Security Architecture

How TextSafe protects your data through client-side encryption and zero-knowledge design.

Zero-Knowledge Design

TextSafe operates on a zero-knowledge principle: we cannot read your data. This is not a policy choice-it is a technical constraint built into the architecture.

Client-Side Encryption

All encryption and decryption happens in your browser using the Web Crypto API. Plaintext never leaves your device.

No Credential Storage

Your passcode and color are never transmitted. We receive only a derived storage ID (hash) and encrypted ciphertext.

Opaque Data

The server stores encrypted blobs. Without your credentials, the data is computationally indistinguishable from random noise.

Encryption Specifications

Algorithm: AES-256-GCM (Galois/Counter Mode)

Key Derivation: Argon2id (memory-hard, GPU-resistant)

Memory Cost: 64 MB (resists GPU/ASIC attacks)

Time Cost: 3 iterations

IV: 12 bytes, cryptographically random per encryption

Storage ID: SHA-256 hash of derived key bytes

What We Cannot Do

Read your text: Without your passcode and color, decryption is computationally infeasible
Reset your password: We do not have your credentials
Recover deleted data: Expired entries are purged at the database level
Link storage to identity: No accounts, no tracking, no logs of credential attempts

Rate Limiting

To prevent brute-force attacks on the color selection:

10 failed retrieve attempts trigger a 1-hour lockout
Rate limits apply per IP address and per storage ID
Lockout data is cleared automatically after expiration

Data Lifecycle

Creation: Encrypted data stored with expiration timestamp
Storage: PostgreSQL database with connection pooling
Expiration: Background job runs hourly to delete expired entries
Deletion: Permanent removal at database level-no soft deletes

Limitations: TextSafe protects content confidentiality. It does not provide anonymity against network-level surveillance. For high-threat environments, combine with Tor or a VPN.

Questions?

Security concerns can be sent to our contact email.

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