There's a ton of ways to get this done, namely nicklockwood's FXBlurView and radi's LiveFrost but those solutions requires you to use a subclass of UIView in order to make it work. For older iOS version support you should go with those solutions, but for iOS7 only, this is a lighter solution.

This category uses the UIToolbar layer hack as described so many times all over the web.

add UIView+Blur.h/.m to your project, then import .h file

#import "UIView+Blur.h"

Create your UIView and activate the blur

UIView* view = [[UIView alloc] initWithFrame:CGRectMake(100, 160, 100, 100)];    
[view enableBlur:YES];
[view setBlurTintColor:[UIColor redColor]];

Here's what can be customized, (check the .h file for more explanations):

/* The UIToolbar that has been put on the current view, use it to do your bidding */
@property (strong,nonatomic,readonly) UIView* blurBackground;

/* tint color of the blurred view */
@property (strong,nonatomic) UIColor* blurTintColor;

/* intensity of blurTintColor applied on the blur 0.0-1.0, default 0.6f */
@property (assign,nonatomic) CGFloat blurTintColorIntensity;

/* returns if blurring is enabled */
@property (readonly,nonatomic) BOOL isBlurred;

/* Style of Toolbar, remapped to UIViewBlurStyle typedef above */
@property (assign,nonatomic) UIViewBlurStyle blurStyle;

No requirements, I've tested this project with iOS 7.1

Any suggestions are welcome ! as I am looking to learn good practices, to understand better behaviors and Objective-C in general ! Thank you.