# Using Scrambler **URL:** \ **Category:** GNU Radio\ **Created:** [December 23, 2014, 10:49am UTC](https://www.ruby-forum.com/t/using-scrambler/233545 "2014-12-23T10:49:57Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [December 23, 2014, 10:49am UTC](https://www.ruby-forum.com/t/using-scrambler/233545/1 "2014-12-23T10:49:57Z")
Hi,I want to use the scrambling polynomial: 1 + X^12 + X^17. This means the currentlytransmitted bit is the EXOR of the current data bit, plus the bits thatwere transmitted 12 and 17 bits earlier.But I’m not sure what are the suitable values for Mask and Seed for the gnuradio Scramble Block.Any help will be appreciated. ThanksDaniel ---
**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\ **Post date:** [January 16, 2015, 1:22pm UTC](https://www.ruby-forum.com/t/using-scrambler/233545/2 "2015-01-16T13:22:06Z")
Hi again, a question on the same subject. Gnuradio has 2 blocks for scrambling “Scrambler” and “Additive Scrambler” but only one block for descrambling.I suppose the “Descrambler” grc block corresponds to the “Scrambler” block.How can I descramble messages that are scrambled with the “Additive Scrambler” block?Do I have to write my own block? Thank youDaniel ``` On Tuesday, December 23, 2014 11:48 AM, Daniel B. ``` [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi,I want to use the scrambling polynomial: 1 + X^12 + X^17. This means the currentlytransmitted bit is the EXOR of the current data bit, plus the bits thatwere transmitted 12 and 17 bits earlier.But I’m not sure what are the suitable values for Mask and Seed for the gnuradio Scramble Block.Any help will be appreciated. ThanksDaniel