diff --git a/library/cipher.c b/library/cipher.c
index 63f1f41..e854cf6 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -1236,7 +1236,7 @@
             (mbedtls_cipher_context_psa *) ctx->cipher_ctx;
 
         psa_status_t status;
-        psa_cipher_operation_t cipher_op;
+        psa_cipher_operation_t cipher_op = PSA_CIPHER_OPERATION_INIT;
         size_t part_len;
 
         if( ctx->operation == MBEDTLS_DECRYPT )