/**

@page Security_signatures Digital signatures

A digital signature is used to verify that a message (or data) actually came from the sender (the one who signed the 

message) and that it has not been tampered with.

A signature is formed by producing a fixed-length digest (@ref hash) of the message using a hash algorithm, which is then 

encrypted using the sender's private key. This signature and the message are then sent to the recipient.

The receiver can then verify the signature as follows: a @ref hash is produced of the sender's message (using the hashing 

algorithm sent with the signature); also, using the sender's public key, their signature is decrypted into a @ref hash. 

These two hashes are compared: if they are the same, it is more or less certain that the public key used for the 

@ref decryption corresponds to the private key used to create the signature, thus data integrity is validated.