Bitcoin Optech newsletter #416 is here:
- warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices
- summarizes the disclosure of two denial-of-service vulnerabilities in Core Lightning
- describes a proof of concept for a zero-knowledge proof of reserves
- summarizes popular Q&A from Stack Exchange
- Optech Newsletter #416 Podcast
If you used a COLDCARD to generate a wallet, any funds received by that wallet are at risk of theft and should be carefully moved to an unaffected wallet as soon as possible...
On 30 July 2026, some Bitcoin users discovered that funds from their COLDCARD wallets had been stolen in a series of unexpected transactions on 29 July. Over the course of the day, a bug was identified in the firmware of the COLDCARD that causes wallets to be generated with insufficient entropy. As of this writing, estimated losses exceed 1,000 BTC, a figure that may continue to rise as the situation develops...
Chandra Pratap posted to Delving Bitcoin about two denial-of-service (DoS) vulnerabilities he found in Core Lightning...
fabohax posted about zkPoH (“zero-knowledge proof-of-hodl”), a proof of concept for a non-custodial proof of reserves system for Bitcoin...
Selected Q&A from Bitcoin Stack Exchange
- What is Bitcoin’s objective definition of transaction neutrality?
- Why does BIP110’s decentralization benefit not outweigh its impact on transaction neutrality?
- Why does BIP110 require a 55% signaling threshold if its nodes reject non-signaling blocks?
- Why use ElligatorSwift encoding in BIP324?
- Was the OP_SUCCESSx reservation in BIP342 designed with specific opcode families in mind?
- What is the difference between the long-term feerate and the discard feerate?
- What is the quickest method for migrating a legacy wallet to a descriptor wallet on a pruned node?
- Is there historical data on orphan/stale block rates during high-fee periods?
Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 16:30 UTC.
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...
Bitcoin Optech
Bitcoin Optech Newsletter #416
This week’s newsletter warns about a severe vulnerability affecting wallets generated by COLDCARD signing devices, summarizes the disclosure of t...