code: def sign_message(privkey_path, message, passphrase=None):
      '''
      Use Crypto.Signature.PKCS1_v1_5 to sign a message. Returns the signature.
      '''
      key = get_rsa_key(privkey_path, passphrase)
      log.debug('salt.crypt.sign_message: Signing message.')
      if HAS_M2:
          md = EVP.MessageDigest('sha1')
          md.update(salt.utils.stringutils.to_bytes(message))
          digest = md.final()
          return key.sign(digest)
      else:
          signer = PKCS1_v1_5.new(key)
          return signer.sign(SHA.new(salt.utils.stringutils.to_bytes(message))f sign_message(privkey_path, message, passphrase=None):
      '''
      Use Crypto.Signature.PKCS1_v1_5 to sign a message. Returns the signature.
      '''
      key = get_rsa_key(privkey_path, passphrase)
      log.debug('salt.crypt.sign_message: Signing message.')
      if HAS_M2:
          md = EVP.MessageDigest('sha1')
          md.update(salt.utils.stringutils.to_bytes(message))
          digest = md.final()
          return key.sign(digest)
      else:
          signer = PKCS1_v1_5.new(key)
          return signer.sign(SHA.new(salt.utils.stringutils.to_bytes(message)))
docs: Use Crypto.Signature.PKCS1_v1_5 to sign a message. Returns the signature.