diff --git a/common/python/cctrusted_base/tcg.py b/common/python/cctrusted_base/tcg.py
index 919fcca4..5e03feaf 100644
--- a/common/python/cctrusted_base/tcg.py
+++ b/common/python/cctrusted_base/tcg.py
@@ -52,8 +52,8 @@ def get_algorithm_string(alg_id: int) -> str:
         return "UNKNOWN"
 
     def __init__(self, alg_id: int) -> None:
-        assert alg_id in TcgAlgorithmRegistry.TPM_ALG_TABLE, \
-            "invalid parameter alg_id"
+        #assert alg_id in TcgAlgorithmRegistry.TPM_ALG_TABLE, \
+        #    "invalid parameter alg_id"
         self._alg_id = alg_id
 
     @property
diff --git a/common/python/cctrusted_base/tpm/pcr.py b/common/python/cctrusted_base/tpm/pcr.py
index e33d61c2..e29c1a21 100644
--- a/common/python/cctrusted_base/tpm/pcr.py
+++ b/common/python/cctrusted_base/tpm/pcr.py
@@ -3,6 +3,7 @@
 """
 
 from cctrusted_base.imr import TcgIMR
+from cctrusted_base.tcg import TcgAlgorithmRegistry
 
 class TpmPCR(TcgIMR):
     """PCR class defined for TPM"""
@@ -10,3 +11,7 @@ class TpmPCR(TcgIMR):
     @property
     def max_index(self):
         return 23
+
+    def __init__(self, index, digest_hash):
+        super().__init__(index, TcgAlgorithmRegistry.TPM_ALG_SHA256,
+                        digest_hash)