Certen Key Vault od Jason K Gregoire

Certen Key Vault is a secure browser extension for managing cryptographic
keys and signing blockchain transactions across Accumulate and EVM
networks.

Your private keys are encrypted with AES-256-GCM and never leave your
browser. Every signing request requires your explicit approval through a
visual popup showing transaction details and the requesting origin.

Features:

• Password-protected encrypted vault (AES-256-GCM, PBKDF2-SHA512, 600,000
  iterations)
• Ed25519, secp256k1, and BLS12-381 key generation
• BIP-39 mnemonic seed phrase backup and recovery
• HD wallet with BIP-44/SLIP-0010 key derivation
• Transaction signing for Accumulate, Ethereum, and cross-chain intents
• EIP-191 and EIP-712 message signing
• Multi-chain address derivation (Ethereum, Solana, Cosmos, Aptos, Sui,
  TRON, TON, NEAR)
• Auto-lock after 15 minutes of inactivity
• No analytics, no telemetry, no data collection

Integrates with the Certen Protocol web application via the window.certen
provider API.

Open source: https://github.com/certenIO/certen-key-vault