/** * This file is part of the TREZOR project, https://trezor.io/ * * Copyright (c) SatoshiLabs * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include "slip39.h" #include <stdio.h> #include <string.h> #include "slip39_wordlist.h" /** * Returns word at position `index`. */ const char* get_word(uint16_t index) { if (index >= WORDS_COUNT) { return NULL; } return slip39_wordlist[index]; } /** * Finds the index of a given word. * Returns true on success and stores result in `index`. */ bool word_index(uint16_t* index, const char* word, uint8_t word_length) { uint16_t lo = 0; uint16_t hi = WORDS_COUNT; uint16_t mid = 0; while ((hi - lo) > 1) { mid = (hi + lo) / 2; if (strncmp(slip39_wordlist[mid], word, word_length) > 0) { hi = mid; } else { lo = mid; } } if (strncmp(slip39_wordlist[lo], word, word_length) != 0) { return false; } *index = lo; return true; } /** * Returns the index of the first sequence in words_button_seq[] which is not * less than the given sequence. Returns WORDS_COUNT if there is no such * sequence. */ static uint16_t find_sequence(uint16_t sequence) { if (sequence <= words_button_seq[0].sequence) { return 0; } uint16_t lo = 0; uint16_t hi = WORDS_COUNT; while (hi - lo > 1) { uint16_t mid = (hi + lo) / 2; if (words_button_seq[mid].sequence >= sequence) { hi = mid; } else { lo = mid; } } return hi; } /** * Returns a word matching the button sequence prefix or NULL if no match is * found. */ const char* button_sequence_to_word(uint16_t sequence) { if (sequence == 0) { return slip39_wordlist[words_button_seq[0].index]; } uint16_t multiplier = 1; while (sequence < 1000) { sequence *= 10; multiplier *= 10; } uint16_t i = find_sequence(sequence); if (i >= WORDS_COUNT || words_button_seq[i].sequence - sequence >= multiplier) { return NULL; } return slip39_wordlist[words_button_seq[i].index]; } /** * Calculates which buttons on the T9 keyboard can still be pressed after the * prefix was entered. Returns a 9-bit bitmask, where each bit specifies which * buttons can be pressed (there are still words in this combination). The least * significant bit corresponds to the first button. * * Example: 110000110 - second, third, eighth and ninth button still can be * pressed. */ uint16_t slip39_word_completion_mask(uint16_t prefix) { if (prefix >= 1000) { // Four char prefix -> the mask is zero. return 0; } // Determine the range of sequences [min, max), which have the given prefix. uint16_t min = prefix; uint16_t max = prefix + 1; uint16_t divider = 1; while (max <= 1000) { min *= 10; max *= 10; divider *= 10; } divider /= 10; // Determine the range we will be searching in words_button_seq[]. min = find_sequence(min); max = find_sequence(max); uint16_t bitmap = 0; for (uint16_t i = min; i < max; ++i) { uint8_t digit = (words_button_seq[i].sequence / divider) % 10; bitmap |= 1 << (digit - 1); } return bitmap; }