Add cipher_auth_{en,de}crypt()
diff --git a/include/polarssl/cipher.h b/include/polarssl/cipher.h
index c8fdd25..5901592 100644
--- a/include/polarssl/cipher.h
+++ b/include/polarssl/cipher.h
@@ -659,6 +659,71 @@
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
+/**
+ * \brief Generic autenticated encryption (AEAD ciphers).
+ *
+ * \param ctx generic cipher context
+ * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers)
+ * \param iv_len IV length for ciphers with variable-size IV;
+ * discarded by ciphers with fixed-size IV.
+ * \param ad Additional data to authenticate.
+ * \param ad_len Length of ad.
+ * \param input buffer holding the input data
+ * \param ilen length of the input data
+ * \param output buffer for the output data.
+ * Should be able to hold at least ilen.
+ * \param olen length of the output data, will be filled with the
+ * actual number of bytes written.
+ * \param tag buffer for the authentication tag
+ * \param tag_len desired tag length
+ *
+ * \returns 0 on success, or
+ * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or
+ * a cipher specific error code.
+ */
+int cipher_auth_encrypt( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len,
+ const unsigned char *ad, size_t ad_len,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen,
+ unsigned char *tag, size_t tag_len );
+
+/**
+ * \brief Generic autenticated decryption (AEAD ciphers).
+ *
+ * \param ctx generic cipher context
+ * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers)
+ * \param iv_len IV length for ciphers with variable-size IV;
+ * discarded by ciphers with fixed-size IV.
+ * \param ad Additional data to be authenticated.
+ * \param ad_len Length of ad.
+ * \param input buffer holding the input data
+ * \param ilen length of the input data
+ * \param output buffer for the output data.
+ * Should be able to hold at least ilen.
+ * \param olen length of the output data, will be filled with the
+ * actual number of bytes written.
+ * \param tag buffer holding the authentication tag
+ * \param tag_len length of the authentication tag
+ *
+ * \returns 0 on success, or
+ * POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or
+ * POLARSSL_ERR_CIPHER_AUTH_FAILED if data isn't authentic,
+ * or a cipher specific error code.
+ *
+ * \note If the data is not authentic, then the output buffer
+ * is zeroed out to prevent the unauthentic plaintext to
+ * be used by mistake, making this interface safer.
+ */
+int cipher_auth_decrypt( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len,
+ const unsigned char *ad, size_t ad_len,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen,
+ const unsigned char *tag, size_t tag_len );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
+
/**
* \brief Checkup routine
*
diff --git a/library/cipher.c b/library/cipher.c
index daeea13..d8b416a 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -799,6 +799,62 @@
return( 0 );
}
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
+/*
+ * Packet-oriented encryption for AEAD modes
+ */
+int cipher_auth_encrypt( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len,
+ const unsigned char *ad, size_t ad_len,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen,
+ unsigned char *tag, size_t tag_len )
+{
+#if defined(POLARSSL_GCM_C)
+ if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
+ {
+ *olen = ilen;
+ return( gcm_crypt_and_tag( ctx->cipher_ctx, GCM_ENCRYPT, ilen,
+ iv, iv_len, ad, ad_len, input, output,
+ tag_len, tag ) );
+ }
+#endif
+
+ return( POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE );
+}
+
+/*
+ * Packet-oriented decryption for AEAD modes
+ */
+int cipher_auth_decrypt( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len,
+ const unsigned char *ad, size_t ad_len,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen,
+ const unsigned char *tag, size_t tag_len )
+{
+#if defined(POLARSSL_GCM_C)
+ if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
+ {
+ int ret;
+
+ *olen = ilen;
+ ret = gcm_auth_decrypt( ctx->cipher_ctx, ilen,
+ iv, iv_len, ad, ad_len,
+ tag, tag_len, input, output );
+
+ if( ret == POLARSSL_ERR_GCM_AUTH_FAILED )
+ ret = POLARSSL_ERR_CIPHER_AUTH_FAILED;
+
+ return( ret );
+ }
+#endif
+
+ return( POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE );
+}
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
+
+
#if defined(POLARSSL_SELF_TEST)
/*