Zenlok is an online file transfer service that allows you to send large files using your existing e-mail accounts. Using Zenlok, you can send attachments up to 2GB securely and use Zenlok SMTP service to send files up to 25 MB. It offers free as well as premium plans for users with different needs.
Zenlok features secure file transfer, email filtering, email encryption, email archiving and prevents the loss of your data. Zenlok Email Filtering categorizes emails based on recipients, attachment file types, and domains. Email is encrypted using PKI security system and enjoys a High Speed Network.
How to send files with Zenlok:
The interface is really simple and easy. To be honest, its simple and colorful interface emphasized me to give Zenlok a try. It has all the basic fields including To, From, Subject and even a short Message. You can send e-mail up to 10 recipients simultaneously. To add new email address field, click on ‘+’ and address field will appear.To add an attachment, click on ‘Add Attachment’ at the top.
Although it is not mentioned but you can add multiple files as attachments. The files are attached much quickly as compared to other email services. Click on the ‘Send’ button and it will take you to the next dialog box.

If you want to receive a copy of your sent email, look at the options at the bottom. Check Send a copy to yourself. Oops, I forgot to enter the email addresses and the warning message was displayed in Japanese. So, take a quick tip, you will find the language drop down menu at the top-right; select English if you do not understand Japanese. Click on ‘Next’ and set the ‘Zen Pass’.

This password will let you use recall, send confirmation and encryption features. The next step is to validate your email address i.e. a confirmation email will be sent to your email address. It will ask you to enter the ZenPass, you entered previously. You can encrypt the message body also. When you will click the ‘Send’ button, find the ‘Encrypt Message Body’ option at the bottom. Check the box so your message will also be encrypted.
Well, login to your confirmation email through the same browser in which you have attached your file using Zenlok else an error message will be displayed. This error will appears because Zenlok would not be able to fetch data from two different browsers.Enter ZenPass and your email is finally sent! .
Now, lets talk a little about Decryption and Recall mail features as they are not so obvious to understand. As Zenlok automatically encrypts your mails, the recipient is supposed to click on the URL in the email message to decrypt the files or download attachments. As soon as the recipient opens the email, a confirmation email is sent to the sender so that sender can keep a check if the email has been received and seen or not.
A recall mail will let you recall sent mails if the recipient has not decrypted it. Once you have recall an email, the recipient would no longer be able to decrypt the message. The sender can access the recall page by clicking the URL in the recall mail sent to their inbox. You can use this feature if you have emailed to anyone by mistake.
As we stated earlier, Zenlok offers free and premium services plan. Here’s a rapid comparison of them.

How do you send large files? Which services do you use to send large files? Share your experiences with us in comments.
{ 19 comments… read them below or add one }
I am using 7zip which is the best program for compression.
Wetransfer is a better than zenlok.
7 ways to send HUGE files 25X bigger than Gmail
http://mashable.com/2007/05/23/7-ways-to-send-huge-files-25x-bigger-than-gmail/
Most of the services mentioned in Mashable are paid one. We are only looking at the ones which offer free versions too.
By the way what do you think of Actobat SendNow? Is it better than any other service because it is from Adobe? What is the difference between Acrobat SendNow and Zenlok?
Acrobat SendNow is a paid solution only suitable for companies and not for individuals.
Transferbigfiles.com is the easiest and most effective service for sending large files online.
I love dropsend.
Thumbs up for FilesToFriends.com. Perfect step by step solution.
Thank you very much. My gmail does not allow me to send exe files. I will try this service for sending my files now.
Is there any service which supports versioning of files being sent back and forth continuously? Like subversion etc.? I don’t want to create my own file server for this purpose so I would like to have a third party solution.
You can use Dropbox to send files securely online. Dropbox offers file versioning and history.
I am a fan of Send Genie which is the best file sending service with drag and drop operations. Of course it is free
All the services you are telling allow only 2 GB of file transfer. You can use File Dropper to send files up to 5 GB.
I am using Dropbox for sharing files securely. But if I need more space for sharing files larger than 2GB, I will definitely consider SkyDrive or Google Drive. I don’t think any of the methods discussed above are secure enough for sending sensitive data?
You may see the type and level of encryption offered by each service. This will give you a better idea on how much secure each service is.
DropCanvas is the best!
Send6.com
Files Over Miles is a hassle free service to send files directly using P2P from your browser.