JPH1127311A - Information processing unit, electronic mail method and medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the security by employing the information processing unit provided with plural encryption means where kinds and contents of encryption differ from each other and selecting any of plural the encryption means based on an information content described in a header part of an electronic mail for encryption of a main text of the electronic mail being a transmission object. SOLUTION: Base addresses for plural kinds of encryption programs are stored in an encryption system entry table in an ROM 2. An MPU 1 extracts a character code stream in a SUBJECT column of header information of an electronic mail generated in an RAM 3, then acquires a base address for the encryption system entry table and generates a storage address of an encryption program by adding lower 2 digits of a sum of the character code stream to the base address. Then the encryption program corresponding to the storage address is acquired from the ROM 2 to encrypt main text information of the electronic mail generated in the RAM 3. Thus, decoding of the encrypted text is made difficult to enhance the security.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus, and more particularly, to transmitting and receiving electronic mail between a character processing apparatus and a network server of a local area network (LAN) to add security to the electronic mail. The present invention relates to an information processing apparatus, an e-mail method, and a recording medium.

[0002]

2. Description of the Related Art In recent years, with the progress of character processing technology, communication technology, and information processing technology, various information processing devices such as a word processor and a personal computer have been required to transmit and receive e-mail via a local area network (LAN). Is becoming possible.

Further, in order to prevent eavesdropping of e-mails, the e-mail is transmitted after the body area is encrypted, and the e-mail is decrypted and read on the receiving side. The general method was limited to the above method.

[0004]

In the conventional example, since there is only one encryption method, when the eavesdropping side decrypts, if one decryption key is found, all e-mails will be eavesdropped thereafter, and the decryption will be performed. In such a case, a plurality of samples can be easily obtained, so that there is a problem that a decryption keyword can be easily found. Therefore, an object of the present invention is to provide an information processing apparatus, an e-mail method, and a recording medium that further improve security.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an information processing apparatus capable of encrypting the text of an electronic mail and transmitting the encrypted text to another apparatus. A plurality of encrypting means, each of which is capable of encrypting a text and having different types of encryption, and one of the plurality of encrypting means being transmitted based on information content described in a header portion of the e-mail. Selecting means for selecting the body of the e-mail for encryption.

According to a second aspect of the present invention, in the information processing apparatus according to the first aspect, the selecting means determines a sum of the character codes described in a specific field of the header section by using one of the plurality of encrypting means. It is characterized as a determinant for selection.

According to a third aspect of the present invention, in the information processing apparatus according to the first aspect, the selecting means determines the number of characters of a character code described in a specific field of the header part by using one of the plurality of encrypting means. It is characterized as a determinant for selection.

According to a fourth aspect of the present invention, in the information processing apparatus according to the first aspect, the selecting means determines the number of mail addresses described in a specific field of the header section by using one of the plurality of encrypting means. It is characterized as a determinant for selection.

According to a fifth aspect of the present invention, in the information processing apparatus according to the first aspect, the plurality of encryption units have storage units for storing a plurality of encryption programs, and the selection unit includes the header unit. The storage address of the storage means is determined from the information content described in the section.

According to a sixth aspect of the present invention, in an information processing apparatus capable of receiving an encrypted body of an electronic mail from another apparatus and decrypting the body, the body of the electronic mail encrypted by a corresponding encryption method is provided. And a plurality of decrypting means each having a different type of decryption, and one of the plurality of decrypting means serving as a transmission target based on information content described in a header portion of the e-mail. Selecting means for selecting for decrypting the body of the electronic mail.

According to a seventh aspect of the present invention, in the information processing apparatus according to the sixth aspect, the selecting means determines a sum of the character codes described in a specific column of the header section as one of the plurality of decoding means. It is characterized as a determinant for selection.

According to an eighth aspect of the present invention, in the information processing apparatus according to the sixth aspect, the selecting means determines the number of characters of a character code described in a specific field of the header section by using one of the plurality of decoding means. It is characterized as a determinant for selection.

According to a ninth aspect of the present invention, in the information processing apparatus according to the sixth aspect, the selecting means determines the number of e-mail addresses described in a specific column of the header section by using one of the plurality of decoding means. It is characterized as a determinant for selection.

According to a tenth aspect of the present invention, in the information processing apparatus according to the sixth aspect, the plurality of decoding units have a storage unit for storing a plurality of decoding programs, and the selecting unit includes the header unit. The storage address of the storage means is determined from the information content described in the section.

According to an eleventh aspect of the present invention, the body of the e-mail is encrypted by the first information processing apparatus, and the e-mail whose body is encrypted is transmitted from the first information processing apparatus to the second information processing apparatus. In the electronic mail method for decrypting the text encrypted by the second information processing device, the first information processing device can encrypt the text of the email, The second information processing apparatus has a plurality of encryption units each having different contents, and the second information processing apparatus is capable of decrypting the body of the e-mail, and has a plurality of decryption units each having a different decryption type content. The first information processing device selects one of the plurality of encrypting means for encrypting the text of the electronic mail to be transmitted based on the information content described in the header of the electronic mail. , The selected encryption means And send more encrypting the text,
The second information processing device selects one of the decryption means for decrypting the text of the received e-mail based on the information content described in the header portion of the received e-mail, The e-mail body is decrypted by the decrypting means.

According to a twelfth aspect of the present invention, in the electronic mail method according to the eleventh aspect, the sum total of the character codes described in the specific field of the header portion is converted into one of the plurality of encryption means and the plurality of decryption means. It is characterized in that it is used as a determinant for selecting one of the conversion means.

According to a thirteenth aspect of the present invention, in the electronic mail method according to the eleventh aspect, the number of characters of the character code described in the specific field of the header part is set to one of the plurality of encrypting means.
And one of the plurality of decoding means as a determining element.

According to a fourteenth aspect of the present invention, in the electronic mail method according to the eleventh aspect, the number of the mail addresses described in the specific field of the header portion is determined by one of the plurality of encrypting means and the plurality of decryption means. It is characterized in that it is used as a determinant for selecting one of the conversion means.

According to a fifteenth aspect of the present invention, in the electronic mail method according to the eleventh aspect, the plurality of encrypting means include storage means for storing a plurality of encrypting programs, and the first information processing apparatus Determines the storage address of the storage means from the information content described in the header section.

According to a sixteenth aspect of the present invention, in the electronic mail method according to the eleventh aspect, the plurality of decryption units have storage units for storing a plurality of decryption programs, and the second information processing apparatus is provided. Determining the storage address of the storage means from the information content described in the header section.

The invention of claim 17 is the invention of claims 1 to 1
The information processing apparatus according to any one of claims 1 to 3, wherein a program capable of executing the function of the information processing apparatus by a computer is recorded.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a system configuration of a character processing apparatus according to the present invention. In FIG. 1, reference numeral 0 denotes a character processing device.

The character processing device 0 has components described below. That is, the character processing device 0 executes the control of the entire device, the MPU 1 that performs the encryption and decryption of an e-mail described later, the system program of the device,
ROM2 which is a storage area of a flowchart described later
(Read only memory), a RAM (random access memory) 3, which is a work area for temporarily storing a header area and a body area of an e-mail to be described later, and storing calculation data for calculation and comparison, and a character processing device 0. FD (Floppy Disk) 4 for storing created documents, e-mails, etc., KB (keyboard) for inputting documents, header information of e-mails, text area information, and giving operation instructions 7, a CRT (display device) 5 for displaying a document, e-mail or the like input by a user, and a NIC (network interface card) 6 for connecting the character processing device 0 to a local area network. ing.

The communication cable 9 for the local area network uses a communication cable called Ethernet. The Ethernet cable 9 is connected to several mail servers that spool the mail of the character processing device 0, several network terminals with which the character processing device communicates, and the like.

FIG. 2 shows the configuration of the system program of the character processing device 0 developed on the RAM 3. In FIG.
Reference numeral 11 denotes a network system program (hereinafter, referred to as a network system program), which monitors the status of the entire processing related to network communication of the character processing apparatus.
It manages transmission and reception of e-mails, and manages the processing of encryption and decryption of e-mails described later.

Reference numeral 12 denotes an e-mail transmission program, which performs a series of processes for transmitting an e-mail, such as creation of an e-mail to be transmitted, designation of a destination address, and management of encryption, and status management. Reference numeral 13 denotes a header information creation program, which performs a series of processes for creating a header portion required when sending an e-mail, and performs state monitoring. In the present embodiment, an encryption method described later is determined based on header information (data, subject, cc, etc. described later) created by a header information creation program.

Reference numeral 14 denotes a text region creation program for creating a text in the text region of the mail to be transmitted, managing data, and the like. Reference numeral 15 denotes a mail transmission program which performs basic processing when sending an e-mail, status monitoring, and the like. Reference numeral 16 denotes an encrypted mail transmission program. When an encryption instruction is issued by the mail transmission program 15, a series of mail encryption processing, status management, and the like are performed.

Reference numeral 17 denotes an encryption method determination program which determines an encryption method based on the header information created by the header information creation program 13. A text region encryption program 18 encrypts the text in the text region created by the text region creation program 14 in accordance with the encryption method determined by the encryption method determination program 16.

An e-mail receiving program 19 performs a series of operations for receiving an e-mail, such as creation of a received e-mail list, reception of an e-mail, management of e-mail decryption, and status management. A received mail decryption program 20 performs a series of decryption processing, state management, and the like when the received mail is encrypted. Reference numeral 22 denotes a decryption method determination program, which determines a decryption method based on the header information of the e-mail received by the e-mail reception program 19. Reference numeral 21 denotes a text region decryption program which decrypts the text in the text region of the e-mail received by the e-mail reception program 19 based on the decryption method determined by the decryption method determination program 22.

FIG. 3 shows a schematic functional block diagram of the processing of the present embodiment having the above configuration. FIG. 3 shows a processing function of the MPU 1 that performs a process according to the control procedure of the system program developed in the RAM 3.

The functions described below are realized by the MPU 1 executing the program described in FIG. FIG.
First, the e-mail transmitting side and the e-mail transmitting means 30 perform well-known basic operations, state monitoring, and the like when transmitting an e-mail.

The e-mail header information creating means 31 transfers control to this means when an instruction to create header information is issued by the e-mail sending means 30 and sends TO: (after that) as the header information of the e-mail to be sent. The mail address of the transmission destination is entered by the user.), CC: (The mail address of the broadcast destination is entered by the user thereafter.), SUBJECT: (The subject content of the sentence is entered by the user thereafter.) .), DATE: (date information) is formed on the RAM 3.

The e-mail text area creation means 32 transfers control to this means when the e-mail transmission means 30 issues an operation instruction to create a text area, and creates the e-mail text area RAM3. The mail transmitting means 33 is controlled by the electronic mail transmitting means 30 when an operation instruction to transmit an electronic mail is issued by the electronic mail transmitting means 30 and inquires of an operator whether or not encryption has been performed. Pass control to.

When the mail transmission means 33 receives an operation instruction with encryption, the encrypted mail transmission means 34 shifts the control to this means, and determines the encryption method using the header information created by the header information creation means 31 as a parameter. The control is passed to the means 36, and then the control is passed to the text area encryption means 35 based on the text information created by the text area creation means 32.

The encryption method determining means 36 receives control from the encrypted mail transmitting means 34, and determines the encryption method based on the header information developed on the RAM 3 by the header information creating means 31. The text region encryption means 35 receives control from the encrypted mail transmission means 34 and the
3. The text information developed above is encrypted based on the encryption method determined by the encryption method determining means 36.

The e-mail receiving means 37 performs basic operations for receiving e-mail, status monitoring, and the like. The received mail decrypting means 38 shifts control when the electronic mail received by the electronic mail receiving means 37 is encrypted,
Using the header information of the e-mail received by the e-mail receiving means 37 as a parameter, the control is passed to the decryption method determining means 39, and the text region information is received by the e-mail receiving means 37. Pass control.

The decryption method determining means 39 receives control from the received mail decrypting means 38 and
A decoding method is determined on the basis of the header information developed on the RAM 3. The body area decrypting means 40 receives control from the received mail decrypting means 38,
Decrypts the text information developed on the RAM 3 based on the decoding method determined by the decoding method determining means 39.

An electronic mail transmission / reception process executed in the above system configuration will be described with reference to FIGS. FIG. 4 shows the flow of the e-mail transmission process.

The procedure from when the apparatus is turned on to when the control is transferred to the network system program 11 and when the control is transferred to the e-mail transmission processing program is the same as the conventional procedure. In the e-mail transmission processing, the MPU 1 first checks the operation contents of the input keys of the keyboard 7 (S5).
1). In the case of inputting information related to header information creation, the header information creation program 13 is called, header information creation processing is executed (S56), and the input key is checked again (S5).
It returns to the process of 1). Hereinafter, every time the user inputs information, the header information is created by a loop of steps S51 → S56.

If information other than the header information creation has been input (NO in S51), it is checked whether the input key has input information relating to the creation of the body area (S52). In the case of inputting text region creation information, text region creation program 1
4 to execute the body area creation processing (S57),
The process returns to the key input determination process again.

If a negative determination is obtained in S52, it is checked whether the input key has input information relating to mail transmission (S53). In the case of inputting the mail transmission information, the mail transmission program 15 is called to execute the mail transmission processing (S58), and the process returns to the key input determination processing again.

If a negative determination is obtained in S53, it is checked whether the input key has input information relating to environment setting (S54). In the case of the environment setting information, the environment setting process (program) is called to execute the environment setting process (S59), and the process returns to the key input determination process again. If a NO determination is obtained in S54, it is checked whether the input key has instructed termination (S55). In the case of an end instruction, the process returns to the network system program 11. Otherwise, the key input determination process (5
Return to 1).

FIG. 5 shows the details of the mail transmission process (E-mail transmission program 12) in S58 of FIG. In the mail transmission process, it is checked whether there is a request for encryption from the user (S61). If there is no request for encryption by the user's key input, the conventional mail transmission processing is called, executed (S63), and the routine returns.

If there is a request for encryption, the encrypted mail transmission processing (encrypted mail transmission program 16) is called and executed (S62), and the routine returns.

FIG. 6 shows the details of the encrypted mail transmission process (encrypted mail transmission program 16) in S62 of FIG. In the encrypted mail transmission processing, the encryption method determination processing is called, and first, the header information of the electronic mail created on the RAM 3 in the header information creation processing (S56) is transferred to the encryption method determination processing (S71). In this encryption method determination process, one encryption method is selected from a plurality of types of encryption methods.
Next, the text area encryption processing is called using the encryption method determined in the encryption method determination processing (S71) and the text area of the e-mail created on the RAM 3 in the text area creation processing (S57) as parameters (S72). . Finally, a mail transmission process similar to the conventional one is called (S73), and the encrypted electronic mail (encrypted body + header) is transmitted to the destination.

Next, FIG. 7 shows details of the encryption method determination processing in S71 of FIG. In the present embodiment, a part of the storage addresses of the plural types of encryption programs is stored in the encryption method entry table in the ROM 2.

Therefore, in the encryption method determination processing, the MPU
First, at step S56, a character code string described in the SUBJECT column of the header information of the e-mail created on the RAM 3 in the header information creation processing (S56) is obtained, and the operation of each character code is obtained (S81).

Next, a base address of an encryption method entry table described later is obtained (S82).

Then, the last two digits of the sum of the character codes in the SUBJECT column obtained in S81 are added to the address (base address) read from the encryption system entry table, and the storage address of the encryption program (the address corresponding to the encryption system) is obtained. It is created (S83).

Then, an encryption program corresponding to the address corresponding to the encryption method is obtained from the ROM 2 (S84) and the process returns.

Next, FIG. 8 shows details of the text region encryption processing in step S72 in FIG. In the body area encryption process,
First, the encryption program determined in the encryption scheme determination processing (step S71 in FIG. 6) is loaded (S91).

Then, the text information of the e-mail created on the RAM 3 in the text area creation processing (S57) is encrypted by the encryption program (S92).

Next, the flow of the e-mail receiving process is shown in FIG. When the power is turned on to the apparatus, control is transferred to the network system program 11 as in the related art, and then control is transferred to the e-mail reception processing (e-mail reception program 19). In the e-mail receiving process of FIG. 9, first, an e-mail receiving process similar to the conventional one is performed (S103).

Then, it is checked whether or not the received mail is encrypted (S101). If the received mail is encrypted, the received mail decryption processing is called and executed (S10).
2). As a method of determining the presence or absence of encryption, confirmation by an operator, automatic determination of the MPU 1 based on identification information described in a header, or the like can be used.

Next, FIG. 10 shows details of the e-mail decryption processing in step S102 in FIG.

In the e-mail decryption processing, the header information of the mail received in the e-mail reception processing (S103) is set as a parameter, and the decryption method determination processing (decoding method determination program 22) is called to perform decryption. The method is determined (S111).

Next, the decryption method determined in the decryption method determination processing (S111) and the e-mail reception processing (S10
The body area decryption process is called using the body area of the e-mail received on the RAM 3 in step 3) as a parameter (S10).
2). This makes it possible to decrypt the encrypted text region into a sentence before encryption.

Next, FIG. 11 shows details of the decoding method determination processing in S111 of FIG. In the decoding method determination process, M
PU1 first receives the RAM in the e-mail receiving process (S103).
3 of the header information of the e-mail received on
The sum total of each character code described in the t column is obtained (S12
1).

Next, a base address of a decoding method entry table to be described later is obtained (S122).

Then, an address corresponding to the decoding method is created by adding the last two digits of the sum of the character codes in the SUBJECT column obtained in S121 to the decoding method entry table base address (S123). The MPU 1 acquires the decryption program stored at the relevant address of the decryption method from the ROM 2 (S124) and returns.

FIG. 12 shows the details of the text area decoding process in S112 of FIG. In the body region decoding processing, first, the decoding program determined in the decoding method determination processing (S111) is loaded (S131). By the above decryption program, the e-mail receiving process (S103)
3 decrypts the body information of the received e-mail (S
132).

Next, FIG. 13 shows the structure of the above-mentioned encryption method entry table and the table corresponding to the encryption method.
FIG. 14 shows the configurations of the decoding method entry table and the decoding method applicable table.

The encryption method entry table of FIG.
The decryption method entry table has entry pointers 1 to 100, respectively.

Similarly, the table corresponding to the encryption method and the table corresponding to the decryption method respectively store encryption and decryption programs defining processing methods 1 to 100.

When the transmission side and the reception side of the mail make the configuration of the processing method of each table the same, when the transmission side transmits the encrypted mail, the reception side corresponds to the transmission side encryption method. The mail can be decrypted by the decryption method.

(Other Embodiments) 1) In this embodiment, 100 types of encryption and decryption processing are entered in the encryption system entry table and the decryption system entry table, respectively. A pointer of a processing method that can be used at random is set in the entry table, and operation becomes possible by associating each entry table with encryption and decryption.

The number of entries is 10 and 1000.
When the type is changed, operation becomes possible by changing the number of digits of a variable to be added to the entry table in the encryption method determination processing S83 and the decryption method determination processing S123.

Other than the above, the encryption method decision processing of FIG. 7 and FIG.
The relative position of each entry table was obtained from the sum of the character codes in the SUBJECT column of the e-mail header information in the decoding method determination processing of Total code, number of characters, number of e-mail addresses described in TO column, total of character codes, number of characters, number of characters of header information, total of character codes, date information (decision factor) described in DATE column and entry By determining a correlation with the relative position of the table and determining the encryption program from the correlation, a mail system with more security can be realized.

2) In this embodiment, the programs shown in FIGS. 4 to 12 and the tables shown in FIGS. 13 and 14 are stored in the ROM 2. However, the programs may be stored in a hard disk storage device or a floppy disk or a CD. -It may be installed from a ROM to a hard disk storage device.

[0071]

According to the invention of claims 1, 6, 11, and 17,
The means to be used among the plurality of encryption means and decryption means is determined from the contents described in the header of the e-mail. Since the contents described in the header portion are different for each e-mail, the encryption means and the decryption means used for each e-mail are also different, so that it becomes more difficult to decipher the ciphertext and the security is further improved.

According to the inventions of claims 2 to 4, 7 to 9, and 12 to 14, characters described in a specific field of the header portion, for example, a field for entering a destination (TO) or a field for entering a subject (SUBJECT) are described. A numerical value such as the sum of codes, the number of characters, or the number of e-mail addresses described in a destination (TO) or a broadcast destination column (CC) is associated with a plurality of encryption means and decryption means, and encryption is performed based on this association. The decryption means and the decryption means are associated.

For this reason, even if the encrypting means and the decrypting means themselves are stolen, it is not known which encrypting means has been used for the encrypted text, so that the security is further improved.

According to the fifth, tenth and fifteenth aspects of the present invention,
The storage addresses for reading the encryption program and the decryption program to be used are encrypted, and the storage addresses of the encryption program and the decryption program are not described in numerical form in the e-mail program. For this reason, even if the program analysis is performed by reverse engineering or the like, the storage destinations of the encryption program and the decryption program are unknown, and the encryption program and the decryption program are protected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a system configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a relation between programs according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a functional configuration according to the embodiment of the present invention.

FIG. 4 is a flowchart showing processing contents of an electronic mail transmission processing.

FIG. 5 is a flowchart showing processing contents of a mail transmission processing.

FIG. 6 is a flowchart showing processing contents of an encrypted mail processing.

FIG. 7 is a flowchart showing processing contents of an encryption method determination processing.

FIG. 8 is a flowchart showing the contents of a text region encryption process.

FIG. 9 is a flowchart showing processing contents of an e-mail receiving process.

FIG. 10 is a flowchart showing processing contents of a received mail decryption processing.

FIG. 11 is a flowchart showing a processing content of a decoding method determination process.

FIG. 12 is a flowchart showing the contents of a text region decoding process.

FIG. 13 is a configuration diagram showing the configurations of an encryption entry table and an encryption method applicable table.

FIG. 14 is a configuration diagram showing a configuration of a decryption entry table and a table corresponding to a decryption method.

[Explanation of symbols]

 1 MPU 2 ROM 3 RAM 4 FD 5 CRT 6 NIC 7 KB

Claims (17)

[Claims] An information processing apparatus capable of encrypting the body of an electronic mail and transmitting the encrypted body to another device, wherein the body of the electronic mail can be encrypted, and a plurality of ciphers each having a different type of encryption. Encrypting means, and selecting means for selecting one of the plurality of encrypting means for encrypting the text of the electronic mail to be transmitted based on the information content described in the header portion of the electronic mail. Characteristic information processing device. 2. The information processing apparatus according to claim 1, wherein the selection unit determines a sum of the character codes described in a specific field of the header section for selecting one of the plurality of encryption units. An information processing apparatus characterized by being an element. 3. The information processing apparatus according to claim 1, wherein the selection unit determines the number of characters of a character code described in a specific field of the header section for selecting one of the plurality of encryption units. An information processing apparatus characterized by being an element. 4. The information processing apparatus according to claim 1, wherein the selection unit determines the number of mail addresses described in a specific column of the header section for selecting one of the plurality of encryption units. An information processing apparatus characterized by being an element. 5. The information processing apparatus according to claim 1, wherein the plurality of encryption units have a storage unit for storing a plurality of encryption programs, and the selection unit is included in the header unit. An information processing apparatus, wherein a storage address of the storage unit is determined from information content. 6. An information processing apparatus capable of receiving an encrypted body of an electronic mail from another apparatus and decrypting the body of the electronic mail, decrypting the body of the electronic mail encrypted by a corresponding encryption method. A plurality of decryption means each having a different type of decryption, and one of the plurality of decryption means based on the information content described in the header of the e-mail. An information processing apparatus comprising: a selection unit that selects for decoding. 7. The information processing apparatus according to claim 6, wherein the selection unit determines a sum of character codes described in a specific column of the header section for selecting one of the plurality of decoding units. An information processing apparatus characterized by being an element. 8. The information processing apparatus according to claim 6, wherein the selection unit determines the number of characters of a character code described in a specific column of the header section for selecting one of the plurality of decoding units. An information processing apparatus characterized by being an element. 9. The information processing apparatus according to claim 6, wherein the selection unit determines the number of mail addresses described in a specific column of the header section for selecting one of the plurality of decoding units. An information processing apparatus characterized by being an element. 10. The information processing apparatus according to claim 6, wherein said plurality of decoding means have storage means for storing a plurality of decoding programs, and said selection means is provided in said header section. An information processing apparatus, wherein a storage address of the storage unit is determined from information content. 11. The first information processing device encrypts the body of the electronic mail, and transmits the electronic mail with the body encrypted from the first information processing device to the second information processing device. In the e-mail method for decrypting the text encrypted by the information processing device, the first information processing device is capable of encrypting the text of the e-mail, The second information processing apparatus is capable of decrypting the body of the e-mail, and includes a plurality of decryption means having different types of decryption contents. The first information processing device selects one of the plurality of encrypting means for encrypting the text of the electronic mail to be transmitted based on the information content described in the header portion of the electronic mail. The body is encrypted by encryption means. The second information processing device encrypts and transmits, based on the information content described in the header part of the received e-mail, one of the decryption means for decrypting the text of the received e-mail. And decrypting the body of the e-mail by the selected decryption means. 12. The electronic mail method according to claim 11, wherein the sum of the character codes described in the specific field of the header portion is one of the plurality of encrypting means and one of the plurality of decrypting means. An e-mail method characterized in that the e-mail method is used as a deciding element for selecting an e-mail. 13. The electronic mail method according to claim 11, wherein the number of characters of a character code described in a specific field of the header portion is determined by one of the plurality of encryption units and one of the plurality of decryption units. An e-mail method characterized in that the e-mail method is used as a deciding element for selecting an e-mail. 14. The e-mail method according to claim 11, wherein the number of e-mail addresses described in a specific column of the header portion is determined by one of the plurality of encryption units and one of the plurality of decryption units. An e-mail method characterized in that the e-mail method is used as a deciding element for selecting an e-mail. 15. The electronic mail method according to claim 11, wherein the plurality of encryption units have storage units for storing a plurality of encryption programs, and the first information processing device includes a header unit. An e-mail method, wherein the storage address of the storage means is determined from the information content described in (1). 16. The e-mail method according to claim 11, wherein said plurality of decryption means include storage means for storing a plurality of decryption programs, and wherein said second information processing apparatus includes a header section. An e-mail method, wherein the storage address of the storage means is determined from the information content described in (1). 17. A recording medium having recorded thereon a program capable of executing a function of the information processing apparatus according to claim 1 by a computer.