Problem - Kevin Tafuro

Verifying a password encrypted using PBKDF2 works the same way as verifying a
password encrypted with crypt( ): encrypt the plaintext password with the already
encrypted password as the salt, and compare the result with the already encrypted
password. If they match, the password is correct.
For the sake of both consistency and convenience, you can use the following function,
spc_pbkdf2_verify( ), to verify a password encrypted using PBKDF2.
int spc_pbkdf2_verify(const char *plain_password, const char *crypt_password) {
int match = 0;
char *pbkdf2_result;
if ((pbkdf2_result = spc_pbkdf2_encrypt(plain_password, crypt_password)) != 0) {
match = !strcmp(pbkdf2_result, crypt_password);
free(pbkdf2_result);
}
return match;
}
See Also
Recipes 4.10, 8.9, 8.10
8.12 Authenticating with PAM
Problem
You need to perform authentication in your application, but you do not want to tie
your application to any specific authentication system. Instead, you want to allow
the system administrator to configure an authentication system that is appropriate
for the environment in which the application will run.
Solution
Use Pluggable Authentication Modules (PAM), which provides an API that is independent
of the underlying authentication system. PAM allows the system administrator
to configure the authentication system or systems to use, and it supports a wide
variety of existing systems, such as traditional Unix password-based authentication,
Kerberos, Radius, and many others.
Discussion
We do not discuss building your own PAM modules in this book, but
there is a recipe on that topic on the book’s web site.
This is the Title of the Book, eMatter Edition
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