blarg.m

- (NSString *)stringFromHexString:(NSString *)hexString {
    
    
    if (([hexString length] % 2) != 0)
        return nil;
    
    NSMutableString *string = [NSMutableString string];
    
    for (NSInteger i = 0; i < [hexString length]; i += 2) {
        
        NSString *hex = [hexString substringWithRange:NSMakeRange(i, 2)];
        unsigned int decimalValue = 0;
        sscanf([hex UTF8String], "%x", &decimalValue);
        [string appendFormat:@"%c", decimalValue];
        
    }
    
    
    return string;
}