問69
頻出度★★★
電子メールで使用される S/MIME の説明として, 適切なものはどれか。
平成30年度 春期 ITパスポート試験 問69
This question's explanation and your answers so far.
解説
問 69
Incorrectア
A service in which email is sent and received on a website so that users can use it from a web browser describes 'webmail', not S/MIME. S/MIME is a standard for email encryption and signing, not a term for a browser-based way of using email.
- イ
正解 S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for securely sending and receiving email between mail software programs: it uses the public key contained in a digital certificate to encrypt the email body and attaches the sender's digital signature. This prevents eavesdropping, tampering, and impersonation. Choice イ is exactly this description of 'a standard that uses digital certificates to send and receive email securely between mail software', so it is correct.
Incorrectウ
A protocol for transferring email between mail servers describes SMTP. S/MIME does not define the procedure for server-to-server transfer; it is responsible for encrypting and signing the email content.
Incorrectエ
A protocol used by mail software to receive email from a server describes POP3 or IMAP. S/MIME is not a protocol for the receiving procedure, so it is incorrect.
ここがポイント
- S/MIME is a standard that uses digital certificates (public-key cryptography) to encrypt and digitally sign email, enabling secure sending and receiving between mail software programs.
- Distinguishing email-related terms: sending / server-to-server transfer is SMTP; receiving is POP3 and IMAP; use via a web browser is webmail; and the encryption-and-signing standard that ensures security is S/MIME.
用語