PrintAndLog("The bytes will be added with eachother and than limited with the applied mask");
PrintAndLog("Finally compute ones' complement of the least significant bytes");
PrintAndLog("");
- PrintAndLog("Usage: analyse chksum [h] b <bytes> m <mask>");
+ PrintAndLog("Usage: analyse chksum [h] [v] b <bytes> m <mask>");
PrintAndLog("Options:");
PrintAndLog(" h This help");
+ PrintAndLog(" v supress header");
PrintAndLog(" b <bytes> bytes to calc missing XOR in a LCR");
PrintAndLog(" m <mask> bit mask to limit the outpuyt");
PrintAndLog("");
return LRC;
}
-static uint8_t calcSumCrumbAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumCrumbAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++) {
sum += CRUMB(bytes[i], 0);
sum &= mask;
return sum;
}
-static uint8_t calcSumCrumbAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
- return ~calcSumCrumbAdd(bytes, len, mask);
+static uint16_t calcSumCrumbAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
+ return (~calcSumCrumbAdd(bytes, len, mask) & mask);
}
-static uint8_t calcSumNibbleAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumNibbleAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++) {
sum += NIBBLE_LOW(bytes[i]);
sum &= mask;
return sum;
}
-static uint8_t calcSumNibbleAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask){
- return ~calcSumNibbleAdd(bytes, len, mask);
+static uint16_t calcSumNibbleAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask){
+ return (~calcSumNibbleAdd(bytes, len, mask) & mask);
}
-static uint8_t calcSumCrumbXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumCrumbXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++) {
sum ^= CRUMB(bytes[i], 0);
sum &= mask;
return sum;
}
-static uint8_t calcSumNibbleXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumNibbleXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++) {
sum ^= NIBBLE_LOW(bytes[i]);
sum &= mask;
return sum;
}
-static uint8_t calcSumByteXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumByteXor( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++)
sum ^= bytes[i];
sum &= mask;
return sum;
}
-
-static uint8_t calcSumByteAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumByteAdd( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++)
sum += bytes[i];
return sum;
}
// Ones complement
-static uint8_t calcSumByteAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
- return ~calcSumByteAdd(bytes, len, mask);
+static uint16_t calcSumByteAddOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
+ return (~calcSumByteAdd(bytes, len, mask) & mask);
}
-
-
-static uint8_t calcSumByteSub( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumByteSub( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++)
sum -= bytes[i];
sum &= mask;
return sum;
}
-static uint8_t calcSumByteSubOnes( uint8_t* bytes, uint8_t len, uint32_t mask){
- return ~calcSumByteSub(bytes, len, mask);
+static uint16_t calcSumByteSubOnes( uint8_t* bytes, uint8_t len, uint32_t mask){
+ return (~calcSumByteSub(bytes, len, mask) & mask);
}
-static uint8_t calcSumNibbleSub( uint8_t* bytes, uint8_t len, uint32_t mask) {
+static uint16_t calcSumNibbleSub( uint8_t* bytes, uint8_t len, uint32_t mask) {
uint8_t sum = 0;
for (uint8_t i = 0; i < len; i++) {
sum -= NIBBLE_LOW(bytes[i]);
sum &= mask;
return sum;
}
-static uint8_t calcSumNibbleSubOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
- return ~calcSumNibbleSub(bytes, len, mask);
+static uint16_t calcSumNibbleSubOnes( uint8_t* bytes, uint8_t len, uint32_t mask) {
+ return (~calcSumNibbleSub(bytes, len, mask) & mask);
+}
+
+// BSD shift checksum 8bit version
+static uint16_t calcBSDchecksum8( uint8_t* bytes, uint8_t len, uint32_t mask){
+ uint16_t sum = 0;
+ for(uint8_t i = 0; i < len; i++){
+ sum = ((sum & 0xFF) >> 1) | ((sum & 0x1) << 7); // rotate accumulator
+ sum += bytes[i]; // add next byte
+ sum &= 0xFF; //
+ }
+ sum &= mask;
+ return sum;
+}
+// BSD shift checksum 4bit version
+static uint16_t calcBSDchecksum4( uint8_t* bytes, uint8_t len, uint32_t mask){
+ uint16_t sum = 0;
+ for(uint8_t i = 0; i < len; i++){
+ sum = ((sum & 0xF) >> 1) | ((sum & 0x1) << 3); // rotate accumulator
+ sum += NIBBLE_HIGH(bytes[i]); // add high nibble
+ sum &= 0xF; //
+ sum = ((sum & 0xF) >> 1) | ((sum & 0x1) << 3); // rotate accumulator
+ sum += NIBBLE_LOW(bytes[i]); // add low nibble
+ sum &= 0xF; //
+ }
+ sum &= mask;
+ return sum;
}
// measuring LFSR maximum length
uint8_t cmdp = 0;
uint32_t mask = 0xFFFF;
bool errors = false;
+ bool useHeader = false;
int len = 0;
memset(data, 0x0, sizeof(data));
mask = param_get32ex(Cmd, cmdp+1, 0, 16);
cmdp += 2;
break;
+ case 'v':
+ case 'V':
+ useHeader = true;
+ cmdp++;
+ break;
case 'h':
case 'H':
return usage_analyse_checksum();
//Validations
if(errors) return usage_analyse_checksum();
- PrintAndLog(" add | sub | add 1's compl | sub 1's compl | xor");
- PrintAndLog("byte nibble crumb | byte nibble | byte nibble cumb | byte nibble | byte nibble cumb");
- PrintAndLog("------------------+-------------+------------------+-----------------+--------------------");
- PrintAndLog("0x%02X 0x%02X 0x%02X | 0x%02X 0x%02X | 0x%02X 0x%02X 0x%02X | 0x%02X 0x%02X | 0x%02X 0x%02X 0x%02X",
+ if (useHeader) {
+ PrintAndLog(" add | sub | add 1's compl | sub 1's compl | xor");
+ PrintAndLog("byte nibble crumb | byte nibble | byte nibble cumb | byte nibble | byte nibble cumb | BSD |");
+ PrintAndLog("------------------+-------------+------------------+-----------------+--------------------");
+ }
+ PrintAndLog("0x%X 0x%X 0x%X | 0x%X 0x%X | 0x%X 0x%X 0x%X | 0x%X 0x%X | 0x%X 0x%X 0x%X | 0x%X 0x%X |\n",
calcSumByteAdd(data, len, mask)
, calcSumNibbleAdd(data, len, mask)
, calcSumCrumbAdd(data, len, mask)
, calcSumByteXor(data, len, mask)
, calcSumNibbleXor(data, len, mask)
, calcSumCrumbXor(data, len, mask)
+ , calcBSDchecksum8(data, len, mask)
+ , calcBSDchecksum4(data, len, mask)
);
return 0;
}