--- /n/sources/plan9/sys/include/libsec.h	Thu Jun 18 20:28:32 2026
+++ /sys/include/libsec.h	Tue Jun 23 00:00:00 2026
@@ -190,6 +190,15 @@ enum
 	Maxdlen=	64,
 
 	Hmacblksz	= 64,	/* in bytes; from rfc2104 */
+
+	SHA1blksz=	64,	/* SHA block size */
+	SHA2_224blksz=	64,	/* SHA-224 block size */
+	SHA2_256blksz=	64,	/* SHA-256 block size */
+	SHA2_384blksz=	128,	/* SHA-384 block size */
+	SHA2_512blksz=	128,	/* SHA-512 block size */
+	MD4blksz=	64,	/* MD4 block size */
+	MD5blksz=	64,	/* MD5 block size */
+	Maxblksz		= 128,
 };
 
 typedef struct DigestState DigestState;
--- /n/sources/plan9/sys/include/ape/libsec.h	Thu Jun 18 20:28:32 2026
+++ /sys/include/ape/libsec.h	Tue Jun 23 00:00:00 2026
@@ -153,6 +153,15 @@ enum
 	Maxdlen=	64,
 
 	Hmacblksz	= 64,	/* in bytes; from rfc2104 */
+
+	SHA1blksz=	64,	/* SHA block size */
+	SHA2_224blksz=	64,	/* SHA-224 block size */
+	SHA2_256blksz=	64,	/* SHA-256 block size */
+	SHA2_384blksz=	128,	/* SHA-384 block size */
+	SHA2_512blksz=	128,	/* SHA-512 block size */
+	MD4blksz=	64,	/* MD4 block size */
+	MD5blksz=	64,	/* MD5 block size */
+	Maxblksz		= 128,
 };
 
 typedef struct DigestState DigestState;
--- /n/sources/plan9/sys/src/libsec/port/hmac.c	Wed Aug 29 06:00:01 2007
+++ /sys/src/libsec/port/hmac.c	Tue Jun 23 00:00:00 2026
@@ -6,21 +6,33 @@ DigestState*
 hmac_x(uchar *p, ulong len, uchar *key, ulong klen, uchar *digest, DigestState *s,
 	DigestState*(*x)(uchar*, ulong, uchar*, DigestState*), int xlen)
 {
-	int i;
-	uchar pad[Hmacblksz+1], innerdigest[256];
+	int i, blksz;
+	uchar pad[Maxblksz+1], innerdigest[256], hkey[Maxdlen], *k;
+
+	assert(xlen <= Maxdlen);
+
+	/* MD4, MD5, SHA1 to SHA2_256 block sizes are identical */
+	blksz = SHA1blksz;
+	if(xlen > SHA2_256dlen)
+		blksz = SHA2_384blksz; /* SHA2_384 and SHA2_512 */
 
 	if(xlen > sizeof(innerdigest))
 		return nil;
-	if(klen > Hmacblksz)
-		return nil;
+	if(klen <= blksz) 
+		k = key;
+	else {
+		x(key, klen, hkey, nil);
+		k = hkey;
+		klen = xlen;
+	}
 
 	/* first time through */
 	if(s == nil || s->seeded == 0){
-		memset(pad, 0x36, Hmacblksz);
-		pad[Hmacblksz] = 0;
+		memset(pad, 0x36, blksz);
+		pad[blksz] = 0;
 		for(i = 0; i < klen; i++)
-			pad[i] ^= key[i];
-		s = (*x)(pad, Hmacblksz, nil, s);
+			pad[i] ^= k[i];
+		s = (*x)(pad, blksz, nil, s);
 		if(s == nil)
 			return nil;
 	}
@@ -30,12 +42,12 @@ hmac_x(uchar *p, ulong len, uchar *key, ulong klen, uchar *digest, DigestState *
 		return s;
 
 	/* last time through */
-	memset(pad, 0x5c, Hmacblksz);
-	pad[Hmacblksz] = 0;
+	memset(pad, 0x5c, blksz);
+	pad[blksz] = 0;
 	for(i = 0; i < klen; i++)
-		pad[i] ^= key[i];
+		pad[i] ^= k[i];
 	(*x)(nil, 0, innerdigest, s);
-	s = (*x)(pad, Hmacblksz, nil, nil);
+	s = (*x)(pad, blksz, nil, nil);
 	(*x)(innerdigest, xlen, digest, s);
 	return nil;
 }