Problem in signing with SHA256

[ElyasNaranjeeSani]

Hi,

First, thanks for your awesome tool.
I'm trying to sign a string with SHA256 as below.
,,,

NSData *messageData = [message dataUsingEncoding:NSUTF8StringEncoding];
NSData *signature = [[keyPair private] signWithSHA256:messageData error:&signingError];

,,,

There is no signing error and the signature variable in not nil.
I need the signature as a base64 encoded string but when I wanna convert the signature to string none of the below solutions works and all of them returns nil.

,,,

NSString *str1=[[NSString alloc]initWithData:signature encoding:NSUTF8StringEncoding];
NSString* str2 = [NSString stringWithUTF8String:(char *)[signature bytes]];
NSString* str3 = [NSString stringWithUTF8String:[signature bytes]];

,,,

Appreciate any help,
Thanks

[crono81]

Try:
NSLog(@"%@", [[NSString alloc] initWithData:[signature base64EncodedDataWithOptions:NSDataBase64EncodignEndLineWithLineFeed] encoding:NSUTF8StringEncoding]);