#import <Foundation/Foundation.h>#import <CommonCrypto/CommonDigest.h>@interface NSString (md5String)- (NSString *)md5String;@end

#import "NSString+md5String.h"@implementation NSString (md5String)- (NSString *)md5String{    const char *cStr = [self UTF8String];    unsigned char result[CC_MD5_DIGEST_LENGTH];    CC_MD5(cStr, strlen(cStr), result);        return [[NSString stringWithFormat:@"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",             result[0], result[1], result[2], result[3],             result[4], result[5], result[6], result[7],             result[8], result[9], result[10], result[11],             result[12], result[13], result[14], result[15]             ] lowercaseString];}@end