The password encryption in ZIP/ARJ/RAR/ACE is very strong, and if the password is long enough and well selected, there is no way to recover it in a reasonable time. In most cases, only brute-force and dictionary attacks are available.ZIP的加密非常强，如果密码长而且选择好，是没有办法在有效时间内恢复的，只有通过暴力及字典进行攻击才是有效的。
Also, the files must have the same CRC and uncompressed sizes. 对比加密的压缩包与不加密的压缩包，可以发现CRC值是一致的，原大小是一致的，但压缩后大小是有变化的，变化 的大小占12字节，就是密码所占的位置。
One software recovers protection passwords or unlocks encrypted ZIP and RAR archives created with all versions of popular archivers. Recover passwords for plain and self-extracting archives created with PKZip and WinZip, RAR and WinRAR automatically or with your assistance. 我有一个软件可以进行密码攻击服务。