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| | <pre> | | <pre> |
| − | BIP: BIP-0039 | + | BIP: 39 |
| − | Title: Mnemonic code for generating deterministic keys | + | Layer: Applications |
| − | Author: Pavol Rusnak <stick@gk2.sk> | + | Title: Mnemonic code for generating deterministic keys |
| − | Marek Palatinus <info@bitcoin.cz>
| + | Author: Marek Palatinus <slush@satoshilabs.com> |
| − | Aaron Voisine <voisine@gmail.com>
| + | Pavol Rusnak <stick@satoshilabs.com> |
| − | Status: Draft | + | Aaron Voisine <voisine@gmail.com> |
| − | Type: Standards Track | + | Sean Bowe <ewillbefull@gmail.com> |
| − | Created: 10-09-2013 | + | Comments-Summary: Unanimously Discourage for implementation |
| | + | Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0039 |
| | + | Status: Proposed |
| | + | Type: Standards Track |
| | + | Created: 2013-09-10 |
| | </pre> | | </pre> |
| | | | |
| − | ==Abstract==
| + | {{BipMoved|bip-0039.mediawiki}} |
| − | | |
| − | This BIP proposes a scheme for translating binary data (usually master seeds
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| − | for deterministic keys, but it can be applied to any binary data) into a group
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| − | of easy to remember words also known as mnemonic code or mnemonic sentence.
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| − | | |
| − | ==Motivation==
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| − | | |
| − | Such mnemonic code or mnemonic sentence is much easier to work with than working
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| − | with the binary data directly (or its hexadecimal interpretation). The sentence
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| − | could be writen down on paper (e.g. for storing in a secure location such as
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| − | safe), told over telephone or other voice communication method, or memorized
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| − | in ones memory (this method is called brainwallet).
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| − | | |
| − | ==Backwards Compatibility==
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| − | | |
| − | As this BIP is written, only one Bitcoin client (Electrum) implements mnemonic
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| − | codes, but it uses a different wordlist than the proposed one.
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| − | | |
| − | For compatibility reasons we propose adding a checkbox to Electrum, which will
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| − | allow user to indicate if the legacy code is being entered during import or
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| − | it is a new one that is BIP-0039 compatible. For exporting, only the new format
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| − | will be used, so this is not an issue.
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| − | | |
| − | ==Rationale==
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| − | | |
| − | Our proposal is inspired by implementation used in Electrum, but we enhanced
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| − | the wordlist and algorithm so it meets the following criteria:
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| − | | |
| − | a) smart selection of words
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| − | - wordlist is created in such way that it's enough to type just first four
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| − | letters to unambiguously identify the word
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| − | | |
| − | b) similar words avoided
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| − | - words as "build" and "built", "woman" and "women" or "quick" or "quickly"
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| − | not only make remembering the sentence difficult, but are also more error
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| − | prone and more difficult to guess (see point below)
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| − | - we avoid these words by carefully selecting them during addition
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| − | | |
| − | c) sorted wordlists
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| − | - wordlist is sorted which allow more efficient lookup of the code words
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| − | (i.e. implementation can use binary search instead of linear search)
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| − | - this also allows trie (prefix tree) to be used, e.g. for better compression
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| − | | |
| − | d) localized wordlists
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| − | - we would like to allow localized wordlists, so it is easier for users
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| − | to remember the code in their native language
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| − | - by using wordlists with no colliding words among languages, it's easy to
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| − | determine which language was used just by checking the first word of
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| − | the sentence
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| − | | |
| − | e) mnemonic checksum
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| − | - this leads to better user experience, because user can be notified
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| − | if the mnemonic sequence is wrong, instead of showing the confusing
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| − | data generated from the wrong sequence.
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| − | | |
| − | ==Specification==
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| − | | |
| − | <pre>
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| − | Our proposal implements two methods - "encode" and "decode".
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| − | | |
| − | The first method takes a binary data which have to length (L) in bytes divisable
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| − | by four and returns a sentence that consists of (L/4*3) words from the wordlist.
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| − | | |
| − | The second method takes sentences generated by first method (number of words in
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| − | the sentence has to be divisable by 3) and reconstructs the original binary data.
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| − | | |
| − | Words can repeat in the sentence more than one time.
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| − | | |
| − | Wordlist contains 2048 words (instead of 1626 words in Electrum), allowing
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| − | the code to compute the checksum of the whole mnemonic sequence.
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| − | Each 32 bits of input data add 1 bit of checksum.
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| − | | |
| − | See the following table for relation between input lengths, output lengths and
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| − | checksum sizes for the most common usecases:
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| − | | |
| − | +--------+---------+---------+----------+
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| − | | input | input | output | checksum |
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| − | | (bits) | (bytes) | (words) | (bits) |
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| − | +--------+---------+---------+----------+
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| − | | 128 | 16 | 12 | 4 |
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| − | | 160 | 20 | 15 | 5 |
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| − | | 192 | 24 | 18 | 6 |
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| − | | 224 | 28 | 21 | 7 |
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| − | | 256 | 32 | 24 | 8 |
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| − | +--------+---------+---------+----------+
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| − | </pre>
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| − | | |
| − | ===Algorithm:===
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| − | | |
| − | <pre>
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| − | Encoding:
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| − | 1. Read input data (I).
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| − | 2. Make sure its length (L) is divisable by 32 bits.
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| − | 3. Compute the length of the checkum (LC). LC = L/32
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| − | 4. Split I into chunks of LC bits (I1, I2, I3, ...).
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| − | 5. XOR them altogether and produce the checksum C. C = I1 xor I2 xor I3 ... xor In.
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| − | 5. Concatenate I and C into encoded data (E). Length of E is divisable by 33 bits.
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| − | 6. Keep taking 11 bits from E until there are none left.
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| − | 7. Treat them as integer W, add word with index W to the output.
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| − | | |
| − | Decoding:
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| − | 1. Read input mnemonic (M).
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| − | 2. Make sure its wordcount is divisable by 3.
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| − | 3. Figure out word indexes in a dictionary and output them as binary stream E.
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| − | 4. Length of E (L) is divisable by 33 bits.
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| − | 5. Split E into two parts: B and C, where B are first L/33*32 bits, C are last L/33 bits.
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| − | 6. Make sure C is the checksum of B (using the step 5 from the above paragraph).
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| − | 7. If it's not we have invalid mnemonic code.
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| − | 8. Treat B as binary data and return it as output.
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| − | | |
| − | </pre>
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| − | | |
| − | ==Test vectors==
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| − | | |
| − | <pre>
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| − | input: 00000000 (32 bits)
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| − | mnemonic: abandon abandon abandon (3 words)
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| − | | |
| − | input: 7f7f7f7f (32 bits)
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| − | mnemonic: legal wing taxi (3 words)
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| − | | |
| − | input: 80808080 (32 bits)
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| − | mnemonic: lethal adult bundle (3 words)
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| − | | |
| − | input: ffffffff (32 bits)
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| − | mnemonic: zoo zoo zone (3 words)
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| − | | |
| − | input: 0000000000000000 (64 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon (6 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f (64 bits)
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| − | mnemonic: legal wing taxi yard water salad (6 words)
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| − | | |
| − | input: 8080808080808080 (64 bits)
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| − | mnemonic: lethal adult bunker absurd also dog (6 words)
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| − | | |
| − | input: ffffffffffffffff (64 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo young (6 words)
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| − | | |
| − | input: 000000000000000000000000 (96 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon (9 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f (96 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge lecture (9 words)
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| − | | |
| − | input: 808080808080808080808080 (96 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lens (9 words)
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| − | | |
| − | input: ffffffffffffffffffffffff (96 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo year (9 words)
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| − | | |
| − | input: 00000000000000000000000000000000 (128 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon (12 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f (128 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge legal wing taxi worth (12 words)
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| − | | |
| − | input: 80808080808080808080808080808080 (128 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lethal adult bunker abandon (12 words)
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| − | | |
| − | input: ffffffffffffffffffffffffffffffff (128 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo worth (12 words)
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| − | | |
| − | input: 0000000000000000000000000000000000000000 (160 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon (15 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f (160 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge legal wing taxi yard water salmon winner (15 words)
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| − | | |
| − | input: 8080808080808080808080808080808080808080 (160 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd also domain abandon (15 words)
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| − | | |
| − | input: ffffffffffffffffffffffffffffffffffffffff (160 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo winner (15 words)
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| − | | |
| − | input: 000000000000000000000000000000000000000000000000 (192 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon (18 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f (192 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge legal wing taxi yard water salmon worry urge legal wave (18 words)
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| − | | |
| − | input: 808080808080808080808080808080808080808080808080 (192 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd also domain achieve aunt lethal abandon (18 words)
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| − | | |
| − | input: ffffffffffffffffffffffffffffffffffffffffffffffff (192 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wave (18 words)
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| − | | |
| − | input: 00000000000000000000000000000000000000000000000000000000 (224 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon (21 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f (224 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge legal wing taxi yard water salmon worry urge legal wing taxi yard usage (21 words)
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| − | | |
| − | input: 80808080808080808080808080808080808080808080808080808080 (224 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd abandon (21 words)
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| − | | |
| − | input: ffffffffffffffffffffffffffffffffffffffffffffffffffffffff (224 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo usage (21 words)
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| − | | |
| − | input: 0000000000000000000000000000000000000000000000000000000000000000 (256 bits)
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| − | mnemonic: abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon (24 words)
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| − | | |
| − | input: 7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f (256 bits)
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| − | mnemonic: legal wing taxi yard water salmon worry urge legal wing taxi yard water salmon worry urge legal wing taxi yard water salmon worry team (24 words)
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| − | | |
| − | input: 8080808080808080808080808080808080808080808080808080808080808080 (256 bits)
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| − | mnemonic: lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd also domain achieve aunt lethal adult bunker absurd also domain achieve abandon (24 words)
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| − | | |
| − | input: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff (256 bits)
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| − | mnemonic: zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo team (24 words)
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| − | | |
| − | input: 19458fe8dace41e60617c6667874f6be (128 bits)
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| − | mnemonic: bless cloud wheel regular tiny venue birth web grief security dignity language (12 words)
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| − | | |
| − | input: 2d8fc7c27a52995bc165a0dcead7c169f301652f0b5db145 (192 bits)
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| − | mnemonic: sketch flavor eyebrow height youth rope various pet fish little embryo arena just chicken jump mourn advance unique fork knock general slice short caught (24 words)
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| − | | |
| − | input: ea88c6efbc4028994b8b4ebc0345a474 (128 bits)
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| − | mnemonic: try educate robust joke act erosion color hedge rock blow hat tribe (12 words)
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| − | | |
| − | input: bb8e02d2c0fe4c18f60e173bc38724902395b63b1b47bf18 (192 bits)
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| − | mnemonic: river ignore recycle like tobacco armor straw season despair bosnian sibling burden defy sunset typical harvest sad shadow (18 words)
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| − | | |
| − | input: 0b57161fd701c6c6548db5a71df70166965eec2f16a675acad3ed3460cb3e72f (256 bits)
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| − | mnemonic: approach response map protect both glass fabric remember place upset satisfy slave gravity irish romance squad involve grain excuse pioneer gauge flight open white (24 words)
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| − | | |
| − | input: 666fbb72dada90d6c8f627d77450f366 (128 bits)
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| − | mnemonic: grief last swamp reject pond history car sentence stone patrol diamond slam (12 words)
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| − | | |
| − | input: 29932c2887ff2c72dd8f9cff1b7ee498119f330d1dd81659 (192 bits)
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| − | mnemonic: chunk oak another audit vendor degree iron very year surprise retreat cook blossom obey crowd riot belt slogan (18 words)
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| − | | |
| − | input: 869e2bc8286611bce2159b89c5a8a4029666dc186bbfe8756ac505a4e89f481e (256 bits)
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| − | mnemonic: magnet vacuum van exotic gear tactic march ready matrix coat chin after grief huge genuine jet travel prepare race approach evil excuse burial skirt (24 words)
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| − | | |
| − | input: d0263588b1deee8186818319515c6691 (128 bits)
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| − | mnemonic: soda country ghost glove unusual dose blouse cope bless medal block car (12 words)
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| − | | |
| − | input: 48754ef698334cf9cc5494ccca6a0294bf30224066576a7c (192 bits)
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| − | mnemonic: embrace poverty royal cope cruise lake cotton movie slam false letter chuckle venue awesome accident sing hen tight (18 words)
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| − | | |
| − | input: ee9e8ce85eadcdf0f5473d7490816d9b1335f7204e7776597ac99f9e29186364 (256 bits)
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| − | mnemonic: unlikely victory dentist round swear weapon squeeze traffic insist logo force custom create win liberty snack island skate range display thought merchant migrant nasty (24 words)
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| − | </pre>
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| − | | |
| − | ==Reference Implementation==
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| − | | |
| − | Reference implementation including wordlists is available from http://github.com/trezor/mnemonic
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