[PATCH 2/4] crypto: clarify usage of random numbers in asym

[Arek Kusztal <arkadiuszx.kusztal@intel.com>]

This commit clarifies usage of random numbers in asymmetric
crypto API.

Signed-off-by: Arek Kusztal <arkadiuszx.kusztal@intel.com>
---
 lib/cryptodev/rte_crypto_asym.h | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/cryptodev/rte_crypto_asym.h b/lib/cryptodev/rte_crypto_asym.h
index e0def3d9ab..58d47158de 100644
--- a/lib/cryptodev/rte_crypto_asym.h
+++ b/lib/cryptodev/rte_crypto_asym.h
@@ -33,6 +33,11 @@ extern "C" {
  * These buffers can be used for both input to PMD and output from PMD. When
  * used for output from PMD, application has to ensure the buffer is large
  * enough to hold the target data.
+ *
+ * If an operation requires the PMD to generate a random number,
+ * and the device supports CSRNG, 'data' should be set to NULL.
+ * The crypto parameter in question will not be used by the PMD,
+ * as it is internally generated.
  */
 typedef struct rte_crypto_param_t {
 	uint8_t *data;
@@ -549,7 +554,9 @@ struct rte_crypto_dsa_op_param {
 	/**< input message to be signed or verified */
 	rte_crypto_param k;
 	/**< Per-message secret number, which is an integer
-	 * in the interval (1, q-1)
+	 * in the interval (1, q-1).
+	 * If the random number is generated by the PMD,
+	 * the 'rte_crypto_param.data' parameter should be set to NULL.
 	 */
 	rte_crypto_param r;
 	/**< dsa sign component 'r' value
@@ -589,7 +596,9 @@ struct rte_crypto_ecdsa_op_param {
 
 	rte_crypto_param k;
 	/**< The ECDSA per-message secret number, which is an integer
-	 * in the interval (1, n-1)
+	 * in the interval (1, n-1).
+	 * If the random number is generated by the PMD,
+	 * the 'rte_crypto_param.data' parameter should be set to NULL.
 	 */
 
 	rte_crypto_param r;
-- 
2.13.6