[crypto] Add SHA-512/256 algorithm

SHA-512/256 is almost identical to SHA-512, with differing initial
hash values and a truncated output length.

This implementation has been verified using the NIST SHA-512/256 test
vectors.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 83 insertions, 0 deletions

diff --git a/src/crypto/sha512_256.c b/src/crypto/sha512_256.c
new file mode 100644
index 00000000..f8afaf3e
--- /dev/null
+++ b/src/crypto/sha512_256.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * SHA-512/256 algorithm
+ *
+ */
+
+#include <stdint.h>
+#include <byteswap.h>
+#include <ipxe/crypto.h>
+#include <ipxe/asn1.h>
+#include <ipxe/sha512.h>
+
+/** SHA-512/256 initial digest values */
+static const struct sha512_digest sha512_256_init_digest = {
+	.h = {
+		cpu_to_be64 ( 0x22312194fc2bf72cULL ),
+		cpu_to_be64 ( 0x9f555fa3c84c64c2ULL ),
+		cpu_to_be64 ( 0x2393b86b6f53b151ULL ),
+		cpu_to_be64 ( 0x963877195940eabdULL ),
+		cpu_to_be64 ( 0x96283ee2a88effe3ULL ),
+		cpu_to_be64 ( 0xbe5e1e2553863992ULL ),
+		cpu_to_be64 ( 0x2b0199fc2c85b8aaULL ),
+		cpu_to_be64 ( 0x0eb72ddc81c52ca2ULL ),
+	},
+};
+
+/**
+ * Initialise SHA-512/256 algorithm
+ *
+ * @v ctx		SHA-512/256 context
+ */
+static void sha512_256_init ( void *ctx ) {
+	struct sha512_context *context = ctx;
+
+	sha512_family_init ( context, &sha512_256_init_digest,
+			     SHA512_256_DIGEST_SIZE );
+}
+
+/** SHA-512/256 algorithm */
+struct digest_algorithm sha512_256_algorithm = {
+	.name		= "sha512/256",
+	.ctxsize	= sizeof ( struct sha512_context ),
+	.blocksize	= sizeof ( union sha512_block ),
+	.digestsize	= SHA512_256_DIGEST_SIZE,
+	.init		= sha512_256_init,
+	.update		= sha512_update,
+	.final		= sha512_final,
+};
+
+/** "sha512_256" object identifier */
+static uint8_t oid_sha512_256[] = { ASN1_OID_SHA512_256 };
+
+/** "sha512_256" OID-identified algorithm */
+struct asn1_algorithm oid_sha512_256_algorithm __asn1_algorithm = {
+	.name = "sha512/256",
+	.digest = &sha512_256_algorithm,
+	.oid = ASN1_OID_CURSOR ( oid_sha512_256 ),
+};