SHA1 encode NSString

// SHA1
#import <CommonCrypto/CommonDigest.h>
- (NSString*)getSHA1WithString:(NSString*)string
{
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    uint8_t digest[CC_SHA1_DIGEST_LENGTH];
    CC_SHA1(data.bytes, (CC_LONG)data.length, digest);

    NSMutableString *output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];
    for (int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)
    {
        [output appendFormat:@"%02x", digest[i]];
    }

    return output;
}