SQL-based authentication

⚠️ Warning: This is a draft ⚠️

This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.

If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.

This task has three parts:

Connect to a [[MySQL]] database (connect_db)
Create user/password records in the following table (create_user)
Authenticate login requests against the table (authenticate_user)

This is the table definition:

create table users (
    userid int primary key auto_increment,
    username varchar(32) unique key not null,
    pass_salt tinyblob not null,
            -- a string of 16 random bytes
    pass_md5 tinyblob not null
            -- binary MD5 hash of pass_salt concatenated with the password
);

(pass_salt and pass_md5 would be binary(16) values, but MySQL versions before 5.0.15 strip trailing spaces when selecting them.)

C

{{libheader|mysqlclient}} (MySQL client library) {{libheader|OpenSSL}} (for MD5)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <time.h>

#include <mysql.h>
#include <openssl/md5.h>

void end_with_db(void);

MYSQL *mysql = NULL; // global...

bool connect_db(const char *host, const char *user, const char *pwd,
		const char *db, unsigned int port)
{
  if ( mysql == NULL )
  {
    if (mysql_library_init(0, NULL, NULL)) return false;
    mysql = mysql_init(NULL); if ( mysql == NULL ) return false;
    MYSQL *myp = mysql_real_connect(mysql, host, user, pwd, db, port, NULL, 0);
    if (myp == NULL) {
      fprintf(stderr, "connection error: %s\n", mysql_error(mysql));
      end_with_db();
      return false;
    }
  }
  return true; // already connected... ?
}

#define USERNAMELIMIT 32
// no part of the spec, but it is reasonable!!
#define PASSWORDLIMIT 32
#define SALTBYTE 16
bool create_user(const char *username, const char *password)
{
  int i;
  char binarysalt[SALTBYTE];
  char salt[SALTBYTE*2+1];
  char md5hash[MD5_DIGEST_LENGTH];
  char saltpass[SALTBYTE+PASSWORDLIMIT+1];
  char pass_md5[MD5_DIGEST_LENGTH*2 + 1];
  char user[USERNAMELIMIT*2 + 1];
  char *q = NULL;
  static const char query[] =
    "INSERT INTO users "
    "(username,pass_salt,pass_md5) "
    "VALUES ('%s', X'%s', X'%s')";
  static const size_t qlen = sizeof query;


  for(i=0; username[i] != '\0' && i < USERNAMELIMIT; i++) ;
  if ( username[i] != '\0' ) return false;
  for(i=0; password[i] != '\0' && i < PASSWORDLIMIT; i++) ;
  if ( password[i] != '\0' ) return false;

  srand(time(NULL));

  for(i=0; i < SALTBYTE; i++)
  {
    // this skews the distribution but it is lazyness-compliant;)
    binarysalt[i] = rand()%256;
  }

  (void)mysql_hex_string(salt, binarysalt, SALTBYTE);

  for(i=0; i < SALTBYTE; i++) saltpass[i] = binarysalt[i];
  strcpy(saltpass+SALTBYTE, password);
  (void)MD5(saltpass, SALTBYTE + strlen(password), md5hash);
  (void)mysql_hex_string(pass_md5, md5hash, MD5_DIGEST_LENGTH);

  (void)mysql_real_escape_string(mysql, user, username, strlen(username));

  // salt, pass_md5, user are db-query-ready
  q = malloc(qlen + USERNAMELIMIT*2 + MD5_DIGEST_LENGTH*2 + SALTBYTE*2 + 1);
  if ( q == NULL ) return false;
  sprintf(q, query, user, salt, pass_md5);
#if defined(DEBUG)
  fprintf(stderr, "QUERY:\n%s\n\n", q);
#endif
  int res = mysql_query(mysql, q);
  free(q);
  if ( res != 0 )
  {
    fprintf(stderr, "create_user query error: %s\n", mysql_error(mysql));
    return false;
  }
  return true;
}


bool authenticate_user(const char *username, const char *password)
{
  char user[USERNAMELIMIT*2 + 1];
  char md5hash[MD5_DIGEST_LENGTH];
  char saltpass[SALTBYTE+PASSWORDLIMIT+1];
  bool authok = false;
  char *q = NULL;
  int i;
  static const char query[] =
    "SELECT * FROM users WHERE username='%s'";
  static const size_t qlen = sizeof query;

  // can't be authenticated with invalid username or password
  for(i=0; username[i] != '\0' && i < USERNAMELIMIT; i++) ;
  if ( username[i] != '\0' ) return false;
  for(i=0; password[i] != '\0' && i < PASSWORDLIMIT; i++) ;
  if ( password[i] != '\0' ) return false;

  (void)mysql_real_escape_string(mysql, user, username, strlen(username));

  q = malloc(qlen + strlen(user) + 1);
  if (q == NULL) return false;
  sprintf(q, query, username);

  int res = mysql_query(mysql, q);
  free(q);
  if ( res != 0 )
  {
    fprintf(stderr, "authenticate_user query error: %s\n", mysql_error(mysql));
    return false;
  }

  MYSQL_RES *qr = mysql_store_result(mysql);
  if ( qr == NULL ) return false;

  // should be only a result, or none
  if ( mysql_num_rows(qr) != 1 ) {
    mysql_free_result(qr);
    return false;
  }

  MYSQL_ROW row = mysql_fetch_row(qr);          // 1 row must exist
  unsigned long *len = mysql_fetch_lengths(qr); // and should have 4 cols...

  memcpy(saltpass, row[2], len[2]); // len[2] should be SALTBYTE
  memcpy(saltpass + len[2], password, strlen(password));
  (void)MD5(saltpass, SALTBYTE + strlen(password), md5hash);

  authok = memcmp(md5hash, row[3], len[3]) == 0;
  mysql_free_result(qr);

  return authok;
}

void end_with_db(void)
{
  mysql_close(mysql); mysql = NULL;
  mysql_library_end();
}

int main(int argc, char **argv)
{

  if ( argc < 4 ) return EXIT_FAILURE;

  if ( connect_db("localhost", "devel", "", "test", 0 ) )
  {
    if ( strcmp(argv[1], "add") == 0 )
    {
      if (create_user(argv[2], argv[3]))
	printf("created\n");
    } else if ( strcmp(argv[1], "auth") == 0 ) {
      if (authenticate_user(argv[2], argv[3]))
	printf("authorized\n");
      else
	printf("access denied\n");
    } else {
      printf("unknown command\n");
    }
    end_with_db();
  }
  return EXIT_SUCCESS;
}

From the command line, program add user password to add users, and program auth user password to see if the user with that password is authorized or not.

C#

Class for hashing and random salt generation.

using System.Security.Cryptography;
using System.Text;

namespace rosettaMySQL
{
    class Hasher
    {
        private static string _BytesToHex(byte[] input)
        {
            var strBuilder = new StringBuilder();
            foreach (byte _byte in input)
            {
                strBuilder.Append(_byte.ToString("x2"));
            }
            return strBuilder.ToString();
        }

        public static string Hash(string salt, string input)
        {
            using (MD5 md5 = new MD5CryptoServiceProvider())
            {
                var bytes = Encoding.Default.GetBytes(salt + input);
                var data = md5.ComputeHash(bytes);
                return _BytesToHex(data);
            }
        }

        public static string GenSalt()
        {
            using (RandomNumberGenerator rng = new RNGCryptoServiceProvider())
            {
                var salt = new byte[16];
                rng.GetBytes(salt);
                return _BytesToHex(salt);
            }
        }
    }
}

Class for creating and authenticating users.

using MySql.Data.MySqlClient;

namespace rosettaMySQL
{
    class UserOperator
    {
        private MySqlConnection _connection;

        public UserOperator(MySqlConnection connection)
        {
            _connection = connection;
        }

        public bool CreateUser(string username, string password)
        {
            try
            {
                var salt = Hasher.GenSalt();
                var hash = Hasher.Hash(salt, password);
                var sql = $"INSERT INTO users " +
                          $"(username, pass_salt, pass_md5) " +
                          $"VALUES ('{username}','{salt}','{hash}')";
                using (var command = new MySqlCommand(sql, _connection))
                {
                    command.ExecuteNonQuery();
                    return true;
                }
            }
            catch (MySqlException e)
            {
                if (e.Number == 1062) //username is a duplicate
                {
                    return false;
                }
                else
                {
                    throw e;
                }
            }
        }

        public bool AuthenticateUser(string username, string password)
        {
            var sql = $"SELECT userid, username, pass_salt, pass_md5 " +
                      $"FROM users " +
                      $"WHERE username='{username}';";

            using (var command = new MySqlCommand(sql, _connection))
            using (var reader = command.ExecuteReader())
            {
                if (reader.HasRows)
                {
                    reader.Read();
                    var salt = reader.GetString("pass_salt");
                    var hash = reader.GetString("pass_md5");
                    return (Hasher.Hash(salt, password) == hash);
                }
                else
                {
                    return false;
                }
            }
        }
    }
}

Class with main method and database connection method.

using System;
using MySql.Data.MySqlClient;

namespace rosettaMySQL
{
    class Program
    {
        public static MySqlConnection ConnectDB(string server, int port, string db,
                                                string username, string password)
        {
            var connectStr = $"server={server};" +
                             $"user={username};" +
                             $"database={db};" +
                             $"port={port};" +
                             $"password={password}";
            return new MySqlConnection(connectStr);
        }

        static void Main(string[] args)
        {
            try
            {
                var connection = ConnectDB("localhost", 3306, "test", "root", "password");
                connection.Open();
                var userOperator = new UserOperator(connection);
                Console.WriteLine("Bob has been created: " + userOperator.CreateUser("Bob", "123456"));
                Console.WriteLine("Bob has been duplicated: " + userOperator.CreateUser("Bob", "123456"));
                Console.WriteLine("Wrong password works: " + userOperator.AuthenticateUser("BOB", "notpassword"));
                Console.WriteLine("Right password works: " + userOperator.AuthenticateUser("BOB", "123456"));
            }
            catch(MySqlException e)
            {
                switch(e.Number)
                {
                    case 0:
                        Console.WriteLine("Cannot connect to server");
                        break;
                    case 1045:
                        Console.WriteLine("Invalid database username/password");
                        break;
                    default:
                        Console.WriteLine(e.ToString());
                        Console.WriteLine(e.Number);
                        break;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
    }
}

Output

Bob has been created: True
Bob has been duplicated: False
Wrong password works: False
Right password works: True

Go

package main

import (
    "bytes"
    "crypto/md5"
    "crypto/rand"
    "database/sql"
    "fmt"

    _ "github.com/go-sql-driver/mysql"
)

func connectDB() (*sql.DB, error) {
    return sql.Open("mysql", "rosetta:code@/rc")
}

func createUser(db *sql.DB, user, pwd string) error {
    salt := make([]byte, 16)
    rand.Reader.Read(salt)
    _, err := db.Exec(`insert into users (username, pass_salt, pass_md5)
        values (?, ?, ?)`, user, salt, saltHash(salt, pwd))
    if err != nil {
        return fmt.Errorf("User %s already exits", user)
    }
    return nil
}

func authenticateUser(db *sql.DB, user, pwd string) error {
    var salt, hash []byte
    row := db.QueryRow(`select pass_salt, pass_md5 from users
        where username=?`, user)
    if err := row.Scan(&salt, &hash); err != nil {
        return fmt.Errorf("User %s unknown", user)
    }
    if !bytes.Equal(saltHash(salt, pwd), hash) {
        return fmt.Errorf("User %s invalid password", user)
    }
    return nil
}

func saltHash(salt []byte, pwd string) []byte {
    h := md5.New()
    h.Write(salt)
    h.Write([]byte(pwd))
    return h.Sum(nil)
}

func main() {
    // demonstrate
    db, err := connectDB()
    defer db.Close()
    createUser(db, "sam", "123")
    err = authenticateUser(db, "sam", "123")
    if err == nil {
        fmt.Println("User sam authenticated")
    }

    // extra
    fmt.Println()
    // show contents of database
    rows, _ := db.Query(`select username, pass_salt, pass_md5 from users`)
    var user string
    var salt, hash []byte
    for rows.Next() {
        rows.Scan(&user, &salt, &hash)
        fmt.Printf("%s %x %x\n", user, salt, hash)
    }
    // try creating same user again
    err = createUser(db, "sam", "123")
    fmt.Println(err)
    // try authenticating unknown user
    err = authenticateUser(db, "pam", "123")
    fmt.Println(err)
    // try wrong password
    err = authenticateUser(db, "sam", "1234")
    fmt.Println(err)
    // clear table to run program again
    db.Exec(`truncate table users`)
}


User sam authenticated

sam d5d1ef775a89f2b504dc808e66087f3d a939f77466e91527e748377cc14dfd66
User sam already exits
User pam unknown
User sam invalid password

Java

import java.io.UnsupportedEncodingException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.math.BigInteger;


class UserManager {
    private Connection dbConnection;

    public UserManager() {
    }

    private String md5(String aString) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        MessageDigest md;
        String hex;
        StringBuffer hexString;
        byte[] bytesOfMessage;
        byte[] theDigest;

        hexString = new StringBuffer();
        bytesOfMessage = aString.getBytes("UTF-8");
        md = MessageDigest.getInstance("MD5");
        theDigest = md.digest(bytesOfMessage);

        for (int i = 0; i < theDigest.length; i++) {
            hex = Integer.toHexString(0xff & theDigest[i]);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }

        return hexString.toString();
    }

    public void connectDB(String host, int port, String db, String user, String password)
      throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");

        this.dbConnection =  DriverManager.getConnection("jdbc:mysql://"
                                + host
                                + ":"
                                + port
                                + "/"
                                + db, user, password);
    }

    public boolean createUser(String user, String password) {
        SecureRandom random;
        String insert;
        String salt;

        random = new SecureRandom();
        salt =  new BigInteger(130, random).toString(16);

        insert = "INSERT INTO users "
            + "(username, pass_salt, pass_md5) "
            + "VALUES (?, ?, ?)";

        try (PreparedStatement pstmt = this.dbConnection.prepareStatement(insert)) {
            pstmt.setString(1, user);
            pstmt.setString(2, salt);
            pstmt.setString(3, this.md5(salt + password));
            pstmt.executeUpdate();

            return true;
        } catch(NoSuchAlgorithmException | SQLException | UnsupportedEncodingException ex) {
            return false;
        }
    }

    public boolean authenticateUser(String user, String password) {
        String pass_md5;
        String pass_salt;
        String select;
        ResultSet res;

        select = "SELECT pass_salt, pass_md5 FROM users WHERE username = ?";
        res = null;

        try(PreparedStatement pstmt = this.dbConnection.prepareStatement(select)) {
            pstmt.setString(1, user);
            res = pstmt.executeQuery();

            res.next(); // We assume that username is unique

            pass_salt = res.getString(1);
            pass_md5 = res.getString(2);

            if (pass_md5.equals(this.md5(pass_salt + password))) {
                return true;
            } else {
                return false;
            }

        } catch(NoSuchAlgorithmException | SQLException | UnsupportedEncodingException ex) {
            return false;
        } finally {
            try {
                if (res instanceof ResultSet && !res.isClosed()) {
                    res.close();
                }
            } catch(SQLException ex) {
            }
        }
    }

    public void closeConnection() {
        try {
            this.dbConnection.close();
        } catch(NullPointerException | SQLException ex) {
        }
    }

    public static void main(String[] args) {
        UserManager um;

        um = new UserManager();
        try {
            um.connectDB("localhost", 3306, "test", "root", "admin");

            if (um.createUser("johndoe", "test")) {
                System.out.println("User created");
            }

            if (um.authenticateUser("johndoe", "test")) {
                System.out.println("User authenticated");
            }
        } catch(ClassNotFoundException | SQLException ex) {
            ex.printStackTrace();
        } finally {
            um.closeConnection();
        }
    }
}

Julia


using MySQL
using Nettle  # for md5

function connect_db(uri, user, pw, dbname)
    mydb = mysql_connect(uri, user, pw, dbname)

    const command = """CREATE TABLE IF NOT EXISTS users (
                          userid INT PRIMARY KEY AUTO_INCREMENT,
                          username VARCHAR(32) UNIQUE KEY NOT NULL,
                          pass_salt tinyblob NOT NULL,
                              -- a string of 16 random bytes
                          pass_md5 tinyblob NOT NULL
                              -- binary MD5 hash of pass_salt concatenated with the password
                  );"""
    mysql_execute(mydb, command)
    mydb
end

function create_user(dbh, user, pw)
    mysql_stmt_prepare(dbh, "INSERT IGNORE INTO users (username, pass_salt, pass_md5) values (?, ?, ?);")
    salt = join([Char(c) for c in rand(UInt8, 16)], "")
    passmd5 = digest("md5", salt * user)
    mysql_execute(dbh, [MYSQL_TYPE_VARCHAR, MYSQL_TYPE_VARCHAR, MYSQL_TYPE_VARCHAR], [user, salt, passmd5])
end

function addusers(dbh, userdict)
    for user in keys(userdict)
        create_user(dbh, user, userdict[user])
    end
end

"""
    authenticate_user
Note this returns true if password provided authenticates as correct, false otherwise
"""
function authenticate_user(dbh, username, pw)
    mysql_stmt_prepare(dbh, "SELECT pass_salt, pass_md5 FROM users WHERE username = ?;")
    pass_salt, pass_md5 = mysql_execute(dbh, [MYSQL_TYPE_VARCHAR], [username], opformat=MYSQL_TUPLES)[1]
    pass_md5 == digest("md5", pass_salt * username)
end

const users = Dict("Joan" => "joanspw", "John" => "johnspw", "Mary" => "marpw", "Mark" => "markpw")
const mydb = connect_db("192.168.1.1", "julia", "julia", "mydb")

addusers(mydb, users)
println("""John authenticates correctly: $(authenticate_user(mydb, "John", "johnspw")==false)""")
println("""Mary does not authenticate with password of 123: $(authenticate_user(mydb, "Mary", "123")==false)""")
mysql_disconnect(mydb)

Kotlin

// Version 1.2.41

import java.sql.Connection
import java.sql.DriverManager
import java.sql.ResultSet
import java.security.MessageDigest
import java.security.SecureRandom
import java.math.BigInteger

class UserManager {
    private lateinit var dbConnection: Connection

    private fun md5(message: String): String {
        val hexString = StringBuilder()
        val bytes = message.toByteArray()
        val md = MessageDigest.getInstance("MD5")
        val dig = md.digest(bytes)
        for (i in 0 until dig.size) {
            val hex = (0xff and dig[i].toInt()).toString(16)
            if (hex.length == 1) hexString.append('0')
            hexString.append(hex)
        }
        return hexString.toString()
    }

    fun connectDB(host: String, port: Int, db: String, user: String, pwd: String) {
        Class.forName("com.mysql.jdbc.Driver")
        dbConnection = DriverManager.getConnection(
            "jdbc:mysql://$host:$port/$db", user, pwd
        )
    }

    fun createUser(user: String, pwd: String): Boolean {
        val random = SecureRandom()
        val salt = BigInteger(130, random).toString(16)
        val insert = "INSERT INTO users " +
            "(username, pass_salt, pass_md5) " +
            "VALUES (?, ?, ?)"
        try {
            val pstmt = dbConnection.prepareStatement(insert)
            with (pstmt) {
                setString(1, user)
                setString(2, salt)
                setString(3, md5(salt + pwd))
                val rowCount = executeUpdate()
                close()
                if (rowCount == 0) return false
            }
            return true
        }
        catch (ex: Exception) {
            return false
        }
    }

    fun authenticateUser(user: String, pwd: String): Boolean {
        val select = "SELECT pass_salt, pass_md5 FROM users WHERE username = ?"
        lateinit var res: ResultSet
        try {
            val pstmt = dbConnection.prepareStatement(select)
            with (pstmt) {
                setString(1, user)
                res = executeQuery()
                res.next()  // assuming that username is unique
                val passSalt = res.getString(1)
                val passMD5  = res.getString(2)
                close()
                return passMD5 == md5(passSalt + pwd)
            }
        }
        catch (ex: Exception) {
            return false
        }
        finally {
            if (!res.isClosed) res.close()
        }
    }

    fun closeConnection() {
        if (!dbConnection.isClosed) dbConnection.close()
    }
}

fun main(args: Array<String>) {
    val um = UserManager()
    with (um) {
        try {
            connectDB("localhost", 3306, "test", "root", "admin")
            if (createUser("johndoe", "test")) println("User created")
            if (authenticateUser("johndoe", "test")) {
                println("User authenticated")
            }
        }
        catch(ex: Exception) {
            ex.printStackTrace()
        }
        finally {
            closeConnection()
        }
    }
}

Mathematica

Needs["DatabaseLink`"];
connectDb[dbUser_, dbPass_, dbUrl_] :=
  OpenSQLConnection[JDBC["mysql", dbUrl], "Username" -> dbUser,
   "Password" -> dbPass];
createUser::nameTaken = "The username '`1`' is already taken.";
createUser[dbUser_, dbPass_, dbUrl_, user_, pass_] :=
  Module[{db = connectDb[dbUser, dbPass, dbUrl],
    salt = RandomChoice[Range[32, 127], 16]},
   If[MemberQ[SQLSelect[db, "users", {"username"}], {user}],
    Message[createUser::nameTaken, user]; Return[]];
   SQLInsert[db,
    "users", {"username", "pass_salt", "pass_md5"}, {user,
     SQLBinary[salt],
     SQLBinary[
      IntegerDigits[Hash[FromCharacterCode[salt] <> pass, "MD5"], 256,
        16]]}]; CloseSQLConnection[db];];
authenticateUser[dbUser_, dbPass_, dbUrl_, user_, pass_] :=
  Module[{db = connectDb[dbUser, dbPass, dbUrl], rtn},
   rtn = MemberQ[SQLSelect[db, "users", {"username"}], {user}] &&
     Module[{data =
        SQLSelect[db, "users", {"username", "pass_salt", "pass_md5"},
          SQLColumn["username"] == user][[1]]},
      Hash[FromCharacterCode[data[[2, 1]]] <> pass, "MD5"] ==
       FromDigits[data[[3, 1]], 256]]; CloseSQLConnection[db]; rtn];

Objeck

use ODBC;
use Encryption;

class SqlTest {
  @conn : Connection;

  function : Main(args : String[]) ~ Nil {
    SqlTest->New()->Run();
  }

  New() {
    @conn := Connection->New("test", "root", "helloworld");
  }

  method : Run() ~ Nil {
    CreateUser("objeck", "beer");
    AuthenticateUser("objeck", "beer");
    leaving {
      @conn->Close();
    };
  }

  method : AuthenticateUser(username : String, password : String) ~ Nil {
    status := false;
    ps : ParameterStatement;
    result : ResultSet;
    if(@conn->IsOpen()) {
      sql := "SELECT pass_salt, pass_md5 FROM users WHERE username = ?";
      ps := @conn->CreateParameterStatement(sql);
      ps->SetVarchar(1, username);

      result := ps->Select();
      if(result <> Nil & result->Next()) {
        salt_buffer := Byte->New[16];
        result->GetBlob(1, salt_buffer);
        salt := "";
        for(i := 0; i < 16; i+=1;) {
          salt->Append(salt_buffer[i]);
        };

        db_password_buffer := Byte->New[16];
        result->GetBlob(2, db_password_buffer);

        password->Append(salt);
        user_password_buffer := Hash->MD5(password->ToByteArray());

        IO.Console->Print("user: authenticated=")->PrintLine(IsEqual(db_password_buffer, user_password_buffer));
      };

    };

    leaving {
      if(ps <> Nil) {
        ps->Close();
      };

      if(ps <> Nil) {
        ps->Close();
      };
    };
  }

  method : CreateUser(username : String, password : String) ~ Nil {
    salt := "";
    for(i := 0; i < 16; i+=1;) { salt->Append((Float->Random() * 100)->As(Int)); };
    salt := salt->SubString(16);

    password->Append(salt);
    md5_password := Hash->MD5(password->ToByteArray());

    ps : ParameterStatement;
    if(@conn->IsOpen()) {
      sql := "INSERT INTO users(username, pass_salt, pass_md5) VALUES (?, ?, ?)";
      ps := @conn->CreateParameterStatement(sql);
      ps->SetVarchar(1, username);
      ps->SetBytes(2, salt->ToByteArray());
      ps->SetBytes(3, md5_password);

      IO.Console->Print("adding user: username=")->Print(username)
        ->Print(", salt=")->Print(salt)
        ->Print(", status=")->PrintLine(ps->Update());
    };

    leaving {
      if(ps <> Nil) {
        ps->Close();
      };
    };
  }

  method : IsEqual(left : Byte[], right : Byte[]) ~ Bool {
    if(left->Size() <> right->Size()) {
      return false;
    };

    each(i : left) {
      if(left[i] <> right[i]) {
        return false;
      };
    };

    return true;
  }
}

Perl

use DBI;

 # returns a database handle configured to throw an exception on query errors
sub connect_db {
    my ($dbname, $host, $user, $pass) = @_;
    my $db = DBI->connect("dbi:mysql:$dbname:$host", $user, $pass)
        or die $DBI::errstr;
    $db->{RaiseError} = 1;
    $db
}

 # if the user was successfully created, returns its user id.
 # if the name was already in use, returns undef.
sub create_user {
    my ($db, $user, $pass) = @_;
    my $salt = pack "C*", map {int rand 256} 1..16;
    $db->do("INSERT IGNORE INTO users (username, pass_salt, pass_md5)
        VALUES (?, ?, unhex(md5(concat(pass_salt, ?))))",
        undef, $user, $salt, $pass)
      and $db->{mysql_insertid} or undef
}

 # if the user is authentic, returns its user id.  otherwise returns undef.
sub authenticate_user {
    my ($db, $user, $pass) = @_;
    my $userid = $db->selectrow_array("SELECT userid FROM users WHERE
        username=? AND pass_md5=unhex(md5(concat(pass_salt, ?)))",
        undef, $user, $pass);
    $userid
}

Perl 6


use v6;
use DBIish;

multi connect_db(:$dbname, :$host, :$user, :$pass) {
   my $db = DBIish.connect("mysql",host => $host, database =>$dbname, user =>$user, password =>$pass, :RaiseError)
      or die "ERROR: {DBIish.errstr}.";
   $db;
}

multi create_user(:$db, :$user, :$pass) {
   #https://stackoverflow.com/questions/53365101/converting-pack-to-perl6
   my $salt = Buf.new((^256).roll(16));
   my $sth = $db.prepare(q:to/STATEMENT/);
      INSERT IGNORE INTO users (username, pass_salt, pass_md5)
      VALUES (?, ?, unhex(md5(concat(pass_salt, ?))))
   STATEMENT
   $sth.execute($user,$salt,$pass);
   $sth.insert-id or Any;
}

multi authenticate_user (:$db, :$user, :$pass) {
   my $sth = $db.prepare(q:to/STATEMENT/);
       SELECT userid FROM users WHERE
       username=? AND pass_md5=unhex(md5(concat(pass_salt, ?)))
   STATEMENT
   $sth.execute($user,$pass);
   my $userid =  $sth.fetch;
   $userid[0] or Any;
}

PHP

To use MySQL in PHP you need the php_mysql module installed


function connect_db($database, $db_user, $db_password, $host = 'localhost', $port = NULL, $die = false) {
	// Returns a MySQL link identifier (handle) on success
	// Returns false or dies() on error depending on the setting of parameter $die
	// Parameter $die configures error handling, setting it any non-false value will die() on error
	// Parameters $host, $port and $die have sensible defaults and are not usually required

	if(!$db_handle = @mysql_connect($host.($port ? ':'.$port : ''), $db_user, $db_password)) {
		if($die)
			die("Can't connect to MySQL server:\r\n".mysql_error());
		else
			return false;
	}
	if(!@mysql_select_db($database, $db_handle)) {
		if($die)
			die("Can't select database '$database':\r\n".mysql_error());
		else
			return false;
	}
	return $db_handle;
}

function create_user($username, $password, $db_handle) {
	// Returns the record ID on success or false on failure
	// Username limit is 32 characters (part of spec)
	if(strlen($username) > 32)
		return false;

	// Salt limited to ASCII 32 thru 254 (not part of spec)
	$salt = '';
	do {
		$salt .= chr(mt_rand(32, 254));
	} while(strlen($salt) < 16);

	// Create pass_md5
	$pass_md5 = md5($salt.$password);

	// Make it all binary safe
	$username = mysql_real_escape_string($username);
	$salt = mysql_real_escape_string($salt);

	// Try to insert it into the table - Return false on failure
	if(!@mysql_query("INSERT INTO users (username,pass_salt,pass_md5) VALUES('$username','$salt','$pass_md5')", $db_handle))
		return false;

	// Return the record ID
	return mysql_insert_id($db_handle);
}

function authenticate_user($username, $password, $db_handle) {
	// Checks a username/password combination against the database
	// Returns false on failure or the record ID on success

	// Make the username parmeter binary-safe
	$safe_username = mysql_real_escape_string($username);

	// Grab the record (if it exists) - Return false on failure
	if(!$result = @mysql_query("SELECT * FROM users WHERE username='$safe_username'", $db_handle))
		return false;

	// Grab the row
	$row = @mysql_fetch_assoc($result);

	// Check the password and return false if incorrect
	if(md5($row['pass_salt'].$password) != $row['pass_md5'])
		return false;

	// Return the record ID
	return $row['userid'];
}

Python

{{works with|Python|2.7}} Uses the [http://dev.mysql.com/downloads/connector/python/ official Python MySQL connector]

import mysql.connector
import hashlib

import sys
import random

DB_HOST = "localhost"
DB_USER = "devel"
DB_PASS = "devel"
DB_NAME = "test"

def connect_db():
    ''' Try to connect DB and return DB instance, if not, return False '''
    try:
        return mysql.connector.connect(host=DB_HOST, user=DB_USER, passwd=DB_PASS, db=DB_NAME)
    except:
        return False

def create_user(username, passwd):
    ''' if user was successfully created, returns its ID; returns None on error '''
    db = connect_db()
    if not db:
        print "Can't connect MySQL!"
        return None

    cursor = db.cursor()

    salt = randomValue(16)
    passwd_md5 = hashlib.md5(salt+passwd).hexdigest()

    # If username already taken, inform it
    try:
        cursor.execute("INSERT INTO users (`username`, `pass_salt`, `pass_md5`) VALUES (%s, %s, %s)", (username, salt, passwd_md5))
        cursor.execute("SELECT userid FROM users WHERE username=%s", (username,) )
        id = cursor.fetchone()
        db.commit()
        cursor.close()
        db.close()
        return id[0]
    except:
        print 'Username was already taken. Please select another'
        return None

def authenticate_user(username, passwd):
    db = connect_db()
    if not db:
        print "Can't connect MySQL!"
        return False

    cursor = db.cursor()

    cursor.execute("SELECT pass_salt, pass_md5 FROM users WHERE username=%s", (username,))

    row = cursor.fetchone()
    cursor.close()
    db.close()
    if row is None:     # username not found
        return False
    salt = row[0]
    correct_md5 = row[1]
    tried_md5 = hashlib.md5(salt+passwd).hexdigest()
    return correct_md5 == tried_md5

def randomValue(length):
    ''' Creates random value with given length'''
    salt_chars = 'abcdefghijklmnopqrstuvwxyz0123456789'

    return ''.join(random.choice(salt_chars) for x in range(length))

if __name__ == '__main__':
    user = randomValue(10)
    passwd = randomValue(16)

    new_user_id = create_user(user, passwd)
    if new_user_id is None:
        print 'Failed to create user %s' % user
        sys.exit(1)
    auth = authenticate_user(user, passwd)
    if auth:
        print 'User %s authenticated successfully' % user
    else:
        print 'User %s failed' % user

Racket

#lang racket
(require db file/md5)
(define-logger authentication)
(current-logger authentication-logger)

(define DB-HOST "localhost")
(define DB-USER "devel")
(define DB-PASS "devel")
(define DB-NAME "test")

(define (connect-db)
  (mysql-connect
   #:user DB-USER
   #:database DB-NAME
   #:password DB-PASS))

(define (salt+password->hash salt password #:hex-encode? (hex-encode? #f))
  (md5 (bytes-append salt password) hex-encode?))

(define (report-sql-error e)
  (log-authentication-error "Failed to create user:~s" (exn-message e))
  #f)

(define (create-user db username passwd)
  ; if user was successfully created, returns its ID else #f
  (define salt (list->bytes (for/list ((i (in-range 16))) (random 256))))
  (define hash (salt+password->hash salt passwd))
  (with-handlers ((exn:fail:sql? report-sql-error))
    (query db "INSERT INTO users (username, pass_salt, pass_md5) VALUES (?, ?, ?)"
           username salt hash)))

(define (authenticate-user db username password)
  (or
   (match (query-maybe-row db "SELECT pass_salt, pass_md5 FROM users WHERE username = ?" username)
     [#f #f]
     [(vector salt hash) (bytes=? hash (salt+password->hash salt password))])
   ; don't let the deviants know whether it's the username or password that's dodgy
   (error "the username, password combination does not exist in system")))

(module+ test
  (require rackunit)
  (define test-DB (connect-db))
  ; typically, you only do this the once (or risk upsetting your users bigtime!)
  ; call this just the once!
  (define (create-users-table db)
    (query-exec db "DROP TABLE IF EXISTS users")
    (query-exec db #<<EOS
CREATE TABLE users (
    userid INT PRIMARY KEY AUTO_INCREMENT,
    username VARCHAR(32) UNIQUE KEY NOT NULL,
    pass_salt tinyblob NOT NULL,
            -- a string of 16 random bytes
    pass_md5 tinyblob NOT NULL
            -- binary MD5 hash of pass_salt concatenated with the password
);
EOS
                ))
  (create-users-table test-DB)
  (create-user test-DB #"tim" #"shh! it's a secret!")
  ; ensure the user exists (for testing purposes)
  (check-match (query-list test-DB "SELECT userid FROM users WHERE username = 'tim'") (list _))
  ; (ah... but tim exists!!!)
  (check-false (create-user test-DB #"tim" #"tim's password"))
  (check-exn exn:fail? (λ () (authenticate-user test-DB #"tim" #"password")))
  (check-true (authenticate-user test-DB #"tim" #"shh! it's a secret!")))

Raven

MySQL connectivity is available out of the box. Below, we do not ever send the plain text password over the wire.

 'mysql://root@localhost/test' open as mysql
'abcdefghijklmnopqrstuvwxyz0123456789' as $salt_chars

# return userid for success and FALSE for failure.
define create_user use $user, $pass
    group 16 each as i
        $salt_chars choose chr
    join as $pass_salt
     "%($pass_salt)s%($pass)s" md5 as $pass_md5
    $user copy mysql escape as $user_name
    group 'INSERT IGNORE into users (username, pass_md5, pass_salt)'
        " VALUES ('%($user_name)s', unhex('%($pass_md5)s'), '%($pass_salt)s')"
    join mysql query inserted

# return userid for success and FALSE for failure.
define authenticate_user use $user, $pass
    FALSE as $userid
    $user copy mysql escape as $user_name
    group 'SELECT userid, pass_salt, hex(pass_md5)'
        " FROM users WHERE username = '%($user_name)s'"
    join mysql query as rs
    rs selected
    if  rs fetch values into $possible_userid, $pass_salt, $pass_md5
        "%($pass_salt)s%($pass)s" md5 $pass_md5 lower =
        if  $possible_userid as $userid
    $userid

'foo' 'bar' create_user       !if "could not create user\n"       print bye
'foo' 'bar' authenticate_user !if "could not authenticate user\n" print bye

"user successfully created and authenticated!\n" print

Ruby

Uses the [https://github.com/brianmario/mysql2 mysql2 gem]

require 'mysql2'
require 'securerandom'
require 'digest'

def connect_db(host, port = nil, username, password, db)
  Mysql2::Client.new(
    host: host,
    port: port,
    username: username,
    password: password,
    database: db
  )
end

def create_user(client, username, password)
  salt = SecureRandom.random_bytes(16)
  password_md5 = Digest::MD5.hexdigest(salt + password)

  statement = client.prepare('INSERT INTO users (username, pass_salt, pass_md5) VALUES (?, ?, ?)')
  statement.execute(username, salt, password_md5)
  statement.last_id
end

def authenticate_user(client, username, password)
  user_record = client.prepare("SELECT SELECT pass_salt, pass_md5 FROM users WHERE username = '#{client.escape(username)}'").first
  return false unless user_record

  password_md5 = Digest::MD5.hexdigest(user_record['pass_salt'] + password)
  password_md5 == user_record['pass_md5']
end

Sidef

require('DBI')

 # returns a database handle configured to throw an exception on query errors
func connect_db(dbname, host, user, pass) {
    var db = %s<DBI>.connect("dbi:mysql:#{dbname}:#{host}", user, pass)
    db || die (global DBI::errstr)
    db{:RaiseError} = 1
    db
}

 # if the user was successfully created, returns its user id.
 # if the name was already in use, returns nil.
func create_user(db, user, pass) {
    var salt = "C*".pack(16.of { 256.irand }...)
    db.do(
        "INSERT IGNORE INTO users (username, pass_salt, pass_md5)
         VALUES (?, ?, unhex(md5(concat(pass_salt, ?))))", nil, user, salt, pass
    ) ? db{:mysql_insertid} : nil
}

 # if the user is authentic, returns its user id.  otherwise returns nil.
func authenticate_user(db, user, pass) {
    db.selectrow_array("SELECT userid FROM users WHERE
        username=? AND pass_md5=unhex(md5(concat(pass_salt, ?)))",
        nil, user, pass
    )
}

Tcl

{{works with|Tcl|8.6}} Also requires the TDBC driver for MySQL.

package require tdbc

proc connect_db {handleName dbname host user pass} {
    package require tdbc::mysql
    tdbc::mysql::connection create $handleName -user $user -passwd $pass \
        -host $host -database $dbname
    return $handleName
}

# A simple helper to keep code shorter
proc r64k {} {
    expr int(65536*rand())
}

proc create_user {handle user pass} {
    set salt [binary format ssssssss \
        [r64k] [r64k] [r64k] [r64k] [r64k] [r64k] [r64k] [r64k]]
    # Note that we are using named parameters below, :user :salt :pass
    # They are bound automatically to local variables with the same name
    $handle allrows {
        INSERT IGNORE INTO users (username, pass_salt, pass_md5)
            VALUES (:user, :salt, unhex(md5(concat(:salt, :pass))))
    }
    return   ;# Ignore the result of the allrows method
}

proc authenticate_user {handle user pass} {
    $handle foreach row {
        SELECT userid FROM users WHERE
            username=:user AND pass_md5=unhex(md5(concat(pass_salt, :pass)))
    } {
        return [dict get $row userid]
    }
    # Only get here if no rows selected
    error "authentication failed for user \"$user\""
}

{{omit from|Batch File|Does not have network access.}} {{omit from|Brainfuck}} {{omit from|Lotus 123 Macro Scripting}} {{omit from|M4}} {{omit from|Maxima}} {{omit from|ML/I}} {{omit from|PARI/GP}} {{omit from|PostScript}} {{omit from|Retro|We have support for sqlite, but not MySQL}} {{omit from|SNOBOL4}} {{omit from|SQL|except maybe MySQL where this becomes trivial?}} {{omit from|SQL PL|Db2 is a database}} {{omit from|TI-83 BASIC}} {{omit from|TI-89 BASIC}} {{omit from|Unlambda|Does not have network access.}} {{omit from|Yorick|Does not have network access.}} {{omit from|ZX Spectrum Basic|Does not have network access.}}