We do not have access to PureVPN's network infrastructure or PKI so we
cannot comment on PureVPN.
However, assuming you use a full PKI and not just PSK, if it were easy to decrypt VPN data with only the client side key all internet security would be rendered useless.
Encryption is an enormously complex subject and it is in constant development, most
normal mortals (like me) have only a basic understanding of it and we are forced to accept the situation as is, learn as much as we can and hope .. or not bother using it at all.
Here is a reasonable explanation of PKI:
http://www.techrepublic.com/article/a-beginners-guide-to-public-key-infrastructure/
Here is a more in depth look at what OpenVPN does:
OpenVPN cryptographic layer
Bhakta wroteAll the client-oxxxxx files are posted publicly online which in affect make this whole system defective
I will correct you here ...
From the link above:
OpenVPN cryptographic layer wroteIn SSL/TLS mode, an SSL session is established with bidirectional authentication (i.e. each side of the connection must present its own certificate). If the SSL/TLS authentication succeeds, encryption/decryption and HMAC key source material is then randomly generated by OpenSSL's RAND_bytes function and exchanged over the SSL/TLS connection. Both sides of the connection contribute random source material. This mode never uses any key bidirectionally, so each peer has a distinct send HMAC, receive HMAC, packet encrypt, and packet decrypt key
So each client, on a properly configured public VPN server, is unique and and their data will also be unique .: Having the client side keys shared amongst many clients still allows all clients to have individual privacy.
