Simplify user verification state

MatrixSDK/Crypto/CrossSigning/Data/MXCrossSigningInfo.h

@@ -17,7 +17,6 @@
 #import <Foundation/Foundation.h>
 
 #import "MXCrossSigningKey.h"
-#import "MXUserTrustLevel.h"
 
 @class MXCryptoUserIdentityWrapper;
 
@@ -56,7 +55,7 @@ extern NSString *const MXCrossSigningInfoTrustLevelDidChangeNotification;
 
 #pragma mark - Additional information
 
-@property (nonatomic, readonly) MXUserTrustLevel *trustLevel;
+@property (nonatomic, readonly) BOOL isVerified;
 
 @end
 

MatrixSDK/Crypto/CrossSigning/Data/MXCrossSigningInfo.m

@@ -21,6 +21,40 @@
 
 NSString *const MXCrossSigningInfoTrustLevelDidChangeNotification = @"MXCrossSigningInfoTrustLevelDidChangeNotification";
 
+#pragma mark - Deprecated user trust
+
+/**
+ Deprecated model of user trust that distinguished local vs cross-signing verification
+ 
+ This model is no longer used and is replaced by a combined `isVerified` property on `MXCrossSigningInfo`.
+ For backwards compatibility (reading archived values) the model needs to be kept around, albeit as private only.
+ */
+@interface MXDeprecatedUserTrustLevel : NSObject <NSCoding>
+@property (nonatomic, readonly) BOOL isCrossSigningVerified;
+@property (nonatomic, readonly) BOOL isLocallyVerified;
+@end
+
+@implementation MXDeprecatedUserTrustLevel
+- (id)initWithCoder:(NSCoder *)aDecoder
+{
+    self = [super init];
+    if (self)
+    {
+        _isCrossSigningVerified = [aDecoder decodeBoolForKey:@"isCrossSigningVerified"];
+        _isLocallyVerified = [aDecoder decodeBoolForKey:@"isLocallyVerified"];
+    }
+    return self;
+}
+
+- (void)encodeWithCoder:(NSCoder *)aCoder
+{
+    [aCoder encodeBool:_isCrossSigningVerified forKey:@"isCrossSigningVerified"];
+    [aCoder encodeBool:_isLocallyVerified forKey:@"isLocallyVerified"];
+}
+@end
+
+#pragma mark - CrossSigningInfo
+
 @implementation MXCrossSigningInfo
 
 - (instancetype)initWithUserIdentity:(MXCryptoUserIdentityWrapper *)userIdentity
@@ -43,7 +77,7 @@ - (instancetype)initWithUserIdentity:(MXCryptoUserIdentityWrapper *)userIdentity
             keys[MXCrossSigningKeyType.userSigning] = userIdentity.userSignedKeys;
         }
         _keys = keys.copy;
-        _trustLevel = userIdentity.trustLevel;
+        _isVerified = userIdentity.isVerified;
     }
     return self;
 }
@@ -92,7 +126,21 @@ - (id)initWithCoder:(NSCoder *)aDecoder
     {
         _userId = [aDecoder decodeObjectForKey:@"userId"];
         _keys = [aDecoder decodeObjectForKey:@"keys"];
-        _trustLevel = [aDecoder decodeObjectForKey:@"trustLevel"];
+
+        // Initial version (i.e. version 0) of the model stored user trust via `MXUserTrustLevel` submodel.
+        // If we are reading this version out we need to decode verification state from this model before
+        // migrating it over to `isVerified`
+        NSInteger version = [aDecoder decodeIntegerForKey:@"version"];
+        if (version == 0)
+        {
+            [NSKeyedUnarchiver setClass:MXDeprecatedUserTrustLevel.class forClassName:@"MXUserTrustLevel"];
+            MXDeprecatedUserTrustLevel *trust = [aDecoder decodeObjectForKey:@"trustLevel"];
+            _isVerified = trust.isLocallyVerified || trust.isCrossSigningVerified;
+        }
+        else
+        {
+            _isVerified = [aDecoder decodeBoolForKey:@"isVerified"];
+        }
     }
     return self;
 }
@@ -101,7 +149,8 @@ - (void)encodeWithCoder:(NSCoder *)aCoder
 {
     [aCoder encodeObject:_userId forKey:@"userId"];
     [aCoder encodeObject:_keys forKey:@"keys"];
-    [aCoder encodeObject:_trustLevel forKey:@"trustLevel"];
+    [aCoder encodeBool:_isVerified forKey:@"isVerified"];
+    [aCoder encodeInteger:1 forKey:@"version"];
 }
 
 
@@ -113,31 +162,23 @@ - (instancetype)initWithUserId:(NSString *)userId
     if (self)
     {
         _userId = userId;
-        _trustLevel = [MXUserTrustLevel new];
+        _isVerified = NO;
     }
     return self;
 }
 
-- (void)setTrustLevel:(MXUserTrustLevel*)trustLevel
-{
-    _trustLevel = trustLevel;
-}
-
-- (BOOL)updateTrustLevel:(MXUserTrustLevel*)trustLevel
+- (void)setIsVerified:(BOOL)isVerified
 {
-    BOOL updated = NO;
-
-    if (![_trustLevel isEqual:trustLevel])
+    if (_isVerified == isVerified)
     {
-        _trustLevel = trustLevel;
-        updated = YES;
-        [self didUpdateTrustLevel];
+        return;
     }
-
-    return updated;
+
+    _isVerified = isVerified;
+    [self didUpdateVerificationState];
 }
 
-- (void)didUpdateTrustLevel
+- (void)didUpdateVerificationState
 {
     dispatch_async(dispatch_get_main_queue(),^{
         [[NSNotificationCenter defaultCenter] postNotificationName:MXCrossSigningInfoTrustLevelDidChangeNotification object:self userInfo:nil];
@@ -158,7 +199,7 @@ - (void)addCrossSigningKey:(MXCrossSigningKey*)crossSigningKey type:(NSString*)t
 
 - (NSString *)description
 {
-    return [NSString stringWithFormat:@"<MXCrossSigningInfo: %p> Trusted: %@\nMSK: %@\nSSK: %@\nUSK: %@", self, @(self.trustLevel.isCrossSigningVerified), self.masterKeys, self.selfSignedKeys, self.userSignedKeys];
+    return [NSString stringWithFormat:@"<MXCrossSigningInfo: %p> Verified: %@\nMSK: %@\nSSK: %@\nUSK: %@", self, @(self.isVerified), self.masterKeys, self.selfSignedKeys, self.userSignedKeys];
 }
 
 @end

MatrixSDK/Crypto/CrossSigning/Data/MXCrossSigningInfo_Private.h

@@ -23,8 +23,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (instancetype)initWithUserId:(NSString *)userId;
 
-- (void)setTrustLevel:(MXUserTrustLevel*)trustLevel;
-- (BOOL)updateTrustLevel:(MXUserTrustLevel*)trustLevel;
+- (void)setIsVerified:(BOOL)isVerified;
 - (void)addCrossSigningKey:(MXCrossSigningKey*)crossSigningKey type:(NSString*)type;
 
 @end

MatrixSDK/Crypto/CrossSigning/Data/MXCryptoUserIdentityWrapper.swift

@@ -27,7 +27,7 @@ import MatrixSDKCrypto
     public let masterKeys: MXCrossSigningKey?
     public let selfSignedKeys: MXCrossSigningKey?
     public let userSignedKeys: MXCrossSigningKey?
-    public let trustLevel: MXUserTrustLevel
+    public let isVerified: Bool
 
     internal init(identity: UserIdentity, isVerified: Bool) {
         switch identity {
@@ -43,13 +43,7 @@ import MatrixSDKCrypto
             self.selfSignedKeys = .init(jsonString: selfSigningKey)
             self.userSignedKeys = nil
         }
-
-        // `MatrixSDKCrypto` does not distinguish local and cross-signed
-        // verification status for users
-        trustLevel = MXUserTrustLevel(
-            crossSigningVerified: isVerified,
-            locallyVerified: isVerified
-        )
+        self.isVerified = isVerified
     }
 }
 

MatrixSDK/Crypto/CrossSigning/MXCrossSigning.m

@@ -135,7 +135,7 @@ - (void)setupWithAuthParams:(NSDictionary*)authParams
         [self.crypto.matrixRestClient uploadDeviceSigningKeys:signingKeys authParams:authParams success:^{
 
             // Store our user's keys
-            [keys updateTrustLevel:[MXUserTrustLevel trustLevelWithCrossSigningVerified:YES locallyVerified:YES]];
+            [keys setIsVerified:YES];
             [self.crypto.store storeCrossSigningKeys:keys];
 
             // Cross-signing is bootstrapped
@@ -585,7 +585,7 @@ - (BOOL)isDeviceVerified:(MXDeviceInfo*)device
     BOOL isDeviceVerified = NO;
 
     MXCrossSigningInfo *userCrossSigning = [self.crypto.store crossSigningKeysForUser:device.userId];
-    MXUserTrustLevel *userTrustLevel = [self.crypto trustLevelForUser:device.userId];
+    BOOL isUserVerified = [self.crypto isUserVerified:device.userId];
 
     MXCrossSigningKey *userSSK = userCrossSigning.selfSignedKeys;
     if (!userSSK)
@@ -610,7 +610,7 @@ - (BOOL)isDeviceVerified:(MXDeviceInfo*)device
     // ...then we trust this device as much as far as we trust the user
     if (userSSKVerify && deviceVerify)
     {
-        isDeviceVerified = userTrustLevel.isCrossSigningVerified;
+        isDeviceVerified = isUserVerified;
     }
 
     return isDeviceVerified;
@@ -685,17 +685,14 @@ - (void)resetTrust
     for (MXCrossSigningInfo *crossSigningInfo in self.crypto.store.crossSigningKeys)
     {
         BOOL isCrossSigningVerified = [self isUserWithCrossSigningKeysVerified:crossSigningInfo];
-        if (crossSigningInfo.trustLevel.isCrossSigningVerified != isCrossSigningVerified)
+        if (crossSigningInfo.isVerified != isCrossSigningVerified)
         {
             MXLogDebug(@"[MXCrossSigning] resetTrust: Change trust for %@: %@ -> %@", crossSigningInfo.userId,
-                  @(crossSigningInfo.trustLevel.isCrossSigningVerified),
+                  @(crossSigningInfo.isVerified),
                   @(isCrossSigningVerified));
 
-            MXUserTrustLevel *newTrustLevel = [MXUserTrustLevel trustLevelWithCrossSigningVerified:isCrossSigningVerified locallyVerified:crossSigningInfo.trustLevel.isLocallyVerified];
-            if ([crossSigningInfo updateTrustLevel:newTrustLevel])
-            {
-                [self.crypto.store storeCrossSigningKeys:crossSigningInfo];
-            }
+            [crossSigningInfo setIsVerified:isCrossSigningVerified];
+            [self.crypto.store storeCrossSigningKeys:crossSigningInfo];
 
             // Update trust on associated devices
             [self checkTrustLevelForDevicesOfUser:crossSigningInfo.userId];
@@ -747,7 +744,7 @@ - (BOOL)isSelfTrusted
 
     // Is the master key trusted?
     MXCrossSigningInfo *myCrossSigningInfo = [_crypto.store crossSigningKeysForUser:myUserId];
-    if (myCrossSigningInfo && myCrossSigningInfo.trustLevel.isLocallyVerified)
+    if (myCrossSigningInfo && myCrossSigningInfo.isVerified)
     {
         isMasterKeyTrusted = YES;
     }

MatrixSDK/Crypto/CrossSigning/MXCrossSigningV2.swift

@@ -28,7 +28,7 @@ class MXCrossSigningV2: NSObject, MXCrossSigning {
             return .notBootstrapped
         }
 
-        if info.trustLevel.isVerified {
+        if info.isVerified {
             return hasAllPrivateKeys ? .canCrossSign : .trustCrossSigning
         } else {
             return .crossSigningExists
@@ -217,17 +217,11 @@ class MXCrossSigningV2: NSObject, MXCrossSigning {
 }
 
 extension MXCrossSigningV2: MXRecoveryServiceDelegate {
-    func setUserVerification(
-        _ verificationStatus: Bool,
-        forUser userId: String,
+    func setUserVerificationForUserId(
+        _ userId: String,
         success: @escaping () -> Void,
         failure: @escaping (Swift.Error?) -> Void
     ) {
-        guard verificationStatus else {
-            log.failure("Cannot unset user trust")
-            failure(Error.cannotUnsetTrust)
-            return
-        }
         signUser(withUserId: userId, success: success, failure: failure)
     }
 }

MatrixSDK/Crypto/Data/MXDeviceListOperationsPool.m

@@ -137,24 +137,11 @@ - (void)doKeyDownloadForUsers:(NSArray<NSString *> *)users token:(NSString *)tok
                     MXLogDebug(@"[MXDeviceListOperationsPool] doKeyDownloadForUsers: Detected cross-signing keys rotation");
                     myUserCrossSigningKeysChanged = YES;
                 }
-
-                // Use current trust level
-                MXUserTrustLevel *oldTrustLevel = storedCrossSigningKeys.trustLevel;
-                if (myUserCrossSigningKeysChanged)
-                {
-                    // Except if we cannot trust it anymore
-                    oldTrustLevel = [MXUserTrustLevel new];
-                }
-
-                [crossSigningKeys setTrustLevel:oldTrustLevel];
 
                 // Compute trust on this user
                 // Note this overwrites the previous value
                 BOOL isCrossSigningVerified = [self.crossSigning isUserWithCrossSigningKeysVerified:crossSigningKeys];
-                MXUserTrustLevel *newTrustLevel = [MXUserTrustLevel trustLevelWithCrossSigningVerified:isCrossSigningVerified
-                                                                                       locallyVerified:oldTrustLevel.isLocallyVerified];
-
-                [crossSigningKeys updateTrustLevel:newTrustLevel];
+                [crossSigningKeys setIsVerified:isCrossSigningVerified];
 
                 // Note that keys which aren't in the response will be removed from the store
                 [self->crypto.store storeCrossSigningKeys:crossSigningKeys];

MatrixSDK/Crypto/MXCrypto.h

@@ -229,19 +229,22 @@ extern NSString *const MXDeviceListDidUpdateUsersDevicesNotification;
                       failure:(nullable void (^)(NSError *error))failure;
 
 /**
- Update the verification state of the given user.
+ Verify the given user via cross-signing
  
- @param verificationStatus the new verification status.
  @param userId the user.
  
  @param success A block object called when the operation succeeds.
  @param failure A block object called when the operation fails.
  */
-- (void)setUserVerification:(BOOL)verificationStatus forUser:(NSString*)userId
-                    success:(nullable void (^)(void))success
-                    failure:(nullable void (^)(NSError *error))failure;
+- (void)setUserVerificationForUserId:(NSString*)userId
+                             success:(nullable void (^)(void))success
+                             failure:(nullable void (^)(NSError *error))failure;
+
+/**
+ Is the user verified via cross-signing
+ */
+- (BOOL)isUserVerified:(NSString *)userId;
 
-- (MXUserTrustLevel*)trustLevelForUser:(NSString*)userId;
 - (nullable MXDeviceTrustLevel*)deviceTrustLevelForDevice:(NSString*)deviceId ofUser:(NSString*)userId;
 
 /**