Converting NSString to NSData and vice versa

Question

I am having an issue while trying to convert NSString to NSData and vice versa. I am trying to store encrypted string to my database. For that I am using AES algorithm. Now what I am doing is I get encrypted NSData and I am converting this to NSString using following:

// Not woking
NSString *strTemp = [[NSString alloc] initWithData:encData encoding:NSUTF8StringEncoding]; 

// Working
NSString *strTemp = [[NSString alloc] initWithData:encData encoding:NSASCIIStringEncoding];

Why NSData is not converting while using NSUTF8StringEncoding. Same way when I try to convert the string got by NSASCIIStringEncoding using:

// Not working
[strTemp dataUsingEncoding:NSASCIIStringEncoding];

// Working
[strTemp dataUsingEncoding:NSUTF8StringEncoding];

Why NSASCIIStringEncoding is not working while converting the NSString to NSData?

score 29 · Accepted Answer · edited Oct 05 '12 at 11:57

29

NSString to NSData:

NSString* str= @"teststring";
NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];

NSData to NSString:

NSString* newStr = [[NSString alloc] initWithData:theData
                                         encoding:NSUTF8StringEncoding];

edited Oct 05 '12 at 11:57

JJD

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answered Jul 19 '11 at 10:33

Maulik

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This is what I am doing in my first code spinit.. but getting a nil string – Kapil Choubisa Jul 19 '11 at 10:41
the code is total here... I have a string I m converting it in Data using `[strTemp dataUsingEncoding:NSUTF8StringEncoding]` working but `[strTemp dataUsingEncoding:NSASCIIStringEncoding]` not working similarly the data I got using `[strTemp dataUsingEncoding:NSUTF8StringEncoding]` I am converting back to string using `[[NSString alloc] initWithData:encData encoding:NSASCIIStringEncoding]` is working but `[[NSString alloc] initWithData:encData encoding:NSUTF8StringEncoding]` is not. So Every time my conversion occurs I am using different encoding that have no surety of same result. – Kapil Choubisa Jul 20 '11 at 08:37
NSString* str= @"teststring"; NSData* data=[str dataUsingEncoding:NSASCIIStringEncoding]; NSLog(@"%@",data); NSString* newStr = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding]; NSLog(@"%@",newStr); NSString* str1= @"teststring"; NSData* data1=[str1 dataUsingEncoding:NSUTF8StringEncoding]; NSLog(@"%@",data1); NSString* newStr1 = [[NSString alloc] initWithData:data1 encoding:NSUTF8StringEncoding]; NSLog(@"%@",newStr1); I have tested it and its working fine !!! in both cases – Maulik Jul 20 '11 at 08:59

score 2 · Answer 2 · edited Oct 05 '12 at 11:59

2

Please mind that NSASCIIStringEncoding and NSUTF8StringEncoding need to match the characters in the string.

edited Oct 05 '12 at 11:59

JJD

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answered Sep 15 '11 at 21:59

zaph

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Converting NSString to NSData and vice versa

2 Answers2

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