SafePal S1 adopts a dual-chip architect, separating sensitive security logic from general business logic inside the product. An independent security element is built in each S1 hardware device, and the purpose of the secure element is to solely protect the safety of private keys.
This article covers the following security features of the SafePal S1 secure element:
- Qualification of Common Criteria EAL5+ level
- Multiple security sensors
- Self-destroy mechanism
- Other important security schemes
Qualification of Common Criteria EAL5+ level
The Evaluation Assurance Level is a numerical grade assigned following the completion of a Common Criteria security evaluation, an international standard in effect since 1999. There are 7 levels in the criteria(EAL1 through EAL7). The increasing assurance levels reflect added assurance requirements that must be met to achieve Common Criteria certification. EAL is widely adopted to evaluate whether an IT product or system can provide its security features more reliably (and the required third-party analysis and testing performed by security experts is reasonable evidence in this direction). It is also widely adopted in the financial industry, where most of the debit cards and credit cards are using the EAL4+ standard, one level lower than EAL5+.
Learn more about EAL: Evaluation Assurance Level here.
Multiple security sensors
SafePal S1 is embedded with multiple sensors. Should there be any attacks, such as a non-intrusive attack, semi-intrusive attack, and intrusive attack, detected by any of these sensors or modules, the security element will execute a self-destroy mechanism, wiping all security data, thus preventing the attackers from gaining the private key.
High and low voltage detection module: to confront fault injection attacks such as voltage attack or extreme temperature attack
High and low-frequency detection module: to confront with frequency and electromagnetic attack
Filter: to shield and filter abnormal frequency
Light sensor: to detect light conditions when the chip is opened up. In such an attack when the light sensor detects any light exposure, the secure element will clean all RAM data and enter protection mode, meaning no core program can be operated on the chip and the chip is under reset status, thus preventing the attackers to conduct any further attacks.
Pulse sensor: to detect abnormal pulse signals caused by physical attacks, and transfer warnings toward element processor
Temperature sensor: to detect abnormal temperature caused by electronic attack
Metallic shield: to detect the electromagnetic attack when an attacker tries to open up and probe the chip
SafePal S1 is embedded with multiple sensors, the security chip would execute a self-destroy mechanism, erasing all wallet data and leave no trace for the hackers. Don’t worry if the data is erased, your assets are still secure on-chain and you can recover them with the correct mnemonic phrase. (See the security practice of keeping your mnemonic phrase secure).
Other important security schemes
RAM protection: supports RAM verification, data verification, un-readable verification area, and RAM encryption scrambler, thus confronting intrusive attacks and fault injections.
BUS encryption: encryption and verification of internal data transfer BUS including AHB(Advanced High-performance Bus), APB(Advanced Peripheral Bus), etc. This is to protect the data from intrusive attacks and fault injections.
Algorithm authentication and protection: including DES algorithm module and AES algorithm module, to prevent non-intrusive side-channel attacks