Which of the following statements is/are TRUE about encryption techniques?
A. In symmetric key cryptography, the secrecy/protection of the key generating function must be of higher level than the decrypting function.
B. The DES technique works by taking a 64 bit chunk value and 56 bit key over a series of transformations.
C. The Twofish symmetric block algorithm works on variable key length of up to 196 bits over a block of 128 bits.
D. RC4 is the most commonly used stream cipher that encrypts & decrypts a stream of bits/bytes instead of blocks.
Choose the correct answer from the options given below:

1. AB, C Only
2. BA, D Only
3. CA, C Only
4. DB, D Only

Pick an option to check yourself, or open the answer below.