There are several different types and formats dealing with the securing of documents, data and voice.
You need to choose the level of protection you feel you require.
There are low level forms known as PGP (Pretty Good Privacy), DES (Data Encryption Standard) Based on F.I.P.S (Federal Information Processing Standard), and you have tighter encrytption, known as AES, which is one of the current forms available, which relate to physical strength of the key, such as AES-256, 512 and 1024.
There are hash/sha strings to contend with, as the constant key requirement each and every time you update r change your encrypted data.
There are different protocols required with securing data, and what I have revealed, pales to the extent of the encryption algorithm that is being used.
Digital phones really do not require encryption, especially voice, but all carriers do encrypt the data channels to and from the home network, I know as the 'switch'.
Data is handled transparently to all the users of the cellular network, and you really can't tell by looking at a screen shot of a carrier's uplink or downlink signal to know what is, and what is not being secured.
This process is handled automatically.
There are no commercially available scanning receivers made that can decode a cellphone conversation, the listener would only hear raspy, digital tones and sounds, while the actual data, is being transmitted to its destination, same goes for your Email and texts. All this data is encrypted on the fly, so aside from securing your own phone from snoopy people, encryption is not actually a necessity.
Although if you are only desiring to encrypt your voice, there are several companies that offer such add-on boards to many different brands of cellphones, but for data, no issues,that is already secured from casual spies.
