For practice, see if you can't identify the hashing algorithm for the following stored passwords:
$6$AhHvI8ay$I0ED2wWVU9eheJKvCxzcbc/ZYRoN60q5XNHruYp8yFlQvEOjJ1WtIHUwjG6L4ZGntf3ei8osB7s2GYdkN01gx1
dGhpcyBpcyBzdHVwaWQKCg==
286755fad04869ca523320acce0dc6a4
some_salt:ac01346ad1553221506dd091800a1974
c8fed00eb2e87f1cee8e90ebbe870c190ac3848c
6b3a55e0261b0304143f805a24924d0c1c44524821305f31d9277843b8a10f4e
/5L0cR/wpFqSA
Note how they don't look the same, so it's quite easy for an attacker to tell the difference.Want to see how you did? Here's the answer key, in base64:
MTogTW9kZXJuIGNyeXB0LCBsaWtlIHRoZSBraW5kIHlvdSdkIGZpbmQgaW4gL2V0Yy9zaGFkb3cK
MjogSnVzdCBiYXNlNjRpbmcgdGhlIHJhdyBwYXNzd29yZCAoc3R1cGlkKQozOiBVbnNhbHRlZCBt
ZDVzdW0KNDogbWQ1c3VtLCB3aXRoIHNhbHQgcHJlcGVuZGVkCjU6IFVuc2FsdGVkIHNoYTFzdW0K
NjogVW5zYWx0ZWQgc2hhMjU2c3VtCjc6IE9sZCBVTklYIGNyeXB0KCk=
That said, revealing the exact algorithm would basically be throwing people with weak passwords to the wolves while really only supplying the rest of us with a false sense of security (because it will probably be cracked anyway).
We'd also be better off if they didn't announce the algorithm if the passwords get leaked (like with LinkedIn).