Calculating CRC with Gamma Command

[techoman]

Is anyone able to assist with clarifying & calculating the correct CRC (XX) for this Gamma Command:

020100000038F4C5DFB319879422CB61AFB1B28A 838C324A1A7D6E94BA5074A25CF4AEEECB9B44D1 9E01608F9B6D78412C6C80D42AF3AB9B94003CF9 CDXX

I believe it should be E1 however I am not sure if the CRC Tool is working properly.

[techoman]

Just a quick note that I have worked this one out.

Thanks to all those members that have helped me out.

[ladrono15]

Is anyone able to assist with clarifying & calculating the correct CRC (XX) for this Gamma Command:

020100000038F4C5DFB319879422CB61AFB1B28A 838C324A1A7D6E94BA5074A25CF4AEEECB9B44D1 9E01608F9B6D78412C6C80D42AF3AB9B94003CF9 CDXX

I believe it should be E1 however I am not sure if the CRC Tool is working properly.

xor all bytes than the result byte xor it on 0x3f , thats all

[techoman]

xor all bytes than the result byte xor it on 0x3f , thats all

Thanks for the reply

This may look simple however now I think I am lost.

"xor all bytes" ... with what??

There is a Gamma CRC calculator available and that does not seem to help either??

[michael318]

Thanks for the reply

This may look simple however now I think I am lost.

"xor all bytes" ... with what??

There is a Gamma CRC calculator available and that does not seem to help either??

where i can find that calculator??

[techoman]

Here you go.

If someone can explain how to use this properly or how to do it manually this would be much appreciated.

[ladrono15]

Here you go.

If someone can explain how to use this properly or how to do it manually this would be much appreciated.

example :
the crc in irdeto is after data
so if u know c programming or algorithms

unsigned char crc=0;//( initialize crc with 0)
for(i=0;i<ur_data_size;i++)//start a loop from 0 pos till last byte
crc^=ur_data[i]; //(crc =crc ^ ur_data[i]; xor crc on byte of pos i

now we will insert the crc byte at the end of data (so ur data size will data size +1 (1 byte of crc)

ur_data[ur_data_size]=crc^0x3f;// final task we xor the result crc on 0x3f and we save it at end of data

i think is very clear to anybody
b.r

[techoman]

Thanks Buddy

Appreciate the explanation

I do not know C Programming, but one can always learn - I just love the challenge

[Tobycat]

Can someone give an example with an actual string ?

[mdrmc]

great post if it actualy gets anywhere