[bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Hi Everyone, Thank you very much in this thanks giving day for the detailed and well thought out responses. :) Steven Hatzakis via bitcoin-dev https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>>: >* *Option 2*: Perhaps a revision is needed to how the BIP39 seed is *>* generated in the first place, such as by hashing the entropy instead of the *>* words. Any thoughts on how viable that could be where the initial entropy *>* is fed into the PBKDF2 function and not the words?* If we go this direction, I'd suggest that we pull Shamir's Secret Sharing into the game. Trezor's SLIP-0039 proposal is great and has many security aspects already covered. However, it does not allow any language other than English and Trezor team clearly stated that no other language will be supported. While I really want to keep the language independent design. So in the revision, I'd like to see a language id (allocated to each one having a defined wordlist) in the SSS share, as well as share id, threshold, index, share value, checksum etc. Regarding checksum scheme, SLIP-0039 proposals a 3-word Reed-Solomon design. It has a very good error checking capability but not very good at providing hints to error recovery. Trezor team opposes to the idea of providing hints to users regarding how to fix an error. This could lead to difficulties for some vendors, and in small probability, confusions to users (when there is a 2-word error) I do agree with Trezor team that it should be users' responsibility to recover from a detected error. However, there is a better way than solely rely on checksum. That is, as in our revision, we can support mnemonic in multiple languages simultaneously, why don't we use two languages, or one language + numbers to check each other? In Steven's example (language id, share id, etc. skipped) we could record a SSS share (assuming it is one of the shares just for the sake of example) like: >* *In English*: minimum fee sure ticket faculty banana gate purse caught *>* valley globe shift *>* *In Spanish*: mercado faja soledad tarea evadir aries gafas peine búho *>* tumor gerente reja* Or >* *In English*: minimum fee sure ticket faculty banana gate purse caught *>* valley globe shift* >* Word Indexes: 1128, 676, 1744, 1805, 653, 145, 770, 1396, 291, 1927, 794, 1582* Then software will have to check checksum as well as to check if words match each other. For example, "minimum"'s index value in English wordlist should equal to " *mercado*"'s in Spanish, or should equal to 1128. If any error is detected, combining the checksum value and dual-encoding information, it is much easier to figure out which word was handprinted incorrectly. BTW, it is very error prone to handprint. Some study suggests about 0.9% per word rate. See http://panko.shidler.hawaii.edu/HumanErr/Basic.htm Hotopf [1980] W sample (written exam). Per word 0.9% It is important to have an error recovery mechanism easy to understand and implement. Thanks, Weiji ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Den mån 19 nov. 2018 21:21 skrev Steven Hatzakis via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org>: > Hi Weiji, and Everyone, > > I think this is an important topic so sharing my two cents in case in > helps: It makes sense for users to know that they can't merely just > translate a word from one language into another and expect the same > underlying entropy to be mapped, as the wordlists are not the same (i.e. > words differ at the same index values across languages). > > However, while the words for each language cannot translate directly to > their equivalent in another language, in terms of entropy (bits), the > underlying entropy is, in fact, the same, when comparing mnemonics > generated across languages (see English/Spanish comparison below) when > sourced from the same initial entropy. > > Importantly, the entropy is a pre-image of the resulting mnemonic and > doesn't change as the language changes, where the only changes are to the > resulting words which depend on the language chosen, for a given entropy > string. Ideally, the wallet/software should deal with these nuances, I > don't think the protocol needs any revision (except for how the BIP39 seed > is derived, perhaps), even if someone made up their own wordlist, as long > as the wallet/software has a copy of it to map those words to the > underlying index values, it's *those underlying index values and the > entropy they map too is what really matters**. * > > I fully support the idea for users to back up this pre-image (initial > entropy) as it can also be used to check the validity of the mnemonic and > check that it mapped correctly, see Ian Coleman's BIP39 tool which shows > index values, a feature that I proposed last year and was since > implemented. Below is an example of how two mnemonics generated with the > same entropy will produce different BIP39 seeds. > > * Example initial entropy of 128 bits +4 bit checksum derived from hash of > byte array: * > > 10001101000 01010100100 1101101 1111101 01010001101 00010010001 > 0110010 10101110100 00100100011 111 01100011010 1100010 (+1110 > checksum) > > *In English*: minimum fee sure ticket faculty banana gate purse caught > valley globe shift > > The same initial entropy above (all 132 bits) produces this mnemonic: > > *In Spanish*: mercado faja soledad tarea evadir aries gafas peine búho > tumor gerente reja > > And the underlying index values below are the same for both the English > and Spanish mnemonics above: > > Word Indexes: 1128, 676, 1744, 1805, 653, 145, 770, 1396, 291, 1927, 794, > 1582 > > *ISSUE AT HAND*: While the initial entropy is the same, and word indexes > the same for a given entropy, (i.e. same pre-image), the resulting BIP39 > seed is not the same when comparing the above English mnemonic with its > Spanish counterpart: > >- *English BIP39 seed:* > > ce7618075099c89e986f18dc495daa3be190450ed07bef77d4334a54dbc1cd7e205797ffed2615ac0999a5d691f65bf316e2cdbfd2c9d7d90b03e77ff1e6a6f5 >- *Spanish BIP39 seed*: > > 9f164de0fb09af51b5831886e424d6d2479d49b5e5a1b28f5c09467ea36089b144cd94bb9b636b3c27ccff96a8958e5b7ce43cf1dea81423fc66fa7fef0aea2c > > > *Option 1:* Without changing anything in terms of the entropy > generation/mapping process in the BIP39 spec, the wallet/client-side > software would ideally recognize the language and show the corresponding > index value per wordlist, and reverse-calculate the entropy and then re-map > it to the language selected. > > *Option 2*: Perhaps a revision is needed to how the BIP39 seed is > generated in the first place, such as by hashing the entropy instead of the > words. Any thoughts on how viable that could be where the initial entropy > is fed into the PBKDF2 function and not the words? > > *Closing thoughts and tiny checksum nitpick: * > > - The multiple BIP39 seeds per language lend some similarities to > BIP44 multi-account, so perhaps this can be an advantage, depends on how it > is applied in UI/UX's (compared to having one BIP39 seed regardless of > language, for a given initial entropy). > - There is perhaps an opportunity to add greater detail to the BIP39 > spec in terms of standards/best-practices for computing checksum values, as > some software may be hashing bits, versus hashing bytes, or hashing the > entropy as a hex string, etc.. for a given entropy, which will result in > different checksum values for the same "valid" mnemonic, that might not be > "valid" in another wallet which may format the data differently before > hashing to compute the checksum. > This probably wouldn't work as a drop-in replacement, but having the identifier of the chosen wordlist be part of the mnemonic might work? Perhaps the raw seed would then be [hash of chosen dictionary]+[sequence of word indexes]. The user experience then involves always selecting a dictionary by name. I also suggest maintaining an official list of named dictionaries. The purpose of including the dictionary
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Hi Weiji, and Everyone, I think this is an important topic so sharing my two cents in case in helps: It makes sense for users to know that they can't merely just translate a word from one language into another and expect the same underlying entropy to be mapped, as the wordlists are not the same (i.e. words differ at the same index values across languages). However, while the words for each language cannot translate directly to their equivalent in another language, in terms of entropy (bits), the underlying entropy is, in fact, the same, when comparing mnemonics generated across languages (see English/Spanish comparison below) when sourced from the same initial entropy. Importantly, the entropy is a pre-image of the resulting mnemonic and doesn't change as the language changes, where the only changes are to the resulting words which depend on the language chosen, for a given entropy string. Ideally, the wallet/software should deal with these nuances, I don't think the protocol needs any revision (except for how the BIP39 seed is derived, perhaps), even if someone made up their own wordlist, as long as the wallet/software has a copy of it to map those words to the underlying index values, it's *those underlying index values and the entropy they map too is what really matters**. * I fully support the idea for users to back up this pre-image (initial entropy) as it can also be used to check the validity of the mnemonic and check that it mapped correctly, see Ian Coleman's BIP39 tool which shows index values, a feature that I proposed last year and was since implemented. Below is an example of how two mnemonics generated with the same entropy will produce different BIP39 seeds. * Example initial entropy of 128 bits +4 bit checksum derived from hash of byte array: * 10001101000 01010100100 1101101 1111101 01010001101 00010010001 0110010 10101110100 00100100011 111 01100011010 1100010 (+1110 checksum) *In English*: minimum fee sure ticket faculty banana gate purse caught valley globe shift The same initial entropy above (all 132 bits) produces this mnemonic: *In Spanish*: mercado faja soledad tarea evadir aries gafas peine búho tumor gerente reja And the underlying index values below are the same for both the English and Spanish mnemonics above: Word Indexes: 1128, 676, 1744, 1805, 653, 145, 770, 1396, 291, 1927, 794, 1582 *ISSUE AT HAND*: While the initial entropy is the same, and word indexes the same for a given entropy, (i.e. same pre-image), the resulting BIP39 seed is not the same when comparing the above English mnemonic with its Spanish counterpart: - *English BIP39 seed:* ce7618075099c89e986f18dc495daa3be190450ed07bef77d4334a54dbc1cd7e205797ffed2615ac0999a5d691f65bf316e2cdbfd2c9d7d90b03e77ff1e6a6f5 - *Spanish BIP39 seed*: 9f164de0fb09af51b5831886e424d6d2479d49b5e5a1b28f5c09467ea36089b144cd94bb9b636b3c27ccff96a8958e5b7ce43cf1dea81423fc66fa7fef0aea2c *Option 1:* Without changing anything in terms of the entropy generation/mapping process in the BIP39 spec, the wallet/client-side software would ideally recognize the language and show the corresponding index value per wordlist, and reverse-calculate the entropy and then re-map it to the language selected. *Option 2*: Perhaps a revision is needed to how the BIP39 seed is generated in the first place, such as by hashing the entropy instead of the words. Any thoughts on how viable that could be where the initial entropy is fed into the PBKDF2 function and not the words? *Closing thoughts and tiny checksum nitpick: * - The multiple BIP39 seeds per language lend some similarities to BIP44 multi-account, so perhaps this can be an advantage, depends on how it is applied in UI/UX's (compared to having one BIP39 seed regardless of language, for a given initial entropy). - There is perhaps an opportunity to add greater detail to the BIP39 spec in terms of standards/best-practices for computing checksum values, as some software may be hashing bits, versus hashing bytes, or hashing the entropy as a hex string, etc.. for a given entropy, which will result in different checksum values for the same "valid" mnemonic, that might not be "valid" in another wallet which may format the data differently before hashing to compute the checksum. Best regards, Steven Hatzakis ___________ [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support*Weiji Guo* weiji.g at gmail.com *Tue Nov 6 16:16:41 UTC 2018* - Previous message: [bitcoin-dev] draft proposal: change forwarding (improved fungibility through wallet interoperability) <https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016469.html> - Next message: [bitcoin-dev] Considering starting a toy full-node implementation. Any advice? <https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016470.html> - *Messages sorted by:* [ date ] <https://lists.li
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
On Fri, Nov 09, 2018 at 02:17:30PM +0900, Jonathan Underwood via bitcoin-dev wrote: > If more apps would implement to the word of the BIP39 spec, multiple > languages make sense, but since reality is no one follows the spec (/the > spec is way too open to interpretation) then expecting every app to load > every language is unreasonable. > > Electrum actually handles BIP39 recovery the way the BIP specifies. I can > restore random strings if I want, and it warns me, and I can ignore it if I > wish. Electrum mnemonics are not based on BIP39, which is why it can do this. -Neill. ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Ah, ok. I've worked with the non-BIP39 Electrum mnemonics, which have this behaviour, but haven't tried the BIP39 support within it. Thanks, -Neill. On Fri, Nov 16, 2018 at 11:05:50PM +0900, Jonathan Underwood wrote: > Nope. > > This is how Electrum treats BIP39 restoring as well, try it out. > > -Jon > > 2018年11月16日(金) 23:04、Neill Miller さん（nei...@thecodefactory.org）のメッセージ: > > > On Fri, Nov 09, 2018 at 02:17:30PM +0900, Jonathan Underwood via > > bitcoin-dev wrote: > > > If more apps would implement to the word of the BIP39 spec, multiple > > > languages make sense, but since reality is no one follows the spec (/the > > > spec is way too open to interpretation) then expecting every app to load > > > every language is unreasonable. > > > > > > Electrum actually handles BIP39 recovery the way the BIP specifies. I can > > > restore random strings if I want, and it warns me, and I can ignore it > > if I > > > wish. > > > > Electrum mnemonics are not based on BIP39, which is why it can do > > this. > > > > -Neill. > > > > ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Nope. This is how Electrum treats BIP39 restoring as well, try it out. -Jon 2018年11月16日(金) 23:04、Neill Miller さん（nei...@thecodefactory.org）のメッセージ: > On Fri, Nov 09, 2018 at 02:17:30PM +0900, Jonathan Underwood via > bitcoin-dev wrote: > > If more apps would implement to the word of the BIP39 spec, multiple > > languages make sense, but since reality is no one follows the spec (/the > > spec is way too open to interpretation) then expecting every app to load > > every language is unreasonable. > > > > Electrum actually handles BIP39 recovery the way the BIP specifies. I can > > restore random strings if I want, and it warns me, and I can ignore it > if I > > wish. > > Electrum mnemonics are not based on BIP39, which is why it can do > this. > > -Neill. > > ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
> as it seems bad design to have to fix and maintain a wordlist for every language as the checksum depends on it. >From BIP39: > The conversion of the mnemonic sentence to a binary seed is completely independent from generating the sentence. This results in rather simple code; there are no constraints on sentence structure and clients are free to implement their own wordlists or even whole sentence generators, allowing for flexibility in wordlists for typo detection or other purposes. > > Although using a mnemonic not generated by the algorithm described in "Generating the mnemonic" section is possible, this is not advised and software must compute a checksum for the mnemonic sentence using a wordlist and issue a warning if it is invalid. So BIP39 states "no constraints on sentence structure and clients are free to implement their own wordlists or even whole sentence generators" and yet at the same time one paragraph later "this is not advised and software must compute a checksum for the mnemonic sentence using a wordlist and issue a warning if it is invalid"... My interpretation of this: 1. ChecksumCheck function attempts to 1. find the wordlist 2. calculate the checksum. 2. If it fails to find the wordlist, return false 3. If the checksum doesn't match return false 4. If ChecksumCheck returns false, "issue a warning" but do not block seed generation. "We couldn't check if your phrase is correct... you're on your own" 99.99% of implementing apps interpretation: (remember, error handling for userspace is not done by the BIP39 library, but the app that uses it) 1. Run ChecksumCheck 2. If False, hard fail, do not allow seed generation. If more apps would implement to the word of the BIP39 spec, multiple languages make sense, but since reality is no one follows the spec (/the spec is way too open to interpretation) then expecting every app to load every language is unreasonable. Electrum actually handles BIP39 recovery the way the BIP specifies. I can restore random strings if I want, and it warns me, and I can ignore it if I wish. Anywho. The BIP39 multi-language feature is crucial for non-English speakers especially from Asia. Maybe northern Europeans have no problem with English word spelling, but watching a normal Japanese person write down their English mnemonic is painful. One letter at a time, worried they wrote it wrong... still make mistakes... lose money because of it. Whereas users of Copay etc. that support Japanese wordlist write down their seed easily, and I have never heard of a Japanese newbie complaining about "but I'm writing it just how I have it written down" about their Japanese seed... only English. Not trying to give anyone a hard time, just telling the facts: lack of localized words for recovery phrase causes more money loss than supporting it. (When push comes to shove, at the very least Electrum will always support their recovery because it lets you hash anything) This is all anecdotal of course. Just sharing my experience evangelizing in Japan. Thanks, Jon 2018年11月8日(木) 21:16 SomberNight via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org>: > Do you specifically want to support changing the language of seed > words, while keeping the bip32 root seed they generate unchanged? > What is the usecase for this? > > You mention that BIP39 already supports a few different languages. > While this is true, many (I would guess most!) wallets only > support the English wordlist. > There are doubts even from the authors of the BIP whether it was > a good idea in the first place to support multiple languages [0]. > I don't find this surprising as it seems bad design to have to fix and > maintain a wordlist for every language as the checksum depends on it. > The supported wordlists are effectively a part of the specification, > and every new list would just make that specification larger. > > If changing the language of seeds is not a requirement, then look > into Electrum seeds. They are language/wordlist agnostic. > > Mnemonic Sentence => PBKDF2 => BIP-0032 Seed > > The bip32 seed is derived by hashing the normalized mnemonic, and the > checksum is derived the same way but by using a different cheaper > hash (single round of HMAC-SHA512; generation grinds until it matches > a pattern) [1]. For example, "9dk" is a valid segwit electrum seed. > > > [0]: > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-January/015507.html > [1]: http://docs.electrum.org/en/latest/seedphrase.html > > > > Date: Wed, 7 Nov 2018 00:16:41 +0800 > > From: Weiji Guo weij...@gmail.com > > Subject: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language > > support > > > > Hello everyone, > > > > I just realized that BIP-0039 is language depende
Re: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Do you specifically want to support changing the language of seed words, while keeping the bip32 root seed they generate unchanged? What is the usecase for this? You mention that BIP39 already supports a few different languages. While this is true, many (I would guess most!) wallets only support the English wordlist. There are doubts even from the authors of the BIP whether it was a good idea in the first place to support multiple languages [0]. I don't find this surprising as it seems bad design to have to fix and maintain a wordlist for every language as the checksum depends on it. The supported wordlists are effectively a part of the specification, and every new list would just make that specification larger. If changing the language of seeds is not a requirement, then look into Electrum seeds. They are language/wordlist agnostic. Mnemonic Sentence => PBKDF2 => BIP-0032 Seed The bip32 seed is derived by hashing the normalized mnemonic, and the checksum is derived the same way but by using a different cheaper hash (single round of HMAC-SHA512; generation grinds until it matches a pattern) [1]. For example, "9dk" is a valid segwit electrum seed. [0]: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-January/015507.html [1]: http://docs.electrum.org/en/latest/seedphrase.html > Date: Wed, 7 Nov 2018 00:16:41 +0800 > From: Weiji Guo weij...@gmail.com > Subject: [bitcoin-dev] BIP- & SLIP-0039 -- better multi-language > support > > Hello everyone, > > I just realized that BIP-0039 is language dependent. I was assuming the > other way till I looked closer. The way the seed is derived from a BIP-0039 > entropy, as is shown below, depends on which language to generate the > mnemonic sentence: > > Entropy <=> Mnemonic Sentence => PBKDF2 => BIP-0032 Seed > > Therefore when a user choose a non-English mnemonic code he or she is stuck > with that language. Meanwhile only a few native languages are supported. > > SLIP-0039 does not solve this issue in a user friendly way by providing > only an English wordlist. That's understandable as it aims to provide SSS > capability. However those users who do not speak English or recognize > English words will suffer. > > What I am trying to bring to attention of the community is that, no matter > if we make a new version of BIP-0039, or a new BIP (with SSS support), or > to enhance SLIP-0039, we really need to address this language issue. > > Here are what I propose: > > 1. The mnemonic code should be only a representation of underlying entropy > or (pre) master secret, seed, whatever. In this way, the same seed/secret > could be displayed in English or in Chinese or other languages. Then there > could be 3rd party conversion tools to support translations in case any > wallet software or device does not support all specified languages. Now it > looks like: > > Mnemonic Sentence <=> Entropy => PBKDF2 => BIP-0032 Seed > > > 2. Given that only 8 languages are supported in BIP-0039, we should allow > the seed/secret to be represented in decimal numbers, each ranging from 0 > to 2047. So those who cannot find a native language support yet having > difficulty coping words in other languages could choose to just use numbers. > > So far I don't have a preference how this should be implemented. I'd like > to hear from community first. ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
[bitcoin-dev] BIP- & SLIP-0039 -- better multi-language support
Hello everyone, I just realized that BIP-0039 is language dependent. I was assuming the other way till I looked closer. The way the seed is derived from a BIP-0039 entropy, as is shown below, depends on which language to generate the mnemonic sentence: Entropy <=> Mnemonic Sentence => PBKDF2 => BIP-0032 Seed Therefore when a user choose a non-English mnemonic code he or she is stuck with that language. Meanwhile only a few native languages are supported. SLIP-0039 does not solve this issue in a user friendly way by providing only an English wordlist. That's understandable as it aims to provide SSS capability. However those users who do not speak English or recognize English words will suffer. What I am trying to bring to attention of the community is that, no matter if we make a new version of BIP-0039, or a new BIP (with SSS support), or to enhance SLIP-0039, we really need to address this language issue. Here are what I propose: 1. The mnemonic code should be only a representation of underlying entropy or (pre) master secret, seed, whatever. In this way, the same seed/secret could be displayed in English or in Chinese or other languages. Then there could be 3rd party conversion tools to support translations in case any wallet software or device does not support all specified languages. Now it looks like: Mnemonic Sentence <=> Entropy => PBKDF2 => BIP-0032 Seed 2. Given that only 8 languages are supported in BIP-0039, we should allow the seed/secret to be represented in decimal numbers, each ranging from 0 to 2047. So those who cannot find a native language support yet having difficulty coping words in other languages could choose to just use numbers. So far I don't have a preference how this should be implemented. I'd like to hear from community first. Thanks, Weiji Guo ___ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
