Welcome to Bitcoin Stack Exchange
Bitcoin is a question and answer site for Bitcoin professionals and enthusiasts. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about technologies supporting the Bitcoin project in the past, present, or future.
Questions about other cryptocurrencies or general concepts may be on-topic for other sites in our network
We're a little bit different from other sites. Here's how:
Ask questions, get answers, no distractions
This site is all about getting answers. It's not a discussion forum. There's no chit-chat.
Just questions...
...and answers.
Good answers are voted up and rise to the top.
The best answers show up first so that they are always easy to find.
The person who asked can mark one answer as "accepted".
Accepting doesn't mean it's the best answer, it just means that it worked for the person who asked.
Does BIP39 mnemonic construction avoid repeating words?
Will all 24 words of a seed-phrase be unique by specification? Or is it possible for a word to occupy two positions (ie the word "tool" is #8 AND #20 in a valid, securely generated seed)
5,1642 gold badges24 silver badges43 bronze badges
2 Answers
There is nothing stopping a word to be repeated more than once. In a 24 word mnemonic, with 2048 possible words in the dictionary (BIP 39), there is a probability of at least one duplicate around 12.7% of the time (variation of the birthday paradox).
11.9k4 gold badges26 silver badges53 bronze badges
No, the BIP39 construction does not avoid repeating words.
It is possible for a word to show up multiple times, but since there are 2048 words it is fairly unlikely for repeats to show up in randomly generated keys.
7,7272 gold badges21 silver badges47 bronze badges
Get answers to practical, detailed questions
Focus on questions about an actual problem you have faced. Include details about what you have tried and exactly what you are trying to do.
Not all questions work well in our format. Avoid questions that are primarily opinion-based, or that are likely to generate discussion rather than answers.
Questions that need improvement may be closed until someone fixes them.
Tags make it easy to find interesting questions
All questions are tagged with their subject areas. Each can have up to 5 tags, since a question might be related to several subjects.
Click any tag to see a list of questions with that tag, or go to the tag list to browse for topics that interest you.
Does BIP39 mnemonic construction avoid repeating words?
Will all 24 words of a seed-phrase be unique by specification? Or is it possible for a word to occupy two positions (ie the word "tool" is #8 AND #20 in a valid, securely generated seed)
5,1642 gold badges24 silver badges43 bronze badges
You earn reputation when people vote on your posts
Your reputation score goes up when others vote up your questions, answers and edits.
As you earn reputation, you'll unlock new privileges like the ability to vote, comment, and even edit other people's posts.
At the highest levels, you'll have access to special moderation tools. You'll be able to work alongside our community moderators to keep the site focused and helpful.
Improve posts by editing or commenting
Our goal is to have the best answers to every question, so if you see questions or answers that can be improved, you can edit them.
Use edits to fix mistakes, improve formatting, or clarify the meaning of a post.
Use comments to ask for more information or clarify a question or answer.
You can always comment on your own questions and answers. Once you earn 50 reputation, you can comment on anybody's post.
Remember: we're all here to learn, so be friendly and helpful!
There is nothing stopping a word to be repeated more than once. In a 24 word mnemonic, with 2048 possible words in the dictionary (BIP 39), there is a probability of at least one duplicate around 12.7% of the time (variation of the birthday paradox).
11.9k4 gold badges26 silver badges53 bronze badges
Unlock badges for special achievements
Sign up to get started
Signing up allows you to:
- Earn reputation when you help others with questions, answers and edits.
- Select favorite tags to customize your home page.
- Claim your first badge: Informed
Bitcoin Stack Exchange is part of the Stack Exchange network
Like this site? Stack Exchange is a network of 182 Q&A sites just like it. Check out the full list of sites.
