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
diff --git a/xmss_hash.c b/xmss_hash.c
new file mode 100644
index 0000000..963b584
--- /dev/null
+++ b/xmss_hash.c
@@ -0,0 +1,133 @@
+/*
+hash.c version 20160722
+Andreas Hülsing
+Joost Rijneveld
+Public domain.
+*/
+
+#include "xmss_hash_address.h"
+#include "xmss_commons.h"
+#include "xmss_hash.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <openssl/sha.h>
+#include <openssl/hmac.h>
+#include <openssl/evp.h>
+
+int core_hash_SHA2(unsigned char *, const unsigned int, const unsigned char *,
+ unsigned int, const unsigned char *, unsigned long long, unsigned int);
+
+unsigned char* addr_to_byte(unsigned char *bytes, const uint32_t addr[8]){
+#if IS_LITTLE_ENDIAN==1
+ int i = 0;
+ for(i=0;i<8;i++)
+ to_byte(bytes+i*4, addr[i],4);
+ return bytes;
+#else
+ memcpy(bytes, addr, 32);
+ return bytes;
+#endif
+}
+
+int core_hash_SHA2(unsigned char *out, const unsigned int type, const unsigned char *key, unsigned int keylen, const unsigned char *in, unsigned long long inlen, unsigned int n){
+ unsigned long long i = 0;
+ unsigned char buf[inlen + n + keylen];
+
+ // Input is (toByte(X, 32) || KEY || M)
+
+ // set toByte
+ to_byte(buf, type, n);
+
+ for (i=0; i < keylen; i++) {
+ buf[i+n] = key[i];
+ }
+
+ for (i=0; i < inlen; i++) {
+ buf[keylen + n + i] = in[i];
+ }
+
+ if (n == 32) {
+ SHA256(buf, inlen + keylen + n, out);
+ return 0;
+ }
+ else {
+ if (n == 64) {
+ SHA512(buf, inlen + keylen + n, out);
+ return 0;
+ }
+ }
+ return 1;
+}
+
+/**
+ * Implements PRF
+ */
+int prf(unsigned char *out, const unsigned char *in, const unsigned char *key, unsigned int keylen)
+{
+ return core_hash_SHA2(out, 3, key, keylen, in, 32, keylen);
+}
+
+/*
+ * Implemts H_msg
+ */
+int h_msg(unsigned char *out, const unsigned char *in, unsigned long long inlen, const unsigned char *key, const unsigned int keylen, const unsigned int n)
+{
+ if (keylen != 3*n){
+ // H_msg takes 3n-bit keys, but n does not match the keylength of keylen
+ return -1;
+ }
+ return core_hash_SHA2(out, 2, key, keylen, in, inlen, n);
+}
+
+/**
+ * We assume the left half is in in[0]...in[n-1]
+ */
+int hash_h(unsigned char *out, const unsigned char *in, const unsigned char *pub_seed, uint32_t addr[8], const unsigned int n)
+{
+
+ unsigned char buf[2*n];
+ unsigned char key[n];
+ unsigned char bitmask[2*n];
+ unsigned char byte_addr[32];
+ unsigned int i;
+
+ setKeyAndMask(addr, 0);
+ addr_to_byte(byte_addr, addr);
+ prf(key, byte_addr, pub_seed, n);
+ // Use MSB order
+ setKeyAndMask(addr, 1);
+ addr_to_byte(byte_addr, addr);
+ prf(bitmask, byte_addr, pub_seed, n);
+ setKeyAndMask(addr, 2);
+ addr_to_byte(byte_addr, addr);
+ prf(bitmask+n, byte_addr, pub_seed, n);
+ for (i = 0; i < 2*n; i++) {
+ buf[i] = in[i] ^ bitmask[i];
+ }
+ return core_hash_SHA2(out, 1, key, n, buf, 2*n, n);
+}
+
+int hash_f(unsigned char *out, const unsigned char *in, const unsigned char *pub_seed, uint32_t addr[8], const unsigned int n)
+{
+ unsigned char buf[n];
+ unsigned char key[n];
+ unsigned char bitmask[n];
+ unsigned char byte_addr[32];
+ unsigned int i;
+
+ setKeyAndMask(addr, 0);
+ addr_to_byte(byte_addr, addr);
+ prf(key, byte_addr, pub_seed, n);
+
+ setKeyAndMask(addr, 1);
+ addr_to_byte(byte_addr, addr);
+ prf(bitmask, byte_addr, pub_seed, n);
+
+ for (i = 0; i < n; i++) {
+ buf[i] = in[i] ^ bitmask[i];
+ }
+ return core_hash_SHA2(out, 0, key, n, buf, n, n);
+}