Crypho 3.5.3 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Productivity Tools, more precisely Cloud Services. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The actual developer of this free software for Mac is Crypho AS.
From the developer:
Crypho is enterprise file-sharing and chat with end-to-end encryption. There are chat-rooms for invited members only. You can send confidential messages in real time. You can encrypt and transfer files with a key-press, or simply by dragging and dropping them on the app. The teams can keep a shared folder of strongly encrypted files. You can establish an encrypted communications channel in a few minutes.
You may want to check out more Mac applications, such as Everport - for moving 37signals' Backpack data to Evernote or Zeta Uploader, which might be similar to Crypho.