diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index ff49eb9..bd20937 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -498,10 +498,18 @@
  *
  */
 struct psa_sign_hash_interruptible_operation_s {
+    /** Unique ID indicating which driver got assigned to do the
+     * operation. Since driver contexts are driver-specific, swapping
+     * drivers halfway through the operation is not supported.
+     * ID values are auto-generated in psa_crypto_driver_wrappers.h
+     * ID value zero means the context is not valid or not assigned to
+     * any driver (i.e. none of the driver contexts are active). */
+    unsigned int MBEDTLS_PRIVATE(id);
+
     size_t MBEDTLS_PRIVATE(num_ops);
 };
 
-#define PSA_SIGN_HASH_INTERRUPTIBLE_OPERATION_INIT { 0 }
+#define PSA_SIGN_HASH_INTERRUPTIBLE_OPERATION_INIT { 0, 0 }
 
 static inline struct psa_sign_hash_interruptible_operation_s
 psa_sign_hash_interruptible_operation_init(void)
@@ -519,10 +527,18 @@
  *
  */
 struct psa_verify_hash_interruptible_operation_s {
+    /** Unique ID indicating which driver got assigned to do the
+     * operation. Since driver contexts are driver-specific, swapping
+     * drivers halfway through the operation is not supported.
+     * ID values are auto-generated in psa_crypto_driver_wrappers.h
+     * ID value zero means the context is not valid or not assigned to
+     * any driver (i.e. none of the driver contexts are active). */
+    unsigned int MBEDTLS_PRIVATE(id);
+
     size_t MBEDTLS_PRIVATE(num_ops);
 };
 
-#define PSA_VERIFY_HASH_INTERRUPTIBLE_OPERATION_INIT { 0 }
+#define PSA_VERIFY_HASH_INTERRUPTIBLE_OPERATION_INIT { 0, 0 }
 
 static inline struct psa_verify_hash_interruptible_operation_s
 psa_verify_hash_interruptible_operation_init(void)