How to reverse the output of crc.crc16ccitt to the original input. Used npm module named crc.
Package used: https://github.com/alexgorbatchev/crc
Method used: crc.crc16ccitt(inputString)
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If the CRC algorithm has been properly implemented, then you will not be able to reverse it to get the original input. – Rory McCrossan Jul 03 '23 at 10:05
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@RoryMcCrossan I have just used the npm module. Looks like this npm is little popular, hope its properly implemented. Why its not reversible? – Easwaramoorthy Kanagaraj Jul 03 '23 at 10:12
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Because a CRC is a hash of the input. A hashed value should not, by definition, be reversible – Rory McCrossan Jul 03 '23 at 10:13
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@RoryMcCrossan I read CRC is not actually a hashing? In that case, it should be reversible right? Honestly tried many ways to reverse this, but nothing worked for me so far.. – Easwaramoorthy Kanagaraj Jul 03 '23 at 10:19
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1A correctly implemented CRC is absolutely a hash function, and is not reversible. – Rory McCrossan Jul 03 '23 at 10:21
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1@RoryMcCrossan OK, thanks for your inputs.. – Easwaramoorthy Kanagaraj Jul 03 '23 at 10:24
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Unless the input is two bytes or less, you cannot reconstruct it from a two-byte CRC.
Mark Adler
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Any sample with generation of a hash and reversing it back to the original string would be of more helpful.. – Easwaramoorthy Kanagaraj Jul 03 '23 at 18:06
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You actually have a two-byte CRC of a two-byte message, and you want to know what the message is? – Mark Adler Jul 03 '23 at 21:15