Md5 is 64 bits long?

Question

Cryptography

Is it possible, and if so, how, to get a 64-bit md5 hash? The variant of a piece in 64 bits from 128 bits is not considered.
PS And what's the catch of minus?

Answer 1

md5 is no way... You can take the first 64 bits and xor with the second 64 bits. But the quality of the hash will drop, respectively, by 2 ^ 64 times ...

Answer 2

Minus, obviously, because it is difficult to give an answer to the wrong question. An MD5 hash is a 128 bit hash. If you want a 64 bit hash, it's not MD5. To give any hash advice, you need to know why you need it, because there are cryptographic hashes, there are ordinary hashes for hash tables, and sometimes checksums are also called hashes. Most likely you need a hash for tables, but 64 bits is something very large for it.

Answer 3

The variant of a piece in 64 bits from 128 bits is not considered.

And why?
As far as I know, thanks to the avalanche effect that md5 has, a 64-bit hash from md5 will have the same properties as the whole md5, with the exception of, in fact, bitness.
And XOR of the first half from the second does not carry any payload.
If wrong, correct.

Answer 4

Choose what you like:
en.wikipedia.org/wiki/List_of_hash_functions

Answer 5

If you need a 64-bit random value based on md5, try xoring the first half of the hash with the second. But this (as far as I understand) is practically no different from just half a hash, since the number of possible values ​​\u200b\u200bis the same.
If you need a 64-bit hash, look for another hash.

Answer 6

Impossible.