AES-256-CBC Encryption

AES-256-CBC Encryption Algorithm

AES-256-CBC Encryption Algorithm

AES-256-CBC (Cipher Block Chaining), the algorithm used to encrypt user data, is a standard cipher implemented by the United States government and other government agencies around the world to protect classified data. With proper implementation and a sufficiently strong Encryption Key (derived from the user’s Master Password), the AES-256-CBC algorithm is considered unbreakable. AES-256-CBC is an encryption system that uses the AES specification, a 256-bit key

K

, and operates in CBC mode. The input data is padded and divided into fixed-length blocks

P_i

, where

For block $P_1$ , perform an $XOR$ operation with $P_1$ and the initialization vector $VI$ : $PP_1 = P_1 \oplus VI$
Encrypt the result $PP_1$ from step 1 using $AES$ with key $K$ : $C_1 = AES_E(PP_1, K)$
From block $P_2$ onward, $P_i$ is $XOR$ -ed with the encrypted result of the previous block: $PP_i = P_i \oplus C_{i-1}$ $C_i = AES_E(PP_i, K)$
The encrypted blocks $C_i$ are concatenated to form the final encrypted data: $C = C_1 \| C_2 \| ...$

The decryption process occurs in reverse, where the encrypted data

C

is divided into blocks

C_i

Decrypt block $C_1$ using $AES$ with key $K$ : $PP_1 = AES_D(C_1, K)$
Perform an $XOR$ operation with $PP_1$ and the initialization vector $VI$ to recover the original data block $P_1$ : $P_1 = PP_1 \oplus VI$
From block $C_2$ onward, $PP_i$ is $XOR$ -ed with the decrypted data of the previous block: $PP_i = AES_D(C_i, K)$ $P_i = PP_i \oplus C_{i-1}$
The decrypted data blocks $P_i$ are concatenated to reconstruct the original data: $P = P_1 \| P_2 \| ...$

Zero-Knowledge Encryption Password-based Key Derivation Function 2 (PBKDF2)

Introduction

Security Fundamentals

Encryption and Decryption

Data Sharing