replace OLM SHA256 with the native one

Author: Velin92

MatrixSDK/Crypto/CrossSigning/MXCrossSigningTools.h

@@ -16,8 +16,6 @@
 
 #import <Foundation/Foundation.h>
 
-#import "MXCrossSigningKey.h"
-
 NS_ASSUME_NONNULL_BEGIN
 
 

MatrixSDK/Crypto/CrossSigning/MXCrossSigningTools.m

@@ -16,11 +16,6 @@
 
 #import "MXCrossSigningTools.h"
 
-#import "MXCryptoTools.h"
-#import "MXKey.h"
-#import "MXCryptoConstants.h"
-#import "MXBase64Tools.h"
-
 #pragma mark - Constants
 
 NSString *const MXCrossSigningToolsErrorDomain = @"org.matrix.sdk.crosssigning.tools";

MatrixSDK/IdentityServer/MXIdentityServerRestClient.m

@@ -17,6 +17,7 @@
 #import "MXIdentityServerRestClient.h"
 
 #import <AFNetworking/AFNetworking.h>
+#import <CommonCrypto/CommonDigest.h>
 
 #import "MXHTTPClient.h"
 #import "MXError.h"
@@ -385,6 +386,17 @@ - (MXHTTPOperation*)lookup3pids:(NSArray<NSArray<NSString*>*> *)threepids
                     hashedTreePid = [NSString stringWithFormat:@"%@ %@", threepid, medium];
                     break;
                 case MXIdentityServerHashAlgorithmSHA256:
+                {
+                    NSString *threePidConcatenation = [NSString stringWithFormat:@"%@ %@ %@", threepid, medium, pepper];
+
+                    // Hash the concatenated string using the helper method
+                    NSString *hashedSha256ThreePid = sha256(threePidConcatenation);
+
+                    // Convert hashed SHA-256 string to base64 URL
+                    hashedTreePid = [MXBase64Tools base64ToBase64Url:hashedSha256ThreePid];
+                    
+                    threePidArrayByThreePidConcatHash[hashedTreePid] = threepidArray;
+                }
                     break;
                 default:
                     break;
@@ -473,6 +485,20 @@ - (MXHTTPOperation*)lookup3pids:(NSArray<NSArray<NSString*>*> *)threepids
 
 }
 
+// Helper method to perform SHA256 hashing
+NSString *sha256(NSString *input) {
+    const char *str = [input UTF8String];
+    unsigned char result[CC_SHA256_DIGEST_LENGTH];
+    CC_SHA256(str, (CC_LONG)strlen(str), result);
+    
+    NSMutableString *hash = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH * 2];
+    for (int i = 0; i < CC_SHA256_DIGEST_LENGTH; i++) {
+        [hash appendFormat:@"%02x", result[i]];
+    }
+    
+    return hash;
+}
+
 #pragma mark Establishing associations
 
 - (MXHTTPOperation*)requestEmailValidation:(NSString*)email