diff --git a/examples/spdm_requester.rs b/examples/spdm_requester.rs
index a8d8440..335143f 100644
--- a/examples/spdm_requester.rs
+++ b/examples/spdm_requester.rs
@@ -323,7 +323,7 @@ fn full_flow(stream: TcpStream, config: &RequesterConfig) -> IoResult<()> {
         &mut message_buffer,
         Some(&ext_asym),
         Some(&ext_hash),
-        alg_structure,
+        Some(alg_structure),
         Some(&alg_external),
     )
     .unwrap();
diff --git a/src/commands/algorithms/mod.rs b/src/commands/algorithms/mod.rs
index 0c2a603..1a3e601 100644
--- a/src/commands/algorithms/mod.rs
+++ b/src/commands/algorithms/mod.rs
@@ -150,9 +150,10 @@ impl NegotiateAlgorithmsReq {
         other_param_support: OtherParamSupport,
         base_asym_algo: BaseAsymAlgo,
         base_hash_algo: BaseHashAlgo,
-        ext_asyn_count: u8,
+        ext_asym_count: u8,
         ext_hash_count: u8,
         mel_specification: MelSpecification,
+        alg_ext_count: u8,
     ) -> SpdmResult<NegotiateAlgorithmsReq> {
         let mut req = NegotiateAlgorithmsReq {
             num_alg_struct_tables,
@@ -163,13 +164,14 @@ impl NegotiateAlgorithmsReq {
             base_asym_algo,
             base_hash_algo,
             reserved_1: [0u8; 12],
-            ext_asym_count: ext_asyn_count,
+            ext_asym_count,
             ext_hash_count,
             reserved_2: 0,
             mel_specification,
         };
 
-        req.length = req.min_req_len();
+        req.length = req.min_req_len()
+            + (size_of::<ExtendedAlgo>() * alg_ext_count as usize) as u16;
 
         if req.length > MAX_SPDM_REQUEST_LENGTH {
             return Err(SpdmError::InvalidParam);
@@ -188,8 +190,7 @@ impl NegotiateAlgorithmsReq {
             + size_of::<NegotiateAlgorithmsReq>()
             + total_alg_struct_len
             + total_ext_asym_len
-            + total_ext_hash_len
-            + 4) as u16
+            + total_ext_hash_len) as u16
     }
 
     /// Calculate the size of the extended algorithm structures in bytes.
diff --git a/src/commands/algorithms/request.rs b/src/commands/algorithms/request.rs
index 4a3255d..7f8d2c1 100644
--- a/src/commands/algorithms/request.rs
+++ b/src/commands/algorithms/request.rs
@@ -169,7 +169,7 @@ pub fn generate_negotiate_algorithms_request<'a>(
     req_buf: &mut MessageBuf<'a>,
     ext_asym: Option<&'a [ExtendedAlgo]>,
     ext_hash: Option<&'a [ExtendedAlgo]>,
-    req_alg_struct: AlgStructure,
+    req_alg_struct: Option<AlgStructure>,
     alg_external: Option<&'a [ExtendedAlgo]>, // req_alg_struct.AlgCount.ExtAlgCount many
 ) -> CommandResult<()> {
     let local_algorithms = &ctx.local_algorithms.device_algorithms;
@@ -184,9 +184,12 @@ pub fn generate_negotiate_algorithms_request<'a>(
         None => 0,
     };
 
+    let num_alg_struct_tables = req_alg_struct.is_some() as u8;
+    let alg_ext_count = req_alg_struct.map_or(0, |s| s.ext_alg_count());
+
     // Generate base structure **without** the variable length structures
     let negotiate_algorithms_req = NegotiateAlgorithmsReq::new(
-        req_alg_struct.ext_alg_count(),
+        num_alg_struct_tables,
         0, // param2
         local_algorithms.measurement_spec,
         local_algorithms.other_param_support,
@@ -195,6 +198,7 @@ pub fn generate_negotiate_algorithms_request<'a>(
         ext_asym_count,
         ext_hash_count,
         local_algorithms.mel_specification,
+        alg_ext_count,
     )
     .map_err(|_| (false, CommandError::UnsupportedRequest))?;
 
@@ -253,27 +257,23 @@ pub fn generate_negotiate_algorithms_request<'a>(
         }
     }
 
-    // 3.2
-    if req_alg_struct.fixed_alg_count() != 0 && !req_alg_struct.is_multiple() {
-        return Err((false, CommandError::UnsupportedRequest));
-    }
+    // 3.3 + 3.4: encode AlgStructure and its extended algorithms if present
+    if let Some(alg_struct) = req_alg_struct {
+        if alg_struct.fixed_alg_count() != 0 && !alg_struct.is_multiple() {
+            return Err((false, CommandError::UnsupportedRequest));
+        }
 
-    // If this is 1, we have an additional extended algorithm structure to add.
-    if negotiate_algorithms_req.num_alg_struct_tables > 0 {
-        // 3.3
-        req_alg_struct
+        alg_struct
             .encode(req_buf)
             .map_err(|e| (false, CommandError::Codec(e)))?;
 
-        // 3.4
-        if let Some(extended_algos) = alg_external {
+        // If ext_alg_count > 0, we must have the extended algorithm structures.
+        if alg_struct.ext_alg_count() > 0 {
+            let extended_algos = alg_external.ok_or((false, CommandError::UnsupportedRequest))?;
             for ext in extended_algos {
                 ext.encode(req_buf)
                     .map_err(|e| (false, CommandError::Codec(e)))?;
             }
-        } else {
-            // If ext_alg_count > 0, we must have the extended algorithm structure.
-            return Err((false, CommandError::UnsupportedRequest));
         }
     }
 
diff --git a/src/commands/algorithms/response.rs b/src/commands/algorithms/response.rs
index ed9540b..adf0631 100644
--- a/src/commands/algorithms/response.rs
+++ b/src/commands/algorithms/response.rs
@@ -134,6 +134,13 @@ fn process_negotiate_algorithms_request<'a>(
         if fixed_alg_count != 2 {
             Err(ctx.generate_error_response(req_payload, ErrorCode::InvalidRequest, 0, None))?;
         }
+
+        // Skip extended algorithm structures embedded in this AlgStructure
+        for _ in 0..ext_alg_count {
+            ExtendedAlgo::decode(req_payload).map_err(|_| {
+                ctx.generate_error_response(req_payload, ErrorCode::InvalidRequest, 0, None)
+            })?;
+        }
     }
 
     // Total number of extended algorithms check