code: def generate_iv_for_export(self, client_random, server_random,
                                 con_end, read_or_write, req_len):
          
          s = con_end + read_or_write
          s = (s == "clientwrite" or s == "serverread")
  
          if self.tls_version < 0x0300:
              return None
          elif self.tls_version == 0x0300:
              if s:
                  tbh = client_random + server_random
              else:
                  tbh = server_random + client_random
              iv = _tls_hash_algs["MD5"]().digest(tbh)[:req_len]
          else:
              iv_block = self.prf("",
                                  b"IV block",
                                  client_random + server_random,
                                  2 * req_len)
              if s:
                  iv = iv_block[:req_len]
              else:
                  iv = iv_block[req_len:]
          return iv
docs: Generate IV for EXPORT ciphersuite, i.e. weakens it.
          An export IV generation example is given in section 6.3.1 of RFC 2246.
          See also page 86 of EKR's book.