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, chartype
   8 from ctypescrypto.digest import DigestType
   9 from ctypescrypto.exception import LibCryptoError
  10
  11 __all__ = ['pbkdf2']
  12
  13 def pbkdf2(password, salt, outlen, digesttype="sha1", iterations=2000):
  14     """
  15     Interface to PKCS5_PBKDF2_HMAC function
  16     Parameters:
  17
  18     @param password - password to derive key from
  19     @param salt - random salt to use for key derivation
  20     @param outlen - number of bytes to derive
  21     @param digesttype - name of digest to use to use (default sha1)
  22     @param iterations - number of iterations to use
  23
  24     @returns outlen bytes of key material derived from password and salt
  25     """
  26     dgst = DigestType(digesttype)
  27     out = create_string_buffer(outlen)
  28     if isinstance(password,chartype):
  29         pwd = password.encode("utf-8")
  30     else:
  31         pwd = password
  32     res = libcrypto.PKCS5_PBKDF2_HMAC(pwd, len(pwd), salt, len(salt),
  33                                       iterations, dgst.digest, outlen, out)
  34     if res <= 0:
  35         raise LibCryptoError("error computing PBKDF2")
  36     return out.raw
  37
  38 libcrypto.PKCS5_PBKDF2_HMAC.argtypes = (c_char_p, c_int, c_char_p, c_int, c_int,
  39                                         c_void_p, c_int, c_char_p)
  40 libcrypto.PKCS5_PBKDF2_HMAC.restupe = c_int