#import <CommonCrypto/CommonDigest.h>

@interface NSString (md5)

-(NSString *) md5HexDigest;

@end

#import "NSString+MD5HexDigest.h"

@implementation NSString (md5)

-(NSString *) md5HexDigest

{

   const char *original_str = [self UTF8String];

   unsigned char result[CC_MD5_DIGEST_LENGTH];

   CC_MD5(original_str, strlen(original_str), result);

   NSMutableString *hash = [NSMutableString string];

   for (int i = ; i < ; i++)

        [hash appendFormat:@"%02X", result[i]];

   return [hash lowercaseString];

}

@end