File hash: Does it change for same content but in different order?

Question

Let's say there is a file called myfile.txt with the following contents:

one two three

Another file called yourfile.txt with following contents:

two three one

Will the SHA-1 hash be the same for both of these files, because the content are same but in different order?

Answer 1

No, it'll be different. Most good general purpose hashing algorithms take order into account. About the only commonly used hash functions that don't are simple checksums.

Answer 2

No, it will be different. Hashes typically work iteratively over a series of bytes.

Of course, you could just try it ;)

Answer 3

Depends on the hash algorithm. I can create one right now that returns two equal hashes for both files.

But since you specifically asked about SHA-1 then yes, they will be completely different.

    SHA1("one two three") = a10600b129253b1aaaa860778bef2043ee40c715
    SHA1("two three one") = 5b836799b259835e762c93964a68b958eb19461a

Answer 4

'Cryptographic' hashes are designed to detect changes like transpositions, otherwise someone could take an electronic payment message and change the $1900.00 amount to $9100.00 without detection (by the hash anyway), which would kind of defeat the purpose.