Ubuntu 如何加密用户(会话)密码?
其中涉及哪些算法/机制?
答案1
请参阅man crypt
,其中部分内容如下:
NOTES
Glibc notes
The glibc2 version of this function supports additional encryption
algorithms.
If salt is a character string starting with the characters "$id$"
followed by a string terminated by "$":
$id$salt$encrypted
then instead of using the DES machine, id identifies the encryption
method used and this then determines how the rest of the password
string is interpreted. The following values of id are supported:
ID | Method
─────────────────────────────────────────────────────────
1 | MD5
2a | Blowfish (not in mainline glibc; added in some
| Linux distributions)
5 | SHA-256 (since glibc 2.7)
6 | SHA-512 (since glibc 2.7)
So $5$salt$encrypted is an SHA-256 encoded password and
$6$salt$encrypted is an SHA-512 encoded one.
"salt" stands for the up to 16 characters following "$id$" in the salt.
The encrypted part of the password string is the actual computed
password. The size of this string is fixed: