Add crypto_stream_xsalsa20_ic()

src/libsodium/crypto_stream/xsalsa20/ref/api.h

@@ -2,6 +2,7 @@
 #include "crypto_stream_xsalsa20.h"
 
 #define crypto_stream crypto_stream_xsalsa20
+#define crypto_stream_xor_ic crypto_stream_xsalsa20_xor_ic
 #define crypto_stream_xor crypto_stream_xsalsa20_xor
 #define crypto_stream_KEYBYTES crypto_stream_xsalsa20_KEYBYTES
 #define crypto_stream_NONCEBYTES crypto_stream_xsalsa20_NONCEBYTES

src/libsodium/crypto_stream/xsalsa20/ref/xor_xsalsa20.c

@@ -13,6 +13,21 @@ static const unsigned char sigma[16] = {
     'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'
 };
 
+int crypto_stream_xor_ic(
+        unsigned char *c,
+  const unsigned char *m,unsigned long long mlen,
+  const unsigned char *n,uint64_t ic,
+  const unsigned char *k
+)
+{
+  unsigned char subkey[32];
+  int ret;
+  crypto_core_hsalsa20(subkey,n,k,sigma);
+  ret = crypto_stream_salsa20_xor_ic(c,m,mlen,n + 16,ic,subkey);
+  sodium_memzero(subkey, sizeof subkey);
+  return ret;
+}
+
 int crypto_stream_xor(
         unsigned char *c,
   const unsigned char *m,unsigned long long mlen,
@@ -20,10 +35,5 @@ int crypto_stream_xor(
   const unsigned char *k
 )
 {
-  unsigned char subkey[32];
-  int ret;
-  crypto_core_hsalsa20(subkey,n,k,sigma);
-  ret = crypto_stream_salsa20_xor(c,m,mlen,n + 16,subkey);
-  sodium_memzero(subkey, sizeof subkey);
-  return ret;
+  return crypto_stream_xor_ic(c, m, mlen, n, 0ULL, k);
 }

src/libsodium/include/sodium/crypto_stream_xsalsa20.h

@@ -10,6 +10,7 @@
  */
 
 #include <stddef.h>
+#include <stdint.h>
 #include "export.h"
 
 #ifdef __cplusplus
@@ -36,6 +37,11 @@ int crypto_stream_xsalsa20_xor(unsigned char *c, const unsigned char *m,
                                unsigned long long mlen, const unsigned char *n,
                                const unsigned char *k);
 
+SODIUM_EXPORT
+int crypto_stream_xsalsa20_xor_ic(unsigned char *c, const unsigned char *m,
+                                  unsigned long long mlen,
+                                  const unsigned char *n, uint64_t ic,
+                                  const unsigned char *k);
 #ifdef __cplusplus
 }
 #endif

test/default/stream.c

@@ -19,13 +19,25 @@ int main(void)
 {
     int i;
 
-    crypto_stream(output, 4194304, nonce, firstkey);
+    crypto_stream(output, sizeof output, nonce, firstkey);
     crypto_hash_sha256(h, output, sizeof output);
 
     for (i = 0; i < 32; ++i)
         printf("%02x", h[i]);
     printf("\n");
 
+    assert(sizeof output > 4000);
+
+    crypto_stream_xsalsa20_xor_ic(output, output, 4000, nonce, 0U, firstkey);
+    for (i = 0; i < 4000; ++i)
+        assert(output[i] == 0);
+
+    crypto_stream_xsalsa20_xor_ic(output, output, 4000, nonce, 1U, firstkey);
+    crypto_hash_sha256(h, output, sizeof output);
+    for (i = 0; i < 32; ++i)
+        printf("%02x", h[i]);
+    printf("\n");
+
     assert(crypto_stream_keybytes() > 0U);
     assert(crypto_stream_noncebytes() > 0U);
     assert(strcmp(crypto_stream_primitive(), "xsalsa20") == 0);

test/default/stream.exp

@@ -1 +1,2 @@
 662b9d0e3463029156069b12f918691a98f7dfb2ca0393c96bbfc6b1fbd630a2
+0cc9ffaf60a99d221b548e9762385a231121ab226d1c610d2661ced26b6ad5ee