[macOS] Beta Test: Perfect Privacy VPN Software


New Member
GCM and CBC modes internally work quite differently; they both involve a block cipher and an exclusive-or, but they use them in different ways.

In CBC mode, you encrypt a block of data by taking the current plaintext block and exclusive-oring that wth the previous ciphertext block (or IV), and then sending the result of that through the block cipher; the output of the block cipher is the ciphertext block.
CBC has an IV and thus needs randomness every time a message is encrypted, changing a part of the message requires re-encrypting everything after the change, transmission errors in one ciphertext block completely destroy the plaintext and change the decryption of the next block, decryption can be parallelized / encryption can't, the plaintext is malleable to a certain degree

GCM mode provides both privacy (encryption) and integrity. To provide encryption, GCM maintains a counter; for each block of data, it sends the current value of the counter through the block cipher. Then, it takes the output of the block cipher, and exclusive or's that with the plaintext to form the ciphertext.
GCM is a very fast but arguably complex combination of CTR mode and GHASH, a MAC over the Galois field with 2^128 elements.

CBC provides confidentiality, but it does not protect against accidental modification or malicious tampering. In contrario GCM offers the integral and authentic transfer of data.

IMHO CGM is different but better than CBC.


New Member
@PP Simon Thanks for the replies!

I'm using High Sierra, but with the updates today, it still doesn't work.

How/where do you want me to send these log file?


New Member
I am confused - I can chain several servers/countires/cities but then I can also chose to enable cascading mode in Preferences. How do those two differ? On top of that I can also chose to have NeuroRouting enabled via the website account panel, bit confusing it all, is there an easy writeup taking those three options into account?