ctypescrypto/pbkdf2.py

   1 """
   2 PKCS5 PBKDF2 function.
   3
   4 """
   5
   6 from ctypes import c_char_p,c_int, c_void_p, create_string_buffer
   7 from ctypescrypto import libcrypto
   8 from ctypescrypto.digest import DigestType
   9
  10 __all__ = ['pbkdf2']
  11
  12 def pbkdf2(password,salt,outlen,digesttype="sha1",iterations=2000):
  13     """
  14         Interface to PKCS5_PBKDF2_HMAC function
  15         Parameters:
  16
  17                 @param password - password to derive key from
  18                 @param salt - random salt to use for key derivation
  19                 @param outlen - number of bytes to derive
  20                 @param digesttype - name of digest to use to use (default sha1)
  21                 @param iterations - number of iterations to use
  22
  23                 @returns outlen bytes of key material derived from password and salt
  24     """
  25     dt=DigestType(digesttype)
  26     out=create_string_buffer(outlen)
  27     res=libcrypto.PKCS5_PBKDF2_HMAC(password,len(password),salt,len(salt),
  28         iterations,dt.digest,outlen,out)
  29     if res<=0:
  30         raise LibCryptoError("error computing PBKDF2")
  31     return out.raw
  32
  33 libcrypto.PKCS5_PBKDF2_HMAC.argtypes=(c_char_p,c_int,c_char_p,c_int,c_int,
  34     c_void_p,c_int,c_char_p)
  35 libcrypto.PKCS5_PBKDF2_HMAC.restupe=c_int