Linux password Encryption Program (can be used to replace the user in the shadow file password)

Source code such as the following:

#include <stdio.h>#include <unistd.h>intMainintARGC, Char*ARGV[]){if(ARGC! =3){printf("%s <salt> <crypt>\n", argv[0]);return-1; } Char*passwd=Crypt(argv[1],argv[2]);printf("passwd: %s\ n", passwd);return 0;}

Summarize:

char  *crypt (const  char  *key , const  char  *salt); Crypt is a password cryptographic function, which is based on the Data Encryption Standard (DES) algorithm. Crypt is only applicable to the use of password and is not suitable for data encryption. 
 
 
crypt()将參数key所指的字符串加以加密。key字符串长度仅取前8个字符，超过此长度的字符没有意义。參数salt为两个字符组成的字符串，由a-z、A-Z、0-9。“.”和“/”所组成，用来决定使用4096 （a-z、A-Z、0-9。“.”和“/”共64个字符。64的平方为4096）种不同内建表格的哪一个。函数运行成功后会返回指向编码过的字符串指针，參数key 所指的字符串不会有所更动。编码过的字符串长度为13 个字符。前两个字符为參数salt代表的字符串。返回值： 返回一个指向以NULL结尾的password字符串。注意编译时要在末尾加入 -lcrypt 选项。

Linux password Encryption Program (can be used to replace the user in the shadow file password)