KR20030070213A - Secure Webmail Sever System for providing function of isolating key management and encode/decode of mail and method thereof - Google Patents

Abstract

The present invention relates to a secure web mail server system and a method for separating mail encryption / decryption and key management, and to download a client program for encrypting / decrypting a predetermined mail written by a user to a user computer. And when a request signal for encryption / decryption for a predetermined mail is input from the user's computer, key / certificate data for performing the encryption / decryption of the mail is transmitted to the user's computer. Encryption / decryption is performed for a given mail using a key / certificate transmitted from the server.

Accordingly, the present invention intensively manages a key / certificate for performing encryption / decryption of a predetermined mail in a secure web mail server and performs encryption / decryption of the mail by performing encryption / decryption on the user's computer. It provides convenience of management of key / certificate, double encryption of communication channel, and convenience of secure web mail user by load reduction.

Description

Secure Webmail Sever System for providing function of isolating key management and encode / decode of mail and method

The present invention relates to a secure web mail server system and method for separating mail encryption / decryption and key management. More particularly, the present invention relates to the management of a key / certificate required for encryption / decryption of mail and the use of the key / certificate. The present invention relates to a secure web mail server system and method in which encryption / decryption and key management of mail, which are performed separately from execution of encryption or decryption of mail, are separated.

The Internet is a global computer network system. It is an open network that can be freely connected and used by applying a common protocol, TCP / IP, to any computer that anyone wants to access anywhere in the world. Along with the development, various services such as e-mail, file transfer, and the World Wide Web (WWW) can be used for the delivery of multimedia information.

As the use of the Internet is rapidly increasing both domestically and globally, the importance of the Internet is rapidly increasing as a strategic tool for improving efficiency and productivity in all parts of the existing industry, and new business opportunities are continuously created through the Internet. The number of service providers on the Internet is increasing.

In recent years, the exchange of personal information and important electronic documents through e-mail, such as e-mail via the Internet, has been spreading. Therefore, in the exchange of such personal information and important electronic documents, not only personal information but also documents requiring security in particular The importance of secure mail to prohibit unauthorized users from accessing documents is increasing.

Here, two types of document exchange using secure mail are classified into electronically signed mail and encrypted mail. The electronic signature mail is a personal message after each sender writes a predetermined mail. When a digital signature mail is generated and sent to a recipient by using a key, the receiver performs verification of the digital signature mail using the sender's public key included in the certificate attached to the electronic signature mail. Together with the sender's identity, the sender's identity is assured, and the recipient can confirm that the mail has not been tampered with since the mail was sent.

In addition, the encrypted mail decrypts the encrypted mail using a private key owned by the sender when the sender creates a predetermined mail and encrypts the mail using the recipient's public key, and then sends the encrypted mail to the receiver. The sender composes the mail so that only a specific recipient can check the contents of the received mail, thus ensuring that the user of another unauthorized document has not read the mail either during transmission or after arrival since the mail was created. .

The basic principle of the secure mail as described above is based on a public key encryption algorithm, and the sender can encrypt the mail using the sender's private key and can only be decrypted by using the corresponding public key. If the mail is successfully decrypted with a known public key, it can be confirmed that the mail is written by the sender who owns the private key. In addition, since the encrypted mail is encrypted using the recipient's public key, only the recipient owns the private key corresponding to the public key used for encryption, so no one can decrypt the mail.

Conventionally, in the case of a secure web mail system using the above-described public key-based encryption technology, a secure web manages encryption / decryption of a predetermined mail prepared by a sender and management of a key / certificate used when generating an encrypted mail or an electronic signature mail. By performing the mail server, the user who has not leaked personal information or other security contents even when sending the mail written by the sender to the secure web mail server using a secure communication channel, for example, SSL or TLS There was a problem accessing the document.

In addition, by performing encryption / decryption on a predetermined mail written by a sender in a secure web mail server, the ease of use is reduced based on a problem such as an increase in the load of the secure web mail server and delay in sending and receiving mail. There was this.

An object of the present invention is to solve the problem as described above, by separating the operation of the encryption / decryption for a predetermined mail and the management of the key / certificate for it, the security of the transmission mail by the secure communication channel and In addition, the present invention provides a secure webmail server system and method for separating mail encryption / decryption and key management that perform double encryption of a communication channel between a server and a client.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram schematically illustrating a configuration of a secure web mail server system in which mail encryption / decryption and key management are separated according to the present invention.

Figure 2 is a block diagram showing in detail the operation of the secure web mail server system separated from the encryption / decryption and key management of the mail for generating the secure mail according to the present invention.

Figure 3 is a flow chart illustrating in detail the operation of the secure web mail server system separated from the encryption / decryption and key management of the mail for performing the decryption of the secure mail according to the present invention.

* Explanation of symbols for main parts of the drawing

10: network communication network 20: user computer

30: secure web mail server 31: web server

32: client module 33: key / certificate manager

34: database

A secure web mail server system having separate encryption / decryption and key management of mail according to the present invention for achieving the above object, comprising: a network communication network which connects a plurality of unspecified communication lines to perform mutual data communication; A client module for encrypting / decrypting a predetermined mail input from the outside through the network communication network is stored in a predetermined storage means, and the client module is driven to request a key / certificate used for encryption / decryption of the predetermined mail. Is transmitted to the outside, the key / certificate inputted from the outside based on the request signal is received and stored in a predetermined storage means, and the key for the mail written by the user through a web browser and the mail inputted from the outside. A user computer performing encryption / decryption using a certificate / certificate; And a web server which receives predetermined general mail and secure mail data transmitted from the user computer through the network communication network, and automatically encrypts / decrypts predetermined mail when the user connects to the web server through the network communication network. A client module for automatically downloading a client program to the user computer, and a predetermined key / certificate used for encrypting / decrypting mail based on a request signal of a key / certificate of the client module downloaded to the user computer. It comprises a secure web mail server consisting of a key / certificate manager for transmitting to the database and a database for storing the key / certificate used for encryption / decryption of a predetermined mail.

According to the present invention, a method for providing a secure web mail server system in which encryption / decryption and key management of mail are separated is performed by a user, when a user connects to a web server of a secure web mail server through a network communication network. Transmitting a client program for performing / managing / decoding to a user computer; When a user writes a predetermined mail through a web browser on a user's computer and inputs a selection signal for general mail or secure mail for the mail, whether the selection signal is a selection signal for general mail or secure mail. Determining; Transmitting a predetermined mail written by a user to a web server of a secure web mail server when a selection signal of general mail is input from a user computer; If the selection signal input from the user computer is a selection signal for creating a secure mail for a predetermined mail, a client program is executed to transmit a request signal of a key / certificate for generating a predetermined type of secure mail to a secure web mail server. step; In the secure web mail server, the key / certificate request signal for creating a secure mail of the mail from the user computer through the network communication network is executed when the key / certificate manager is operated. Transmitting; Receiving the key / certificate for generating a secure mail for a predetermined mail from the user computer through the network communication network and temporarily storing the key / certificate in a predetermined storage means; Determining whether the security mail generation method selected by the user to create a security mail for a predetermined mail in the user computer is an encryption method, an electronic signature method, or an electronic signature encryption method; If the security method selected by the user in the user computer is a selection signal for an encryption method for a predetermined mail, driving an encryption module to encrypt the predetermined mail using a public key included in a recipient's certificate; ; If the security method selected by the user in the user computer is a selection signal for generating an electronic signature mail for a predetermined mail, driving an encryption module to perform the electronic signature of the predetermined mail using a sender's private key; And when the security method selected by the user in the user computer is a selection signal for an encryption method that is electronically signed for a predetermined mail, the encryption module is operated to perform the electronic signature of the predetermined mail using the sender's private key, And encrypting the predetermined mail using the public key included in the certificate.

In addition, according to the present invention, a method for providing a secure web mail server system, in which mail encryption / decryption and key management are separated, performs encryption / decryption of a mail when a user connects to a web server via a network communication network in a secure web mail server. And transmitting the managing client program to the user computer. Determining whether the mail is a normal mail or a secure mail when a predetermined mail is transmitted from the secure web mail server through the network through a user computer; Displaying contents of the mail through a web browser when the mail transmitted from the user computer through the network is general mail; If a mail transmitted from the user computer through the network communication network is a predetermined secure mail, driving a client module to transmit a request signal for a key / certificate for decrypting the secure mail to the secure web mail server; Transmitting a key / certificate to each user computer based on the request signal after driving the key / certificate manager when the key / certificate request signal is transmitted from the user computer through the network in a secure web mail server; Receiving the key / certificate for generating a secure mail for a predetermined mail from the user computer through the network communication network and temporarily storing the key / certificate in a predetermined storage means; Determining whether the security mail transmitted from the user computer is an encrypted mail, an electronic signature mail, or an electronic signed encryption mail; Performing decryption of the encrypted mail using a private key of a receiver stored in the temporary storage means when the predetermined security mail transmitted through the network communication network is a encrypted mail from a user computer; Verifying the electronic signature mail using the sender's public key included in the certificate stored in the temporary storage means when the predetermined security mail transmitted through the network communication network is a user's computer; If the predetermined security mail transmitted from the user's computer through the network communication is the encrypted mail electronically signed, the encryption module (S / MIME) is driven to use the recipient's private key included in the certificate stored in the predetermined storage means. And performing a digital signature verification on the digitally signed encrypted mail by using the sender's public key after decrypting the signed encrypted mail.

Hereinafter, a secure web mail server system and a method for separating mail encryption / decryption and key management will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically illustrating a configuration of a secure web mail server system in which mail encryption / decryption and key management are separated according to the present invention.

As shown in FIG. 1, the network communication network 10 is a communication network such as a wired / wireless internet, and connects a communication line between a user computer 20 and an operator server 30 to be described later to perform mutual data communication.

In addition, the network communication network 10 uses a communication method such as SSL (Secure Sockete Layer) or TLS (Transport Layer Security) when transmitting mail by e-mail between the user computer 20 and the secure web mail server 30 which will be described later. Form a communication channel.

When the sender / receiver of the mail inputs an encryption / decryption signal for the predetermined mail, the user computer 20 performs a predetermined secure mail, for example, an encrypted mail or the like, without installing an additional program through the network communication network 10. Automatically downloads a predetermined client program for creating and managing electronic signature mail in a plug-in method by Active-X Control and stores it in a predetermined storage means.

The user computer 20 generates a signal for a predetermined secure mail, for example, a secure mail such as an encrypted mail, an electronic signature mail, and an electronically signed encrypted mail, after the mail sender creates a mail through a web browser. When inputting the key, the client program is driven to transmit a request signal for key / certificate data for writing a predetermined secure mail to the key / certificate manager 33 of the secure web mail server 30 which will be described later.

The user computer 20 transmits the key / transmitted from the secure webmail server 30 to be described later through the network communication network 10 based on a request signal for the key / certificate data of a mail sender / receiver for creating a secure mail. The certificate data is received and stored in a predetermined storage means.

When the mail sender creates a predetermined mail using a web browser and inputs a signal for selecting an encrypted mail for the mail, the user computer 20 drives the encryption module (S / MIME) and stores it in the predetermined storage means. After encrypting using the public key included in the certificate of the mail recipient, it is transmitted to the secure web mail server 30 through the network communication network 10.

The user computer 20, when a mail sender creates a predetermined mail using a web browser and inputs a selection signal of an electronic signature mail for the mail, drives the encryption module (S / MIME) to the predetermined storage means. After performing the electronic signature using the stored mail sender's private key, the electronic signature is transmitted to the secure web mail server 30 through the network communication network 10.

When the mail sender creates a predetermined mail using a web browser and inputs a selection signal of an electronically signed encrypted mail for the mail, the user computer 20 drives the encryption module (S / MIME) to store the predetermined mail. After performing the electronic signature using the mail sender's private key stored in the means, the secured web mail server 30 stores the electronically signed encrypted mail encrypted using the public key included in the mail receiver's certificate through the network. To send).

The user computer 20 drives the encryption module S / MIME when the encrypted mail is encrypted based on the public key included in the certificate of the receiver through the network communication network 10 and stored in a predetermined storage means. Decrypt the encrypted mail using the recipient's private key.

The user computer 20 drives the encryption module (S / MIME) stored in a predetermined storage means by driving an encryption module (S / MIME) when an electronically signed electronic signature mail is input based on the sender's private key through the network communication network 10. The digital signature mail is verified using the public key included in the certificate.

When the electronically signed encrypted mail is input through the network communication network 10, the user computer 20 drives the encryption module (S / MIME) to use the private key of the recipient stored in a predetermined storage means. After the decryption of the secured e-mail, the digital signature is verified for the electronically signed secured mail using the public key included in the sender's certificate.

The secure web mail server 30, as shown in FIG. 1, includes a web server 31, a client module 32, a key / certificate manager 33, and a database (DB). More details about the components are described below.

The web server 31 of the secure web mail server 30 receives predetermined general mail and secure mail data transmitted from the user computer through the network communication network.

The client module 32 of the secure web mail server 30 allows each user to automatically download a client program for encrypting / decrypting a predetermined mail to each user's computer when the communication connection is made through the network communication network. The plug-in method is automatically downloaded to the user's computer 20.

The client module 32 of the secure web mail server 30 transmits a request signal for a key / certificate for performing encryption / decryption of a mail written by a user to the key / certificate manager 33 of the secure web mail server.

The key / certificate manager 33 of the secure web mail server 30 is used for encrypting / decrypting predetermined mail transmitted from the client module 32 downloaded to the user computer via the network communication network 10 /. Based on the certificate request signal, the predetermined key / certificate stored in the database 34 to be described later is transmitted to the user computer 20.

The database of the secure web mail server 30 stores a predetermined key / certificate data used for encrypting / decrypting a predetermined mail written by a user, for example, a certificate including a private key or a public key of a mail sender and receiver. .

The secure web mail server 30 runs a client module 32 when a user connects through the network communication network 10 to encrypt / decrypt encrypted mail and electronic signature mail written by each user. The program is automatically downloaded to the user's computer 20 by plug-in method by Active-X Control.

The secure web mail server 30 drives the web server 31 when a selection signal for writing a predetermined message from the user computer 20 is inputted, thereby generating a web browser for writing a mail through the network communication network 10. Transfer to computer 20.

The secure web mail server 30 stores, in the database 34, predetermined key / certificate data for encrypting and digitally signing mail written by each user.

The secure web mail server 30 transmits the key / certificate manager 33 when the encryption / decryption request signal for encrypted mail and electronic signature mail is input through the client program of the user computer 20 through the network communication network 10. And transmits predetermined key / certificate data to the user computer 20.

Hereinafter, an operation process of a method for providing a secure web mail server in which mail encryption / decryption and key management are separated according to the present invention will be described in detail with reference to FIGS. 2 to 3.

First, a method of providing a secure web mail server system in which encryption / decryption and key management are separated according to the present invention for encrypting a predetermined mail will be described with reference to FIG. 2. When the user communicates with the web server via the network communication network 10 to generate general mail and predetermined secure mail (S100), the secure web mail server 30 drives the client module 32 to create a predetermined user. The client program that performs and manages the encryption / decryption of the mail is automatically transmitted to the user computer 20 based on the plug-in method by Active-X Control (S101).

Subsequently, when each user composes a mail through a web browser and then transmits a selection signal for a predetermined type of mail, for example, general mail or secure mail (S102), the user computer 20 receives the input selection signal. It is determined whether one of the selection signals for the normal mail or the predetermined security mail (S103).

As a result of the determination in step S103, when the selection signal is a selection signal for creating a general mail, the user computer 20 sends a secure web through the network communication network 10 to the general mail created by each user through the web browser. The transmission is sent to the mail server 30 (S104).

As a result of the determination in step S103, if the selection signal is a selection signal for creating a predetermined security mail, the user computer 20 runs the client program to provide a key / certificate for writing the predetermined security mail for the mail. The request signal is transmitted to the secure webmail server 30 (S105).

When the key / certificate request signal for creating a secure mail of the mail is transmitted from the user computer 20 through the network communication network 10, the secure web mail server 30 drives the key / certificate manager 33 to The predetermined key / certificate data used in forming a predetermined secure mail for the mail written by the user is transmitted to the user computer 20 (S106).

When the predetermined key / certificate data used in forming a secure mail for the predetermined mail transmitted through the network communication network 10 is transmitted, the user computer 20 stores the key / certificate data in predetermined storage means. (S107).

Thereafter, after receiving a selection signal for creating a predetermined security mail input by the user, the user computer 20 determines whether the input selection signal is an encrypted mail, an electronic signature mail, or an electronic signature encrypted mail. (S108).

If the selection signal for generating the encrypted mail is input as a result of the determination in step S108, the user computer 20 drives the encryption module S / MIME to include the public key included in the certificate of the mail recipient stored in the predetermined storage means. Generate an encrypted mail using (S109).

As a result of the determination in step S108, when a selection signal for generating the electronic signature mail is input, the user computer 20 drives the encryption module S / MIME and uses the sender's private key stored in a predetermined storage means. A signature mail is generated (S110).

As a result of the determination in step S108, when a selection signal for generating an electronically signed encrypted mail is input, the user computer 20 drives the encryption module S / MIME to use the sender's private key stored in a predetermined storage means. After the digital signature is encrypted using the public key included in the certificate of the mail recipient to generate a digitally signed encrypted mail (S111).

Next, a method of providing a secure web mail server in which encryption / decryption and key management are separated according to the present invention for decrypting an encrypted mail will be described with reference to FIG. 3.

When the user communicates with the web server through the network communication network 10 for decryption of the general mail and the predetermined secure mail (S200), the secure web mail server 30 drives the client module 32 to create the predetermined user. The client program for performing the encryption / decryption of the mail and managing it is automatically transmitted to the user computer 20 based on the Plug-In method by Active-X Control (S201).

Then, when a predetermined mail is transmitted from the secure web mail server 30 through the network communication network 10 (S202), the user computer 20 determines whether the mail is a normal mail or a predetermined secure mail. (S203).

If it is determined in step S203 that the mail transmitted through the network communication network 10 is a general mail, the user computer 20 downloads the general mail through a web browser and displays it (S204).

As a result of the determination in step S203, if the mail transmitted through the network communication network 10 is a predetermined secure mail, the user computer 20 runs the client program to the key / certificate used for decrypting the secure mail. The request signal is transmitted to the secure web mail server 30 (S205).

When the key / certificate request signal for encrypting the mail is transmitted from the user computer 20 through the network communication network 10, the secure web mail server 30 drives the key / certificate manager 33 so that each user Predetermined key / certificate data for performing encryption on the created mail is transmitted to the user computer 20 (S206).

When predetermined key / certificate data for encrypting a predetermined mail transmitted through the network communication network 10 is transmitted, the user computer 20 stores the key / certificate data in predetermined storage means (S207). ).

Thereafter, the user computer determines whether the predetermined secure mail transmitted from the secure web mail server 20 through the network communication network 10 is an encrypted mail, an electronic signature mail, or an electronic signed encryption mail (S208). .

As a result of the determination in step S208, if the secure mail transmitted through the network communication network 10 is an encrypted mail, the user computer 20 drives an encryption module (S / MIME) to store the individual of the recipient stored in a predetermined storage means. The decryption of the encrypted mail is performed using the key (S209).

If the secure mail transmitted through the network communication network 910 is an electronic signature mail as a result of the determination in step S208, the user computer 20 drives an encryption module (S / MIME) to be included in a certificate stored in a predetermined storage means. The verification of the digital signature mail is performed using the sender's public key (S210).

If the secure mail transmitted through the network communication network 910 is an electronically signed encrypted mail in step S208, the user computer 20 drives the encryption module S / MIME to store the certificate stored in a predetermined storage means. After decrypting the digitally signed encrypted mail using the recipient's private key included in the digital signature, the electronic signature verification is performed on the digitally signed encrypted mail using the sender's public key (S211).

As described above, according to the secure web mail server system and method in which mail encryption / decryption and key management are separated according to the present invention, key / certificate data for performing encryption / decryption for predetermined mail in a secure web mail server. Management by intensively managing and encrypting and decrypting mail on the user's computer, and convenience of management of key / certificate that performs encryption and decryption of mail, double encryption of communication channel, and secure web by load reduction Provides the effect of increasing the convenience of the mail user.

Herein, while the present invention has been described with reference to the preferred embodiments, those skilled in the art will variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. And can be changed.

Claims (6)

A network communication network which connects a plurality of unspecified communication lines to perform mutual data communication; A client module for encrypting / decrypting a predetermined mail input from the outside through the network communication network is stored in a predetermined storage means, and the client module is driven to request a key / certificate used for encryption / decryption of the predetermined mail. Is transmitted to the outside, the key / certificate inputted from the outside based on the request signal is received and stored in a predetermined storage means, and the key for the mail written by the user through a web browser and the mail inputted from the outside. A user computer performing encryption / decryption using a certificate / certificate; And A web server that receives predetermined general mail and secure mail data transmitted from the user computer through the network communication network, and a client for automatically encrypting / decrypting a predetermined mail when the user connects to the web server through the network communication network. A client module for automatically downloading a program to the user computer, and a predetermined key / certificate used for encrypting / decrypting mail based on a request signal of a key / certificate of the client module downloaded to the user computer to the user computer. Secure web mail server consisting of a key / certificate manager to transmit and a database to store the key / certificate used when encrypting / decrypting predetermined mail. Secure web mail server system is separated from the encryption / decryption and key management of the mail, characterized in that configured to include. The method of claim 1, wherein the secure web mail server, When a user connects to a web server via the network, the client program for encrypting / decrypting mail written by each user without installing additional programs is plugged in by Active-X Control. Secure web mail server system of which encryption / decryption and key management of mail are automatically downloaded to the user's computer according to the method. The method of claim 1, wherein the secure web mail server, Encrypting / decrypting mail, characterized in that for transmitting the key / certificate stored in the database to the user computer based on a request signal of a key / certificate used for encrypting / decrypting a predetermined mail input from a client program of the user computer. And secure web mail server system with separate key management. The method according to any one of claims 1 to 3, The key / certificate of the sender / receiver used when encrypting / decrypting And private key data and public key data of the sender and receiver. Secure web mail server system with separate key encryption / decryption and key management. When the user communicates with the web server of the secure web mail server through a network communication network, transmitting a client program for performing encryption / decryption of the mail from the secure web mail server to the user computer (S101); When a user writes a predetermined mail through a web browser and inputs a selection signal for general mail or secure mail for the mail, the selection signal for the predetermined mail input by the user on the user's computer is transmitted to the general mail or the secure mail. Determining whether one of the selection signals is selected (S103); When the input selection signal is a selection signal for creating a general mail for a predetermined mail, transmitting, by the user computer, the predetermined mail written by the user to the web server of the secure web mail server through the network communication network (S104); When the input selection signal is a selection signal for creating a secure mail for a predetermined mail, a request signal of a key / certificate for generating a secure mail of a predetermined type is generated by running the client program on a user computer to a secure web mail server. Transmitting (S105); When a key / certificate request signal for creating a secure mail of a mail is transmitted from the user computer through the network communication network, a key is transmitted to each user computer based on the request signal after driving the key / certificate manager in a secure web mail server. / Transmitting a certificate (S106); Receiving, by the user computer, the key / certificate for generating a secure mail for a predetermined mail through the network communication network and temporarily storing the key / certificate in a predetermined storage means (S107); Determining whether the secure mail method selected by the user to create a secure mail for a predetermined mail in the user computer is one of an encryption method, an electronic signature method, and an electronic signed encryption method (S108); If the security method selected by the user is a selection signal for an encryption method for a predetermined mail, driving the encryption module on the user computer to encrypt the predetermined mail using a public key included in a recipient's certificate (S109). ); If the security method selected by the user is a selection signal for generating an electronic signature mail for a predetermined mail, driving the encryption module on the user computer to perform the electronic signature of the predetermined mail using a sender's private key (S110). ; And When the security method selected by the user is a selection signal for generating an electronically signed encrypted mail for a predetermined mail, the encryption module is executed on the user's computer to perform an electronic signature using the sender's private key and included in the recipient's certificate. Encrypting the predetermined e-mail using the stored public key (S111). Method for providing a secure web mail server system is separated and encrypted / decryption and key management of the mail comprising a. Transmitting a client program to a user computer to perform encryption / decryption of a mail in a secure web mail server to a user computer when the user connects to the web server through a network communication network (S201); When the predetermined mail is transmitted from the secure web mail server through the network communication network, determining whether the mail is a predetermined general mail or a secure mail (S203); If the mail transmitted through the network communication network is a predetermined general mail, displaying the content of the general mail through a web browser at the user computer (S204); If the mail transmitted through the network is a predetermined secure mail, driving a client module in the user computer to transmit a request signal for a key / certificate for decrypting the secure mail to the secure webmail server ( S205); When the key / certificate request signal is transmitted from the user computer through the network communication network, driving the key / certificate manager in a secure web mail server and transmitting the key / certificate to each user computer based on the request signal ( S206); Receiving the key / certificate for generating a secure mail for a predetermined mail from the user computer through the network communication network and temporarily storing the key / certificate in a predetermined storage means (S207); Determining whether the secure mail transmitted from the user computer is an encrypted mail, an electronic signature mail, or an electronic signed encryption mail (S208); If the predetermined security mail transmitted through the network communication network is an encrypted mail, decrypting the encrypted mail using a private key of a recipient stored in a temporary storage means in a user computer (S209); When the predetermined security mail transmitted through the network communication network is an electronic signature mail, performing digital signature verification on the electronic signature mail using a sender's public key included in a certificate stored in a temporary storage means in a user computer; (S210) and If the predetermined secure mail transmitted through the network communication network is an electronically signed encrypted mail, the encrypted mail electronically signed using the recipient's private key included in the certificate stored in the temporary storage means by running the encryption module in the user's computer. Performing digital signature verification on the digitally signed encrypted mail using the sender's public key after decrypting Method for providing a secure webmail server system, characterized in that configured to include a separate encryption / decryption and key management of the mail.