diff --git a/lib/libmd/md4c.c b/lib/libmd/md4c.c
index a30027b1fb45..4cb136814019 100644
--- a/lib/libmd/md4c.c
+++ b/lib/libmd/md4c.c
@@ -183,7 +183,7 @@ MD4_CTX *context;                                        /* context */
 
   /* Zeroize sensitive information.
    */
-  memset ((POINTER)context, 0, sizeof (*context));
+  explicit_bzero(context, sizeof(*context));
 }
 
 /* MD4 basic transformation. Transforms state based on block.
diff --git a/lib/libmd/md5c.c b/lib/libmd/md5c.c
index a2c71b6a6960..fc852b913464 100644
--- a/lib/libmd/md5c.c
+++ b/lib/libmd/md5c.c
@@ -220,7 +220,7 @@ MD5Final (unsigned char digest[16], MD5_CTX *context)
 	Encode (digest, context->state, 16);
 
 	/* Zeroize sensitive information. */
-	memset ((void *)context, 0, sizeof (*context));
+	explicit_bzero(context, sizeof(*context));
 }
 
 /* MD5 basic transformation. Transforms state based on block. */
diff --git a/lib/libmd/mdX.3 b/lib/libmd/mdX.3
index daa5c36176cf..9440c286b212 100644
--- a/lib/libmd/mdX.3
+++ b/lib/libmd/mdX.3
@@ -8,7 +8,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 26, 2016
+.Dd July 20, 2018
 .Dt MDX 3
 .Os
 .Sh NAME
@@ -78,7 +78,9 @@ initialize it with
 run over the data with
 .Fn MDXUpdate ,
 and finally extract the result using
-.Fn MDXFinal .
+.Fn MDXFinal ,
+which will also erase the
+.Vt MDX_CTX .
 .Pp
 The
 .Fn MDXPad
diff --git a/lib/libmd/ripemd.3 b/lib/libmd/ripemd.3
index 8e868b88e8da..e4c5fa4a41c8 100644
--- a/lib/libmd/ripemd.3
+++ b/lib/libmd/ripemd.3
@@ -9,7 +9,7 @@
 .\" 	From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
 .\" $FreeBSD$
 .\"
-.Dd April 26, 2016
+.Dd July 20, 2018
 .Dt RIPEMD 3
 .Os
 .Sh NAME
@@ -65,7 +65,9 @@ initialize it with
 run over the data with
 .Fn RIPEMD160_Update ,
 and finally extract the result using
-.Fn RIPEMD160_Final .
+.Fn RIPEMD160_Final ,
+which will also erase the
+.Vt RIPEMD160_CTX .
 .Pp
 The
 .Fn RIPEMD160_End
diff --git a/lib/libmd/rmd160c.c b/lib/libmd/rmd160c.c
index 5a3b78325728..a8a4ced70b0a 100644
--- a/lib/libmd/rmd160c.c
+++ b/lib/libmd/rmd160c.c
@@ -523,10 +523,8 @@ RIPEMD160_CTX *c;
 	l=c->D; l2c(l,cp);
 	l=c->E; l2c(l,cp);
 
-	/* clear stuff, ripemd160_block may be leaving some stuff on the stack
-	 * but I'm not worried :-) */
-	c->num=0;
-/*	memset((char *)&c,0,sizeof(c));*/
+	/* Clear the context state */
+	explicit_bzero(&c, sizeof(c));
 	}
 
 #ifdef undef
diff --git a/lib/libmd/sha.3 b/lib/libmd/sha.3
index 95c0603651b9..90cc93662429 100644
--- a/lib/libmd/sha.3
+++ b/lib/libmd/sha.3
@@ -9,7 +9,7 @@
 .\" 	From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
 .\" $FreeBSD$
 .\"
-.Dd April 26, 2016
+.Dd July 20, 2018
 .Dt SHA 3
 .Os
 .Sh NAME
@@ -100,7 +100,9 @@ initialize it with
 run over the data with
 .Fn SHA1_Update ,
 and finally extract the result using
-.Fn SHA1_Final .
+.Fn SHA1_Final ,
+which will also erase the
+.Vt SHA_CTX .
 .Pp
 .Fn SHA1_End
 is a wrapper for
diff --git a/lib/libmd/sha0c.c b/lib/libmd/sha0c.c
index b35b7f275ffd..ee4407939598 100644
--- a/lib/libmd/sha0c.c
+++ b/lib/libmd/sha0c.c
@@ -446,9 +446,7 @@ SHA_CTX *c;
 	l=c->h3; nl2c(l,cp);
 	l=c->h4; nl2c(l,cp);
 
-	/* clear stuff, sha_block may be leaving some stuff on the stack
-	 * but I'm not worried :-) */
-	c->num=0;
-/*	memset((char *)&c,0,sizeof(c));*/
+	/* Clear the context state */
+	explicit_bzero(&c, sizeof(c));
 	}
 
diff --git a/lib/libmd/sha1c.c b/lib/libmd/sha1c.c
index 93a4ff37683b..d0bcc35f93d7 100644
--- a/lib/libmd/sha1c.c
+++ b/lib/libmd/sha1c.c
@@ -482,10 +482,8 @@ SHA_CTX *c;
 	l=c->h3; nl2c(l,cp);
 	l=c->h4; nl2c(l,cp);
 
-	/* clear stuff, sha1_block may be leaving some stuff on the stack
-	 * but I'm not worried :-) */
-	c->num=0;
-/*	memset((char *)&c,0,sizeof(c));*/
+	/* Clear the context state */
+	explicit_bzero(&c, sizeof(c));
 	}
 
 #ifdef WEAK_REFS
diff --git a/lib/libmd/sha256.3 b/lib/libmd/sha256.3
index 25bbb1220486..eeac4041f479 100644
--- a/lib/libmd/sha256.3
+++ b/lib/libmd/sha256.3
@@ -9,7 +9,7 @@
 .\" 	From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
 .\" $FreeBSD$
 .\"
-.Dd July 9, 2018
+.Dd July 20, 2018
 .Dt SHA256 3
 .Os
 .Sh NAME
@@ -88,7 +88,9 @@ initialize it with
 run over the data with
 .Fn SHA256_Update ,
 and finally extract the result using
-.Fn SHA256_Final .
+.Fn SHA256_Final ,
+which will also erase the
+.Vt SHA256_CTX .
 .Pp
 .Fn SHA256_End
 is a wrapper for
diff --git a/lib/libmd/sha512.3 b/lib/libmd/sha512.3
index c5f9ac6f1770..a842e9cada61 100644
--- a/lib/libmd/sha512.3
+++ b/lib/libmd/sha512.3
@@ -9,7 +9,7 @@
 .\" 	From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
 .\" $FreeBSD$
 .\"
-.Dd April 22, 2016
+.Dd July 20, 2018
 .Dt SHA512 3
 .Os
 .Sh NAME
@@ -110,7 +110,9 @@ initialize it with
 run over the data with
 .Fn SHA512_Update ,
 and finally extract the result using
-.Fn SHA512_Final .
+.Fn SHA512_Final ,
+which will also erase the
+.Vt SHA512_CTX .
 .Pp
 .Fn SHA512_End
 is a wrapper for
diff --git a/lib/libmd/skein.3 b/lib/libmd/skein.3
index 11c78a797aa3..2d6a9e3fd4b1 100644
--- a/lib/libmd/skein.3
+++ b/lib/libmd/skein.3
@@ -124,7 +124,9 @@ initialize it with
 run over the data with
 .Fn SKEIN256_Update ,
 and finally extract the result using
-.Fn SKEIN256_Final .
+.Fn SKEIN256_Final ,
+which will also erase the
+.Vt SKEIN256_CTX .
 .Pp
 .Fn SKEIN256_End
 is a wrapper for
diff --git a/sys/crypto/sha2/sha256c.c b/sys/crypto/sha2/sha256c.c
index 70980ac5fb7a..135fb68ccc65 100644
--- a/sys/crypto/sha2/sha256c.c
+++ b/sys/crypto/sha2/sha256c.c
@@ -298,7 +298,7 @@ SHA256_Final(unsigned char digest[static SHA256_DIGEST_LENGTH], SHA256_CTX *ctx)
 	be32enc_vect(digest, ctx->state, SHA256_DIGEST_LENGTH);
 
 	/* Clear the context state */
-	memset(ctx, 0, sizeof(*ctx));
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 /*** SHA-224: *********************************************************/
diff --git a/sys/crypto/sha2/sha512c.c b/sys/crypto/sha2/sha512c.c
index 21c7efabe156..e0dd36120a90 100644
--- a/sys/crypto/sha2/sha512c.c
+++ b/sys/crypto/sha2/sha512c.c
@@ -331,7 +331,7 @@ SHA512_Final(unsigned char digest[static SHA512_DIGEST_LENGTH], SHA512_CTX *ctx)
 	be64enc_vect(digest, ctx->state, SHA512_DIGEST_LENGTH);
 
 	/* Clear the context state */
-	memset(ctx, 0, sizeof(*ctx));
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 /*** SHA-512t: *********************************************************/
@@ -374,7 +374,7 @@ SHA512_224_Final(unsigned char digest[static SHA512_224_DIGEST_LENGTH], SHA512_C
 	be64enc_vect(digest, ctx->state, SHA512_224_DIGEST_LENGTH);
 
 	/* Clear the context state */
-	memset(ctx, 0, sizeof(*ctx));
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 void
@@ -413,7 +413,7 @@ SHA512_256_Final(unsigned char digest[static SHA512_256_DIGEST_LENGTH], SHA512_C
 	be64enc_vect(digest, ctx->state, SHA512_256_DIGEST_LENGTH);
 
 	/* Clear the context state */
-	memset(ctx, 0, sizeof(*ctx));
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 /*** SHA-384: *********************************************************/
@@ -463,7 +463,7 @@ SHA384_Final(unsigned char digest[static SHA384_DIGEST_LENGTH], SHA384_CTX *ctx)
 	be64enc_vect(digest, ctx->state, SHA384_DIGEST_LENGTH);
 
 	/* Clear the context state */
-	memset(ctx, 0, sizeof(*ctx));
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 #ifdef WEAK_REFS
diff --git a/sys/crypto/skein/skein.c b/sys/crypto/skein/skein.c
index b8d5905078a3..fd17623db21a 100644
--- a/sys/crypto/skein/skein.c
+++ b/sys/crypto/skein/skein.c
@@ -812,6 +812,7 @@ SKEIN256_Final(unsigned char digest[static SKEIN_256_BLOCK_BYTES], SKEIN256_CTX
 {
 
 	Skein_256_Final(ctx, digest);
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 void
@@ -819,6 +820,7 @@ SKEIN512_Final(unsigned char digest[static SKEIN_512_BLOCK_BYTES], SKEIN512_CTX
 {
 
 	Skein_512_Final(ctx, digest);
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 void
@@ -826,6 +828,7 @@ SKEIN1024_Final(unsigned char digest[static SKEIN1024_BLOCK_BYTES], SKEIN1024_CT
 {
 
 	Skein1024_Final(ctx, digest);
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 #ifdef WEAK_REFS