Add EVP_aead_chacha20_poly1305_ietf() - The informational RFC 7539,

"ChaCha20 and Poly1305 for IETF Protocols", introduced a modified AEAD
construction that is incompatible with the common style that has been
already used in TLS with EVP_aead_chacha20_poly1305().  The IETF
version also adds a constant (salt) that is prepended to the nonce.

OK mikeb@ jsing@

1 files changed, 30 insertions, 3 deletions

diff --git a/lib/libcrypto/man/EVP_AEAD_CTX_init.3 b/lib/libcrypto/man/EVP_AEAD_CTX_init.3
index a2b4efea541..e6abc282d30 100644
--- a/lib/libcrypto/man/EVP_AEAD_CTX_init.3
+++ b/lib/libcrypto/man/EVP_AEAD_CTX_init.3
@@ -1,4 +1,4 @@
-.\" $OpenBSD: EVP_AEAD_CTX_init.3,v 1.2 2015/10/14 09:11:25 schwarze Exp $
+.\" $OpenBSD: EVP_AEAD_CTX_init.3,v 1.3 2015/11/02 15:40:53 reyk Exp $
 .\"
 .\" Copyright (c) 2014, Google Inc.
 .\" Parts of the text were written by Adam Langley and David Benjamin.
@@ -16,7 +16,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: October 14 2015 $
+.Dd $Mdocdate: November 2 2015 $
 .Dt EVP_AEAD_CTX_INIT 3
 .Os
 .Sh NAME
@@ -30,7 +30,8 @@
 .Nm EVP_AEAD_nonce_length ,
 .Nm EVP_aead_aes_128_gcm ,
 .Nm EVP_aead_aes_256_gcm ,
-.Nm EVP_aead_chacha20_poly1305
+.Nm EVP_aead_chacha20_poly1305 ,
+.Nm EVP_aead_chacha20_poly1305_ietf
 .Nd authenticated encryption with additional data
 .Sh SYNOPSIS
 .In openssl/evp.h
@@ -101,6 +102,10 @@
 .Fo EVP_aead_chacha20_poly1305
 .Fa void
 .Fc
+.Ft const EVP_AEAD *
+.Fo EVP_aead_chacha20_poly1305_ietf
+.Fa void
+.Fc
 .Sh DESCRIPTION
 AEAD (Authenticated Encryption with Additional Data) couples
 confidentiality and integrity in a single primitive.
@@ -219,6 +224,11 @@ AES-128 in Galois Counter Mode.
 AES-256 in Galois Counter Mode.
 .It Fn EVP_aead_chacha20_poly1305
 ChaCha20 with a Poly1305 authenticator.
+.It Fn EVP_aead_chacha20_poly1305_ietf
+ChaCha20 with a Poly1305 authenticator for IETF Protocols.
+The IETF standardised variant of the AEAD is incompatible with the
+original version.
+It uses a constant salt that is prepended to the nonce.
 .El
 .Pp
 Where possible the
@@ -270,6 +280,23 @@ EVP_AEAD_CTX_cleanup(&ctx);
 .Ed
 .Sh SEE ALSO
 .Xr evp 3
+.Sh STANDARDS
+.Rs
+.%A A. Langley
+.%A W. Chang
+.%D November 2013
+.%R draft-agl-tls-chacha20poly1305-04
+.%T ChaCha20 and Poly1305 based Cipher Suites for TLS
+.Re
+.Pp
+.Rs
+.%A Y. Nir
+.%A A. Langley
+.%D May 2015
+.%R RFC 7539
+.%T ChaCha20 and Poly1305 for IETF Protocols
+.Re
+.Pp
 .Sh HISTORY
 AEAD is based on the implementation by
 .An Adam Langley