diff --git a/src/aeb_fate_abi.erl b/src/aeb_fate_abi.erl
index 91f05b2..bd6d305 100644
--- a/src/aeb_fate_abi.erl
+++ b/src/aeb_fate_abi.erl
@@ -9,7 +9,12 @@
 %%%-------------------------------------------------------------------
 -module(aeb_fate_abi).
 
--export([ create_calldata/2 ]).
+-export([ create_calldata/2
+        , get_function_hash_from_calldata/1
+        , get_function_name_from_function_hash/2
+        , get_function_type_from_function_hash/2 ]).
+
+-include("../include/aeb_fate_data.hrl").
 
 %%%===================================================================
 %%% API
@@ -21,3 +26,37 @@ create_calldata(FunName, Args) ->
     {ok, aeb_fate_encoding:serialize(
            aeb_fate_data:make_tuple({FunctionId,
                                      aeb_fate_data:make_tuple(list_to_tuple(Args))}))}.
+
+-spec get_function_name_from_function_hash(binary(), aeb_fate_code:fcode()) ->
+    {ok, term()} | {error, term()}.
+get_function_name_from_function_hash(<<SymbolHash:4/binary, _:28/binary>>, FateCode) ->
+    get_function_name_from_function_hash(SymbolHash, FateCode);
+get_function_name_from_function_hash(SymbolHash = <<_:4/binary>>, FateCode) ->
+    Symbols = aeb_fate_code:symbols(FateCode),
+    case maps:get(SymbolHash, Symbols, undefined) of
+        undefined -> {error, no_function_matching_function_hash};
+        Function  -> {ok, Function}
+    end.
+
+-spec get_function_hash_from_calldata(binary()) ->
+    {ok, binary()} | {error, term()}.
+get_function_hash_from_calldata(CallData) ->
+    try ?FATE_TUPLE_ELEMENTS(aeb_fate_encoding:deserialize(CallData)) of
+        [FunHash, _Args] -> {ok, FunHash};
+        _                -> {error, bad_calldata}
+    catch _:_ ->
+        {error, bad_calldata}
+    end.
+
+-spec get_function_type_from_function_hash(binary(), aeb_fate_code:fcode()) ->
+    {ok, term()} | {error, term()}.
+get_function_type_from_function_hash(<<SymbolHash:4/binary, _:28/binary>>, FateCode) ->
+    get_function_type_from_function_hash(SymbolHash, FateCode);
+get_function_type_from_function_hash(SymbolHash, FateCode) ->
+    Functions = aeb_fate_code:functions(FateCode),
+    case maps:get(SymbolHash, Functions, undefined) of
+        undefined ->
+            {error, no_function_matching_function_hash};
+        {{ArgTypes, RetType}, _Code} ->
+            {ok, ArgTypes, RetType}
+    end.
diff --git a/src/aeb_fate_code.erl b/src/aeb_fate_code.erl
index a60858b..5d010bc 100644
--- a/src/aeb_fate_code.erl
+++ b/src/aeb_fate_code.erl
@@ -27,7 +27,7 @@
 -include("../include/aeb_fate_data.hrl").
 
 -ifdef(EQC).
--export([update_annotations/2
+-export([ update_annotations/2
         , update_functions/2
         , update_symbols/2]).
 -endif.
@@ -39,6 +39,9 @@
 
 -define(HASH_BYTES, 32).
 
+-type fcode() :: #fcode{}.
+-export_type([fcode/0]).
+
 %%%===================================================================
 %%% API
 %%%===================================================================
diff --git a/src/aeb_fate_generate_ops.erl b/src/aeb_fate_generate_ops.erl
index 757ecb2..1458a34 100644
--- a/src/aeb_fate_generate_ops.erl
+++ b/src/aeb_fate_generate_ops.erl
@@ -166,6 +166,7 @@ ops_defs() ->
     , { 'ECVERIFY_SECP256K1',  16#73,  false, 1300, [a,a,a,a], ecverify_secp256k1,  {hash, signature, signature}, boolean, "Arg0 := ecverify_secp256k1(Hash, PubKey, Signature)"}
 
     , { 'CONTRACT_TO_ADDRESS', 16#74,  false,   3, [a,a], contract_to_address,                        {contract}, address, "Arg0 := Arg1 - A no-op type conversion"}
+    , { 'AUTH_TX_HASH',        16#75,  false,   3, [a],          auth_tx_hash,                                {}, variant, "If in GA authentication context return Some(TxHash) otherwise None."}
 
     , { 'DEACTIVATE',          16#fa,  false,   3, [],           deactivate,                                  {},    none, "Mark the current contract for deactivation."}
     , { 'ABORT',               16#fb,   true,   3, [a],               abort,                            {string},    none, "Abort execution (dont use all gas) with error message in Arg0."}
diff --git a/test/asm_code/all_instructions.fate b/test/asm_code/all_instructions.fate
index d40dbbb..0516967 100644
--- a/test/asm_code/all_instructions.fate
+++ b/test/asm_code/all_instructions.fate
@@ -243,3 +243,7 @@ FUNCTION foo () : {tuple, []}
   BALANCE_OTHER a arg0
 
   SETELEMENT a 2 (1, "two", 3) 2
+
+  AUTH_TX_HASH
+
+  CONTRACT_TO_ADDRESS @ct_nv5B93FPzRHrGNmMdTDfGdd5xGZvep3MVSpJqzcQmMp59bBCv