Merge pull request #19 from AElfProject/feat/Web_API

Adding WEB API pages

docs/Architecture/Cross Chain/Verify.md

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+# Cross Chain Transaction Verification
+
+This section provides guidance on verifying transactions across different blockchain chains, assuming that a side chain has already been deployed and indexed by the main chain.
+
+## Sending a Transaction
+
+Any transaction with the status "Mined" can be verified, provided that the transaction has been indexed.
+
+## Verifying the Transaction
+
+There are two scenarios for verification:
+
+- Verifying a transaction on the main chain.
+- Verifying a transaction on a side chain.
+
+```protobuf
+rpc VerifyTransaction (VerifyTransactionInput) returns (google.protobuf.BoolValue) {
+  option (aelf.is_view) = true;
+}
+
+message VerifyTransactionInput {
+    aelf.Hash transaction_id = 1;
+    aelf.MerklePath path = 2;
+    int64 parent_chain_height = 3;
+    int32 verified_chain_id = 4;
+}
+```
+
+The **VerifyTransaction** method is used for verification and returns whether the transaction was mined and indexed by the destination chain. The method is the same for both scenarios; only the input values differ.
+
+### Verifying a Main Chain Transaction
+
+To verify a main chain transaction on a side chain, use the **VerifyTransaction** method on the side chain with the following input values:
+
+- `parent_chain_height`: The height of the block on the main chain where the transaction was packed.
+- `transaction_id`: The ID of the transaction to verify.
+- `path`: The Merkle path obtained from the main chain's API using **GetMerklePathByTransactionIdAsync** with the transaction ID.
+- `verified_chain_id`: The chain ID of the main chain.
+
+You can retrieve the Merkle path of a transaction in a block by using the chain's API method **GetMerklePathByTransactionIdAsync**.
+
+### Verifying a Side Chain Transaction
+
+For verifying a side chain transaction:
+
+1. Obtain the Merkle path using **GetMerklePathByTransactionIdAsync**, similar to main chain verification.
+2. Retrieve the `CrossChainMerkleProofContext` of the transaction from the source chain using **GetBoundParentChainHeightAndMerklePathByHeight**.
+
+```protobuf
+rpc GetBoundParentChainHeightAndMerklePathByHeight (google.protobuf.Int64Value) returns (CrossChainMerkleProofContext) {
+    option (aelf.is_view) = true;
+}
+
+message CrossChainMerkleProofContext {
+    int64 bound_parent_chain_height = 1;
+    aelf.MerklePath merkle_path_from_parent_chain = 2;
+}
+```
+
+Using the result from the above API, call **VerifyTransaction** on the target chain with:
+
+- `transaction_id`: The ID of the transaction to verify.
+- `parent_chain_height`: Use the `bound_parent_chain_height` field from `CrossChainMerkleProofContext`.
+- `path`: Concatenate the two Merkle paths in order:
+  - The Merkle path of the transaction (obtained from **GetMerklePathByTransactionIdAsync**).
+  - The `merkle_path_from_parent_chain` field from `CrossChainMerkleProofContext`.
+- `verified_chain_id`: The chain ID of the side chain where the transaction was mined.