diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 2bc6807..694fdf4 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -706,17 +706,58 @@
 
 /** The type of the state data structure for multipart hash operations.
  *
+ * Before calling any function on a hash operation object, the application must
+ * initialize it by any of the following means:
+ * - Set the structure to all-bits-zero, for example:
+ *   \code
+ *   psa_hash_operation_t operation;
+ *   memset(&operation, 0, sizeof(operation));
+ *   \endcode
+ * - Initialize the structure to logical zero values, for example:
+ *   \code
+ *   psa_hash_operation_t operation = {0};
+ *   \endcode
+ * - Initialize the structure to the initializer #PSA_HASH_OPERATION_INIT,
+ *   for example:
+ *   \code
+ *   psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT;
+ *   \endcode
+ * - Assign the result of the function psa_hash_operation_init()
+ *   to the structure, for example:
+ *   \code
+ *   psa_hash_operation_t operation;
+ *   operation = psa_hash_operation_init();
+ *   \endcode
+ *
  * This is an implementation-defined \c struct. Applications should not
  * make any assumptions about the content of this structure except
  * as directed by the documentation of a specific implementation. */
 typedef struct psa_hash_operation_s psa_hash_operation_t;
 
+/** \def PSA_HASH_OPERATION_INIT
+ *
+ * This macro returns a suitable initializer for a hash operation object
+ * of type #psa_hash_operation_t.
+ */
+#ifdef __DOXYGEN_ONLY__
+/* This is an example definition for documentation purposes.
+ * Implementations should define a suitable value in `crypto_struct.h`.
+ */
+#define PSA_HASH_OPERATION_INIT {0}
+#endif
+
+/** Return an initial value for a hash operation object.
+ */
+static psa_hash_operation_t psa_hash_operation_init(void);
+
 /** Start a multipart hash operation.
  *
  * The sequence of operations to calculate a hash (message digest)
  * is as follows:
  * -# Allocate an operation object which will be passed to all the functions
  *    listed here.
+ * -# Initialize the operation object with one of the methods described in the
+ *    documentation for #psa_hash_operation_t, e.g. PSA_HASH_OPERATION_INIT.
  * -# Call psa_hash_setup() to specify the algorithm.
  * -# Call psa_hash_update() zero, one or more times, passing a fragment
  *    of the message each time. The hash that is calculated is the hash
@@ -725,7 +766,7 @@
  *    To compare the hash with an expected value, call psa_hash_verify().
  *
  * The application may call psa_hash_abort() at any time after the operation
- * has been initialized with psa_hash_setup().
+ * has been initialized.
  *
  * After a successful call to psa_hash_setup(), the application must
  * eventually terminate the operation. The following events terminate an
@@ -733,7 +774,9 @@
  * - A failed call to psa_hash_update().
  * - A call to psa_hash_finish(), psa_hash_verify() or psa_hash_abort().
  *
- * \param[out] operation    The operation object to use.
+ * \param[in,out] operation The operation object to set up. It must have
+ *                          been initialized as per the documentation for
+ *                          #psa_hash_operation_t and not yet in use.
  * \param alg               The hash algorithm to compute (\c PSA_ALG_XXX value
  *                          such that #PSA_ALG_IS_HASH(\p alg) is true).
  *
diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index 320466f..4a6e168 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -85,6 +85,13 @@
     } ctx;
 };
 
+#define PSA_HASH_OPERATION_INIT {0, {0}}
+static inline struct psa_hash_operation_s psa_hash_operation_init( void )
+{
+    const struct psa_hash_operation_s v = PSA_HASH_OPERATION_INIT;
+    return( v );
+}
+
 #if defined(MBEDTLS_MD_C)
 typedef struct
 {