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Selfish Mining Explained Simply

You can also read the math behind α in Warren’s reply on X

![](https://m.stacker.news/111229)


https://x.com/AchimWar/status/1975600429871603971

## Selfish Mining Explained

Selfish mining is a strategy used by miners to gain more profits  
by **not immediately broadcasting newly found blocks** and keeping them secret.

---

### ⚙️ Scenario
Imagine two miners — Alice and Bob — competing to extend the same blockchain.

![](https://m.stacker.news/111225)

---

### 🧩 How It Works
**Round 1:** Alice finds a block but doesn’t broadcast it (keeps it secret).  
**Round 2:** Bob mines a block and broadcasts it.  
**Round 3:** Alice mines another secret block and then publishes both, creating a longer chain.

![](https://m.stacker.news/111224)

---

### 💰 Outcome
The network adopts Alice’s chain since it’s longer,  
and she earns a greater reward for both blocks.

![](https://m.stacker.news/111226)

Selfish mining becomes profitable when **α > 33%**,  
where α is the miner’s share of the total computational power.

![](https://m.stacker.news/111228)

*From: https://eprint.iacr.org/2014/007.pdf*

---

🧡 *Follow for more Bitcoin visual explainers.*


### 🧠 Bitcoin Dev Mailing List TLDR — Week of Oct 1st, 2025

Here’s a summary of new and active Bitcoin Dev and DelvingBitcoin discussions this week.  

📬 **Subscribe at [tldr.bitcoinsearch.xyz](https://tldr.bitcoinsearch.xyz)**  
*Stay up to date on the latest in Bitcoin Dev,  DelvingBitcoin discussions*

---

#### 🧾 Summary of Threads Started This Week

AdamISZ, under the pseudonym waxwing, explores the complexities of embedding data within Schnorr signatures, specifically within the tuple format outlined by BIP340. He concludes that such embedding compromises the security of the unspent transaction outputs (UTXOs) by potentially revealing the private key, challenging previous notions that alternative methods might avoid such security breaches. This analysis not only addresses technical concerns but also raises broader questions about the implications for blockchain privacy and security, inviting further discussion and critique on these findings through his work available on [GitHub](https://github.com/AdamISZ/schnorr-unembeddability).

Coperbyte Solutions introduces an innovative proposal for "Emoji Seed Mnemonics for Deterministic Keys," aiming to simplify the interaction with cryptographic keys through a visual mnemonic system. This system, designed to be backwards-compatible with the BIP-39 wordlist, facilitates a more intuitive and language-independent method for managing keys, enhancing user accessibility without altering the existing security infrastructure. Detailed documentation and invitation for community feedback highlight the collaborative effort to refine this proposal, available for review at [https://emojiseed.comreadme](https://emojiseed.comreadme) and [https://github.com/emojiseed/bip-emojiseed](https://github.com/emojiseed/bip-emojiseed).

Blocktraveler addresses the challenges associated with importing private keys into Bitcoin Core descriptor wallets, proposing a Python-based tool and an 'importprivkeys' RPC call to streamline this process. This initiative reflects a broader effort within the Bitcoin development community to enhance the usability and accessibility of digital asset management, with further details and the technical proposal accessible on [Gist](https://gist.github.com/blocktraveler/3e6198c698a272bd8b13b16e0f13d390).

Sindurasaraswathi's research into threshold signatures for Bitcoin transactions after the Taproot upgrade offers a nuanced analysis of setting optimal thresholds to balance security benefits against the risk of self-lockout. Through dynamic models, this work provides a conceptual framework for managing threshold signatures and suggests evolving strategies to adapt to changing security conditions. This significant contribution to the Bitcoin ecosystem's understanding of threshold signatures is detailed further in the [GitHub repository](https://github.com/sindurasaraswathi/Optimal_Threshold_Signatures).

---

#### 🧵 New Threads This Week

- **[On (in)ability to embed data into Schnorr](https://gnusha.org/pi/bitcoindev/aN21KbXTORgXAVH0@mail.wpsoftware.net/T/#m27239f8a634b8db07be258948dba65795f3af9ef)** — by waxwing / AdamISZ  
  - Embedding data risks revealing private keys and compromising UTXO security.  
  - Contributors: Greg Maxwell, Andrew Poelstra, Peter Todd  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Oct_2025/m27239f8a634b8db07be258948dba65795f3af9ef_On-in-ability-to-embed-data-into-Schnorr)

- **[[BIP Draft] Emoji Seed Mnemonics for Deterministic Keys](https://gnusha.org/pi/bitcoindev/66bd5da8-9114-4ddc-b926-c9349c57e8c3n@googlegroups.com/T/#ma46bae528a1c0c4307afe213467fd9fce22dbc1d)** — by Coperbyte Solutions  
  - Introduces emoji mnemonics for deterministic keys, backward-compatible with BIP-39.  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Oct_2025/ma46bae528a1c0c4307afe213467fd9fce22dbc1d_-BIP-Draft-Emoji-Seed-Mnemonics-for-Deterministic-Keys)

- **[Add importprivkeys RPC](https://gnusha.org/pi/bitcoindev/ad14b140-9e02-466c-8226-304ec651f4ben@googlegroups.com/T/#u#m4475f37e62eba1160bd9018f1f0fe19649a78290)** — by Blocktraveler  
  - Proposes new RPC call for importing private keys into Bitcoin Core descriptor wallets.  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Oct_2025/m4475f37e62eba1160bd9018f1f0fe19649a78290_Add-importprivkeys-RPC)

- **[Bitcoin Inquisition 29.1](https://delvingbitcoin.org/t/bitcoin-inquisition-29-1/2019)** — by ajtowns  
  - Adds support for consensus changes and template sharing.  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/delvingbitcoin/Sept_2025/5987_Bitcoin-Inquisition-29-1)

- **[Optimal Threshold Signatures in Bitcoin](https://delvingbitcoin.org/t/optimal-threshold-signatures-in-bitcoin/2023)** — by sindurasaraswathi  
  - Explores dynamic threshold management after Taproot.  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/delvingbitcoin/Oct_2025/5996_Optimal-Threshold-Signatures-in-Bitcoin)

---

#### 🔥 Active Discussions This Week

- **[[BIP Proposal] Mempool Validation and Relay Policies via User-Defined Scripts](https://gnusha.org/pi/bitcoindev/1A33D206-444A-49E7-B1F1-E9FE5F4E32FB@drbonez.dev/T/#m1f3244d2d165cdd59c084b6c99690d51d2e4788c)** — Aiden McClelland  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Sept_2025/m1f3244d2d165cdd59c084b6c99690d51d2e4788c_-BIP-Proposal-Mempool-Validation-and-Relay-Policies-via-User-Defined-Scripts)

- **[[BIP Proposal] Limit ScriptPubkey Size >= 520 Bytes Consensus](https://gnusha.org/pi/bitcoindev/CALiT-Zo8wiZGCFeMwfd92zptw_cKz7ajMOjFWW=rdS9by3zYHQ@mail.gmail.com/T/#m3e2bdc7ae5f63854c971fd6feef54ca644d135fb)** — Brandon Black  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Oct_2025/m3e2bdc7ae5f63854c971fd6feef54ca644d135fb_-BIP-Proposal-Limit-ScriptPubkey-Size-520-Bytes-Consensus-)

- **[Changes to BIP-360 - Pay to Quantum Resistant Hash (P2QRH)](https://delvingbitcoin.org/t/changes-to-bip-360-pay-to-quantum-resistant-hash-p2qrh/1811/31)** — moonsettler  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/delvingbitcoin/Oct_2025/5995_Changes-to-BIP-360-Pay-to-Quantum-Resistant-Hash-P2QRH-)

- **[OP_CHECKUTXOSETHASH idea](https://gnusha.org/pi/bitcoindev/CAJowKgLpix4KjzJGKNzR3JpiKLDJKSiuuOdcebCyGJnDuw0wJw@mail.gmail.com/T/#m8e157812cddf8459bcb15f5467092dc0a5e8b682)** — Peter Todd  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/bitcoin-dev/Oct_2025/m8e157812cddf8459bcb15f5467092dc0a5e8b682_OP-CHECKUTXOSETHASH-idea)

- **[Stealth addresses using nostr](https://delvingbitcoin.org/t/stealth-addresses-using-nostr/1816/9)** — setavenger  
  - [Summary link](https://tldr.bitcoinsearch.xyz/summary/delvingbitcoin/Sept_2025/5986_Stealth-addresses-using-nostr)

---

📚 Full summaries and sources:  
👉 [tldr.bitcoinsearch.xyz](https://tldr.bitcoinsearch.xyz)

---

*(Bitcoin Dev Project - TLDR product)*


This Week in Bitcoin Development (Oct 2025, Week 1)

## Introducing Bitcoin TLDR v2

![](https://m.stacker.news/108344)

Did you know the **bitcoin-dev mailing list** has over **20,000 posts** going back to *June 2011*?  

If each post takes ~30 minutes to read, that’s **over 400 days of nonstop reading**! 😅  

To be fair:  

1️⃣ Posts aren't easily searchable  
2️⃣ Threads that span multiple months can be broken  
3️⃣ Your inbox probably has enough emails competing for your attention  

Things can easily go ignored & unread.  
Few, if any, can say they have read it all.  

For the rest of us, we started working on a way to download the mailing list straight to your brain.  
While we haven’t quite figured that out (yet), we've built the next best thing…  

---

## 📚 Meet Bitcoin TLDR v2 📚  
A collection of summaries for:  
- **bitcoin-dev**  
- **lightning-dev**  
- **Delving Bitcoin**  

➡️ [tldr.bitcoinsearch.xyz](https://tldr.bitcoinsearch.xyz)


📢 Introducing Bitcoin TLDR v2

#  How Mining Pools Delegate Work to Miners



Here’s a simple visual explanation of how it works 👇

---

### 1️⃣ Pool Prepares Work
- The pool selects transactions from the mempool and builds a **block header** (incomplete).
- This incomplete header is the "work" miners will hash.
- The pool tweaks the **nonce** or **extranonce** so each miner gets a unique piece of work.



![](https://m.stacker.news/107946)

---

### 2️⃣ Miners Hash & Submit Shares
- Each miner receives a unique **nonce range** and starts hashing.
- When miners exhaust their nonce ranges, the pool tweaks the extranonce to give them more work.
- Miners submit a **share** when their hash is below the **share target** (much easier than bitcoin’s real network target)


![](https://m.stacker.news/107945)

---

###  Remember
- **Network Target:** Hash must be below this to mine a valid block. (Rare, what actually “wins” a block reward.)
- **Share Target:** Easier target set by the pool. Miners find shares every few seconds to prove they’re hashing and to measure their contribution.

![Share target vs network target](upload://fa1313a1-9ee2-4434-bdf5-f153b6b6a11a.png)

---

### What Happens Next?
When a share is also below the **network target**, the pool broadcasts the block to the bitcoin network and everyone in the pool shares the reward, based on how many shares they submitted.

---

### 👀 Coming Up Next
In our next post, we’ll look at **how pools calculate payouts**  
PPS, PPLNS, FPPS, and other reward algorithms that decide how miners get paid.

Follow @bitcoin_devs so you don’t miss it!


How pools delegate work to miners ?

## SigHash Explained 📝

SigHash determines **which parts of a Bitcoin transaction are signed**.  
This affects how the transaction can be modified by others after you sign it.

There are 4 main types:

![](https://m.stacker.news/107861)




---

### 1. `SIGHASH_ALL`
Signs **all inputs and all outputs**.  
This is the most common type,  the entire transaction must remain unchanged for the signature to stay valid.

---

### 2. `SIGHASH_NONE`
Signs **all inputs**, but **no outputs**.  
This means someone else can change the outputs (e.g., the destination) **without invalidating your signature**.  
⚠️ **Use with caution!**

---

### 3. `SIGHASH_SINGLE`
Signs **all inputs**, but only the output with the **same index** as the input being signed.  
Useful for collaborative transactions where each participant only commits to their own output.

---

### 4. `SIGHASH_ANYONECANPAY` (modifier)
This is a flag that can be combined with the above types.  
It makes the signature commit to **only one input**, allowing others to add more inputs to the transaction.  
Example: Crowdfunding or shared transactions where multiple people contribute inputs.

---


SigHash Explained 📝

How to generate nonce for schnorr signature ?

more on that here: 
https://bitcoindevs.xyz/decoding/nonce-reuse-attack

### How to generate nonce for schnorr signature ?

![](https://m.stacker.news/107745)

If you're still confused about how it works, check out our explanation with code here:
https://bitcoindevs.xyz/decoding/schnorr-signature

# Type of P2P connections:

1- Outbound Connections
2- Inbound Connections
3- Feeler Connections
4- Block-relay-only Connections:
5- Anchor Connections
6- One-shot Connections: https://github.com/bitcoin/bitcoin/pull/22096
7- Manual Connections
8- Full-Relay Connections

![](https://m.stacker.news/107374)

![](https://m.stacker.news/107373)

![](https://m.stacker.news/107375)

![](https://m.stacker.news/107376)

Type of P2P connections

deleted by author

# Cheat sheet of the cryptographic hashes powering Bitcoin


![](https://m.stacker.news/107175)

---

## 1- Core Bitcoin Hashes

#### SHA-256
- Mining (Proof of Work): miners hash block headers  
- Transaction IDs (txid): each transaction gets a unique SHA-256 hash  
- Merkle tree construction (organizing transactions in blocks)  

#### SHA-256d (Double SHA-256)
- Block hashes (each block header hashed twice)  
- Extra security against length extension attacks  
- Checksums in addresses

#### RIPEMD-160
- Address generation: `RIPEMD160(SHA256(pubkey))`
- Shortens 256-bit SHA-256 into 160-bit hash  

#### HASH-160 (SHA-256 + RIPEMD-160)
- Used in P2PKH & P2SH addresses  

---

## 2- Wallet & Key Management Hashes

#### HMAC-SHA256 / SHA512
- Key derivation in BIP32 (HD wallets)  
- Secure key stretching  

### HKDF
- BIP-324 encrypted P2P transport
- Secure key expansion from master keys  
- Advanced key derivation


---

## 3- Networking & Protocol

#### SipHash-2-4
- Short IDs in Compact Block relay (BIP-152)
- DoS protection
- Fast hash for hash tables  
- Prevents hash collision attacks  

#### MuHash 
- Accumulators for UTXO set commitments (useful for AssumeUTXO, UTXO snapshots)
---

## 4- Encryption (Not Core Bitcoin)

#### ChaCha20
- Stream cipher for encrypting data  
- Used in BIP324 (v2 P2P transport encryption)  

#### Poly1305
- Works with ChaCha20 for authenticated encryption  
- Ensures data integrity  

---

#### SHA-3 (SHA3-256)

- Not used in Bitcoin itself. It’s only needed for Tor v3 onion addresses (ed25519 → onion domain)


Core bitcoin hashes

![](https://m.stacker.news/106321)

![](https://m.stacker.news/106322)

![](https://m.stacker.news/106323)

![](https://m.stacker.news/106324)

![](https://m.stacker.news/106325)

![](https://m.stacker.news/106326)

Follow @bitcoin_devs for more bitcoin technical posts

Segwit explained simply

Understanding Bitcoin Mining Process:

![](https://m.stacker.news/106175)


1. Running a Node: The Miner must run a full Bitcoin node. This allows them to stay updated with latest state of the blockchain

2. Begin construction of a new block template

3. Select Transactions: From the pool of unconfirmed transactions, miners pick those they wish to include in the new block. Usually, tx with higher fees are prioritized.

4. Create coinbase Tx: This is the first transaction in a new block, where miners award themselves the block reward and tx fees.

5. Constructing Merkle Trees: Transactions are organized into a Merkle tree

6. Hashing for the Block Solution: Miner hashes the block's header, which includes the Merkle root, timestamp, the previous block's hash, and a nonce. The goal is to find a hash that meets the network's difficulty target.

7.1. If success, submit the block
7.2. If another block is added to the chain by other miner, update  block template to reflect this change and start the mining process anew.

Understanding Bitcoin Mining Process

## WOTS+ Key Generation explained

### Part 3: SPHINCS+

1/
![](https://m.stacker.news/104797)

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![](https://m.stacker.news/104798)

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![](https://m.stacker.news/104799)

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![](https://m.stacker.news/104800)

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![](https://m.stacker.news/104802)

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![](https://m.stacker.news/104806)

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![](https://m.stacker.news/104805)



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![](https://m.stacker.news/104808)



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![](https://m.stacker.news/104807)


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![](https://m.stacker.news/104817)

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![](https://m.stacker.news/104819)


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![](https://m.stacker.news/104815)


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![](https://m.stacker.news/104811)



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![](https://m.stacker.news/104816)



Follow @Bitcoin_Devs so you don't miss it!

Resources:
- https://eprint.iacr.org/2023/411.pdf
- https://sphere10.com/articles/cryptography/pqc/wots
- https://er4hn.info/blog/2023.12.16-sphincs_plus-step-by-step/



WOTS+ Key Generation explained

crypto

SPHINCS+ - explained by nifty

Scoresby

WOTS (Witernitz One Time Signatures) explained

Small correction: in the signature part, it should be Priv[0], Priv[1], ..., Priv[31] instead of Priv[0] repeated 🙏

![](https://m.stacker.news/103373)

# WOTS (Winternitz One Time Signatures) explained

**Part 3: SPHINCS+**  
1/

![](https://m.stacker.news/103368)

2/

![](https://m.stacker.news/103369)

3/

![](https://m.stacker.news/103370)

4/

![](https://m.stacker.news/103371)

---

We’ve now seen how WOTS works.  
But it’s not quite secure enough on its own…

**WOTS+**, with checksums and bitmasks, patches those holes.

---

**Next Post:**  
👉 *WOTS+*

![](https://m.stacker.news/103372)

📌 Follow [@Bitcoin_Devs](https://x.com/Bitcoin_Devs) so you don't miss it!

**Resources:**  
- https://sphere10.com/articles/cryptography/pqc/wots
- https://er4hn.info/blog/2023.12.16-sphincs_plus-step-by-step/



# Lamport Signature
In **Part 1**  we introduced **SPHINCS+** as a tower built entirely from hash-based ideas.


![Lamport Start](https://m.stacker.news/103266)

Now we start from the very first block…  
**Lamport Signatures**

In **1979**, Leslie Lamport had a simple idea:

> *"What if we could sign messages using just hashes?"*

📄 [Original Paper (1979)](https://www.loper-os.org/pub/lam-par/lamport79.pdf)

This was the **first hash-based signature**.

But how does it work?

---
0/

![Slide 0](https://m.stacker.news/103276)



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![Slide 1](https://m.stacker.news/103277)



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![Slide 2](https://m.stacker.news/103278)

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![Slide 3](https://m.stacker.news/103279)

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![](https://m.stacker.news/103281)


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![](https://m.stacker.news/103282)

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![](https://m.stacker.news/103283)


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![](https://m.stacker.news/103284)


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![](https://m.stacker.news/103285)

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![](https://m.stacker.news/103286)

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![](https://m.stacker.news/103287)

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![](https://m.stacker.news/103288)

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![](https://m.stacker.news/103289)

---


**Next Post:**  
👉 *FORS (Forest of Random Subsets)*

![FORS Teaser](https://m.stacker.news/103280)


---

📌 Follow **@Bitcoin_Devs** so you don't miss it!

---

**Resources:**

- [L. Lamport Paper (1979)](http://loper-os.org/pub/lam-par/lamport79.pdf)  
- [SPHINCS+ Walkthrough by Ethan Rahn](https://er4hn.info/blog/2023.12.16-sphincs_plus-step-by-step/)





SPHINCS+ (Part 2 Lamport Signature)

![Quantum Threat](https://m.stacker.news/103102)

**Quantum computers will break most digital signatures we rely on today**

- **RSA** → Broken by **Shor’s Algorithm**  
- **ECDSA** → Weakened by **Grover’s Algorithm**

---

**NIST** (National Institute of Standards and Technology) is selecting new algorithms that resist quantum attacks.

They fall into several categories:

- Hash-based  
- Lattice-based  
- Code-based  
- Multivariate  
- Isogeny-based

Among the **hash-based** options, NIST picked **SPHINCS+** as the *conservative fallback*  
📄 [Ref paper](https://eprint.iacr.org/2023/411.pdf)

---

**SPHINCS+** is built entirely from **hash functions**

> Why hash functions?  
> *"There’s no known good attacks against hash functions."*  

*The best attempt so far is the BHT algorithm which proposes a quantum collision attack using Grover’s algorithm. But DJB dismissed it in [his paper](https://cr.yp.to/hash/collisioncost-20090823.pdf)*

--- 
It’s a pretty complicated algorithm.

![SPHINCS+ Stack](https://m.stacker.news/103103)

---

So in this series, **we’ll break it down, one layer at a time.**

![Layer Breakdown](https://m.stacker.news/103104)

---

**Next Post:**  
👉 *Lamport Signature*

---

📌 Make sure to follow **@bitcoin_devs** so you don't miss it.

---

**More resources:**

- [SPHINCS+ paper](https://eprint.iacr.org/2023/411.pdf)  
- [SPHINCS+ explainer by @ roasbeef](https://drive.google.com/file/d/12UlzfGvG09IwvzWscL2FT8CoewGBWlGD/view)  
- [Quantum Bitcoin Summit by @PresidioBitcoin](https://youtube.com/watch?v=GeUdu4hrBPI&t=10728s)


SPHINCS+ explained (Part 1)

Bitchat explained simply

Yep, these are real-world applications mentioned in the whitepaper:

https://github.com/permissionlesstech/bitchat/blob/main/WHITEPAPER.md#real-world-applications

Yep, these are real-world applications also mentioned in the whitepaper:

https://github.com/permissionlesstech/bitchat/blob/main/WHITEPAPER.md#real-world-applications