iOS md5加密

   32位的MD5加密方法

- (NSString *)getMd5_32Bit_String:(NSString *)srcString{

    const char * cStr = [srcString UTF8String];

    unsigned char digest[CC_MD5_DIGEST_LENGTH];

    CC_MD5( cStr, (CC_LONG)strlen(cStr), digest);

    NSMutableString *result = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];

    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)

        [result appendFormat:@"%02x", digest[i]];

    

    return result;

}