How to authenticate user ? (Android/Java/Symfony) -

i'm developping android app need authentication. however, there existing web application (using symfony) accounts, , have reuse same accounts authenticate users.

in db, have basicals : username, salt, encryptedpassword, encryption_type(sha1)...

the problem don't know how authenticate users, using these informations.

if can me solving this...

many thanks!

depending on encryption algorithm this:

public final boolean authenticate(string attemptedpassword, byte[] encryptedpassword, byte[] salt) throws nosuchalgorithmexception, invalidkeyspecexception {   string algorithm = "pbkdf2withhmacsha1";   int derivedkeylength = 160;   int iterations = 20000;   keyspec spec = new pbekeyspec(password.tochararray(), salt, iterations, derivedkeylength);   secretkeyfactory f = secretkeyfactory.getinstance(algorithm);    byte[] encryptedpassword = f.generatesecret(spec).getencoded();    return arrays.equals(encryptedpassword, encryptedattemptedpassword); } 

you need know settings used generate encrypted passwords in database.