File Upload Architecture
Learn how we protect your files with enterprise-grade security and optional zero-knowledge encryption
Two security levels for your files
Our platform offers a robust file storage architecture with two security levels, designed to meet different compliance requirements.
Standard Mode
Secure storage with AWS-managed encryption
Zero Knowledge Mode
End-to-end encryption where not even system administrators can access your file contents
Encryption Mode Recommendation
We recommend using Standard Mode as it enables AI-powered validation to automatically verify if your compliance files are filled out correctly. However, if you need to store highly confidential information, you can enable Zero Knowledge Mode, which provides maximum privacy but disables automatic AI validation.
Storage Infrastructure (AWS S3)
All files are stored in Amazon S3 buckets configured with the strictest security policies.
Public Access Block
Mandatory Encryption
Secure Transport
File Versioning
Object Lock (Optional)
Granular Access Control
Data Classification
All buckets are classified and tagged with: DataClassification: Sensitive, Compliance: Required, Purpose: File storage bucket for organization documents - Compliance Retention
Zero Knowledge Architecture
Zero Knowledge architecture is an end-to-end encryption system where your files are encrypted in your browser before being sent to the server.
What is Zero Knowledge?
Three-layer cryptographic key system
User Key Pair
Protection: Uses Argon2id algorithm (resistant to brute force attacks) to derive a key from your password, which then encrypts your private key with AES-256-GCM.
Organization Master Key (TMK)
Protection: ECDH P-256 + HKDF-SHA256 follows the RFC 9180 (HPKE) construction. AAD binding ensures a wrap intended for one member at one generation cannot be reused elsewhere.
File Key (DEK)
Protection: Body-hash binding ties the wrapped DEK to the exact ciphertext on disk — defeats both DEK-swap and server-driven body substitution.
Upload Flow
Data Security & Auditing
What Is Stored on the Server
Key Operations Log
Password and User Key Protection
Your Password is NEVER Sent to the Server
Key Derivation Algorithm (Argon2id)
Configuration used:
Security Chain
If any link in this chain is missing, the file remains inaccessible. Not even system administrators can break this chain.
Encryption Modes
Optional Encryption
Zero Knowledge encryption is optional and can be enabled per organization. Only owners or administrators can enable it.
Access Recovery
We cannot reset your password without you losing access to encrypted files
Available options:
Algorithms and Standards Used
Symmetric Encryption (AEAD)
AES-256-GCM
Key Agreement + KDF
ECDH P-256 + HKDF-SHA256
Password Key Derivation
Argon2id
Envelope Format
Versioned envelopes
Body Integrity Binding
Per-file body hash
Hash Function
SHA-256
Standards and Specifications
Every primitive on this page maps to a published standard. The links below go to the source documents — useful for security review or independent verification.
Symmetric & Authenticated Encryption
Key Agreement & Derivation
- NIST FIPS 186-4 — Digital Signature Standard (P-256 / secp256r1)Specifies the P-256 curve used for ECDH wrap-target keys.
- RFC 5869 — HKDF: HMAC-based Extract-and-Expand KDFThe KDF applied to the ECDH shared secret before it becomes an AES key.
- RFC 9180 — Hybrid Public Key Encryption (HPKE)Our wrap construction follows the HPKE base-mode KDF pattern (empty salt, info carries suite ID + recipient/ephemeral public keys).
- RFC 9106 — Argon2 Memory-Hard FunctionArgon2id parameters and security guidance for password-based key derivation.
Hashes & Integrity
Browser Cryptography APIs
Threat-Model Background
Zero-Knowledge & End-to-End Encrypted Storage
- Signal Protocol — Technical DocumentationFoundational reference for end-to-end encryption design. The wrap-to-recipient pattern we use for member TMK delivery is built on the same primitives (ECDH, KDF, AEAD) Signal documents in detail.
- Tresorit — Encryption WhitepaperDirect analog: zero-knowledge encrypted file storage. Useful comparison for the per-file DEK + per-org master key layering, soft-delete recovery windows, and key rotation semantics.
- Proton — Security Model and EncryptionProduction zero-knowledge encrypted email and file storage. Discusses password-derived private keys, key escrow trade-offs, and the operational realities of an end-to-end-encrypted service.
- Bitwarden — Security WhitepaperClosest analog for the password-derived key half of our design (Argon2id stretching → key-encryption key → encrypted private key blob). Same threat model around server compromise.
- MEGA — Security WhitepaperLong-running zero-knowledge cloud storage. Also a useful counter-example: their early protocol weaknesses (Heninger et al., 2022) are exactly the class of issues HKDF + AAD binding are designed to prevent.
Compliance and Certifications
Regulations
Security Standards
Architecture Benefits
For Your Organization
Maximum Security
Facilitated Compliance
Total Control
For Your Users
Total Privacy
Transparency
Ease of Use
Frequently Asked Questions
The impact is minimal. Encryption happens in your browser using hardware acceleration (AES-NI on modern processors). For files up to 100 MB, the difference is imperceptible. For larger files, there may be a few extra seconds.
Since your password is the only way to decrypt your private key, you would lose access to encrypted files. Therefore, we recommend:
• Use a trusted password manager
• Set up a strong password hint
• An administrator can re-encapsulate the TMK for a new key of yours (you won't lose access to organization files)
No. This is the essence of Zero Knowledge - not even we can access your files without your password. An organization administrator can grant access again through TMK re-encapsulation, but your old private key will be inaccessible.
We don't recommend it, but it's technically possible:
1. New uploads will not be encrypted
2. Already encrypted files remain encrypted
3. You will need to decide if you want to decrypt and re-upload old files
Visual indicators:
• "Encrypted" badge appears on files
• Each envelope carries an explicit format version field; readers reject unknown versions
• Audit logs record key operations and rotations
• You can inspect raw data in S3 (it will be unreadable)
Yes. Owners can run a TMK rotation that generates a fresh master key and re-wraps every member, integration, and file key against it.
Rotation is done in the browser by an admin who already holds the current TMK — the server never sees plaintext key material.
The previous generation is kept in a soft-delete recovery window (7 days) so an aborted or mistaken rotation can be rolled back. After the window the old generation is purged.
Each rotation is locked to a per-rotation token so stale clients can't write into a rotation that has been replaced.
Encrypted files can only be accessed by organization members who have the encapsulated TMK. To share externally:
• Add the person as an organization member (will receive TMK)
• Download and re-upload the decrypted file through another means
• Use temporary sharing links (future feature)
Partially. Content is fully protected, but some metadata remains visible:
• File name
• File size
• Upload date
• MIME type
• Who uploaded it
This is necessary for basic functionality (search, sorting, etc.). If you need full metadata protection, contact us for custom solutions.
Encryption does not affect listing or search performance, as these operations use only metadata (not encrypted). Decryption only happens when you download/view the file.
Contact and Support
For questions about encryption activation, key problems, compliance and auditing, or customizations, please contact our team.
Email Support
Contact your administrator or our support team
Documentation
Check our technical documentation for more details