C4

Establishing #cryptocurrency standards • Curators of the 🄲🄱🄿 | 🄲🄴🄿 | 🄲🄲🅂🅂🄰 Designations • Earn your #CBP and #CEP today! • #bitcoin #ethereum

[C4 @LearnMoreWithC4]

🚨 CCSS v9.0 is HERE! 🚨

The updated CryptoCurrency Security Standard strengthens private key management & tackles emerging threats.

✅ Clearer requirements
✅ New governance & logging controls
✅ Training for key management teams
✅ Smart contracts

https://t.co/ylCcxVJY79

[C4 @LearnMoreWithC4]

How was nearly 4,000 BTC taken from the Liquid Network without the keys being compromised?

The attacker/s called themselves 'white hats' and returned most of the bitcoin. But does that make them white hats?

Listen to @Abstr_ct explain more here:
https://t.co/KqvLmNc5Kg

[C4 @LearnMoreWithC4]

Join C4 for a live discussion on Sept. 22 at 1pm edt. We'll look at recent cryptocurrency incidents, where security failed, and what we can learn from each one.

Understanding how incidents happen makes for better security decisions.

Join here:https://t.co/KqvLmNc5Kg

[C4 @LearnMoreWithC4]

Brevo, an email service provider used by C4 and many other companies, experienced a security incident.

As far as we know, C4 was not impacted.

Be cautious of links and downloads. Never share credentials, authentication codes, seed phrases, passphrases, or private keys.

[C4 @LearnMoreWithC4]

Strong cryptography doesn't automatically mean a secure system.

During the Secure Key Generation panel at the C4 Security Summit, @Adatm_T_H at @station_70 discussed why implementation matters, particularly when it comes to something as fundamental as entropy.

[C4 @LearnMoreWithC4]

Not enough randomness has cost millions.

CCSS Steering Committee member @forwardsecrecy explains why sufficient entropy is foundational to secure key generation. It's why its been part of the CCSS since 2014.

Learn more about the (CCSS): https://t.co/F2j1NaZzp2

[C4 @LearnMoreWithC4]

If your work touches Bitcoin, demonstrating that you understand how it actually works matters.

The Certified Bitcoin Professional (CBP) credential proves your knowledge of Bitcoin.

Get certified: https://t.co/NmuVGcSW1u

[C4 @LearnMoreWithC4]

Security folks spend a lot of time thinking about what could go wrong. We may seem paranoid, but billions lost to hacks give us good reason to be.

A SOC 2 is useful, but it doesn’t tell you everything.
Want to align with CCSS? Start with a CCSSI like Justin from @HalbornSecurity

[C4 @LearnMoreWithC4]

“AI cannot break what is not broken.”

At C4’s security summit, @0xGianfranco from @OpenZeppelin talked about the growing role of AI in finding and exploiting vulnerabilities.

More clips from the C4 Security Summit coming soon.

[C4 @LearnMoreWithC4]

During his keynote at the C4 Security Summit @lopp from @CasaHODL talked how attackers are increasingly going after the people behind the systems.

Strong technology matters, but attackers often look for another way in, like through human behavior.

More Summit clips coming soon!

[Dirk Anderson @SDirkAnderson]

This entire event is going to be great! There are some great speakers lined up, incredibly pertinent and timely topics, and it’s free! Looking forward to helping kick it off with a look at the current threats to the blockchain and digital asset industry.

[Gianfran.co @0xGianfranco]

Excited to be on this one. The crypto threat landscape has shifted fast over the last year, and this panel is a good crowd to unpack it with.

Free, virtual, Aug 19 · 9am–12pm ET 👇
https://t.co/t9Vdn847Ji

[C4 @LearnMoreWithC4]

How do you choose the right approach to crypto custody?

At the C4 Security Summit, our Choosing a Custody Model session discusses options and how different needs and risks lead to different designs.
With speakers from:
@FireblocksHQ
@RipioApp
Zanarc
Plusninone Security

[C4 @LearnMoreWithC4]

We're kicking off the C4 Security Summit sessions by looking at the threats affecting cryptocurrency systems.

August 19, 2026 | 9:00 AM–12:00 PM ET
Free live virtual event

Register: https://t.co/HMbqLnItrK

@lopp @SDirkAnderson @0xGianfranco @OpenZeppelin @CasaHODL

[C4 @LearnMoreWithC4]

We’re excited to have @lopp from @CasaHODL, part of our CCSS committee, deliver the keynote, Why Cryptocurrency Security Matters, at the C4 Security Summit.

📅 August 19, 2026
🕘 9:00 AM–12:00 PM ET
💻 Free live virtual event

Register: https://t.co/byCxXiFY6v

[C4 @LearnMoreWithC4]

C4 Security Summit!

📅 August 19, 2026
🕘 9:00 AM–12:00 PM Eastern
💻 Free Live Virtual Event

Registration Required: https://t.co/HMbqLnItrK

Hear from industry experts, with a keynote from @lopp

[C4 @LearnMoreWithC4]

The Coldcard entropy incident remidns us that strong crypto systems depend on strong operational processes.

Upcoming CryptoCurrency Security Standard (CCSS™) trainings are in Aug. for EMEA, Oct. for APAC, and Nov. for AMER.

Reserve your spot today: https://t.co/ecjYG50nPm

[Jameson Lopp @lopp]

We at the Cryptocurrency Certification Consortium did an hour-long stream about key entropy last year, but of course it only got 100 views. 🥲
https://t.co/t3elCW1PsH

[C4 @LearnMoreWithC4]

Catch our livestream on the Coldcard seed generation incident: https://t.co/8sZIgcA1kA

Members of C4's CCSS™ Committee, @lopp, @mperklin, @forwardsecrecy, discuss entropy, secure key generation, and the security lessons highlighted by the incident.

[Michael Perklin @mperklin]

@Abstr_ct gave a fantastic class on crypto key creation at #BTC2019 and shared https://t.co/9UeCFoDVCl as a way to understand how unguessable keys can be created.
It's a great way to get a practical feel for how keys work @LearnMoreWithC4

[C4 @LearnMoreWithC4]

Special Livestream Today 🎲

Our CCSS™ Committee will discuss the seed generation issue affecting certain Coldcard hardware wallet devices and firmware versions and the importance of entropy.

🗓️ July 31 • 2 PM ET

https://t.co/iRkEYcmidm