Home >  Support >  Online Manual >  How to use AEP PRO >  File Encryption - PKI Mode >  About public key infrastructure

About public key infrastructure

Since 4.0.0 version was released, it is possible to use RSA for files encryption in AEP PRO.

What is PKI?

Public-key infrastructure (PKI) is the combination of software, encryption technologies, and services that enables enterprises to protect the security of their communications and business transactions on the Internet.

Public key cryptography is a type of cryptography (a process of creating and deciphering communications to keep them secure) that uses a -key pair- to securely encrypt and decrypt messages. One key is used to encrypt a message and the other key decrypts the message. One key is kept secret and is referred to as the private key while the other is made available to others and is called the public key since anyone can access this key. These keys are large mathematically-related numbers derived from algorithms that form a unique pair. Either key may be used to encrypt a message, but only the other corresponding key is used to decrypt the message.


What is RSA algirithm?

RSA is a Public Key (asymmetric) cryptosystem that offers both encryption and digital signatures (authentication). RSA was developed in 1977 and is named after the three developers of the technology—Ron Rivest, Adi Shamir, and Leonard Adleman.

Public Key encryption is based on two mathematically related keys that are generated together. Each key in the pair performs the inverse function of the other so what one key encrypts, the other key decrypts, and vice versa. Because each key only encrypts or decrypts in a single direction, Public Key encryption is also known as asymmetric encryption.

A Public Key system has two keys: one of the keys in the pair is made publicly available (thus the term "Public Key encryption"), and the other is kept private, either on a hardware token such as a smart card, or hidden in software that performs the cryptographic functions on your computer (typically secured with a password).

Encryption and authentication take place without any sharing of Private Keys: each person uses only another's Public Key or their own Private Key. Anyone can send an encrypted message or verify a signed message, but only someone in possession of the correct Private Key can decrypt or sign a message.


What is a digital envelope?

The digital envelope involves transmitting a file that has been encrypted using secret key (symmetric) cryptography combined with an encrypted secret key that usually has been encrypted using Public Key (asymmetric) cryptography. (Public Key cryptography is not always necessary, such as in cases where both parties already know the secret key.)

Not only do digital envelopes help solve the key management/key transfer problem, they increase performance (relative to using a Public Key system for direct encryption of message data) without sacrificing security. The increase in performance is obtained by using the more efficient symmetric encryption to encrypt the potentially large and variably sized amount of message data, while the less efficient asymmetric cryptography is reserved only for encryption of the symmetric keys.

Generally speaking, secret key cryptosystems are much faster than Public Key cryptosystems


Advanced Encryption Package Professional uses technology of "digital envelope". It combines the reliability and speed of symmetric encryption algorithms (AES, Twofish and etc) and convenience of PKI infrastructure (RSA).

AEP PRO uses RSA algorithm to generate PKI Keys. It can generate and use keys: 512, 768, 1024 and 2048 bit.

An unique feature of AEP is ability to protect use of private key by password. I.e. in other words, private key file can also be encrypted. And in case, if private key file was stolen, it cannot be used by another person because the key was encrypted using strong cryptography.

Back to the Table of Contents

Looking for best File Encryption Software?

Are you looking for strong file encryption software, with tons of features, easy to use, constantly improved?

Advanced Encryption Package 2017- is the software you are looking for. Just try it!

Read More

Read more about all program features.


Look How to use file encryption software (in screenshots).

Free Download

Download evaluation version and try it free for 30 days!

Christmas and New Year Savings!

Christmas and New Year Savings!

Get 25% discount on AEP PRO until January 10, 2013.

Complete protection offer

Self Defence Package

3 product bundle (CD Encryption + USB Encryption + File Encryption + Drive Encryption) at a special price


Subscribe to our Newsletter.

Get notified about new products releases, new significant updates of existing products. Be first to know about short season's discounts and special offers.


Great tool to help make things just a little easier

Advanced Encryption Package Professional is a tool that can ease some of the pain of working with encrypted messages and files.