diff --git a/sbin/md5/md5.1 b/sbin/md5/md5.1
--- a/sbin/md5/md5.1
+++ b/sbin/md5/md5.1
@@ -1,5 +1,5 @@
 .\" $FreeBSD$
-.Dd June 19, 2021
+.Dd June 24, 2021
 .Dt MD5 1
 .Os
 .Sh NAME
@@ -14,6 +14,7 @@
 .Op Fl c Ar string
 .Op Fl s Ar string
 .Op Ar
+.Pp
 .Nm md5sum
 .Op Fl pqrtx
 .Op Fl c Ar file
@@ -80,13 +81,28 @@
 .Nm -sum
 programs.
 .It Fl c Ar string
-Compare the digest of the file against this string.
+If the program was called with a name that does not end in
+.Nm sum ,
+compare the digest of the file against this string.
 .Pq Note that this option is not yet useful if multiple files are specified.
-This option causes an error in for the
-.Nm -sum
-programs because it check the checksums listed in a file for the coreutils
-.Nm -sum
-programs that is not yet implemented.
+.It Fl c Ar file
+If the program was called with a name that does end in
+.Nm sum ,
+the file passed as argument must contain digest lines generated by the same digest algorithm
+with or without the
+.Fl r
+option
+.Pq i.e. in either classical BSD format or in GNU coreutils format .
+A line with file name followed by
+.Dq :
+and either OK or FAILED is written for each well-formed line in the digest file.
+If applicable, the number of failed comparisons and the number of lines that were
+skipped since they were not well-formed are printed at the end.
+The
+.Fl q
+option can be used to quiesce the output unless there are mismatched entries in
+the digest.
+.Pp
 .It Fl s Ar string
 Print a checksum of the given
 .Ar string .
@@ -141,8 +157,8 @@
 Calculate the checksum of multiple files reversing the output:
 .Bd -literal -offset indent
 $ md5 -r /boot/loader.conf /etc/rc.conf
-ada5f60f23af88ff95b8091d6d67bef6 /boot/loader.conf
-d80bf36c332dc0fdc479366ec3fa44cd /etc/rc.conf
+ada5f60f23af88ff95b8091d6d67bef6  /boot/loader.conf
+d80bf36c332dc0fdc479366ec3fa44cd  /etc/rc.conf
 .Ed
 .Pp
 Write the digest for
@@ -165,6 +181,27 @@
 $ md5 -c randomstring /boot/loader.conf
 MD5 (/boot/loader.conf) = ada5f60f23af88ff95b8091d6d67bef6 [ Failed ]
 .Ed
+.Pp
+If invoked with a name ending in
+.Nm -sum
+the
+.Fl c
+option does not compare against a hash string passed as parameter.
+Instead, it expects a digest file, as created under the name
+.Pa digest
+for
+.Pa /boot/loader.conf
+in the example above.
+.Bd -literal -offset indent
+$ md5 -c digest /boot/loader.conf
+/boot/loader.conf: OK
+.Ed
+.Pp
+The digest file may contain any number of lines in the format generated with or without the
+.Fl r
+option
+.Pq i.e. in either classical BSD format or in GNU coreutils format .
+If a hash value does not match the file, FAILED is printed instead of OK.
 .Sh SEE ALSO
 .Xr cksum 1 ,
 .Xr md5 3 ,
@@ -203,9 +240,7 @@
 All of the utilities that end in
 .Sq sum
 are intended to be compatible with the GNU coreutils programs.
-However, the long arguments and the
-.Fl -check
-functionality are not provided.
+However, the long option functionality is not provided.
 .Sh ACKNOWLEDGMENTS
 This program is placed in the public domain for free general use by
 RSA Data Security.
diff --git a/sbin/md5/md5.c b/sbin/md5/md5.c
--- a/sbin/md5/md5.c
+++ b/sbin/md5/md5.c
@@ -53,6 +53,7 @@
 #define TEST_BLOCK_COUNT 100000
 #define MDTESTCOUNT 8
 
+static int cflag;
 static int pflag;
 static int qflag;
 static int rflag;
@@ -152,12 +153,93 @@
 		(DIGEST_End*)&SKEIN1024_End, &SKEIN1024_Data, &SKEIN1024_Fd }
 };
 
+static unsigned	digest;
+static unsigned	malformed;
+static bool	gnu_emu = false;
+
 static void
 MD5_Update(MD5_CTX *c, const unsigned char *data, size_t len)
 {
 	MD5Update(c, data, len);
 }
 
+struct chksumrec {
+	char	*filename;
+	char	*chksum;
+	struct	chksumrec	*next;
+};
+
+static struct chksumrec *head = NULL;
+static struct chksumrec **next = &head;
+
+#define PADDING	7	/* extra padding for "SHA512t256 (...) = ...\n" style */
+#define CHKFILELINELEN	(HEX_DIGEST_LENGTH + MAXPATHLEN + PADDING)
+
+static int gnu_check(const char *checksumsfile)
+{
+	FILE	*inp;
+	char	linebuf[CHKFILELINELEN];
+	int	linelen;
+	int	lineno;
+	char	*filename;
+	char	*hashstr;
+	struct chksumrec	*rec;
+	const char	*digestname;
+	int	digestnamelen;
+	int	hashstrlen;
+
+	if ((inp = fopen(checksumsfile, "r")) == NULL)
+		err(1, "%s", checksumsfile);
+	digestname = Algorithm[digest].name;
+	digestnamelen = strlen(digestname);
+	hashstrlen = strlen(*(Algorithm[digest].TestOutput[0]));
+	lineno = 1;
+	while (fgets(linebuf, sizeof(linebuf), inp) != NULL) {
+		linelen = strlen(linebuf) - 1;
+		if (linelen <= 0)
+			break;
+		if (linebuf[linelen] != '\n')
+			errx(1, "malformed input line %d (len=%d)", lineno, linelen);
+		linebuf[linelen] = '\0';
+		filename = linebuf + digestnamelen + 2;
+		hashstr = linebuf + linelen - hashstrlen;
+		/*
+		 * supported formats:
+		 * BSD: <DigestName> (<Filename>): <Digest>
+		 * GNU: <Digest> [ *]<Filename>
+		 */
+		if (linelen >= digestnamelen + hashstrlen + 6 &&
+		    strncmp(linebuf, digestname, digestnamelen) == 0 &&
+		    strncmp(filename - 2, " (", 2) == 0 &&
+		    strncmp(hashstr - 4, ") = ", 4) == 0) {
+			*(hashstr - 4) = '\0';
+		} else if (linelen >= hashstrlen + 3 &&
+		    linebuf[hashstrlen] == ' ') {
+			linebuf[hashstrlen] = '\0';
+			hashstr = linebuf;
+			filename = linebuf + hashstrlen + 1;
+			if (*filename == ' ' || *filename == '*')
+				filename++;
+		} else {
+			malformed++;
+			continue;
+		}
+		rec = malloc(sizeof (*rec));
+		if (rec == NULL)
+			errx(1, "malloc failed");
+		rec->chksum = strdup(hashstr);
+		rec->filename = strdup(filename);
+		if (rec->chksum == NULL || rec->filename == NULL)
+			errx(1, "malloc failed");
+		rec->next = NULL;
+		*next = rec;
+		next = &rec->next;
+		lineno++;
+	}
+	fclose(inp);
+	return (lineno - 1);
+}
+
 /* Main driver.
 
 Arguments (may be any combination):
@@ -177,9 +259,9 @@
 	char   *p, *string;
 	char	buf[HEX_DIGEST_LENGTH];
 	size_t	len;
- 	unsigned	digest;
 	char	*progname;
-	bool	gnu_emu = false;
+	struct chksumrec	*rec;
+	int	numrecs;
 
  	if ((progname = strrchr(argv[0], '/')) == NULL)
  		progname = argv[0];
@@ -199,13 +281,13 @@
 	 */
 	len = strlen(progname);
 	if (len > 3 && strcmp(progname + len - 3, "sum") == 0) {
-		progname[len - 3] = '\0';
+		len -= 3;
 		rflag = 1;
 		gnu_emu = true;
 	}
 
  	for (digest = 0; digest < sizeof(Algorithm)/sizeof(*Algorithm); digest++)
- 		if (strcasecmp(Algorithm[digest].progname, progname) == 0)
+ 		if (strncasecmp(Algorithm[digest].progname, progname, len) == 0)
  			break;
 
  	if (digest == sizeof(Algorithm)/sizeof(*Algorithm))
@@ -220,9 +302,11 @@
 		case 'b':
 			break;
 		case 'c':
+			cflag = 1;
 			if (gnu_emu)
-				errx(1, "-c check option not supported");
-			checkAgainst = optarg;
+				numrecs = gnu_check(optarg);
+			else
+				checkAgainst = optarg;
 			break;
 		case 'p':
 			pflag = 1;
@@ -258,6 +342,20 @@
 		err(1, "unable to limit rights for stdio");
 #endif
 
+	if (cflag && gnu_emu) {
+		/*
+		 * Replace argv by an array of filenames from the digest file
+		 */
+		argc = 0;
+		argv = (char**)calloc(sizeof(char *), numrecs + 1);
+		for (rec = head; rec != NULL; rec = rec->next) {
+			argv[argc] = rec->filename;
+			argc++;
+		}
+		argv[argc] = NULL;
+		rec = head;
+	}
+
 	if (*argv) {
 		do {
 			if ((fd = open(*argv, O_RDONLY)) < 0) {
@@ -279,11 +377,15 @@
 					err(1, "capsicum");
 #endif
 			}
+			if (cflag && gnu_emu) {
+				checkAgainst = rec->chksum;
+				rec = rec->next;
+			}
 			p = Algorithm[digest].Fd(fd, buf);
 			(void)close(fd);
 			MDOutput(&Algorithm[digest], p, argv);
 		} while (*++argv);
-	} else if (!sflag && !skip) {
+	} else if (!cflag && !sflag && !skip) {
 #ifdef HAVE_CAPSICUM
 		if (caph_limit_stdin() < 0 || caph_enter() < 0)
 			err(1, "capsicum");
@@ -295,7 +397,12 @@
 		p = Algorithm[digest].Data(string, len, buf);
 		MDOutput(&Algorithm[digest], p, &string);
 	}
-
+	if (gnu_emu) {
+		if (malformed > 0)
+			warnx("WARNING: %d lines are improperly formatted", malformed);
+		if (checksFailed > 0)
+			warnx("WARNING: %d computed checksums did NOT match", checksFailed);
+	}
 	if (failed != 0)
 		return (1);
 	if (checksFailed != 0)
@@ -310,6 +417,8 @@
 static void
 MDOutput(const Algorithm_t *alg, char *p, char *argv[])
 {
+	bool checkfailed = false;
+
 	if (p == NULL) {
 		warn("%s", *argv);
 		failed++;
@@ -318,21 +427,27 @@
 		 * If argv is NULL we are reading from stdin, where the output
 		 * format has always been just the hash.
 		 */
-		if (qflag || argv == NULL)
-			printf("%s", p);
-		else if (rflag)
-			printf("%s %s", p, *argv);
-		else
-			printf("%s (%s) = %s",
-			    alg->name, *argv, p);
-		if (checkAgainst && strcasecmp(checkAgainst, p) != 0)
-		{
-			checksFailed++;
-			if (!qflag)
-				printf(" [ Failed ]");
+		if (cflag && gnu_emu) {
+			checkfailed = strcasecmp(checkAgainst, p) != 0;
+			if (!qflag || checkfailed)
+				printf("%s: %s\n", *argv, checkfailed ? "FAILED" : "OK");
+		} else if (qflag || argv == NULL) {
+			printf("%s\n", p);
+		} else {
+			if (rflag)
+				printf("%s  %s", p, *argv);
+			else
+				printf("%s (%s) = %s", alg->name, *argv, p);
+			if (checkAgainst) {
+				checkfailed = strcasecmp(checkAgainst, p) != 0;
+				if (!qflag && checkfailed)
+					printf(" [ Failed ]");
+			}
+			printf("\n");
 		}
-		printf("\n");
 	}
+	if (checkfailed)
+		checksFailed++;
 }
 
 /*
@@ -559,6 +674,9 @@
 usage(const Algorithm_t *alg)
 {
 
-	fprintf(stderr, "usage: %s [-pqrtx] [-c string] [-s string] [files ...]\n", alg->progname);
+	if (gnu_emu)
+		fprintf(stderr, "usage: %ssum [-pqrtx] [-c file] [-s string] [files ...]\n", alg->progname);
+	else
+		fprintf(stderr, "usage: %s [-pqrtx] [-c string] [-s string] [files ...]\n", alg->progname);
 	exit(1);
 }
diff --git a/sbin/md5/tests/Makefile b/sbin/md5/tests/Makefile
--- a/sbin/md5/tests/Makefile
+++ b/sbin/md5/tests/Makefile
@@ -32,6 +32,7 @@
 PLAIN_TESTS_SH+=	bsd-c-test
 PLAIN_TESTS_SH+=	bsd-p-test
 PLAIN_TESTS_SH+=	bsd-s-test
+PLAIN_TESTS_SH+=	coreutils-c-test
 
 .SUFFIXES:		.SH
 
diff --git a/sbin/md5/tests/coreutils-c-test.SH b/sbin/md5/tests/coreutils-c-test.SH
new file mode 100644
--- /dev/null
+++ b/sbin/md5/tests/coreutils-c-test.SH
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+/bin/cp %%TESTSBASE%%/sbin/md5/*.inp . || exit 127
+
+exitcode=0
+
+testloop () {
+	opt=$1
+
+	while read algorithm; do
+		${algorithm}sum -c %%TESTSBASE%%/sbin/md5/${algorithm}.digest || exitcode=1
+		${algorithm}sum -c %%TESTSBASE%%/sbin/md5/${algorithm}sum.digest || exitcode=1
+	done < %%TESTSBASE%%/sbin/md5/algorithms.txt
+}
+
+testloop ""
+testloop -q
+testloop -r
+testloop -qr
+
+exit $exitcode