FlowCrypt vs gpg4o

FlowCrypt is an email encryption service that lets users send encrypted messages to OpenPGP users and password-protected messages to other recipients. Recipients can reply securely without installing a plugin. It is offered as a Chrome extension, with other platforms and a mobile application also listed. Gmail and Outlook integration are listed, along with message expiry and password-based recipient verification. The free plan is for fewer than 100 users and lists a 5 MB attachment threshold, while product details say free users can add attachments up to 25 MB. Enterprise supports domains with more than 100 users, and administrators can set domain-wide controls and enforce rules for passphrases, keys, and signing. Enterprise also supports SSO through Google, OIDC providers, and delegated identity providers, and can connect with public key servers, HSMs, and internal systems. Enterprise commercial-use pricing requires contacting FlowCrypt. Its enterprise data processing agreement is described as GDPR-compliant, and enterprise support includes an SLA for availability and response times for fixes and patches.

gpg4o is a Microsoft Outlook add-in for encrypting, decrypting, signing, and checking messages and attachments. It uses public and private keys under the OpenPGP standard, and supports encrypted HTML email, PGP/MIME, and PGP/Inline. Its key management can synchronize keys, use local or public key servers, and check the Web of Trust; central management requires Enterprise KeyServer. The product also supports terminal servers, Microsoft Policy Manager, automatic key generation, and working groups. When encryption is enabled, it protects message text and attachments, but not the subject line or recipient list. The current feature page lists Outlook 2024 or 365 Classic on Windows 11 and marks Mac OS unsupported. A limited free version is available without a time limit, and a 180-day trial is noted. The listed gpg4o plan costs €99.95 a month. After maintenance expires, users can still send and read encrypted or signed email, but they do not receive further updates.