+"""
+PKCS5 PBKDF2 function.
+
+"""
+
+from ctypes import c_char_p,c_int, c_void_p, create_string_buffer
+from ctypescrypto import libcrypto
+from ctypescrypto.digest import DigestType
+
+def pbkdf2(password,salt,outlen,digesttype="sha1",iterations=2000):
+ """
+ Interface to PKCS5_PBKDF2_HMAC function
+ Parameters:
+
+ @param password - password to derive key from
+ @param salt - random salt to use for key derivation
+ @param outlen - number of bytes to derive
+ @param digesttype - name of digest to use to use (default sha1)
+ @param iterations - number of iterations to use
+
+ @returns outlen bytes of key material derived from password and salt
+ """
+ dt=DigestType(digesttype)
+ out=create_string_buffer(outlen)
+ res=libcrypto.PKCS5_PBKDF2_HMAC(password,len(password),salt,len(salt),
+ iterations,dt.digest,outlen,out)
+ if res<=0:
+ raise LibCryptoError("error computing PBKDF2")
+ return out.raw
+
+libcrypto.PKCS5_PBKDF2_HMAC.argtypes=(c_char_p,c_int,c_char_p,c_int,c_int,
+ c_void_p,c_int,c_char_p)
+libcrypto.PKCS5_PBKDF2_HMAC.restupe=c_int