[Background]
In the past, it was common practice—including at our company—to send and receive files using password-protected attachments. However, the following issues have been raised recently:
・Encrypted attachments cannot be virus-scanned, posing a risk of malware infection.
・When passwords are sent through the same channel as the files, the effectiveness of preventing information leaks is limited.
・Some email services cannot receive encrypted files or automatically delete them.
In light of these issues, we are implementing measures to strengthen the security of our file-sharing methods.
[Future Operations]
Effective Date
From Monday, December 1, 2025
■ Details of the Change
Scope: All types of password-protected and encrypted files, including zip and Office files
■ List of files that will be rejected:
【Subject to rejection】
All encrypted files
The following are examples only. Any encrypted file will be rejected regardless of its extension.
Examples of commonly rejected files:
・Password-protected .pdf
・Password-protected .zip
・Password-protected .xlsx (and other Office files)
Files automatically determined to be encrypted based on their file extensions:
.p7m, .p7s, .p7c, .rpmsg, .ppdf, .ptxt, .pmsg, .asc, .gpg, .pgp, .pem, .cer, .crt, .nxl, .rmsdoc, .rmsxls, .rmsppt
Response: Emails containing the above file types will not be received by our mail servers. The sender will receive an error email with the subject line:
"Due to our company policy, we cannot receive password-protected files."
■ Alternative Methods
Please select one of the following three options when sending files:
Use Microsoft SharePoint to exchange files
Upon request, we can create a dedicated shared folder for your company, and our representative will provide the access link
Remove the password protection before sending the file
We apologize for any inconvenience this may cause and kindly ask for your understanding and cooperation in our efforts to enhance security.
