Encryption algorithms are used to secure digital transmissions, but what are they? Encryption algorithms are complex mathematical equations that use a number called a key to change the data before transmission. In order to decrypt the transmission, the decoder must use the same key that was used to encrypt the transmission. The decoder will reverse the calculations of the encoder and, if the key is the same, recover the original data. With a good encryption algorithm, if any one bit changes in the original data, at least 50% of the bits will change after encryption. Therefore, one bit changing in the counter can make the encrypted transmission look completely different from the previous encrypted transmission. Further, encryption algorithms are non-linear. The counter is linear, going from 1 to 2 to 3, etc. Non-linear encryption means that there is no way to predict what the next result will be given any number of previous results. These two elements mean that the encrypted portion of a transmission will appear random to an outsider.