#include "iso14443a.h"
#include "crapto1.h"
#include "mifareutil.h"
-
+#include "BigBuf.h"
static uint32_t iso14a_timeout;
int rsamples = 0;
-int tracing = TRUE;
uint8_t trigger = 0;
// the block number for the ISO14443-4 PCB
static uint8_t iso14_pcb_blocknum = 0;
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};
+
void iso14a_set_trigger(bool enable) {
trigger = enable;
}
-void iso14a_clear_trace() {
- uint8_t *trace = BigBuf_get_addr();
- uint16_t max_traceLen = BigBuf_max_traceLen();
- memset(trace, 0x44, max_traceLen);
- traceLen = 0;
-}
-
-void iso14a_set_tracing(bool enable) {
- tracing = enable;
-}
void iso14a_set_timeout(uint32_t timeout) {
iso14a_timeout = timeout;
+ if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
}
+
+void iso14a_set_ATS_timeout(uint8_t *ats) {
+
+ uint8_t tb1;
+ uint8_t fwi;
+ uint32_t fwt;
+
+ if (ats[0] > 1) { // there is a format byte T0
+ if ((ats[1] & 0x20) == 0x20) { // there is an interface byte TB(1)
+ if ((ats[1] & 0x10) == 0x10) { // there is an interface byte TA(1) preceding TB(1)
+ tb1 = ats[3];
+ } else {
+ tb1 = ats[2];
+ }
+ fwi = (tb1 & 0xf0) >> 4; // frame waiting indicator (FWI)
+ fwt = 256 * 16 * (1 << fwi); // frame waiting time (FWT) in 1/fc
+
+ iso14a_set_timeout(fwt/(8*16));
+ }
+ }
+}
+
+
//-----------------------------------------------------------------------------
// Generate the parity value for a byte sequence
//
ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
}
-// The function LogTrace() is also used by the iClass implementation in iClass.c
-bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag)
-{
- if (!tracing) return FALSE;
-
- uint8_t *trace = BigBuf_get_addr();
- uint16_t num_paritybytes = (iLen-1)/8 + 1; // number of valid paritybytes in *parity
- uint16_t duration = timestamp_end - timestamp_start;
-
- // Return when trace is full
- uint16_t max_traceLen = BigBuf_max_traceLen();
- if (traceLen + sizeof(iLen) + sizeof(timestamp_start) + sizeof(duration) + num_paritybytes + iLen >= max_traceLen) {
- tracing = FALSE; // don't trace any more
- return FALSE;
- }
-
- // Traceformat:
- // 32 bits timestamp (little endian)
- // 16 bits duration (little endian)
- // 16 bits data length (little endian, Highest Bit used as readerToTag flag)
- // y Bytes data
- // x Bytes parity (one byte per 8 bytes data)
-
- // timestamp (start)
- trace[traceLen++] = ((timestamp_start >> 0) & 0xff);
- trace[traceLen++] = ((timestamp_start >> 8) & 0xff);
- trace[traceLen++] = ((timestamp_start >> 16) & 0xff);
- trace[traceLen++] = ((timestamp_start >> 24) & 0xff);
-
- // duration
- trace[traceLen++] = ((duration >> 0) & 0xff);
- trace[traceLen++] = ((duration >> 8) & 0xff);
-
- // data length
- trace[traceLen++] = ((iLen >> 0) & 0xff);
- trace[traceLen++] = ((iLen >> 8) & 0xff);
-
- // readerToTag flag
- if (!readerToTag) {
- trace[traceLen - 1] |= 0x80;
- }
-
- // data bytes
- if (btBytes != NULL && iLen != 0) {
- memcpy(trace + traceLen, btBytes, iLen);
- }
- traceLen += iLen;
-
- // parity bytes
- if (parity != NULL && iLen != 0) {
- memcpy(trace + traceLen, parity, num_paritybytes);
- }
- traceLen += num_paritybytes;
-
- return TRUE;
-}
-
//=============================================================================
// ISO 14443 Type A - Miller decoder
//=============================================================================
Uart.twoBits = (Uart.twoBits << 8) | bit;
- if (Uart.state == STATE_UNSYNCD) { // not yet synced
+ if (Uart.state == STATE_UNSYNCD) { // not yet synced
- if (Uart.highCnt < 7) { // wait for a stable unmodulated signal
+ if (Uart.highCnt < 2) { // wait for a stable unmodulated signal
if (Uart.twoBits == 0xffff) {
Uart.highCnt++;
} else {
Uart.highCnt = 0;
}
} else {
- Uart.syncBit = 0xFFFF; // not set
- // look for 00xx1111 (the start bit)
- if ((Uart.twoBits & 0x6780) == 0x0780) Uart.syncBit = 7;
- else if ((Uart.twoBits & 0x33C0) == 0x03C0) Uart.syncBit = 6;
- else if ((Uart.twoBits & 0x19E0) == 0x01E0) Uart.syncBit = 5;
- else if ((Uart.twoBits & 0x0CF0) == 0x00F0) Uart.syncBit = 4;
- else if ((Uart.twoBits & 0x0678) == 0x0078) Uart.syncBit = 3;
- else if ((Uart.twoBits & 0x033C) == 0x003C) Uart.syncBit = 2;
- else if ((Uart.twoBits & 0x019E) == 0x001E) Uart.syncBit = 1;
- else if ((Uart.twoBits & 0x00CF) == 0x000F) Uart.syncBit = 0;
- if (Uart.syncBit != 0xFFFF) {
+ Uart.syncBit = 0xFFFF; // not set
+ // we look for a ...1111111100x11111xxxxxx pattern (the start bit)
+ if ((Uart.twoBits & 0xDF00) == 0x1F00) Uart.syncBit = 8; // mask is 11x11111 xxxxxxxx,
+ // check for 00x11111 xxxxxxxx
+ else if ((Uart.twoBits & 0xEF80) == 0x8F80) Uart.syncBit = 7; // both masks shifted right one bit, left padded with '1'
+ else if ((Uart.twoBits & 0xF7C0) == 0xC7C0) Uart.syncBit = 6; // ...
+ else if ((Uart.twoBits & 0xFBE0) == 0xE3E0) Uart.syncBit = 5;
+ else if ((Uart.twoBits & 0xFDF0) == 0xF1F0) Uart.syncBit = 4;
+ else if ((Uart.twoBits & 0xFEF8) == 0xF8F8) Uart.syncBit = 3;
+ else if ((Uart.twoBits & 0xFF7C) == 0xFC7C) Uart.syncBit = 2;
+ else if ((Uart.twoBits & 0xFFBE) == 0xFE3E) Uart.syncBit = 1;
+ if (Uart.syncBit != 0xFFFF) { // found a sync bit
Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
Uart.startTime -= Uart.syncBit;
Uart.endTime = Uart.startTime;
if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {
if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) { // Modulation in both halves - error
UartReset();
- Uart.highCnt = 6;
} else { // Modulation in first half = Sequence Z = logic "0"
if (Uart.state == STATE_MILLER_X) { // error - must not follow after X
UartReset();
- Uart.highCnt = 6;
} else {
Uart.bitCount++;
Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
if (Uart.len) {
return TRUE; // we are finished with decoding the raw data sequence
} else {
- UartReset(); // Nothing receiver - start over
+ UartReset(); // Nothing received - start over
+ Uart.highCnt = 1;
}
}
if (Uart.state == STATE_START_OF_COMMUNICATION) { // error - must not follow directly after SOC
UartReset();
- Uart.highCnt = 6;
+ Uart.highCnt = 1;
} else { // a logic "0"
Uart.bitCount++;
Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
LEDsoff();
- // We won't start recording the frames that we acquire until we trigger;
- // a good trigger condition to get started is probably when we see a
- // response from the tag.
- // triggered == FALSE -- to wait first for card
- bool triggered = !(param & 0x03);
-
+ iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
// Allocate memory from BigBuf for some buffers
// free all previous allocations first
BigBuf_free();
uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
// init trace buffer
- iso14a_clear_trace();
- iso14a_set_tracing(TRUE);
+ clear_trace();
+ set_tracing(TRUE);
uint8_t *data = dmaBuf;
uint8_t previous_data = 0;
bool TagIsActive = FALSE;
bool ReaderIsActive = FALSE;
- iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
// Set up the demodulator for tag -> reader responses.
DemodInit(receivedResponse, receivedResponsePar);
// Setup and start DMA.
FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
+ // We won't start recording the frames that we acquire until we trigger;
+ // a good trigger condition to get started is probably when we see a
+ // response from the tag.
+ // triggered == FALSE -- to wait first for card
+ bool triggered = !(param & 0x03);
+
// And now we loop, receiving samples.
for(uint32_t rsamples = 0; TRUE; ) {
FpgaDisableSscDma();
Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
- Dbprintf("traceLen=%d, Uart.output[0]=%08x", traceLen, (uint32_t)Uart.output[0]);
+ Dbprintf("traceLen=%d, Uart.output[0]=%08x", BigBuf_get_traceLen(), (uint32_t)Uart.output[0]);
LEDsoff();
}
.modulation_n = 0
};
+ // We need to listen to the high-frequency, peak-detected path.
+ iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
BigBuf_free_keep_EM();
// allocate buffers:
free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
// clear trace
- iso14a_clear_trace();
- iso14a_set_tracing(TRUE);
+ clear_trace();
+ set_tracing(TRUE);
// Prepare the responses of the anticollision phase
// there will be not enough time to do this at the moment the reader sends it REQA
int happened2 = 0;
int cmdsRecvd = 0;
- // We need to listen to the high-frequency, peak-detected path.
- iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
cmdsRecvd = 0;
tag_response_info_t* p_response;
CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
}
+
//-----------------------------------------------------------------------------
// Wait for commands from reader
// Stop when button is pressed (return 1) or field was gone (return 2)
// Set ADC to read field strength
AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
AT91C_BASE_ADC->ADC_MR =
- ADC_MODE_PRESCALE(32) |
- ADC_MODE_STARTUP_TIME(16) |
- ADC_MODE_SAMPLE_HOLD_TIME(8);
+ ADC_MODE_PRESCALE(63) |
+ ADC_MODE_STARTUP_TIME(1) |
+ ADC_MODE_SAMPLE_HOLD_TIME(15);
AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
// start ADC
AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
// Clear RXRDY:
uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-
+
for(;;) {
WDT_HIT();
analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
if (analogCnt >= 32) {
- if ((33000 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
+ if ((MAX_ADC_HF_VOLTAGE * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
vtime = GetTickCount();
if (!timer) timer = vtime;
// 50ms no field --> card to idle state
}
// Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
- for (i = 0; i < 2 ; ) {
+ uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;
+ for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = SEC_F;
FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
i++;
}
}
-
+
LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
return 0;
// clear RXRDY:
uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-
+
c = 0;
for(;;) {
WDT_HIT();
if(ManchesterDecoding(b, offset, 0)) {
NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
return TRUE;
- } else if (c++ > iso14a_timeout) {
+ } else if (c++ > iso14a_timeout && Demod.state == DEMOD_UNSYNCD) {
return FALSE;
}
}
// reset the PCB block number
iso14_pcb_blocknum = 0;
+
+ // set default timeout based on ATS
+ iso14a_set_ATS_timeout(resp);
+
return 1;
}
{
iso14a_command_t param = c->arg[0];
uint8_t *cmd = c->d.asBytes;
- size_t len = c->arg[1];
- size_t lenbits = c->arg[2];
+ size_t len = c->arg[1] & 0xffff;
+ size_t lenbits = c->arg[1] >> 16;
+ uint32_t timeout = c->arg[2];
uint32_t arg0 = 0;
byte_t buf[USB_CMD_DATA_SIZE];
uint8_t par[MAX_PARITY_SIZE];
if(param & ISO14A_CONNECT) {
- iso14a_clear_trace();
+ clear_trace();
}
- iso14a_set_tracing(TRUE);
+ set_tracing(TRUE);
if(param & ISO14A_REQUEST_TRIGGER) {
iso14a_set_trigger(TRUE);
}
if(param & ISO14A_SET_TIMEOUT) {
- iso14a_set_timeout(c->arg[2]);
+ iso14a_set_timeout(timeout);
}
if(param & ISO14A_APDU) {
nttmp1 = prng_successor(nttmp1, 1);
if (nttmp1 == nt2) return i;
nttmp2 = prng_successor(nttmp2, 1);
- if (nttmp2 == nt1) return -i;
+ if (nttmp2 == nt1) return -i;
}
return(-99999); // either nt1 or nt2 are invalid nonces
uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
+ if (first_try) {
+ iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+ }
+
// free eventually allocated BigBuf memory. We want all for tracing.
BigBuf_free();
- iso14a_clear_trace();
- iso14a_set_tracing(TRUE);
+ clear_trace();
+ set_tracing(TRUE);
byte_t nt_diff = 0;
uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
if (first_try) {
mf_nr_ar3 = 0;
- iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
sync_time = GetCountSspClk() & 0xfffffff8;
sync_cycles = 65536; // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
nt_attacked = 0;
LED_B_OFF();
LED_C_OFF();
-
+
+ #define DARKSIDE_MAX_TRIES 32 // number of tries to sync on PRNG cycle. Then give up.
+ uint16_t unsuccessfull_tries = 0;
+
for(uint16_t i = 0; TRUE; i++) {
+ LED_C_ON();
WDT_HIT();
// Test if the action was cancelled
if(BUTTON_PRESS()) {
+ isOK = -1;
break;
}
- LED_C_ON();
-
if(!iso14443a_select_card(uid, NULL, &cuid)) {
if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card");
continue;
nt_attacked = nt;
}
else {
- if (nt_distance == -99999) { // invalid nonce received, try again
- continue;
+ if (nt_distance == -99999) { // invalid nonce received
+ unsuccessfull_tries++;
+ if (!nt_attacked && unsuccessfull_tries > DARKSIDE_MAX_TRIES) {
+ isOK = -3; // Card has an unpredictable PRNG. Give up
+ break;
+ } else {
+ continue; // continue trying...
+ }
}
sync_cycles = (sync_cycles - nt_distance);
if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
if (nt_diff == 0 && first_try)
{
par[0]++;
+ if (par[0] == 0x00) { // tried all 256 possible parities without success. Card doesn't send NACK.
+ isOK = -2;
+ break;
+ }
} else {
par[0] = ((par[0] & 0x1F) + 1) | par_low;
}
memcpy(buf + 16, ks_list, 8);
memcpy(buf + 24, mf_nr_ar, 4);
- cmd_send(CMD_ACK,isOK,0,0,buf,28);
+ cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
// Thats it...
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LEDsoff();
- iso14a_set_tracing(FALSE);
+ set_tracing(FALSE);
}
/**
uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
uint8_t ar_nr_collected = 0;
- // free eventually allocated BigBuf memory but keep Emulator Memory
- BigBuf_free_keep_EM();
- // clear trace
- iso14a_clear_trace();
- iso14a_set_tracing(TRUE);
-
// Authenticate response - nonce
uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
if (_7BUID) {
rATQA[0] = 0x44;
rUIDBCC1[0] = 0x88;
+ rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
}
- // We need to listen to the high-frequency, peak-detected path.
- iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-
if (MF_DBGLEVEL >= 1) {
if (!_7BUID) {
Dbprintf("4B UID: %02x%02x%02x%02x",
}
}
+ // We need to listen to the high-frequency, peak-detected path.
+ iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+ // free eventually allocated BigBuf memory but keep Emulator Memory
+ BigBuf_free_keep_EM();
+
+ // clear trace
+ clear_trace();
+ set_tracing(TRUE);
+
+
bool finished = FALSE;
while (!BUTTON_PRESS() && !finished) {
WDT_HIT();
// find reader field
- // Vref = 3300mV, and an 10:1 voltage divider on the input
- // can measure voltages up to 33000 mV
if (cardSTATE == MFEMUL_NOFIELD) {
- vHf = (33000 * AvgAdc(ADC_CHAN_HF)) >> 10;
+ vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
if (vHf > MF_MINFIELDV) {
cardSTATE_TO_IDLE();
LED_A_ON();
LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
break;
}
+
uint32_t ar = bytes_to_num(receivedCmd, 4);
uint32_t nr = bytes_to_num(&receivedCmd[4], 4);
ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0);
num_to_bytes(ans, 4, rAUTH_AT);
}
+
EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
//Dbprintf("Sending rAUTH %02x%02x%02x%02x", rAUTH_AT[0],rAUTH_AT[1],rAUTH_AT[2],rAUTH_AT[3]);
cardSTATE = MFEMUL_AUTH1;
|| receivedCmd[0] == 0xB0) { // transfer
if (receivedCmd[1] >= 16 * 4) {
EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
- if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
+ if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
break;
}
if (receivedCmd[1] / 4 != cardAUTHSC) {
EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
- if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
+ if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
break;
}
}
if(ar_nr_collected > 1) {
Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
- ar_nr_responses[0], // UID
+ ar_nr_responses[0], // UID
ar_nr_responses[1], //NT
ar_nr_responses[2], //AR1
ar_nr_responses[3], //NR1
}
}
}
- if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, traceLen);
+ if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, BigBuf_get_traceLen());
+
}
// C(red) A(yellow) B(green)
LEDsoff();
// init trace buffer
- iso14a_clear_trace();
- iso14a_set_tracing(TRUE);
+ clear_trace();
+ set_tracing(TRUE);
// The command (reader -> tag) that we're receiving.
// The length of a received command will in most cases be no more than 18 bytes.
uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
- // As we receive stuff, we copy it from receivedCmd or receivedResponse
- // into trace, along with its length and other annotations.
- //uint8_t *trace = (uint8_t *)BigBuf;
-
+ iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
// free eventually allocated BigBuf memory
BigBuf_free();
// allocate the DMA buffer, used to stream samples from the FPGA
bool ReaderIsActive = FALSE;
bool TagIsActive = FALSE;
- iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
// Set up the demodulator for tag -> reader responses.
DemodInit(receivedResponse, receivedResponsePar);
projects / proxmark3-svn / blobdiff