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About PPAP

PPAP is an acronym that refers to a method of sending a zip file with a password by e-mail and the password by a separate e-mail. In Japan, PPAP is referred to as the following acronym.

  • Password付きzip暗号化ファイルを送ります
    Send a zipped encrypted file with password

  • Passwordを送ります
    Send Password

  • Aん号化 (暗号化) します
    Encrypting (In Japanese, it's called Angoka.)

  • Protocol

Although this method is widely used in Japan, it is deprecated due to security issues.Although this method is widely used in Japan, it is deprecated due to security issues.


Problems with PPAP

The following are some of the problems with PPAP

  • Does not prevent third parties from eavesdropping on the network
    Even if an e-mail with a zip file attached and the password are sent in two separate e-mails, if the communication path is intercepted by a third party, both pieces of information will be compromised.

  • It is not a countermeasure against misdirected transmissions.
    PPAP may be effective to some extent as a countermeasure against misdirects, but it is possible to send both letters by mistake.

  • Passwords are easily analyzed
    If the zip file is in the hands of a third party, the password can be analyzed by a zip file password analysis tool.

  • Malware infection risk
    In some cases, the fact that password-protected zip files slip through the checks of antivirus software is exploited, and malware is made into a password-protected zip file and sent.

PPAP Countermeasure by YubiOn SecureFileTransfer


YubiOn SecureFileTransfer uses SSL / TLS communication to prevent eavesdropping on the communication path. In addition, data storage servers that temporarily store data are encrypted, and it is possible to set limits on the number of days and number of times data can be downloaded. Furthermore, files are delivered securely by requiring authentication of the recipient. 



SSL / TLS communication prevents third parties from intercepting the communication path.

access control


File access control provides peace of mind in the event that a download URL is mistakenly sent.



Reduced risk of malware infection because files are exchanged with trusted parties.​​

YubiOn SecureFileTransfer requires no software to install or configure, and all you need is a browser and an email address to use the service. You can try the service for free, so please take advantage of it.

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