NiFi Legacy KDF

The original KDF used by NiFi for internal key derivation for PBE, this is 1000 iterations of the MD5 digest over the concatenation of the password and 8 or 16 bytes of random salt (the salt length depends on the selected cipher block size).

This KDF is deprecated as of NiFi 0.5.0 and should only be used for backwards compatibility to decrypt data that was previously encrypted by a legacy version of NiFi.