Research on transmission of technology of downward information security for wellbore trajectory control

EURASIP Journal on Information Security

Table 1 Encryption-level classification

Security level	Example	Key length
High	Private information, bank, and confidential business information	256
Normal	Private information	192
Little	Wireless information	128
Not require	Public information	No encryption

AES algorithm accepts a 128-bit plaintext, and a 128, 192, 256 for the key under the control to generate a 128-bit ciphertext. Specific operations by known round (round) a collection of steps, in which the number of rounds can be 9, 11, 13 (depending on key length). AES has a four-step operation: (1) SubBytes, (2) ShiftRows, (3) MixColumns, and (4) AddRoundKey