How can I send encrypted files?

If you want to send encrypted files to protect sensitive data from unauthorized persons, you have several options. For one thing, most operating systems already have programmes for sending encrypted files. You can also find many other programmes on the Internet that allow you to send encrypted files. Here, you can learn about what other options there are and how exactly file encryption works.

What are encrypted files?

Basically, encryption is the process of changing information cryptographically in such a way that the information is then only readable with a specific key. The information is thus transformed into a kind of secret language and can only be read with the key.
This precaution is intended to ensure that…

• only those who know the password can access the files
• nobody can change the files during the transfer.
• the sender can be clearly identified.

Encrypt and send files – how does it work?

There are two common methods for encrypting files: symmetric and asymmetric encryption. The main difference between these two methods is the number of keys. With symmetric encryption, there is only one key. With asymmetric encryption, however, there is a secret key in addition to a public key.

Sending encrypted files with Windows

If you want to encrypt and send files by e-mail, you must first encrypt them on your computer. The Windows operating system usually has an internal program for this.

All you have to do is select the files or put them in a folder. Then right-click on the selected files and click “Properties”. Under “Advanced”, you then set a checkmark for “Encrypt content”. You can now assign a password that protects the folder.

You can now also send the encrypted files by e-mail. Please note, however, that the attachment size is usually limited to 25 MB for e-mail providers.

Sending encrypted files with macOS

If you are using macOS, you can send encrypted files by following these steps:

1. Create a new folder and drag all files you want to encrypt into this folder.
2. Using the Spotlight (at the top right of the screen), search for “Disk Utility” and open it.
3. The Disk Utility will open at the top of the screen. Click on “File”, then on “New Image” and finally on “Image from Folder”.
4. Now a new window will open in which you can search and select the folder you created at the beginning.
5. Specify the storage location and name the newly created image. Select the 256-bit AES encryption, assign a password and click on “Backup”.
6. As a precaution, you should delete the folder you created at the beginning so that there is no second, unprotected version on your computer.
7. Now you can upload the newly created image to the e-mail attachment and send the encrypted files.

By the way: the larger the files are and the more files you want to pack into a new image, the more time it takes to encrypt them.

Encrypt and send files quickly and easily with TransferXL

Encrypting and sending files with TransferXL is somewhat less complicated because with TransferXL, you can send up to 5 GB free of charge and up to 200 GB in total. Go to the homepage https://transferxl.com/de and click on “File Upload” or drag and drop the files into the appropriate field. Now all you have to do is specify a recipient.

You’ll have no need to encrypt the files at all – TransferXL encrypts the files on your computer and protects them with end-to-end encryption. This ensures that only you and authorized recipients have access to the files.

Another advantage is that TransferXL also compresses the file, but don’t worry: compressing does not mean that the files are modified. Only the required storage space is restructured, allowing for even better use of the maximum data volume.

TransferXL combines the advantages of different providers and is a simple and straightforward way to send encrypted files.

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The most important questions and answers about encrypting files

What is the difference between symmetrical and asymmetrical encryption?

Asymmetric encryption is secured by two keys. Symmetric encryption, on the other hand, requires only one key, which makes it easier for unauthorized persons to access.

What is the maximum data volume of the attachment from e-mail providers?

Generally, you can send up to 25 MB by e-mail.

What is the maximum data volume of TransferXL?

You can send up to 5 GB free of charge with TransferXL. The maximum data volume with an Enterprise account is 200 GB.

How does the encryption with TransferXL work?

If you send your files encrypted with TransferXL, you have several benefits: the encryption takes place before the upload, you can specify a storage location and the files can only be downloaded by the recipient with a password.

How long does manual encryption take?

The following applies to both Windows and macOS: the larger the files are, the more time the encryption takes.