diff --git a/object/types.proto b/object/types.proto
index 0baf35a..68c42e4 100644
--- a/object/types.proto
+++ b/object/types.proto
@@ -17,8 +17,8 @@ message Attribute {
 }
 
 message ExtendedHeader {
-    // Attribute is a set of K-V object attributes
-    Attribute Attribute = 3;
+    // Attributes carries list of the object attributes in a string key-value format.
+    repeated Attribute Attributes = 3;
     // Split carries the position of the object in the split hierarchy.
     SplitHeader SplitHeader = 4;
     // Tombstone header that set up in deleted objects
diff --git a/proto-docs/object.md b/proto-docs/object.md
index fc95f02..73e2a75 100644
--- a/proto-docs/object.md
+++ b/proto-docs/object.md
@@ -379,7 +379,7 @@ Attribute groups the parameters of the object attributes.
 
 | Field | Type | Label | Description |
 | ----- | ---- | ----- | ----------- |
-| Attribute | [Attribute](#object.Attribute) |  | Attribute is a set of K-V object attributes |
+| Attributes | [Attribute](#object.Attribute) | repeated | Attributes carries list of the object attributes in a string key-value format. |
 | SplitHeader | [SplitHeader](#object.SplitHeader) |  | Split carries the position of the object in the split hierarchy. |
 | Tombstone | [Tombstone](#object.Tombstone) |  | Tombstone header that set up in deleted objects |
 | Token | [service.Token](#service.Token) |  | Token header contains token of the session within which the object was created |
@@ -408,8 +408,8 @@ Header groups the information about the NeoFS object.
 
 | Field | Type | Label | Description |
 | ----- | ---- | ----- | ----------- |
-| PayloadChecksum | [bytes](#bytes) |  | PayloadChecksum carries the checksum of object payload bytes. Changing any byte of the payload changes the checksum. |
-| HeaderChecksum | [bytes](#bytes) |  | HeaderChecksum carries checksum of the object header structure. It covers all object attributes. Changing any field of the object except CreatorKey and ChecksumSignature changes the checksum. PayloadChecksum and HeaderChecksum cannot be merged due to the need to verify the header in the absence of a payload (e.g. in object.Head rpc). |
+| PayloadChecksum | [bytes](#bytes) |  | PayloadChecksum carries the checksum of object payload bytes. Changing any byte of the payload changes the checksum. It is calculated as a SHA-256 hash over payload bytes. |
+| HeaderChecksum | [bytes](#bytes) |  | HeaderChecksum carries checksum of the object header structure. It covers all object attributes. Changing any field of the object except CreatorKey and ChecksumSignature changes the checksum. PayloadChecksum and HeaderChecksum cannot be merged due to the need to verify the header in the absence of a payload (e.g. in object.Head rpc). It is calculated as a SHA-256 hash over marshaled object header with cut CreatorKey and ChecksumSignature. |
 | CreatorKey | [bytes](#bytes) |  | CreatorKey carries public key of the object creator in a binary format. |
 | ChecksumSignature | [bytes](#bytes) |  | ChecksumSignature is an user's signature of checksum to verify if it is correct |