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bio website github.com/vilhelmgray
location Florida
age 22
visits member for 1 year, 3 months
seen May 16 '13 at 13:41

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Feb
2
awarded  Autobiographer
May
14
comment Using an MD5 hash as a password
@RolandSmith Not necessarily: virtually all *nix operating systems come with an md5sum command.
May
14
awarded  Scholar
May
14
accepted Using an MD5 hash as a password
May
14
comment Using an MD5 hash as a password
I see, so even though the entropy may technically drop, the drop is probably so small that there's no significant difference to the entropy.
May
14
comment Using an MD5 hash as a password
After reading a bit more, I realized I was confusing a collision attack with a second-preimage attack. Regarding my second question, I'm still confused about whether there is an inherent drop to entropy due to an unintentional collision.
May
14
awarded  Student
May
14
comment Using an MD5 hash as a password
Also, in the case of a brute-force attack -- where a random guess is hashed then attempted as the password -- wouldn't the possibility of a collision drop the entropy, or does it only drop for passphrases with entropy greater than MD5's 2^128?
May
14
comment Using an MD5 hash as a password
While I'm aware MD5 is cryptographically broken (which is why I specifically used it in the example), I'm not familiar with actual exploitation techniques. Is the fact the hash is kept a secret the reason why a collision attack is impossible here?
May
14
comment Using an MD5 hash as a password
Do you mean "second-preimage resistance?"
May
14
awarded  Supporter
May
14
revised Using an MD5 hash as a password
The magnitude of the hexadecimal digit set is 16 (a-f, 0-9), not 36;
May
14
awarded  Editor
May
14
revised Using an MD5 hash as a password
MD5 hash can be represented as 32 hexadecimal digits, not 16;
May
14
comment Using an MD5 hash as a password
Oops, you're right I misread the information about the length of an MD5 hash. Also, what would be the difference between using more modern hash function such as SHA-2 over the older MD5, if there is no security issue with MD5?
May
14
asked Using an MD5 hash as a password