Ledger

Safe{Wallet} is a multisignature smart wallet for secure self-custody, onchain treasury management, and organizational transactions. It distributes control across multiple owners using configurable N-of-M approvals, helping avoid a single point of failure; signers can include Ledger and Trezor hardware wallets. The wallet supports transaction simulation and risk scanning, spending limits and approval roles, multi-chain account management, DeFi and protocol interactions, and transaction bundling. Safe describes its contracts as open source and formally verified, and provides features including trustless recovery, transaction guards, and monitoring through Safe Shield.

Tether is a company (Tether Limited) that issues USDT, a fiat-collateralized stablecoin pegged to the US dollar. USDT tokens are issued on multiple blockchains (originally the Bitcoin Omni layer and later on Ethereum as ERC-20, Tron as TRC-20, Solana and others), are used as a dollar-referenced medium for trading and settlement across exchanges and wallets, and Tether's reserves and audit practices have been the subject of regulatory scrutiny and periodic attestations by accounting firms.

Ethereum is an open-source, public blockchain platform (initially proposed by Vitalik Buterin and developed by the Ethereum Foundation and a global developer community) that executes smart contracts and hosts decentralized applications (dApps) using the native cryptocurrency Ether (ETH). The protocol runs as a permissionless network of node client implementations (e.g., Geth, Erigon, Besu, Nethermind, Lighthouse), provides the Ethereum Virtual Machine (EVM) for contract execution, uses token standards such as ERC-20 and ERC-721, and after The Merge operates under proof-of-stake with ongoing roadmap work — including scalability (rollups/sharding), security, and topics such as quantum-resistance — specified via EIPs and community governance.

American Fortress is a private cryptocurrency payments platform described as a private PayPal for crypto. Users register human-readable Fortress names instead of wallet addresses, and the system derives unique stealth addresses for sender-recipient pairs across supported blockchains, including Solana, Cardano, Tron, Arbitrum and Litecoin. The platform uses zero-knowledge proofs of provenance so recipients can verify the sender, while its Safe Send feature routes payments through a shielded pool to obscure balances. The videos also describe encrypted chat, KYC integration represented as post-quantum cryptographic proofs, and distribution through a wallet app, desktop and Windows applications, an SDK, and a MetaMask Snap.

Tangem is a self-custody cryptocurrency hardware wallet and companion app for storing and managing digital assets. Its NFC-powered cards contain a secure element that generates and keeps private keys inside the chip; multiple cards can be linked as backups, while a recovery seed phrase remains optional. Users tap a card to a phone to sign transactions and manage assets in the app, including sending, buying, selling, swapping, staking, and spending crypto across supported blockchain networks. The wallet requires no battery, cable, or charging, and the site describes an EAL6+-certified chip, audited firmware, and a 25-year limited hardware warranty.