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https://github.com/RfidResearchGroup/proxmark3.git
synced 2024-09-21 07:46:12 +08:00
calculate signal periods
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2248eadc7f
commit
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@ -38,7 +38,7 @@ inline uint32_t GetGraphBuffer(uint32_t indx) {
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return g_GraphBuffer[indx] + 128;
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}
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static uint32_t TexkomSearchStart(uint32_t indx, uint8_t threshold) {
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static uint32_t TexkomSearchStart(uint32_t indx, uint32_t threshold) {
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// one bit length = 27, minimal noise = 60
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uint32_t lownoisectr = 0;
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for (uint32_t i = indx; i < g_GraphTraceLen; i++) {
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@ -56,6 +56,26 @@ static uint32_t TexkomSearchStart(uint32_t indx, uint8_t threshold) {
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return 0;
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}
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static uint32_t TexkomSearchLength(uint32_t indx, uint32_t threshold) {
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// one bit length = 27, minimal noise = 60
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uint32_t lownoisectr = 0;
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uint32_t datalen = 0;
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for (uint32_t i = indx; i < g_GraphTraceLen; i++) {
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if (lownoisectr > 60) {
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break;
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} else {
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if (GetGraphBuffer(i) > threshold) {
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lownoisectr = 0;
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datalen = i - indx + 27;
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} else {
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lownoisectr++;
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}
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}
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}
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return datalen;
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}
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static uint32_t TexkomSearchMax(uint32_t indx, uint32_t len) {
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uint32_t res = 0;
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@ -70,6 +90,22 @@ static uint32_t TexkomSearchMax(uint32_t indx, uint32_t len) {
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return res;
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}
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static bool TexkomCorrelate(uint32_t indx, uint32_t threshold) {
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if (indx < 2 || indx + 2 > g_GraphTraceLen)
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return false;
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uint32_t g1 = GetGraphBuffer(indx - 2);
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uint32_t g2 = GetGraphBuffer(indx - 1);
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uint32_t g3 = GetGraphBuffer(indx);
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uint32_t g4 = GetGraphBuffer(indx + 1);
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uint32_t g5 = GetGraphBuffer(indx + 2);
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return (
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(g3 > threshold) &&
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(g3 >= g2) && (g3 >= g1) && (g3 > g4) && (g3 > g5)
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);
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}
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static int CmdHFTexkomReader(const char *Cmd) {
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CLIParserContext *ctx;
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CLIParserInit(&ctx, "hf texkom reader",
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@ -107,14 +143,38 @@ static int CmdHFTexkomReader(const char *Cmd) {
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if (sindx == 0 || sindx > samplesCount - 5)
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break;
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uint32_t slen = TexkomSearchLength(sindx, TEXKOM_NOISE_THRESHOLD);
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if (slen == 0)
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continue;
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uint32_t maxlvl = TexkomSearchMax(sindx, 1760);
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if (maxlvl < TEXKOM_NOISE_THRESHOLD) {
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sindx += 1700;
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continue;
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}
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PrintAndLogEx(WARNING, "--- indx: %d, max: %d", sindx, maxlvl);
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uint32_t noiselvl = maxlvl / 5;
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if (noiselvl < TEXKOM_NOISE_THRESHOLD)
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noiselvl = TEXKOM_NOISE_THRESHOLD;
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PrintAndLogEx(WARNING, "--- indx: %d, len: %d, max: %d, noise: %d", sindx, slen, maxlvl, noiselvl);
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uint32_t implengths[256] = {};
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uint32_t implengthslen = 0;
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uint32_t impulseindx = 0;
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uint32_t impulsecnt = 0;
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for (uint32_t i = 0; i < slen; i++) {
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if (TexkomCorrelate(sindx + i, noiselvl)) {
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impulsecnt++;
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if (impulseindx != 0) {
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if (implengthslen < 256)
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implengths[implengthslen++] = sindx + i - impulseindx;
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}
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impulseindx = sindx + i;
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}
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}
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PrintAndLogEx(WARNING, "--- impulses: %d, lenarray: %d, [%d,%d]", impulsecnt, implengthslen, implengths[0], implengths[1]);
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}
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