[PATCH] Update documentation for Poly1305-ChaCha20 AEAD, RFC-7539

[Jussi Kivilinna]

* cipher/cipher-poly1305.c: Add RFC-7539 to header.
* doc/gcrypt.texi: Update Poly1305 AEAD documentation with mention of
RFC-7539; Drop Salsa from supported stream ciphers for Poly1305 AEAD.
--

Signed-off-by: Jussi Kivilinna <jussi.kivilinna at iki.fi>
---
 cipher/cipher-poly1305.c |    2 +-
 doc/gcrypt.texi          |    9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/cipher/cipher-poly1305.c b/cipher/cipher-poly1305.c
index f283333..965a7b6 100644
--- a/cipher/cipher-poly1305.c
+++ b/cipher/cipher-poly1305.c
@@ -1,4 +1,4 @@
-/* cipher-pol1305.c  -  Poly1305 based AEAD cipher mode
+/* cipher-poly1305.c  -  Poly1305 based AEAD cipher mode, RFC-7539
  * Copyright (C) 2014 Jussi Kivilinna <jussi.kivilinna at iki.fi>
  *
  * This file is part of Libgcrypt.
diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi
index 8683ca8..ab4f685 100644
--- a/doc/gcrypt.texi
+++ b/doc/gcrypt.texi
@@ -1643,9 +1643,10 @@ Associated Data (AEAD) block cipher mode, which is specified in
 'NIST Special Publication 800-38D'.
 
 @item  GCRY_CIPHER_MODE_POLY1305
- at cindex Poly1305 based AEAD mode
-Poly1305 is an Authenticated Encryption with Associated Data (AEAD)
-mode, which can be used with ChaCha20 and Salsa20 stream ciphers.
+ at cindex Poly1305 based AEAD mode with ChaCha20
+This mode implements the Poly1305 Authenticated Encryption with Associated
+Data (AEAD) mode according to RFC-7539. This mode can be used with ChaCha20
+stream cipher.
 
 @item  GCRY_CIPHER_MODE_OCB
 @cindex OCB, OCB3
@@ -1687,7 +1688,7 @@ and the according constants.  Note that some modes are incompatible
 with some algorithms - in particular, stream mode
 (@code{GCRY_CIPHER_MODE_STREAM}) only works with stream ciphers.
 Poly1305 AEAD mode (@code{GCRY_CIPHER_MODE_POLY1305}) only works with
-ChaCha and Salsa stream ciphers. The block cipher modes
+ChaCha20 stream cipher. The block cipher modes
 (@code{GCRY_CIPHER_MODE_ECB}, @code{GCRY_CIPHER_MODE_CBC},
 @code{GCRY_CIPHER_MODE_CFB}, @code{GCRY_CIPHER_MODE_OFB} and
 @code{GCRY_CIPHER_MODE_CTR}) will work with any block cipher