1 files changed, 58 insertions, 0 deletions
diff --git a/src/DotNetOpenId/SecuritySettings.cs b/src/DotNetOpenId/SecuritySettings.cs
new file mode 100644
index 0000000..fb9c079
--- /dev/null
+++ b/src/DotNetOpenId/SecuritySettings.cs
@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DotNetOpenId {
+	/// <summary>
+	/// Security settings that may be applicable to both relying parties and providers.
+	/// </summary>
+	public class SecuritySettings {
+		internal SecuritySettings(bool isProvider) {
+			if (isProvider) {
+				maximumHashBitLength = maximumHashBitLengthOPDefault;
+			}
+		}
+
+		internal const int minimumHashBitLengthDefault = 160;
+		int minimumHashBitLength = minimumHashBitLengthDefault;
+		/// <summary>
+		/// Gets/sets the minimum hash length (in bits) allowed to be used in an <see cref="Association"/>
+		/// with the remote party.  The default is 160.
+		/// </summary>
+		/// <remarks>
+		/// SHA-1 (160 bits) has been broken.  The minimum secure hash length is now 256 bits.
+		/// The default is still a 160 bit minimum to allow interop with common remote parties,
+		/// such as Yahoo! that only supports 160 bits.  
+		/// For sites that require high security such as to store bank account information and 
+		/// health records, 256 is the recommended value.
+		/// </remarks>
+		public int MinimumHashBitLength {
+			get { return minimumHashBitLength; }
+			set { minimumHashBitLength = value; }
+		}
+		internal const int maximumHashBitLengthRPDefault = 256;
+		internal const int maximumHashBitLengthOPDefault = 512;
+		int maximumHashBitLength = maximumHashBitLengthRPDefault;
+		/// <summary>
+		/// Gets/sets the maximum hash length (in bits) allowed to be used in an <see cref="Association"/>
+		/// with the remote party.  The default is 256 for relying parties and 512 for providers.
+		/// </summary>
+		/// <remarks>
+		/// The longer the bit length, the more secure the identities of your visitors are.
+		/// Setting a value higher than 256 on a relying party site may reduce performance
+		/// as many association requests will be denied, causing secondary requests or even
+		/// authentication failures.
+		/// Setting a value higher than 256 on a provider increases security where possible
+		/// without these side-effects.
+		/// </remarks>
+		public int MaximumHashBitLength {
+			get { return maximumHashBitLength; }
+			set { maximumHashBitLength = value; }
+		}
+
+		internal bool IsAssociationInPermittedRange(Protocol protocol, string associationType) {
+			int lengthInBits = HmacShaAssociation.GetSecretLength(protocol, associationType) * 8;
+			return lengthInBits >= MinimumHashBitLength && lengthInBits <= MaximumHashBitLength;
+		}
+	}
+}