Abstract: In a blockchain network, a “cold wallet” allows users to securely create and store their private key and sign their transaction data only when the wallet is completely offline. When a user requests a transaction, a user key tag that identifies the user's key is determined. The transaction data and the user's key tag are transmitted to a cold wallet that includes an HSM Trusted Client and an HSM over a first one-way communication channel during a window in a first sequence of connection windows. Inside the cold wallet, the HSM Trusted Client uses the user key tag to determine an encrypted version of the user's signing key. During a processing window, the transaction data and encrypted signing key are transmitted to the HSM, where a cleartext key is recovered and used to sign the transaction, and the signed transaction is transmitted back to the HSM Trusted Client. During a second connection window, the signed transaction is transmitted from the HSM Trusted Client for transmission to the blockchain network.

Abstract: An air-gapped system enables the secure transfer and control of digital assets, such as those associated with crypto-currency. The system includes an Integration Server for receiving requests from an application interface, a Central Control Center for verifying the requests received and authorizing the requests using digital signatures, and multiple Distributed Data Centers, each including a cold Data Center Hardware Security Module (DC HSM). These DC HSMs securely store and manage cryptographic keys. Each Data Center also includes an offline Processing Unit coupling its DC HSM to a dedicated Remote Controlled Server. The Remote Controlled Server receives requests from the Integration Server and forwards them to the Processing Unit of a DC HSM using a Near-Field Communication (NFC) Interface between the two. Preferably, the NFC interface is physically shielded to resist side channel attacks.

Abstract: An air-gapped system enables the secure transfer and control of digital assets, such as those associated with crypto-currency. The system includes an Integration Server for receiving requests from an application interface, a Central Control Center for verifying the requests received and authorizing the requests using digital signatures, and multiple Distributed Data Centers, each including a cold Data Center Hardware Security Module (DC HSM). These DC HSMs securely store and manage cryptographic keys. Each Data Center also includes an offline Processing Unit coupling its DC HSM to a dedicated Remote Controlled Server. The Remote Controlled Server receives requests from the Integration Server and forwards them to the Processing Unit of a DC HSM using a Near-Field Communication (NFC) Interface between the two. Preferably, the NFC interface is physically shielded to resist side channel attacks.