openssl-entropy

Your mission

Count the distinct keys produced, where each process's key is its process id modulo 32768.

today's brief

In 2008 a Debian maintainer, silencing a memory warning, commented out the line that fed randomness into OpenSSL. For two years every key generated on Debian and Ubuntu leaned on almost nothing but the process id, so only 32768 different keys were ever possible. Attackers could just precompute all of them. Two processes whose ids match modulo 32768 got the exact same key. Count how many truly distinct keys a batch of processes would make.

See it in action

distinct_keys({100,200,300}, 3)

Expected result

Your checklist

For your own tracking. Tests grade your code.

pids holds n process ids (all positive). Each one's key is pids[i] modulo 32768.
Return the number of distinct key values across the batch.
Two ids that share the same value modulo 32768 count as one key.

More examples

distinct_keys({1,32769,5}, 3)

Expected result

distinct_keys({7,7,7}, 3)

Expected result

Constraints

Expected files

keys.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions

openssl-entropy

Your mission

Count the distinct keys produced, where each process's key is its process id modulo 32768.

today's brief

See it in action

distinct_keys({100,200,300}, 3)

Expected result

Your checklist

For your own tracking. Tests grade your code.

pids holds n process ids (all positive). Each one's key is pids[i] modulo 32768.
Return the number of distinct key values across the batch.
Two ids that share the same value modulo 32768 count as one key.

More examples

distinct_keys({1,32769,5}, 3)

Expected result

distinct_keys({7,7,7}, 3)

Expected result

Constraints

Expected files

keys.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions