Digging into the PAM configuration for the supported #Linux crypt #password hashes.

libxcrypt supports scrypt, yescrypt, and gost-yescrypt, among others.

PAM has a "rounds=n" option specifying the CPU cost. But scrypt, yescrypt, and gost-yescrypt are CPU and RAM intensive. How do you set the other params?

yescrypt handles it for you:

if rounds==0 {
rounds=5
} else if rounds>11 {
return ERROR
} else if rounds<3 {
N=2^(rounds+9)
r=8
p=1
} else {
N=2^(rounds+7)
r=32
p=1
}

#unix #passwords

I believe gost-yescrypt follows the same logic as yescrypt, although I'm struggling to read the source code.

However, for scrypt, things are a little different:

if rounds==0 {
rounds=7
} else if rounds<6 || rounds> 11{
return ERROR
} else {
N=2^(rounds+7)
r=32
p=1
}