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using System.Security.Cryptography;

namespace MySql.Data.MySqlClient.Authentication
{
    /// <summary>
    /// The SCRAM-SHA-1 SASL mechanism.
    /// </summary>
    /// <remarks>
    /// A salted challenge/response SASL mechanism that uses the HMAC SHA-1 algorithm.
    /// </remarks>
    internal class ScramSha1Mechanism : ScramBase
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="ScramSha1Mechanism"/> class.
        /// </summary>
        /// <remarks>
        /// Creates a new SCRAM-SHA-1 SASL context.
        /// </remarks>
        /// <param name="username">The user name.</param>
        /// <param name="password">The password.</param>
        /// <param name="host">The host.</param>
        internal ScramSha1Mechanism(string username, string password, string host) : base(username, password, host) { }

        /// <summary>
        /// Gets the name of the method.
        /// </summary>
        internal override string MechanismName
        {
            get { return "SCRAM-SHA-1"; }
        }

        protected override KeyedHashAlgorithm CreateHMAC(byte[] key)
        {
            return new HMACSHA1(key);
        }

        protected override byte[] Hash(byte[] str)
        {
            using (var sha1 = SHA1.Create())
            {
                return sha1.ComputeHash(str);
            }
        }
    }
}