The A refers to the certification on theâ¦ Airframe structure, to work on the wings, structure of the Frame or assemblies such as air vents for repairs. The P stands for Power Plant, The Certification repair for an Engine of a craft which also includes the hydraulic system.
Protocols. There are a number of VPN protocols in use that secure the transport of data traffic over a public network infrastructure. Each protocol varies slightly in the way that data is kept secure. IP security (IPSec) is used to secure communications over the Internet. IPSec traffic can use either transport mode or tunneling to encrypt data traffic in a VPN.
IPsec is an extension to the IP protocol which provides security to the IP and the upper-layer protocols. It was first developed for the new IPv6 standard and then âbackportedâ to IPv4. The IPsec architecture is described in the RFC2401. The following few paragraphs will give you a short introduction into IPsec.o derive this HMAC the IPsec protocols use hash algorithms like MD5 and SHA to calculate a hash based on a secret key and the contents of the IP datagram. This HMAC is then included in the IPsec protocol header and the receiver of the packet can check the HMAC if it has access to the secret key.