With CellEncrypt  protect sensitive cell values from viewers using PBKDF2-derived keys, per-cell encryption, and HMAC integrity verification. No data leaves the environment—encrypted values are stored securely inside Script Properties.
What CellEncrypt protects:
✓ Hides selected cell values from VIEWERS
✓ Protects exported copies & screenshots
✓ Keeps encrypted values visible while data stays hidden
Important limitation:
⚠ Editors can always view version history. Only use CellEncrypt to protect data from viewers, not from trusted editors.
Key Features:


🔒 Password-based encryption (PBKDF2, 10,000 rounds)


🛡 HMAC integrity verification for tamper detection


🔑 Unique encryption keys per cell (UUID-based)


⏱ 6-hour password sessions


📦 Batch encryption/decryption (up to 50 cells)


🧹 Orphan data cleanup


👁 Viewer-safe protection (owner-only encryption/decryption)


Free vs Premium:


Free: 5 KB encrypted storage


Premium: 500 KB (1-year license, from $1)


Perfect for: HR data, financial sheets, client records, research, legal notes, and any spreadsheet shared with viewers where confidentiality matters.
CellEncrypt ensures that only the spreadsheet owner can encrypt/decrypt cells, and no passwords or decrypted data are ever stored.