 collisions, albeit with huge computational loads, I thought it would be topical to show the odds of a SHA-1 collision in the wild using the Birthday Problem. " Triple the number of records and you have 9 times more chance of getting a collision (false positive). The probability of at least one collision is about 1 - 3x10 -51. Trouble starts when we attempt to store more than one item in the same slot. Jan 3, 2022 · Algorithm aside, if you draw 100000 random 32-bit numbers, the probability for at least one collision is 0. SHA256 is a good choice, but BLAKE2s128 isn't bad either. This will also help if someone somehow injects duplicate hashes in order to try to compromise it. Apr 7, 2017 · The chances of generating a collision any collision of a secure hash are negligible, i. It roughly states that for a 2 n algorithm, your probably of a random collision is between any two items is 50% once you generate 2 (n/2) outputs. However you have n chances at a collision if you have previously generated n estimates. Jul 6, 2009 · sql sql-server-2005 checksum hash-collision asked Jun 22, 2009 at 19:42 Cade Roux 89. 2 billion objects. The average number of collisions you would expect is about 116. Starting from this value of n, we can determine more a accurate minimum value for n; however, the described bounds and approximations help us to obtain an estimate quickly. Scala, Daniel T. When looking at a hashing algorithm, the naive consideration of the algorithm is that the odds are bassed only on the last iteration. 787*10^9 years, then the probability that a collision would have been found by now is about 7 × 10^-41 % Abstract. Dec 28, 2016 · The probability of an individual collision is 2 -32. 3. Collisions in Hashing # In computer science, hash functions assign a code called a hash value to each member of a set of individuals. . Quite obviously, this is not a one-to-one function: different byte sequences may yield the same hash, and thus produce a collision. Having different hashes certainly means that the files are different, but getting the same hash doesn't necessarily mean that the files are identical. [7] See full list on preshing. It does not depend on the length of the configuration (so long as the configurations are longer than the CRC). May 12, 2009 · I have keys that can vary in length between 1 and 256 characters*; how can I calculate the probability that any two keys will collide when using md5 (baring a brute force solution of trying each ke Nov 20, 2024 · Various aspects and real-life analogies of the odds of having a hash collision when computing Surrogate Keys using MD5, SHA-1, and SHA-256. May 1, 2020 · In this paper we spot light on dedicated quantum collision attacks on concrete hash functions, which has not received much attention so far. Aug 18, 2023 · The probability suggests it is highly unlikely to encounter collisions in 128-bit hashes accidentally. Obviously, p0 = p1 = 0 p 0 = p 1 Oct 13, 2014 · Percona consultant Arunjith Aravindan details how to avoid hash collisions when using MySQL's non-cryptographic Hash function (CRC32). g. In the classical setting, the generic complexity to find collisions of an n-bit hash function is Apr 21, 2018 · The difference between collision probability and collision resistance, and the futility of studying collision probability as a proxy for collision resistance, is so fundamental it is hopeless to address it as a mere footnote. This article is assuming a cryptographic hash function? For non-cryptographic hash functions, collisions are practically guaranteed. This blog post explores the probability of collision, factors influencing it, detection techniques, and the implications of checksum collisions on data integrity and security. I intend to use a hash function like MD5 to hash the file contents. In other words, it is a situation where two distinct inputs generate an identical output checksum. all of them are of equal difference to each other with a constant difference t or whatever is Jul 28, 2015 · As you can see, the slower and longer the hash is, the more reliable it is. For instance, in what is the probability of collision with 128 bit hash?, it's key for keeping cryptographic systems safe and secure. Feb 1, 2024 · A hash collision occurs when two different keys are assigned the same hash value, meaning they map to the same index in the hash table. You will learn to calculate the expected number of collisions along with the values till which no collision will be expected and much more. Let’s define another hash function to change stuff like Strings into ints! Aug 21, 2017 · You can calculate yourself by using the birthday problem. 6*10^76. Actually, for some (or even all) checksums there are infinite number of inputs that can be shortened to them using BINARY_CHECKSUM function. dtwx usu avns ywxl lrml dzsk wxqkpbhd wcutk lkwqhu pouvm