Mustbin, a Boston-based startup that simply and effectively encrypts SMS and instant messages on your iPhone, just went to the bank with $1.5 million.

The haul, Mustbin’s second round, comes on the heels of their inaugural venture financing in December, which netted the startup $4.5 million.

Investors in this round included DAG Ventures, General Catalyst Partners, Mohr Davidow, Northgate Capital and others. 

Satyender “Saty” Mahajan is Mustbin’s chief tech guru. Affable and good humored, Mahajan and his 14 member team have vowed to make instant encryption available to the average IM user.

In particular, Mahajan and company are swinging for the fences to make Mustbin easy to use.

That means for Mustbin to be successful, their developers need to curtail the friction still inherent in many encryption programs on mobile devices and desktops.

And they’ve done it.

“Anything you send, documents, pictures, messages, is super secure and super easy to use,” Mahajan told VentureBeat.

And one of the best attributes for Mustbin’s encryption, certainly, is that its free.

For now, Mustbin’s solution is available only for iOS. But recognizing Android and its staying power in the mobile space, Mustbin will roll out an Android later this year. Wise move, indeed, Saty!

With Mustbin, the security is local, meaning all data sent and received on your device is automatically encrypted. This means people don’t need to follow a series of prompts to get the encryption they desire.

Messages arrive to the cloud and servers already clothed in security, which means users, with their own keys, see messages delivered as they sent them. Readable.

Mustbin has competition. Mainly from Evernote. And Apple. But Mahajan sees his product as being a beginning, middle, and end when it comes to encryption. The others, he says, including Whatsapp, offer only partial solutions.

With an eye to monetizing Mustbin, Mahajan is looking to offer users an option of paying for storage fees and premium features. That facet of Mustbin will be rolled out shortly.

We think we can be the leaders in giving users high-end security with the best user experience. You almost wouldn’t know the encryption is there,” he said.

“What we’re doing is bringing encryption to the masses, right on your mobile device.”