Add XChaCha20 stream (#28)

NAMESPACE

@@ -27,6 +27,7 @@ export(sig_sign)
 export(sig_verify)
 export(simple_decrypt)
 export(simple_encrypt)
+export(xchacha20)
 export(xsalsa20)
 useDynLib(sodium,R_auth_sha256)
 useDynLib(sodium,R_auth_sha512)
@@ -58,5 +59,6 @@ useDynLib(sodium,R_sodium_bin2hex)
 useDynLib(sodium,R_sodium_hex2bin)
 useDynLib(sodium,R_stream_chacha20)
 useDynLib(sodium,R_stream_salsa20)
+useDynLib(sodium,R_stream_xchacha20)
 useDynLib(sodium,R_stream_xsalsa20)
 useDynLib(sodium,R_xor)

R/stream.R

@@ -48,6 +48,7 @@
 #' # Other stream ciphers
 #' stream <- salsa20(10000, key, nonce8)
 #' stream <- xsalsa20(10000, key, random(24))
+#' stream <- xchacha20(10000, key, random(24))
 #'
 chacha20 <- function(size, key, nonce){
   stopifnot(is.numeric(size))
@@ -56,6 +57,16 @@ chacha20 <- function(size, key, nonce){
   .Call(R_stream_chacha20, size, key, nonce)
 }
 
+#' @export
+#' @useDynLib sodium R_stream_xchacha20
+#' @rdname stream
+xchacha20 <- function(size, key, nonce){
+  stopifnot(is.numeric(size))
+  stopifnot(is.raw(key))
+  stopifnot(is.raw(nonce))
+  .Call(R_stream_xchacha20, size, key, nonce)
+}
+
 #' @export
 #' @useDynLib sodium R_stream_salsa20
 #' @rdname stream

src/stream.c

@@ -12,6 +12,17 @@ SEXP R_stream_chacha20(SEXP n, SEXP key, SEXP nonce){
   return res;
 }
 
+SEXP R_stream_xchacha20(SEXP n, SEXP key, SEXP nonce){
+  if(LENGTH(key) != crypto_stream_xchacha20_KEYBYTES)
+    Rf_error("Invalid key, must be exactly %d bytes", crypto_stream_xchacha20_KEYBYTES);
+  if(LENGTH(nonce) != crypto_stream_xchacha20_NONCEBYTES)
+    Rf_error("Invalid nonce, must be exactly %d bytes", crypto_stream_xchacha20_NONCEBYTES);
+  unsigned long long clen = (unsigned long long) asReal(n);
+  SEXP res = allocVector(RAWSXP, clen);
+  crypto_stream_xchacha20(RAW(res), clen, RAW(nonce), RAW(key));
+  return res;
+}
+
 SEXP R_stream_salsa20(SEXP n, SEXP key, SEXP nonce){
   if(LENGTH(key) != crypto_stream_salsa20_KEYBYTES)
     Rf_error("Invalid key, must be exactly %d bytes", crypto_stream_salsa20_KEYBYTES);