Communication apparatus
A communication apparatus includes: a first storage unit storing a received electronic mail; a verification unit executing a first verification about an electronic signature attached to the received electronic mail; a printing unit printing the received electronic mail if a verification result of the first verification is positive; a deletion unit deleting the printed electronic mail from the first storage unit; and a storage control unit controlling a second storage unit to store the mail information about the received electronic mail in the second storage unit if the verification result of the first verification is negative. The verification unit again executes the first verification about a specific electronic signature attached to a specific electronic mail which mail information is stored in the second storage unit. The printing unit prints the specific electronic mail if a verification result by again executing the first verification about the specific electronic signature is positive.
1. A communication apparatus comprising:
a first data storage;
a second data storage;
a third data storage for storing a particular certificate issued by a particular certificate authority;
a printing device;
a processor; and
memory storing computer readable instructions, that cause, when executed by the processor, the communication apparatus to implement:
receiving an electronic mail;
storing the received electronic mail in the first data storage;
executing a first verification, the first verification comprising determining whether a certificate attached to the received electronic mail matches the particular certificate stored in the third data storage;
generating a first text digest from a text of the received electronic mail stored in the first data storage;
generating a second text digest from an encrypted text of the received electronic mail;
executing a second verification, the second verification comprising determining whether the first text digest matches the second text digest;
controlling the printing device to print the received electronic mail when the first verification indicates verification successful and the second verification indicates verification successful;
controlling the printing device to print the received electronic mail when the second verification indicates verification failed;
deleting the received electronic mail from the first data storage in response to printing the received electronic mail;
storing an address of a sender of the received electronic mail and its related mail information in the second data storage when the second verification indicates verification successful and when the first verification indicates verification failed, where the related mail information comprises the received electronic mail and a certificate of the received electronic mail;
executing a third verification, the third verification comprising determining whether a certificate attached to a specific electronic mail in a specific mail information stored in the second data storage matches the particular certificate stored in the third data storage; and
controlling the printing device to print the specific electronic mail when the third verification indicates verification successful.
2. The communication apparatus according to claim 1 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
controlling the printing device to print the received electronic mail in a first format when the first verification indicates verification-successful and the second verification indicates verification successful; and
controlling the printing device to print the received electronic mail in a second format when the second verification indicates verification-failed, wherein the second format is different from the first format.
3. The communication apparatus according to claim 2 , wherein the second format comprises a message to indicate that the second verification failed.
4. The communication apparatus according to claim 1 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
deleting the address of the sender of the received electronic mail and its related mail information from the second data storage
in accordance with an instruction from a user.
5. The communication apparatus according to claim 1 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
controlling the printing device to print the received electronic mail when the first verification indicates it is determined that the certificate attached to the received electronic mail matches the particular certificate stored in the third data storage and the second verification indicates it is determined that the first text digest matches the second digest.
6. The communication apparatus according to claim 1 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
controlling the printing device to print the received electronic mail when the second verification indicates it is determined that the first text digest does not match the second text digest.
7. The communication apparatus according to claim 1 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
allowing a user to select a combination of a specific address and its related mail information stored in the second data storage for the third verification;
executing the third verification, the third verification comprising determining whether the certificate included in the related mail information of the selected combination matches the particular certificate stored in the third data storage; and
controlling the printing device to print the electronic mail included in the mail information of the selected combination when the third verification indicates verification successful.
8. The communication apparatus according to claim 7 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
controlling the printing device to print the electronic mail included in the mail information of the selected combination when the third verification indicates it is determined that the certificate included in the related mail information matches the particular certificate stored in the third storage device.
9. The communication apparatus according to claim 7 , wherein the computer readable instructions further cause, when executed by the processor, the communication apparatus to implement:
determining the particular certificate authority that has authenticated the certificate in the mail information of the selected combination;
determining whether another certificate in another mail information stored in the second data storage is authenticated by the particular certificate authority;
determining whether the certificate in the mail information of the selected combination matches the particular certificate stored in the third data storage;
controlling the printing device to print the electronic mail included in the mail information of the selected combination when it is determined that the certificate in the mail information of the selected combination matches the particular certificate stored in the third data storage;
determining whether the another certificate in the another mail information stored in the second data storage matches the particular certificate stored in the third data storage; and
controlling the printing device to print the electronic mail included in the another mail information stored in the second data storage when it is determined that the another certificate in the another mail information stored in the second data storage matches the particular certificate stored in the third data storage.