sha1 has the same features that make md5 a bad password hash: It's very memory and computation-efficient. It's relatively easy to implement in hardware. That ma

sha1 has the same features that make md5 a bad password hash: It's very memory and computation-efficient. It's relatively easy to implement in hardware. That makes it susceptible to brute-force attacks since you can test far more passwords than with any other algorithm. That doesn't mean that sha1 is a bad hash, it's just for a different use-case. You can stretch sha1 and make it more cpu-intensive by hashing multiple rounds - then you've invented pbkdf2.