ios Md5加密

首先倒入库#import <CommonCrypto/CommonDigest.h>

//md5 16位加密 （小写）

-(NSString *)md5:(NSString *)str
{
    const char *cStr = [str UTF8String];
    unsigned char result[16];
    CC_MD5(cStr, strlen(cStr), result);    
    NSMutableString *hash = [NSMutableString string];
    for (int i = 0; i < 16; i++)        
    {
        [hash appendFormat:@"%02X", result[i]];        
    }
    return [hash lowercaseString];
}