old_contents: # Copyright (c) 2013 Mirantis Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from Crypto.PublicKey import RSA
  from Crypto import Random
  import paramiko
  import StringIO
  
  
  def generate_private_key(length=2048):
      """Generate RSA private key (str) with the specified length."""
      rsa = RSA.generate(length, Random.new().read)
      return rsa.exportKey('PEM')
  
  
  def to_paramiko_private_key(pkey):
      """Convert private key (str) to paramiko-specific RSAKey object."""
      return paramiko.RSAKey(file_obj=StringIO.StringIO(pkey))
  
  
  def private_key_to_public_key(key):
      """Convert private key (str) to public key (str)."""
      return RSA.importKey(key).exportKey('OpenSSH')
  
new_contents: # Copyright (c) 2013 Mirantis Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from Crypto.PublicKey import RSA
  from Crypto import Random
  import paramiko
  from six import StringIO
  
  
  def generate_private_key(length=2048):
      """Generate RSA private key (str) with the specified length."""
      rsa = RSA.generate(length, Random.new().read)
      return rsa.exportKey('PEM')
  
  
  def to_paramiko_private_key(pkey):
      """Convert private key (str) to paramiko-specific RSAKey object."""
      return paramiko.RSAKey(file_obj=StringIO.StringIO(pkey))
  
  
  def private_key_to_public_key(key):
      """Convert private key (str) to public key (str)."""
      return RSA.importKey(key).exportKey('OpenSSH')
  
subject: Use six to improve python 3 compatibility.