Security Overview

Last updated July 19, 2026 · Written for clinicians, group-practice owners, and anyone doing vendor due diligence.

The architecture, in one line

All clinical data is created, processed, and stored on your Mac. It is never transmitted to us or to any third party. Both AI note generation and speech-to-text run locally, on your own hardware.

Everything below follows from that one decision. We have designed the system so that the sensitive question — "how well does this vendor protect my clients' data?" — mostly does not apply, because the vendor never has it.

Data at rest

• Field-level encryption. Every PHI field — client names, contact details, notes, transcripts, generated notes, case conceptualizations, billing amounts, calendar links, and session reviews — is encrypted with AES-256-GCM via Apple CryptoKit before it is written to the local store.
• Key storage. The 256-bit symmetric key is generated on first launch and stored in the macOS Keychain as a generic password with accessibility kSecAttrAccessibleWhenUnlockedThisDeviceOnly — device-only, and never synced to iCloud.
• No cloud sync. The local database is explicitly configured with CloudKit disabled. There is no sync target.
• Audio is never written to disk. Session audio exists only in memory during a recording and is discarded after transcription; only the encrypted transcript is retained. The same applies to optional telehealth call capture, which uses macOS System Audio Recording (audio only, never the screen), engages only when a call app is playing through headphones, and is processed entirely in memory.

Data in transit

The app makes a small, fixed set of network calls, all over HTTPS/TLS. None of them carry PHI to Flowers or to any Flowers-operated service. They are: a one-time model download at setup, license verification if you subscribe to Pro, any calendar feed you choose to connect, Sparkle update checks, and the two opt-in features below.

The one exception: appointment reminders

If you enable appointment reminders and opt in a specific client, a reminder containing that client's email address and a minimal, non-clinical message is sent over TLS through your own SMTP account. This is a clinician-to-client appointment reminder, a HIPAA-permitted disclosure under 45 CFR 164.510(b). Our infrastructure is never in that path and we never receive the message. Credentials live in the device-only Keychain. It is off by default and opt-in per client.

Card payments

The optional Stripe integration connects from your Mac directly to Stripe using your own restricted API key, stored in the device-only Keychain. Only a payment amount and a generic memo are transmitted — no names, emails, dates of birth, or clinical detail — so this path carries no PHI off-device.

Access control

• The Keychain key unlocks with your macOS user session, so OS login is the first access gate.
• Optional App Lock (Settings → Security) adds a second gate: Touch ID or your account password to open the app, and again after a configurable idle timeout. This addresses HIPAA §164.312(a) access control and automatic logoff. Locking also purges decrypted PHI from in-memory caches.

Integrity, retention, and auditability

• Tamper-evident audit log. Creation, edit, deletion, restoration, backup, and reminder-send events for clinical records are written to a local, encrypted, hash-chained audit log, supporting CMIA §56.101(b). It records the action, the record type, an opaque ID, and a timestamp — never clinical content, names, or email addresses.
• Soft delete. Deleting a client or session sets a retention tombstone rather than destroying data. Records are recoverable from Settings → Security → Recently Deleted and are erased only on explicit permanent deletion.
• Backups you control. User-initiated backups are encrypted with a separate password-derived key (PBKDF2-SHA256, 200,000 iterations, AES-256-GCM) and written wherever you choose. We never receive them.

Software supply chain and distribution

• Distributed directly rather than through the Mac App Store, signed with an Apple Developer ID and notarized by Apple.
• Automatic updates are delivered via Sparkle with Ed25519-signed appcasts, so an update cannot be substituted in transit.
• On-device model weights are downloaded once from a public model host. Software only — no PHI is involved.

What this means for a Business Associate Agreement

Because we never receive, store, process, or transmit PHI — the software runs on your own device, and the single feature that sends PHI off-device routes it solely through your own mail provider — we are not acting as a business associate, and no BAA is required. Where you use a third-party mail provider to send those reminders, that relationship is yours, and you should ensure it is covered by your own BAA where applicable. You remain the sole custodian of the PHI on your device.

Read the full HIPAA & BAA position → If your group practice, employer, or malpractice carrier needs this on letterhead, ask us and we'll send an attestation letter you can file. If their policy requires a signed BAA from every vendor regardless of PHI access, we'll provide one that accurately reflects the on-device architecture described above.

Known limitations

We would rather you hear these from us than discover them yourself.

• The app is not currently sandboxed.
• App Lock is opt-in and off by default. We recommend turning it on, along with FileVault.
• Flowers has not undergone an independent third-party security audit. We are a small company and will say so plainly rather than imply otherwise.
• Encryption protects data at rest. It cannot protect you from someone with access to your unlocked Mac — which is why App Lock and FileVault matter.

Reporting a vulnerability

If you believe you've found a security issue, please email [email protected] rather than filing it publicly. We will acknowledge your report, keep you updated on the fix, and credit you if you'd like. We will not pursue legal action against anyone acting in good faith to report a vulnerability.

This document is provided for due diligence and is not legal advice. Confirm your own obligations with counsel in your jurisdiction.