úÎ Ä    &A reasonable default for rsa pbkdf2.  ) pbkdf2 = pbkdf2' (prfSHA512,64) 5000 64 ASHA512 outputs 64 bytes. At least 1000 iters is suggested by PKCS#š5 (rsa link above). I chose 5000 because this takes my computer a little over a second to compute a simple key derivation (see t test function in source) QDklen of 64 seemed reasonable to me: if this is being stored in a database, doesn't take too much space. CComputational barriers can be raised by increasing number of iters 7Password Based Key Derivation Function, from RSA labs.  > pbkdf2' (prf,hlen) cIters dklen (Password pass) (Salt salt) prf: pseudo random function hlen: length of prf output $cIters: Number of iterations of prf 3dklen: Length of the derived key (hashed password)        PBKDF2-0.3 Crypto.PBKDF2 HashedPassSaltPasswordpbkdf2pbkdf2'toOctets fromOctetsmyxormyor prfSHA512