The fastest way to unlock this achievement is to make 20 ciphers. To unlock the cipher blueprint you must go to the market place and purchase it. It is under Equipment>Gear>Cipher Blueprint. To make a cipher it requires 400 ferrite and 400 salvage. The best missions to grind salvage are:
Olympus (Defense Mission) in Mars has a high drop rate of Salvage. The endless defense mission has a higher concentration of mobs and also contains a high amount of storage containers and lockers, which also have a chance to drop Salvage.
Carme (Capture) on Jupiter has a very high chance to drop salvage, average of 2000 a run if you loot all of the containers and lockers.
Io and Callisto (Defense Mission) in Jupiter also have a very high drop rate of salvage. Approx. 800 - 900 after each run. (wave 5)
The best missions to grind ferrite are:
Apollodorus on Mercury, about 1,000 ferrite for every 5 minutes.
Eurasia (in Earth, Interception) 700 - 1,000 drop.
It takes 1 minute to craft
EDIT:
Bowmanx4587 says it is quicker to make team heal restores and requires less materials. I havent played in ages so i cant say how good it is, but try it first anyway