This patch explains what are the conditions
and how to use digest appended for auth-cipher
operations.
Signed-off-by: Damian Nowak <damianx.no...@intel.com>
---
lib/librte_cryptodev/rte_crypto_sym.h | 43 +++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/lib/librte_cryptodev/rte_crypto_sym.h
b/lib/librte_cryptodev/rte_crypto_sym.h
index c80e90e..b211bf5 100644
--- a/lib/librte_cryptodev/rte_crypto_sym.h
+++ b/lib/librte_cryptodev/rte_crypto_sym.h
@@ -662,6 +662,49 @@ struct rte_crypto_sym_op {
* physically contiguous memory at this
* location.
*
+ * @note
+ * Digest can be generated, appended to
+ * the end of raw data and encrypted
+ * together using chained digest
+ * generation
+ * (@ref RTE_CRYPTO_AUTH_OP_GENERATE)
+ * and encryption
+ * (@ref RTE_CRYPTO_CIPHER_OP_ENCRYPT)
+ * xforms. Similarly, authentication
+ * of the raw data against appended,
+ * decrypted digest, can be performed
+ * using decryption
+ * (@ref RTE_CRYPTO_CIPHER_OP_DECRYPT)
+ * and digest verification
+ * (@ref RTE_CRYPTO_AUTH_OP_VERIFY)
+ * chained xforms.
+ * To perform those operations, a few
+ * additional conditions must be met:
+ * - caller must allocate at least
+ * digest_length of memory at the end of
+ * source and (in case of out-of-place
+ * operations) destination buffer; those
+ * buffers can be linear or split using
+ * scatter-gather lists,
+ * - digest data pointer must point to
+ * the end of source or (in case of
+ * out-of-place operations) destination
+ * data, which is pointer to the raw
+ * data buffer + auth.data.offset +
+ * auth.data.length,
+ * - cipher.data.offset +
+ * cipher.data.length must be greater
+ * than auth.data.offset +
+ * auth.data.length and is typically
+ * equal to auth.data.offset +
+ * auth.data.length + digest_length.
+ *
+ * Note, that for security reasons, it
+ * is PMDs' responsibility to not
+ * leave an unencrypted digest in any
+ * buffer after performing auth-cipher
+ * operations.
+ *
* For digest generation, the digest
result
* will overwrite any data at this
location.
*
--
2.7.4
