Why Ledger is not 100% open source

Satoshi’s Scribe
Feb 6
2 min read

Updated: Feb 14

https://www.youtube.com/watch?v=hDxVyi9KEbg

Charles Guillemet, CTO of Ledger, explains Ledger is critical for digital ownership.

This content includes affiliate links for Ledger products. If you purchase through these links, we earn a commission at no extra cost to you. This is not financial advice. Cryptocurrency assets carry high risks, including the risk of losing your entire investment. Please do your own research and make decisions based on your personal risk tolerance.

Derek Lee from Blockchain Daily asked a question on everyone's minds. Skip to 3:14 to find out.

This video covers:

• Secure transaction signing and private key protection

• Why crypto systems aren’t fully trustless - and never can be

• Why Ledger is not 100% open source

• Why Ledger uses signers instead of general-purpose hardware

• Clear signing for smart contracts and DeFi interactions

• Why clear signing support for Safe is a major security upgrade for DAOs and institutions

• Lessons learned from real-world incidents like the Bybit incident

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1. Secure Element protection (Main Reason Why Ledger is not 100% open source)

Ledger wallets use a Secure Element chip (similar to those in passports and bank cards) to store private keys.
The firmware that controls this chip isn’t fully open source because the chip manufacturers (like STMicroelectronics) keep their internal architecture proprietary.
Revealing this low-level code could expose potential vulnerabilities or help attackers replicate secure chip behavior.

2. BOLOS – Ledger’s custom operating system

Ledger’s BOLOS (Blockchain Open Ledger Operating System) is only partially open source.
The company shares open-source components like Ledger Wallet, apps for Bitcoin, Ethereum, etc., and developer SDKs, but not the complete OS.
The closed parts protect the security model and anti-tampering design, ensuring no one can modify or counterfeit devices.

3. Transparency through open verification

Even though it’s not fully open source:

Ledger provides open-source apps and APIs for community review.
Independent security researchers can audit many components.
Ledger also undergoes third-party security certifications, such as Common Criteria EAL5+ for the Secure Element.

At One Glance

Feature	Open Source?	Reason
Ledger Wallet app	✅ Yes	Transparency & community trust
Crypto apps (BTC, ETH, etc.)	✅ Yes	Publicly auditable
BOLOS OS	⚠️ Partially	Protect secure environment
Secure Element firmware	❌ No	Proprietary chip design

Ledger’s approach is a balance between transparency and physical security. They make as much open as possible while keeping the most sensitive layers protected against hardware attacks.