diff --git a/doc/NEWS.Rd b/doc/NEWS.Rd
index 80aef760f81..cd97248af4f 100644
--- a/doc/NEWS.Rd
+++ b/doc/NEWS.Rd
@@ -91,6 +91,9 @@
       \item \code{md5sum()} can be used to compute an MD5 hash of a raw
       vector of bytes by using the \code{bytes=} argument instead
       of \code{files=}. The two arguments are mutually exclusive.
+
+      \item Added \code{sha256sum()} analogous to \code{md5sum()},
+      but implementing the SHA-256 hashing algorithm.
     }
   }
 
diff --git a/src/library/tools/NAMESPACE b/src/library/tools/NAMESPACE
index 38b82e3c5e2..7713cd1c734 100644
--- a/src/library/tools/NAMESPACE
+++ b/src/library/tools/NAMESPACE
@@ -22,7 +22,7 @@ export("Adobe_glyphs", "HTMLheader", "Rcmd", "Rd2HTML", "pkg2HTML", "Rd2ex",
        "makevars_site", "makevars_user",
        "matchConcordance",
        nonS3methods,
-       "make_translations_pkg", "md5sum",
+       "make_translations_pkg", "md5sum", "sha256sum",
        package.dependencies,# R/package.dependencies.R man/package.dependencies.Rd
        getDepList, pkgDepends, installFoundDepends,# R/pkgDepends.R man/getDepList.Rd man/installFoundDepends.Rd
        vignetteDepends, # deprecated, too as it calls  getDepList()
diff --git a/src/library/tools/R/sha256.R b/src/library/tools/R/sha256.R
new file mode 100644
index 00000000000..f9972c58225
--- /dev/null
+++ b/src/library/tools/R/sha256.R
@@ -0,0 +1,109 @@
+#  File src/library/tools/R/sha256.R
+#  Part of the R package, https://www.R-project.org
+#
+#  Copyright (C) 1995-2024 The R Core Team
+#
+#  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
+#  (at your option) 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.
+#
+#  A copy of the GNU General Public License is available at
+#  https://www.R-project.org/Licenses/
+
+sha256sum <- function(files, bytes) {
+    if (!missing(files) && !missing(bytes))
+        stop("files and bytes are mutually exclusive")
+    if (!missing(bytes)) {
+        if (!is.raw(bytes)) stop("bytes must be a raw vector")
+        .Call(C_Rsha256, bytes)
+    } else {
+        files <- path.expand(files)
+        structure(.Call(C_Rsha256, files), names=files)
+    }
+}
+
+# The following fns are neither used nor exported - for now.
+
+.installSHA256sums <- function(pkgDir, outDir = pkgDir)
+{
+    dot <- getwd()
+    if (is.null(dot))
+        stop("current working directory cannot be ascertained")
+    setwd(pkgDir)
+    x <- sha256sum(dir(".", recursive=TRUE))
+    setwd(dot)
+    x <- x[names(x) != "SHA256"]
+    cat(paste(x, names(x), sep=" *"), sep="\n",
+        file=file.path(outDir, "SHA256"))
+}
+
+checkSHA256sums <- function(package, dir)
+{
+    if(missing(dir)) dir <- find.package(package, quiet = TRUE)
+    if(length(dir) != 1L) return(NA)
+    sha256file <- file.path(dir, "SHA256")
+    if(!file.exists(sha256file)) return(NA)
+    inlines <- readLines(sha256file)
+    ## now split on the first space.
+    xx <- sub("^([0-9a-fA-F]*)(.*)", "\\1", inlines)
+    nmxx <- names(xx) <- sub("^[0-9a-fA-F]* [ |*](.*)", "\\1", inlines)
+    dot <- getwd()
+    if (is.null(dot))
+        stop("current working directory cannot be ascertained")
+    setwd(dir)
+    x <- sha256sum(dir(dir, recursive = TRUE))
+    setwd(dot)
+    x <- x[names(x) != "SHA256"]
+    nmx <- names(x)
+    res <- TRUE
+    not.here <- (nmxx %notin% nmx)
+    if(any(not.here)) {
+        res <- FALSE
+        if (sum(not.here) > 1L)
+            cat("files", paste(sQuote(nmxx[not.here]), collapse = ", "),
+                "are missing\n", sep = " ")
+        else
+            cat("file", sQuote(nmxx[not.here]), "is missing\n", sep = " ")
+    }
+    nmxx <- nmxx[!not.here]
+    diff <- xx[nmxx] != x[nmxx]
+    if(any(diff)) {
+        res <- FALSE
+        files <- nmxx[diff]
+        if(length(files) > 1L)
+            cat("files", paste(sQuote(files), collapse = ", "),
+                "have the wrong SHA256 checksums\n", sep = " ")
+        else cat("file", sQuote(files), "has the wrong SHA256 checksum\n")
+    }
+    res
+}
+
+.hex.chars <- c("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f")
+
+hex2raw <- function(x) {
+  if (length(x) != 1L) stop("x must be a single string")
+  if (!nzchar(x)) return(raw(1L))
+  ## pad with 0 to full bytes
+  m <- match(strsplit(tolower(x),"")[[1L]], .hex.chars)
+  if (any(is.na(m))) stop("invalid hex string")
+  if (length(m) %% 2 == 1) m <- c(1L, m) ## add leading 0 for full byte
+  as.raw(colSums(matrix(m - 1L, 2) * c(16L, 1L)))
+}
+
+.pad <- function(x, n) if (length(x) < n) c(x, raw(n - length(x))) else x
+
+hmac <- function(key, x, hash, block) {
+  key <- .pad(if (length(key) > block) hex2raw(hash(key)) else key, block)
+  # HMAC := HASH( c( key ^ 0x5c, HASH( c( key ^ 0x36, x ) ) ) )
+  hash(c(xor(key, as.raw(0x5c)),
+       hex2raw(hash(c(xor(key, as.raw(0x36)), x)))))
+}
+
+hmac.sha256 <- function(key, x) hmac(key, x, function(x) sha256sum(bytes=x), 64L)
+hmac.md5 <- function(key, x) hmac(key, x, function(x) md5sum(bytes=x), 64L)
diff --git a/src/library/tools/man/md5sum.Rd b/src/library/tools/man/md5sum.Rd
index 437e45a0f77..2986256e444 100644
--- a/src/library/tools/man/md5sum.Rd
+++ b/src/library/tools/man/md5sum.Rd
@@ -1,6 +1,6 @@
 % File src/library/tools/man/md5sum.Rd
 % Part of the R package, https://www.R-project.org
-% Copyright 1995-2014 R Core Team
+% Copyright 1995-2024 R Core Team
 % Distributed under GPL 2 or later
 
 \name{md5sum}
@@ -44,7 +44,7 @@ md5sum(files, bytes)
   a 2001 release of \code{glibc}.
 }
 \seealso{
-  \code{\link{checkMD5sums}}
+  \code{\link{checkMD5sums}}, \code{\link{sha256sum}}
 }
 \examples{
 as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))
diff --git a/src/library/tools/man/sha256sum.Rd b/src/library/tools/man/sha256sum.Rd
new file mode 100644
index 00000000000..c1f12d9281e
--- /dev/null
+++ b/src/library/tools/man/sha256sum.Rd
@@ -0,0 +1,50 @@
+% File src/library/tools/man/sha256sum.Rd
+% Part of the R package, https://www.R-project.org
+% Copyright 1995-2024 R Core Team
+% Distributed under GPL 2 or later
+
+\name{sha256sum}
+\alias{sha256sum}
+\title{Compute SHA-256 Checksums}
+\description{
+  Compute the 32-byte SHA-256 hashes of one or more files, or a raw vector of bytes.
+}
+\usage{
+sha256sum(files, bytes)
+}
+\arguments{
+  \item{files}{character. The paths of file(s) whose contents are to be hashed.}
+  \item{bytes}{raw. Bytes to be hashed.
+    NB: \code{bytes} and \code{files} are mutually exclusive.}
+}
+\details{
+  A SHA-256 \sQuote{hash} or \sQuote{checksum} or \sQuote{message digest} is
+  a 256-bit summary of the file contents represented by 64 hexadecimal
+  digits.
+
+  On Windows all files are read in binary mode (as the \code{sha256sum}
+  utilities there do): on other OSes the files are read in the default
+  mode (almost always text mode where there is more than one).
+}
+\value{
+  A character vector of the same length as \code{files}, with names
+  equal to \code{files} (possibly expanded).  The elements will be
+  \code{NA} for non-existent or unreadable files, otherwise a
+  64-character string of hexadecimal digits.
+  
+  For \code{bytes} the result is a single 64-character string.
+}
+\source{
+  The underlying C code was written by \I{Ulrich Drepper}, extracted from
+  the public domain version SHA-crypt.txt verison 0.6 (2016-8-31).
+}
+\seealso{
+  \code{\link{md5sum}}
+}
+\examples{
+as.vector(sha256sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))
+sha256sum(bytes=raw())
+sha256sum(bytes=charToRaw("abc"))
+}
+\keyword{utilities}
+
diff --git a/src/library/tools/src/Makefile.in b/src/library/tools/src/Makefile.in
index 85767e69ced..acecf0f2c65 100644
--- a/src/library/tools/src/Makefile.in
+++ b/src/library/tools/src/Makefile.in
@@ -14,7 +14,7 @@ R_SHARE_DIR = $(R_HOME)/share
 R_INCLUDE_DIR = $(R_HOME)/include
 
 SOURCES_C = text.c init.c Rmd5.c md5.c signals.c install.c getfmts.c http.c \
-  gramLatex.c gramRd.c pdscan.c
+  gramLatex.c gramRd.c pdscan.c Rsha256.c sha256.c
 DEPENDS = $(SOURCES_C:.c=.d)
 OBJECTS = $(SOURCES_C:.c=.o)
 
diff --git a/src/library/tools/src/Makefile.win b/src/library/tools/src/Makefile.win
index 1235f434a8c..8fe261c7554 100644
--- a/src/library/tools/src/Makefile.win
+++ b/src/library/tools/src/Makefile.win
@@ -12,7 +12,7 @@ subdir = src/library/$(pkg)/src
 R_HOME = $(top_builddir)
 
 SOURCES_C = text.c init.c Rmd5.c md5.c signals.c install.c getfmts.c http.c \
-  gramLatex.c gramRd.c pdscan.c
+  gramLatex.c gramRd.c pdscan.c Rsha256.c sha256.c
 DEPENDS = $(SOURCES_C:.c=.d)
 OBJECTS = $(SOURCES_C:.c=.o) ../../../gnuwin32/dllversion.o
 
diff --git a/src/library/tools/src/Rmd5.c b/src/library/tools/src/Rmd5.c
index d07082c4bef..11512ff19f7 100644
--- a/src/library/tools/src/Rmd5.c
+++ b/src/library/tools/src/Rmd5.c
@@ -47,7 +47,7 @@ SEXP Rmd5(SEXP files)
     /* RAW mode: hash of one buffer instead of files */
     if (TYPEOF(files) == RAWSXP) {
 	/* there is really no failure possible, but just in case... */
-	if (!md5_buffer((char *) RAW(files), XLENGTH(files), resblock))
+	if (!md5_buffer((const char *) RAW(files), XLENGTH(files), resblock))
 	    return ScalarString(NA_STRING);
 	for(j = 0; j < 16; j++)
 	    snprintf (out+2*j, 33-2*j, "%02x", resblock[j]);
diff --git a/src/library/tools/src/Rsha256.c b/src/library/tools/src/Rsha256.c
new file mode 100644
index 00000000000..7fd7a35b4c5
--- /dev/null
+++ b/src/library/tools/src/Rsha256.c
@@ -0,0 +1,101 @@
+/*
+ *  R : A Computer Language for Statistical Data Analysis
+ *  Copyright (C) 2003-2024   The R Core Team.
+ *
+ *  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
+ *  (at your option) 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, a copy is available at
+ *  https://www.R-project.org/Licenses/
+ */
+
+/* <UTF8> OK since this is intended to treat chars as byte streams */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <Defn.h>
+#undef _
+
+#include "tools.h"
+#include "sha256.h"
+
+#define SHA256_HASH_SIZE 32
+#define SHA256_HEX_SIZE  64
+
+/* convenience fn for init + process + finish */
+static void *Rsha256_buffer (const void *buffer, size_t len, void *resblock)
+{
+  struct sha256_ctx ctx;
+  Rsha256_init_ctx(&ctx);
+  Rsha256_process_bytes(buffer, len, &ctx);
+  return Rsha256_finish_ctx(&ctx, resblock);
+}
+
+/* This is essentailly identical to Rmd5 */
+
+/* .Call so manages R_alloc stack */
+SEXP Rsha256(SEXP files)
+{
+    SEXP ans;
+    int i, j, nfiles = length(files), res;
+#ifdef _WIN32
+    const wchar_t *wpath;
+#else
+    const char *path;
+#endif
+    char out[SHA256_HEX_SIZE + 1];
+    FILE *fp;
+    unsigned char resblock[SHA256_HASH_SIZE];
+
+    /* RAW mode: hash of one buffer instead of files */
+    if (TYPEOF(files) == RAWSXP) {
+	/* there is really no failure possible, but just in case... */
+	if (!Rsha256_buffer((const void *) RAW(files), XLENGTH(files), resblock))
+	    return ScalarString(NA_STRING);
+	for(j = 0; j < SHA256_HASH_SIZE; j++)
+	  snprintf (out+2*j, sizeof(out) - 2*j, "%02x", resblock[j]);
+	return mkString(out);
+    }
+    /* otherwise list of files */
+    if(!isString(files)) error(_("argument 'files' must be character"));
+    PROTECT(ans = allocVector(STRSXP, nfiles));
+    for(i = 0; i < nfiles; i++) {
+#ifdef _WIN32
+	wpath = filenameToWchar(STRING_ELT(files, i), FALSE);
+	fp = _wfopen(wpath, L"rb");
+#else
+	path = translateChar(STRING_ELT(files, i));
+	fp = fopen(path, "r");
+#endif
+	if(!fp) {
+	    SET_STRING_ELT(ans, i, NA_STRING);
+	} else {
+	    res = Rsha256_stream(fp, &resblock);
+	    if(res) {
+#ifdef _WIN32
+		warning(_("sha256 failed on file '%ls'"), wpath);
+#else
+		warning(_("sha256 failed on file '%s'"), path);
+#endif
+		SET_STRING_ELT(ans, i, NA_STRING);
+	    } else {
+		for(j = 0; j < SHA256_HASH_SIZE; j++)
+		  snprintf (out+2*j, sizeof(out) - 2*j, "%02x", resblock[j]);
+		SET_STRING_ELT(ans, i, mkChar(out));
+	    }
+	    fclose(fp);
+	}
+    }
+    UNPROTECT(1);
+    return ans;
+}
diff --git a/src/library/tools/src/init.c b/src/library/tools/src/init.c
index 074b8d19fbf..cb5eb95d132 100644
--- a/src/library/tools/src/init.c
+++ b/src/library/tools/src/init.c
@@ -42,6 +42,7 @@ static const R_CallMethodDef CallEntries[] = {
     CALLDEF(dirchmod, 2),
     CALLDEF(getfmts, 1),
     CALLDEF(Rmd5, 1),
+    CALLDEF(Rsha256, 1),
     CALLDEF(check_nonASCII, 2),
     CALLDEF(check_nonASCII2, 1),
     CALLDEF(doTabExpand, 2),
diff --git a/src/library/tools/src/sha256.c b/src/library/tools/src/sha256.c
new file mode 100644
index 00000000000..4217eb6cfb6
--- /dev/null
+++ b/src/library/tools/src/sha256.c
@@ -0,0 +1,319 @@
+/*  SHA256 implementation.
+ *  R : A Computer Language for Statistical Data Analysis
+ *  Copyright (C) 2003-2024   The R Core Team.
+ *  Based on code released into the Public Domain by
+ *  Ulrich Drepper <drepper@redhat.com>.
+ *
+ *  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
+ *  (at your option) 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, a copy is available at
+ *  https://www.R-project.org/Licenses/
+ */
+
+#include <Rconfig.h>
+#include <sys/types.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "sha256.h"
+
+/* re-name our API points to avoid possible conflicts with other implementations */
+#define sha256_init_ctx       Rsha256_init_ctx
+#define sha256_process_bytes  Rsha256_process_bytes
+#define sha256_stream         Rsha256_stream
+#define sha256_finish_ctx     Rsha256_finish_ctx
+
+#ifndef WORDS_BIGENDIAN
+# define SWAP(n) \
+    (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
+#else
+# define SWAP(n) (n)
+#endif
+
+
+/* This array contains the bytes used to pad the buffer to the next
+   64-byte boundary.  (FIPS 180-2:5.1.1)  */
+static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */ };
+
+
+/* Constants for SHA256 from FIPS 180-2:4.2.2.  */
+static const uint32_t K[64] =
+  {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
+    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
+    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
+    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
+    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
+  };
+
+
+/* Process LEN bytes of BUFFER, accumulating context into CTX.
+   It is assumed that LEN % 64 == 0.  */
+static void sha256_process_block (const void *buffer, size_t len, struct sha256_ctx *ctx)
+{
+  const uint32_t *words = buffer;
+  size_t nwords = len / sizeof (uint32_t);
+  uint32_t a = ctx->H[0];
+  uint32_t b = ctx->H[1];
+  uint32_t c = ctx->H[2];
+  uint32_t d = ctx->H[3];
+  uint32_t e = ctx->H[4];
+  uint32_t f = ctx->H[5];
+  uint32_t g = ctx->H[6];
+  uint32_t h = ctx->H[7];
+
+  /* First increment the byte count.  FIPS 180-2 specifies the possible
+     length of the file up to 2^64 bits.  Here we only compute the
+     number of bytes.  Do a double word increment.  */
+  ctx->total[0] += len;
+  if (ctx->total[0] < len)
+    ++ctx->total[1];
+
+  /* Process all bytes in the buffer with 64 bytes in each round of
+     the loop.  */
+  while (nwords > 0)
+    {
+      uint32_t W[64];
+      uint32_t a_save = a;
+      uint32_t b_save = b;
+      uint32_t c_save = c;
+      uint32_t d_save = d;
+      uint32_t e_save = e;
+      uint32_t f_save = f;
+      uint32_t g_save = g;
+      uint32_t h_save = h;
+
+      /* Operators defined in FIPS 180-2:4.1.2.  */
+#define Ch(x, y, z) ((x & y) ^ (~x & z))
+#define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
+#define S0(x) (CYCLIC (x, 2) ^ CYCLIC (x, 13) ^ CYCLIC (x, 22))
+#define S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25))
+#define R0(x) (CYCLIC (x, 7) ^ CYCLIC (x, 18) ^ (x >> 3))
+#define R1(x) (CYCLIC (x, 17) ^ CYCLIC (x, 19) ^ (x >> 10))
+
+      /* It is unfortunate that C does not provide an operator for
+	 cyclic rotation.  Hope the C compiler is smart enough.  */
+#define CYCLIC(w, s) ((w >> s) | (w << (32 - s)))
+
+      /* Compute the message schedule according to FIPS 180-2:6.2.2 step 2.  */
+      for (unsigned int t = 0; t < 16; ++t)
+	{
+	  W[t] = SWAP (*words);
+	  ++words;
+	}
+      for (unsigned int t = 16; t < 64; ++t)
+	W[t] = R1 (W[t - 2]) + W[t - 7] + R0 (W[t - 15]) + W[t - 16];
+
+      /* The actual computation according to FIPS 180-2:6.2.2 step 3.  */
+      for (unsigned int t = 0; t < 64; ++t)
+	{
+	  uint32_t T1 = h + S1 (e) + Ch (e, f, g) + K[t] + W[t];
+	  uint32_t T2 = S0 (a) + Maj (a, b, c);
+	  h = g;
+	  g = f;
+	  f = e;
+	  e = d + T1;
+	  d = c;
+	  c = b;
+	  b = a;
+	  a = T1 + T2;
+	}
+
+      /* Add the starting values of the context according to FIPS 180-2:6.2.2
+	 step 4.  */
+      a += a_save;
+      b += b_save;
+      c += c_save;
+      d += d_save;
+      e += e_save;
+      f += f_save;
+      g += g_save;
+      h += h_save;
+
+      /* Prepare for the next round.  */
+      nwords -= 16;
+    }
+
+  /* Put checksum in context given as argument.  */
+  ctx->H[0] = a;
+  ctx->H[1] = b;
+  ctx->H[2] = c;
+  ctx->H[3] = d;
+  ctx->H[4] = e;
+  ctx->H[5] = f;
+  ctx->H[6] = g;
+  ctx->H[7] = h;
+}
+
+
+/* Initialize structure containing state of computation.
+   (FIPS 180-2:5.3.2)  */
+void sha256_init_ctx (struct sha256_ctx *ctx)
+{
+  ctx->H[0] = 0x6a09e667;
+  ctx->H[1] = 0xbb67ae85;
+  ctx->H[2] = 0x3c6ef372;
+  ctx->H[3] = 0xa54ff53a;
+  ctx->H[4] = 0x510e527f;
+  ctx->H[5] = 0x9b05688c;
+  ctx->H[6] = 0x1f83d9ab;
+  ctx->H[7] = 0x5be0cd19;
+
+  ctx->total[0] = ctx->total[1] = 0;
+  ctx->buflen = 0;
+}
+
+
+/* Process the remaining bytes in the internal buffer and the usual
+   prolog according to the standard and write the result to RESBUF.
+
+   IMPORTANT: On some systems it is required that RESBUF is correctly
+   aligned for a 32 bits value.  */
+void *sha256_finish_ctx (struct sha256_ctx *ctx, void *resbuf)
+{
+  /* Take yet unprocessed bytes into account.  */
+  uint32_t bytes = ctx->buflen;
+  size_t pad;
+
+  /* Now count remaining bytes.  */
+  ctx->total[0] += bytes;
+  if (ctx->total[0] < bytes)
+    ++ctx->total[1];
+
+  pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
+  memcpy (&ctx->buffer[bytes], fillbuf, pad);
+
+  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
+  *(uint32_t *) &ctx->buffer[bytes + pad + 4] = SWAP (ctx->total[0] << 3);
+  *(uint32_t *) &ctx->buffer[bytes + pad] = SWAP ((ctx->total[1] << 3) |
+						  (ctx->total[0] >> 29));
+
+  /* Process last bytes.  */
+  sha256_process_block (ctx->buffer, bytes + pad + 8, ctx);
+
+  /* Put result from CTX in first 32 bytes following RESBUF.  */
+  for (unsigned int i = 0; i < 8; ++i)
+    ((uint32_t *) resbuf)[i] = SWAP (ctx->H[i]);
+
+  return resbuf;
+}
+
+
+void sha256_process_bytes (const void *buffer, size_t len, struct sha256_ctx *ctx)
+{
+  /* When we already have some bits in our internal buffer concatenate
+     both inputs first.  */
+  if (ctx->buflen != 0)
+    {
+      size_t left_over = ctx->buflen;
+      size_t add = 128 - left_over > len ? len : 128 - left_over;
+
+      memcpy (&ctx->buffer[left_over], buffer, add);
+      ctx->buflen += add;
+
+      if (ctx->buflen > 64)
+	{
+	  sha256_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
+
+	  ctx->buflen &= 63;
+	  /* The regions in the following copy operation cannot overlap.  */
+	  memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
+		  ctx->buflen);
+	}
+
+      buffer = (const char *) buffer + add;
+      len -= add;
+    }
+
+  /* Process available complete blocks.  */
+  if (len >= 64)
+    {
+/* To check alignment gcc has an appropriate operator.  Other
+   compilers don't.  */
+#if __GNUC__ >= 2
+# define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
+#else
+# define UNALIGNED_P(p) (((uintptr_t) p) % sizeof (uint32_t) != 0)
+#endif
+      if (UNALIGNED_P (buffer))
+	while (len > 64)
+	  {
+	    sha256_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
+	    buffer = (const char *) buffer + 64;
+	    len -= 64;
+	  }
+      else
+	{
+	  sha256_process_block (buffer, len & ~63, ctx);
+	  buffer = (const char *) buffer + (len & ~63);
+	  len &= 63;
+	}
+    }
+
+  /* Move remaining bytes into internal buffer.  */
+  if (len > 0)
+    {
+      size_t left_over = ctx->buflen;
+
+      memcpy (&ctx->buffer[left_over], buffer, len);
+      left_over += len;
+      if (left_over >= 64)
+	{
+	  sha256_process_block (ctx->buffer, 64, ctx);
+	  left_over -= 64;
+	  memcpy (ctx->buffer, &ctx->buffer[64], left_over);
+	}
+      ctx->buflen = left_over;
+    }
+}
+
+int sha256_stream (FILE *stream, void *resblock)
+{
+  /* read buffer size (BUF_SIZE) must be a multiple of the block size (64) */
+#define BUF_SIZE 4096
+  struct sha256_ctx ctx;
+  char buffer[BUF_SIZE];
+  size_t sum = 0;
+
+  sha256_init_ctx (&ctx);
+  while (1) { /* while there is any content ... */
+    size_t n;
+    /* read next block */
+    while (sum < BUF_SIZE && (n = fread(buffer + sum, 1, BUF_SIZE - sum, stream)) > 0)
+      sum += n;
+    if (n == 0) { /* no more data ? */
+      if (ferror(stream)) return 1; /* error */
+      if (sum < BUF_SIZE) break;    /* EOF */
+    }
+    /* full block */
+    sha256_process_block (buffer, BUF_SIZE, &ctx);
+    sum = 0;
+  }
+
+  /* add any remaining bytes */
+  if (sum > 0) sha256_process_bytes (buffer, sum, &ctx);
+
+  sha256_finish_ctx (&ctx, resblock);
+  return 0;
+}
diff --git a/src/library/tools/src/sha256.h b/src/library/tools/src/sha256.h
new file mode 100644
index 00000000000..bafaedf7af0
--- /dev/null
+++ b/src/library/tools/src/sha256.h
@@ -0,0 +1,44 @@
+/*  SHA256 implementation.
+ *  R : A Computer Language for Statistical Data Analysis
+ *  Copyright (C) 2003-2024   The R Core Team.
+ *  Based on code released into the Public Domain by
+ *  Ulrich Drepper <drepper@redhat.com>.
+ *
+ *  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
+ *  (at your option) 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, a copy is available at
+ *  https://www.R-project.org/Licenses/
+ */
+
+#ifndef R_SHA256_H
+#define R_SHA256_H 1
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdio.h> /* for FILE I/O in Rsha256_stream */
+
+/* Structure to save state of computation between the single steps.  */
+struct sha256_ctx
+{
+  uint32_t H[8];
+
+  uint32_t total[2];
+  uint32_t buflen;
+  char buffer[128];	/* NB: always correctly aligned for uint32_t.  */
+};
+
+extern void  Rsha256_init_ctx(struct sha256_ctx *ctx);
+extern void  Rsha256_process_bytes(const void *buffer, size_t len, struct sha256_ctx *ctx);
+extern void* Rsha256_finish_ctx(struct sha256_ctx *ctx, void *resbuf);
+extern int   Rsha256_stream(FILE *stream, void *resblock);
+
+#endif
diff --git a/src/library/tools/src/tools.h b/src/library/tools/src/tools.h
index 518163caac5..c7ce25cae6e 100644
--- a/src/library/tools/src/tools.h
+++ b/src/library/tools/src/tools.h
@@ -32,6 +32,7 @@
 SEXP delim_match(SEXP x, SEXP delims);
 SEXP dirchmod(SEXP dr, SEXP gwsxp);
 SEXP Rmd5(SEXP files);
+SEXP Rsha256(SEXP files);
 SEXP check_nonASCII(SEXP text, SEXP ignore_quotes);
 SEXP check_nonASCII2(SEXP text);
 SEXP doTabExpand(SEXP strings, SEXP starts);
diff --git a/src/library/tools/tests/hashes.R b/src/library/tools/tests/hashes.R
new file mode 100644
index 00000000000..ab8d79fa382
--- /dev/null
+++ b/src/library/tools/tests/hashes.R
@@ -0,0 +1,64 @@
+require("tools")
+
+## -- MD5 test vectors
+## RFC 1321 A.5:
+stopifnot(identical(md5sum(bytes=raw()),
+  "d41d8cd98f00b204e9800998ecf8427e"))
+stopifnot(identical(md5sum(bytes=charToRaw("a")),
+  "0cc175b9c0f1b6a831c399e269772661"))
+stopifnot(identical(md5sum(bytes=charToRaw("abc")),
+    "900150983cd24fb0d6963f7d28e17f72"))
+## not official, but the FIPS180-2 vectors
+stopifnot(identical(md5sum(bytes=rep(charToRaw("a"),1e6)),
+  "7707d6ae4e027c70eea2a935c2296f21"))
+stopifnot(identical(md5sum(bytes=charToRaw("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq")),
+  "8215ef0796a20bcaaae116d3876c664a"))
+
+## -- SHA256 test vectors
+stopifnot(identical(sha256sum(bytes=raw()),
+  "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"))
+
+## FIPS180-2 Appendix B.3 test vectors
+stopifnot(identical(sha256sum(bytes=charToRaw("abc")),
+  "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"))
+stopifnot(identical(sha256sum(bytes=charToRaw("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq")),
+  "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1"))
+stopifnot(identical(sha256sum(bytes=rep(charToRaw("a"),1e6)),
+  "cdc76e5c9914fb9281a1c7e284d73e67f1809a48a497200e046d39ccc7112cd0"))
+
+## let's see if there are hidden HMAC functions - if so, test them
+if (!is.null(environment(tools::sha256sum)[["hmac"]])) { 
+
+## [[ we have not expoorted HMAC functions yet ]]
+hmac.md5 <- tools:::hmac.md5
+hmac.sha256 <- tools:::hmac.sha256
+
+## -- HMAC test vectors
+## RFC 2202 HMAC-MD5
+stopifnot(identical(hmac.md5(rep(as.raw(0xb),16), charToRaw("Hi There")),
+  "9294727a3638bb1c13f48ef8158bfc9d"))
+stopifnot(identical(hmac.md5(charToRaw("Jefe"), charToRaw("what do ya want for nothing?")),
+  "750c783e6ab0b503eaa86e310a5db738"))
+stopifnot(identical(hmac.md5(rep(as.raw(0xaa),16), rep(as.raw(0xdd), 50)),
+  "56be34521d144c88dbb8c733f0e8b3f6"))
+## skipping test_case = 4,5
+stopifnot(identical(hmac.md5(rep(as.raw(0xaa),80), charToRaw("Test Using Larger Than Block-Size Key - Hash Key First")),
+  "6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd"))
+stopifnot(identical(hmac.md5(rep(as.raw(0xaa),80), charToRaw("Test Using Larger Than Block-Size Key and Larger Than One Block-Size Data")),
+  "6f630fad67cda0ee1fb1f562db3aa53e"))
+
+## RFC 4231 HMAC-SHA256
+stopifnot(identical(hmac.sha256(rep(as.raw(0xb),20), charToRaw("Hi There")),
+  "b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7"))
+stopifnot(identical(hmac.sha256(charToRaw("Jefe"), charToRaw("what do ya want for nothing?")),
+  "5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843"))
+stopifnot(identical(hmac.sha256(rep(as.raw(0xaa),20), rep(as.raw(0xdd), 50)),
+  "773ea91e36800e46854db8ebd09181a72959098b3ef8c122d9635514ced565fe"))
+## skipping test_case = 4,5 (we don't truncate - left to the user)
+stopifnot(identical(hmac.sha256(rep(as.raw(0xaa),131), charToRaw("Test Using Larger Than Block-Size Key - Hash Key First")),
+  "60e431591ee0b67f0d8a26aacbf5b77f8e0bc6213728c5140546040f0ee37f54"))
+stopifnot(identical(hmac.sha256(rep(as.raw(0xaa),131),
+  charToRaw("This is a test using a larger than block-size key and a larger than block-size data. The key needs to be hashed before being used by the HMAC algorithm.")),
+  "9b09ffa71b942fcb27635fbcd5b0e944bfdc63644f0713938a7f51535c3a35e2"))
+
+}