The level of security of digital operations depends on how careful you are and on the medium where the digital certificate holder keeps his private key.
A digital certificate represents a unique connection between the certificate holder and the public key. The certificate includes all basic data on the holder and the public key.
The basic function of a digital signature is in proving the identity of electronic document signer and ensuring the integrity of data or protection against changing the content of e-documents.
Smart cards / USB keys are currently the most secure technology for storing qualified digital certificates.
Encrypting or encoding is the process of converting readable text (fair copy) into crypted text (secret copy) that is very hard or impossible to read without the proper key. Decripting is the process of converting the encoded text into readable form.
Every holder of a qualified digital certificate has a pair of keys, a private and a public key. The private key enables you to create a digital signature that is unigue for every owner, the public key is available to everyone.