  Blockchain transactions are signed by private keys. Secure key storage and
tamper-proof computers are essential requirements for deploying a trusted
infrastructure. In this paper, we identify some threats against blockchain
wallets and propose a set of physical and logical countermeasures to thwart
them. We present the crypto terminal device, operating with a removable secure
element, built on open software and hardware architectures, capable of
detecting a cloned device or corrupted software. These technologies are based
on tamper-resistant computing (javacard), smart card anti-cloning, smart card
content attestation, application firewall, bare-metal architecture, remote
attestation, dynamic Physical Unclonable Function (dPUF), and programming
tokens as a root of trust.This paper is an extended version of the paper
''Innovative Countermeasures to Defeat Cyber Attacks Against Blockchain
Wallets,'' 2021 5th Cyber Security in Networking Conference (CSNet), 2021, pp.
49-54, doi: 10.1109/CSNet52717.2021.9614649
