What are some alternatives?
When comparing Altospam and CryptoPrevent, you can also consider the following products
RansomFree - Protect your PC from ransomware with multiple detection methods.
AppCheck Anti-Ransomware - Protect your PC with 100% Signatureless Anti-Ransomware AppCheck
SpamAssassin - Use this program to "Unspam" your mailbox(es).
Scrollout F1 - Scrollout is a free and easy to use anti-spam email gateway designed for Linux & Windows administrators without advanced email security experience.
Bitdefender Anti-Ransomware - Bitdefender anti-malware researchers have released a new vaccine tool which can protect against known and possible future versions of the CTB-Locker, Locky and TeslaCrypt crypto ransomware families by exploiting flaws in their spreading methods.
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.