Beispiel #1
0
 internal static bool IsDHSessionCompatible(Protocol protocol, string associationType, string sessionType)
 {
     // Under HTTPS, no DH encryption is required regardless of association type.
     if (string.Equals(sessionType, protocol.Args.SessionType.NoEncryption, StringComparison.Ordinal))
     {
         return(true);
     }
     // When there _is_ a DH session, it must match in hash length with the association type.
     foreach (HmacSha sha in HmacShaAssociationTypes)
     {
         if (string.Equals(associationType, sha.GetAssociationType(protocol), StringComparison.Ordinal))
         {
             int    hashSizeInBits      = sha.SecretLength * 8;
             string matchingSessionName = DiffieHellmanUtil.GetNameForSize(protocol, hashSizeInBits);
             if (string.Equals(sessionType, matchingSessionName, StringComparison.Ordinal))
             {
                 return(true);
             }
         }
     }
     return(false);
 }
Beispiel #2
0
        /// <summary>
        /// Looks for the longest hash length for a given protocol for which we have an association,
        /// and perhaps a matching Diffie-Hellman session type.
        /// </summary>
        /// <param name="protocol">The OpenID version that dictates which associations are available.</param>
        /// <param name="minimumHashSizeInBits">The minimum required hash length given security settings.</param>
        /// <param name="maximumHashSizeInBits">The maximum hash length to even attempt.  Useful for the RP side where we support SHA512 but most OPs do not -- why waste time trying?</param>
        /// <param name="requireMatchingDHSessionType">True for HTTP associations, False for HTTPS associations.</param>
        /// <param name="associationType">The resulting association type's well known protocol name.  (i.e. HMAC-SHA256)</param>
        /// <param name="sessionType">The resulting session type's well known protocol name, if a matching one is available.  (i.e. DH-SHA256)</param>
        internal static bool TryFindBestAssociation(Protocol protocol,
                                                    int?minimumHashSizeInBits, int?maximumHashSizeInBits, bool requireMatchingDHSessionType,
                                                    out string associationType, out string sessionType)
        {
            if (protocol == null)
            {
                throw new ArgumentNullException("protocol");
            }
            associationType = null;
            sessionType     = null;

            // We assume this enumeration is in decreasing bit length order.
            foreach (HmacSha sha in HmacShaAssociationTypes)
            {
                int hashSizeInBits = sha.SecretLength * 8;
                if (maximumHashSizeInBits.HasValue && hashSizeInBits > maximumHashSizeInBits.Value)
                {
                    continue;
                }
                if (minimumHashSizeInBits.HasValue && hashSizeInBits < minimumHashSizeInBits.Value)
                {
                    break;
                }
                sessionType = DiffieHellmanUtil.GetNameForSize(protocol, hashSizeInBits);
                if (requireMatchingDHSessionType && sessionType == null)
                {
                    continue;
                }
                associationType = sha.GetAssociationType(protocol);
                if (associationType == null)
                {
                    continue;
                }

                return(true);
            }
            return(false);
        }