They lend their name to the Apennine peninsula which forms the major part of Italy. The mountains are mostly green and wooded, although one side of the highest peak, Corno Grande (2,912 m), is partially covered by the southernmost glacier in Europe.
Decryption is the process of converting ciphertext back to plaintext. To encrypt more than a small amount of data, symmetric encryption is used. A symmetric key is used during both the encryption and decryption processes.
In the case of servers or software systems, a random key is generated. In Kerberos, users are known as principals. The KDC has a database of principals and their secret keys which is uses to perform authentication. In Kerberos knowledge of the secret key is considered sufficient for proof of identity.