upstream: Add experimental support for PQC XMSS keys (Extended

Hash-Based Signatures) The code is not compiled in by default (see WITH_XMSS
in Makefile.inc) Joint work with stefan-lukas_gazdag at genua.eu See
https://tools.ietf.org/html/draft-irtf-cfrg-xmss-hash-based-signatures-12 ok
djm@

OpenBSD-Commit-ID: ef3eccb96762a5d6f135d7daeef608df7776a7ac

1 files changed, 59 insertions, 0 deletions

diff --git a/xmss_wots.h b/xmss_wots.h
new file mode 100644
index 00000000..49543108
--- /dev/null
+++ b/xmss_wots.h
@@ -0,0 +1,59 @@
+/*
+wots.h version 20160722
+Andreas Hülsing
+Joost Rijneveld
+Public domain.
+*/
+
+#ifndef WOTS_H
+#define WOTS_H
+
+#include "stdint.h"
+
+/**
+ * WOTS parameter set
+ * 
+ * Meaning as defined in draft-irtf-cfrg-xmss-hash-based-signatures-02
+ */
+typedef struct {
+  uint32_t len_1;
+  uint32_t len_2;
+  uint32_t len;
+  uint32_t n;
+  uint32_t w;
+  uint32_t log_w;
+  uint32_t keysize;
+} wots_params;
+
+/**
+ * Set the WOTS parameters, 
+ * only m, n, w are required as inputs,
+ * len, len_1, and len_2 are computed from those.
+ *
+ * Assumes w is a power of 2
+ */
+void wots_set_params(wots_params *params, int n, int w);
+
+/**
+ * WOTS key generation. Takes a 32byte seed for the secret key, expands it to a full WOTS secret key and computes the corresponding public key. 
+ * For this it takes the seed pub_seed which is used to generate bitmasks and hash keys and the address of this WOTS key pair addr
+ * 
+ * params, must have been initialized before using wots_set params for params ! This is not done in this function
+ * 
+ * Places the computed public key at address pk.
+ */
+void wots_pkgen(unsigned char *pk, const unsigned char *sk, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]);
+
+/**
+ * Takes a m-byte message and the 32-byte seed for the secret key to compute a signature that is placed at "sig".
+ *  
+ */
+int wots_sign(unsigned char *sig, const unsigned char *msg, const unsigned char *sk, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]);
+
+/**
+ * Takes a WOTS signature, a m-byte message and computes a WOTS public key that it places at pk.
+ * 
+ */
+int wots_pkFromSig(unsigned char *pk, const unsigned char *sig, const unsigned char *msg, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]);
+
+#endif