diff --git a/CHANGES b/CHANGES
index 5e9d4dd7d..4eb839823 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,15 @@
 
  Changes between 0.9.5a and 0.9.6  [xx XXX 2000]
 
+  *) The STACK code has been cleaned up, and certain type declarations
+     that didn't make a lot of sense have been brought in line. This has
+     also involved a cleanup of sorts in safestack.h to more correctly
+     map type-safe stack functions onto their plain stack counterparts.
+     This work has also resulted in a variety of "const"ifications of
+     lots of the code, especially "_cmp" operations which should normally
+     be prototyped with "const" parameters anyway.
+     [Geoff Thorpe]
+
   *) When generating bytes for the first time in md_rand.c, 'stir the pool'
      by seeding with STATE_SIZE dummy bytes (with zero entropy count).
      (The PRNG state consists of two parts, the large pool 'state' and 'md',
diff --git a/crypto/asn1/a_strnid.c b/crypto/asn1/a_strnid.c
index ab8417ffa..1ef147830 100644
--- a/crypto/asn1/a_strnid.c
+++ b/crypto/asn1/a_strnid.c
@@ -65,7 +65,8 @@
 
 static STACK_OF(ASN1_STRING_TABLE) *stable = NULL;
 static void st_free(ASN1_STRING_TABLE *tbl);
-static int sk_table_cmp(ASN1_STRING_TABLE **a, ASN1_STRING_TABLE **b);
+static int sk_table_cmp(const ASN1_STRING_TABLE * const *a,
+			const ASN1_STRING_TABLE * const *b);
 static int table_cmp(ASN1_STRING_TABLE *a, ASN1_STRING_TABLE *b);
 
 
@@ -173,7 +174,8 @@ static ASN1_STRING_TABLE tbl_standard[] = {
 {NID_dnQualifier,		-1, -1, B_ASN1_PRINTABLESTRING, STABLE_NO_MASK}
 };
 
-static int sk_table_cmp(ASN1_STRING_TABLE **a, ASN1_STRING_TABLE **b)
+static int sk_table_cmp(const ASN1_STRING_TABLE * const *a,
+			const ASN1_STRING_TABLE * const *b)
 {
 	return (*a)->nid - (*b)->nid;
 }
diff --git a/crypto/asn1/x_crl.c b/crypto/asn1/x_crl.c
index 12a42d04c..39fe8916f 100644
--- a/crypto/asn1/x_crl.c
+++ b/crypto/asn1/x_crl.c
@@ -61,8 +61,10 @@
 #include <openssl/asn1_mac.h>
 #include <openssl/x509.h>
 
-static int X509_REVOKED_cmp(X509_REVOKED **a,X509_REVOKED **b);
-static int X509_REVOKED_seq_cmp(X509_REVOKED **a,X509_REVOKED **b);
+static int X509_REVOKED_cmp(const X509_REVOKED * const *a,
+				const X509_REVOKED * const *b);
+static int X509_REVOKED_seq_cmp(const X509_REVOKED * const *a,
+				const X509_REVOKED * const *b);
 int i2d_X509_REVOKED(X509_REVOKED *a, unsigned char **pp)
 	{
 	M_ASN1_I2D_vars(a);
@@ -100,7 +102,8 @@ int i2d_X509_CRL_INFO(X509_CRL_INFO *a, unsigned char **pp)
 	{
 	int v1=0;
 	long l=0;
-	int (*old_cmp)(X509_REVOKED **,X509_REVOKED **);
+	int (*old_cmp)(const X509_REVOKED * const *,
+			const X509_REVOKED * const *);
 	M_ASN1_I2D_vars(a);
 	
 	old_cmp=sk_X509_REVOKED_set_cmp_func(a->revoked,X509_REVOKED_seq_cmp);
@@ -325,14 +328,16 @@ void X509_CRL_free(X509_CRL *a)
 	Free(a);
 	}
 
-static int X509_REVOKED_cmp(X509_REVOKED **a, X509_REVOKED **b)
+static int X509_REVOKED_cmp(const X509_REVOKED * const *a,
+			const X509_REVOKED * const *b)
 	{
 	return(ASN1_STRING_cmp(
 		(ASN1_STRING *)(*a)->serialNumber,
 		(ASN1_STRING *)(*b)->serialNumber));
 	}
 
-static int X509_REVOKED_seq_cmp(X509_REVOKED **a, X509_REVOKED **b)
+static int X509_REVOKED_seq_cmp(const X509_REVOKED * const *a,
+				const X509_REVOKED * const *b)
 	{
 	return((*a)->sequence-(*b)->sequence);
 	}
diff --git a/crypto/pkcs7/pk7_mime.c b/crypto/pkcs7/pk7_mime.c
index 5abd0ec8f..36d47ef11 100644
--- a/crypto/pkcs7/pk7_mime.c
+++ b/crypto/pkcs7/pk7_mime.c
@@ -94,8 +94,10 @@ static char * strip_end(char *name);
 static MIME_HEADER *mime_hdr_new(char *name, char *value);
 static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value);
 static STACK_OF(MIME_HEADER) *mime_parse_hdr(BIO *bio);
-static int mime_hdr_cmp(MIME_HEADER **a, MIME_HEADER **b);
-static int mime_param_cmp(MIME_PARAM **a, MIME_PARAM **b);
+static int mime_hdr_cmp(const MIME_HEADER * const *a,
+			const MIME_HEADER * const *b);
+static int mime_param_cmp(const MIME_PARAM * const *a,
+			const MIME_PARAM * const *b);
 static void mime_param_free(MIME_PARAM *param);
 static int mime_bound_check(char *line, int linelen, char *bound, int blen);
 static int multi_split(BIO *bio, char *bound, STACK_OF(BIO) **ret);
@@ -614,12 +616,14 @@ static int mime_hdr_addparam(MIME_HEADER *mhdr, char *name, char *value)
 	return 1;
 }
 
-static int mime_hdr_cmp(MIME_HEADER **a, MIME_HEADER **b)
+static int mime_hdr_cmp(const MIME_HEADER * const *a,
+			const MIME_HEADER * const *b)
 {
 	return(strcmp((*a)->name, (*b)->name));
 }
 
-static int mime_param_cmp(MIME_PARAM **a, MIME_PARAM **b)
+static int mime_param_cmp(const MIME_PARAM * const *a,
+			const MIME_PARAM * const *b)
 {
 	return(strcmp((*a)->param_name, (*b)->param_name));
 }
diff --git a/crypto/x509/x509.h b/crypto/x509/x509.h
index a0aaad836..a5cb55558 100644
--- a/crypto/x509/x509.h
+++ b/crypto/x509/x509.h
@@ -659,11 +659,14 @@ int X509_REQ_sign(X509_REQ *x, EVP_PKEY *pkey, const EVP_MD *md);
 int X509_CRL_sign(X509_CRL *x, EVP_PKEY *pkey, const EVP_MD *md);
 int NETSCAPE_SPKI_sign(NETSCAPE_SPKI *x, EVP_PKEY *pkey, const EVP_MD *md);
 
-int X509_digest(X509 *data,const EVP_MD *type,unsigned char *md,unsigned int *len);
-int X509_CRL_digest(X509_CRL *data,const EVP_MD *type,unsigned char *md,unsigned int *len);
-int X509_REQ_digest(X509_REQ *data,const EVP_MD *type,unsigned char *md,unsigned int *len);
-int X509_NAME_digest(X509_NAME *data,const EVP_MD *type,
-	unsigned char *md,unsigned int *len);
+int X509_digest(const X509 *data,const EVP_MD *type,
+		unsigned char *md, unsigned int *len);
+int X509_CRL_digest(const X509_CRL *data,const EVP_MD *type,
+		unsigned char *md, unsigned int *len);
+int X509_REQ_digest(const X509_REQ *data,const EVP_MD *type,
+		unsigned char *md, unsigned int *len);
+int X509_NAME_digest(const X509_NAME *data,const EVP_MD *type,
+		unsigned char *md, unsigned int *len);
 #endif
 
 #ifndef NO_FP_API
@@ -963,20 +966,20 @@ int X509_REQ_add1_attr_by_txt(X509_REQ *req,
 
 int		X509_check_private_key(X509 *x509,EVP_PKEY *pkey);
 
-int		X509_issuer_and_serial_cmp(X509 *a, X509 *b);
+int		X509_issuer_and_serial_cmp(const X509 *a, const X509 *b);
 unsigned long	X509_issuer_and_serial_hash(X509 *a);
 
-int		X509_issuer_name_cmp(X509 *a, X509 *b);
+int		X509_issuer_name_cmp(const X509 *a, const X509 *b);
 unsigned long	X509_issuer_name_hash(X509 *a);
 
-int		X509_subject_name_cmp(X509 *a,X509 *b);
+int		X509_subject_name_cmp(const X509 *a, const X509 *b);
 unsigned long	X509_subject_name_hash(X509 *x);
 
-int		X509_cmp (X509 *a, X509 *b);
-int		X509_NAME_cmp (X509_NAME *a, X509_NAME *b);
+int		X509_cmp(const X509 *a, const X509 *b);
+int		X509_NAME_cmp(const X509_NAME *a, const X509_NAME *b);
 unsigned long	X509_NAME_hash(X509_NAME *x);
 
-int		X509_CRL_cmp(X509_CRL *a,X509_CRL *b);
+int		X509_CRL_cmp(const X509_CRL *a, const X509_CRL *b);
 #ifndef NO_FP_API
 int		X509_print_fp(FILE *bp,X509 *x);
 int		X509_CRL_print_fp(FILE *bp,X509_CRL *x);
diff --git a/crypto/x509/x509_cmp.c b/crypto/x509/x509_cmp.c
index a8a5ca8b0..0452b025b 100644
--- a/crypto/x509/x509_cmp.c
+++ b/crypto/x509/x509_cmp.c
@@ -63,7 +63,7 @@
 #include <openssl/x509.h>
 #include <openssl/x509v3.h>
 
-int X509_issuer_and_serial_cmp(X509 *a, X509 *b)
+int X509_issuer_and_serial_cmp(const X509 *a, const X509 *b)
 	{
 	int i;
 	X509_CINF *ai,*bi;
@@ -97,17 +97,17 @@ unsigned long X509_issuer_and_serial_hash(X509 *a)
 	}
 #endif
 	
-int X509_issuer_name_cmp(X509 *a, X509 *b)
+int X509_issuer_name_cmp(const X509 *a, const X509 *b)
 	{
 	return(X509_NAME_cmp(a->cert_info->issuer,b->cert_info->issuer));
 	}
 
-int X509_subject_name_cmp(X509 *a, X509 *b)
+int X509_subject_name_cmp(const X509 *a, const X509 *b)
 	{
 	return(X509_NAME_cmp(a->cert_info->subject,b->cert_info->subject));
 	}
 
-int X509_CRL_cmp(X509_CRL *a, X509_CRL *b)
+int X509_CRL_cmp(const X509_CRL *a, const X509_CRL *b)
 	{
 	return(X509_NAME_cmp(a->crl->issuer,b->crl->issuer));
 	}
@@ -139,19 +139,25 @@ unsigned long X509_subject_name_hash(X509 *x)
 
 #ifndef NO_SHA
 /* Compare two certificates: they must be identical for
- * this to work.
+ * this to work. NB: Although "cmp" operations are generally
+ * prototyped to take "const" arguments (eg. for use in
+ * STACKs), the way X509 handling is - these operations may
+ * involve ensuring the hashes are up-to-date and ensuring
+ * certain cert information is cached. So this is the point
+ * where the "depth-first" constification tree has to halt
+ * with an evil cast.
  */
-int X509_cmp(X509 *a, X509 *b)
+int X509_cmp(const X509 *a, const X509 *b)
 {
 	/* ensure hash is valid */
-	X509_check_purpose(a, -1, 0);
-	X509_check_purpose(b, -1, 0);
+	X509_check_purpose((X509 *)a, -1, 0);
+	X509_check_purpose((X509 *)b, -1, 0);
 
 	return memcmp(a->sha1_hash, b->sha1_hash, SHA_DIGEST_LENGTH);
 }
 #endif
 
-int X509_NAME_cmp(X509_NAME *a, X509_NAME *b)
+int X509_NAME_cmp(const X509_NAME *a, const X509_NAME *b)
 	{
 	int i,j;
 	X509_NAME_ENTRY *na,*nb;
diff --git a/crypto/x509/x509_trs.c b/crypto/x509/x509_trs.c
index c779aaf94..8637e56d9 100644
--- a/crypto/x509/x509_trs.c
+++ b/crypto/x509/x509_trs.c
@@ -61,7 +61,8 @@
 #include <openssl/x509v3.h>
 
 
-static int tr_cmp(X509_TRUST **a, X509_TRUST **b);
+static int tr_cmp(const X509_TRUST * const *a,
+		const X509_TRUST * const *b);
 static void trtable_free(X509_TRUST *p);
 
 static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags);
@@ -88,7 +89,8 @@ IMPLEMENT_STACK_OF(X509_TRUST)
 
 static STACK_OF(X509_TRUST) *trtable = NULL;
 
-static int tr_cmp(X509_TRUST **a, X509_TRUST **b)
+static int tr_cmp(const X509_TRUST * const *a,
+		const X509_TRUST * const *b)
 {
 	return (*a)->trust - (*b)->trust;
 }
diff --git a/crypto/x509/x_all.c b/crypto/x509/x_all.c
index b67ca243d..dd5796e20 100644
--- a/crypto/x509/x_all.c
+++ b/crypto/x509/x_all.c
@@ -411,25 +411,25 @@ X509_NAME_ENTRY *X509_NAME_ENTRY_dup(X509_NAME_ENTRY *ne)
 		(char *(*)())d2i_X509_NAME_ENTRY,(char *)ne));
 	}
 
-int X509_digest(X509 *data, const EVP_MD *type, unsigned char *md,
+int X509_digest(const X509 *data, const EVP_MD *type, unsigned char *md,
 	     unsigned int *len)
 	{
 	return(ASN1_digest((int (*)())i2d_X509,type,(char *)data,md,len));
 	}
 
-int X509_CRL_digest(X509_CRL *data, const EVP_MD *type, unsigned char *md,
+int X509_CRL_digest(const X509_CRL *data, const EVP_MD *type, unsigned char *md,
 	     unsigned int *len)
 	{
 	return(ASN1_digest((int (*)())i2d_X509_CRL,type,(char *)data,md,len));
 	}
 
-int X509_REQ_digest(X509_REQ *data, const EVP_MD *type, unsigned char *md,
+int X509_REQ_digest(const X509_REQ *data, const EVP_MD *type, unsigned char *md,
 	     unsigned int *len)
 	{
 	return(ASN1_digest((int (*)())i2d_X509_REQ,type,(char *)data,md,len));
 	}
 
-int X509_NAME_digest(X509_NAME *data, const EVP_MD *type, unsigned char *md,
+int X509_NAME_digest(const X509_NAME *data, const EVP_MD *type, unsigned char *md,
 	     unsigned int *len)
 	{
 	return(ASN1_digest((int (*)())i2d_X509_NAME,type,(char *)data,md,len));
diff --git a/crypto/x509v3/v3_lib.c b/crypto/x509v3/v3_lib.c
index dcdf7d607..aa04fb24a 100644
--- a/crypto/x509v3/v3_lib.c
+++ b/crypto/x509v3/v3_lib.c
@@ -66,7 +66,8 @@
 
 static STACK_OF(X509V3_EXT_METHOD) *ext_list = NULL;
 
-static int ext_cmp(X509V3_EXT_METHOD **a, X509V3_EXT_METHOD **b);
+static int ext_cmp(const X509V3_EXT_METHOD * const *a,
+		const X509V3_EXT_METHOD * const *b);
 static void ext_list_free(X509V3_EXT_METHOD *ext);
 
 int X509V3_EXT_add(X509V3_EXT_METHOD *ext)
@@ -82,7 +83,8 @@ int X509V3_EXT_add(X509V3_EXT_METHOD *ext)
 	return 1;
 }
 
-static int ext_cmp(X509V3_EXT_METHOD **a, X509V3_EXT_METHOD **b)
+static int ext_cmp(const X509V3_EXT_METHOD * const *a,
+		const X509V3_EXT_METHOD * const *b)
 {
 	return ((*a)->ext_nid - (*b)->ext_nid);
 }
diff --git a/crypto/x509v3/v3_purp.c b/crypto/x509v3/v3_purp.c
index 7b4055f1f..488b97f02 100644
--- a/crypto/x509v3/v3_purp.c
+++ b/crypto/x509v3/v3_purp.c
@@ -63,18 +63,19 @@
 
 static void x509v3_cache_extensions(X509 *x);
 
-static int ca_check(X509 *x);
-static int check_ssl_ca(X509 *x);
-static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca);
-static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
-static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
-static int purpose_smime(X509 *x, int ca);
-static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca);
-static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca);
-static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca);
-static int no_check(X509_PURPOSE *xp, X509 *x, int ca);
+static int ca_check(const X509 *x);
+static int check_ssl_ca(const X509 *x);
+static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int purpose_smime(const X509 *x, int ca);
+static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
+static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
 
-static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b);
+static int xp_cmp(const X509_PURPOSE * const *a,
+		const X509_PURPOSE * const *b);
 static void xptable_free(X509_PURPOSE *p);
 
 static X509_PURPOSE xstandard[] = {
@@ -93,15 +94,19 @@ IMPLEMENT_STACK_OF(X509_PURPOSE)
 
 static STACK_OF(X509_PURPOSE) *xptable = NULL;
 
-static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b)
+static int xp_cmp(const X509_PURPOSE * const *a,
+		const X509_PURPOSE * const *b)
 {
 	return (*a)->purpose - (*b)->purpose;
 }
 
+/* As much as I'd like to make X509_check_purpose use a "const" X509*
+ * I really can't because it does recalculate hashes and do other non-const
+ * things. */
 int X509_check_purpose(X509 *x, int id, int ca)
 {
 	int idx;
-	X509_PURPOSE *pt;
+	const X509_PURPOSE *pt;
 	if(!(x->ex_flags & EXFLAG_SET)) {
 		CRYPTO_w_lock(CRYPTO_LOCK_X509);
 		x509v3_cache_extensions(x);
@@ -153,7 +158,7 @@ int X509_PURPOSE_get_by_id(int purpose)
 }
 
 int X509_PURPOSE_add(int id, int trust, int flags,
-			int (*ck)(X509_PURPOSE *, X509 *, int),
+			int (*ck)(const X509_PURPOSE *, const X509 *, int),
 					char *name, char *sname, void *arg)
 {
 	int idx;
@@ -343,7 +348,7 @@ static void x509v3_cache_extensions(X509 *x)
 #define ns_reject(x, usage) \
 	(((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 
-static int ca_check(X509 *x)
+static int ca_check(const X509 *x)
 {
 	/* keyUsage if present should allow cert signing */
 	if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
@@ -358,7 +363,7 @@ static int ca_check(X509 *x)
 }
 
 /* Check SSL CA: common checks for SSL client and server */
-static int check_ssl_ca(X509 *x)
+static int check_ssl_ca(const X509 *x)
 {
 	int ca_ret;
 	ca_ret = ca_check(x);
@@ -373,7 +378,7 @@ static int check_ssl_ca(X509 *x)
 }
 	
 
-static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 	if(ca) return check_ssl_ca(x);
@@ -384,7 +389,7 @@ static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 	return 1;
 }
 
-static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 	if(ca) return check_ssl_ca(x);
@@ -397,7 +402,7 @@ static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 
 }
 
-static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	int ret;
 	ret = check_purpose_ssl_server(xp, x, ca);
@@ -408,7 +413,7 @@ static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 }
 
 /* common S/MIME checks */
-static int purpose_smime(X509 *x, int ca)
+static int purpose_smime(const X509 *x, int ca)
 {
 	if(xku_reject(x,XKU_SMIME)) return 0;
 	if(ca) {
@@ -432,7 +437,7 @@ static int purpose_smime(X509 *x, int ca)
 	return 1;
 }
 
-static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	int ret;
 	ret = purpose_smime(x, ca);
@@ -441,7 +446,7 @@ static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 	return ret;
 }
 
-static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	int ret;
 	ret = purpose_smime(x, ca);
@@ -450,7 +455,7 @@ static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 	return ret;
 }
 
-static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
+static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	if(ca) {
 		int ca_ret;
@@ -461,7 +466,7 @@ static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 	return 1;
 }
 
-static int no_check(X509_PURPOSE *xp, X509 *x, int ca)
+static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
 {
 	return 1;
 }
diff --git a/crypto/x509v3/x509v3.h b/crypto/x509v3/x509v3.h
index f2225d398..c04fc42da 100644
--- a/crypto/x509v3/x509v3.h
+++ b/crypto/x509v3/x509v3.h
@@ -334,7 +334,8 @@ typedef struct x509_purpose_st {
 	int purpose;
 	int trust;		/* Default trust ID */
 	int flags;
-	int (*check_purpose)(struct x509_purpose_st *, X509 *, int);
+	int (*check_purpose)(const struct x509_purpose_st *,
+				const X509 *, int);
 	char *name;
 	char *sname;
 	void *usr_data;
@@ -536,7 +537,7 @@ X509_PURPOSE * X509_PURPOSE_get0(int idx);
 int X509_PURPOSE_get_by_sname(char *sname);
 int X509_PURPOSE_get_by_id(int id);
 int X509_PURPOSE_add(int id, int trust, int flags,
-			int (*ck)(X509_PURPOSE *, X509 *, int),
+			int (*ck)(const X509_PURPOSE *, const X509 *, int),
 				char *name, char *sname, void *arg);
 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp);
 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp);
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 6a09d6aa8..197770794 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -69,7 +69,7 @@ static SSL_METHOD *ssl3_get_client_method(int ver);
 static int ssl3_client_hello(SSL *s);
 static int ssl3_get_server_hello(SSL *s);
 static int ssl3_get_certificate_request(SSL *s);
-static int ca_dn_cmp(X509_NAME **a,X509_NAME **b);
+static int ca_dn_cmp(const X509_NAME * const *a,const X509_NAME * const *b);
 static int ssl3_get_server_done(SSL *s);
 static int ssl3_send_client_verify(SSL *s);
 static int ssl3_send_client_certificate(SSL *s);
@@ -1275,7 +1275,7 @@ err:
 	return(ret);
 	}
 
-static int ca_dn_cmp(X509_NAME **a, X509_NAME **b)
+static int ca_dn_cmp(const X509_NAME * const *a, const X509_NAME * const *b)
 	{
 	return(X509_NAME_cmp(*a,*b));
 	}
diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index e134e6f3e..fc8b8a7a5 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -568,7 +568,7 @@ int SSL_CTX_add_client_CA(SSL_CTX *ctx,X509 *x)
 	return(add_client_CA(&(ctx->client_CA),x));
 	}
 
-static int xname_cmp(X509_NAME **a,X509_NAME **b)
+static int xname_cmp(const X509_NAME * const *a, const X509_NAME * const *b)
 	{
 	return(X509_NAME_cmp(*a,*b));
 	}
@@ -649,7 +649,7 @@ int SSL_add_file_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
 	X509 *x=NULL;
 	X509_NAME *xn=NULL;
 	int ret=1;
-	int (*oldcmp)(X509_NAME **a, X509_NAME **b);
+	int (*oldcmp)(const X509_NAME * const *a, const X509_NAME * const *b);
 	
 	oldcmp=sk_X509_NAME_set_cmp_func(stack,xname_cmp);
 	
diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
index a5b2b9705..817b6b31f 100644
--- a/ssl/ssl_ciph.c
+++ b/ssl/ssl_ciph.c
@@ -1037,7 +1037,8 @@ SSL_COMP *ssl3_comp_find(STACK_OF(SSL_COMP) *sk, int n)
 	return(NULL);
 	}
 
-static int sk_comp_cmp(SSL_COMP **a,SSL_COMP **b)
+static int sk_comp_cmp(const SSL_COMP * const *a,
+			const SSL_COMP * const *b)
 	{
 	return((*a)->id-(*b)->id);
 	}
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index c515c41b4..f4eb35b15 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -874,7 +874,7 @@ long SSL_CTX_callback_ctrl(SSL_CTX *ctx, int cmd, void (*fp)())
 		}
 	}
 
-int ssl_cipher_id_cmp(SSL_CIPHER *a,SSL_CIPHER *b)
+int ssl_cipher_id_cmp(const SSL_CIPHER *a, const SSL_CIPHER *b)
 	{
 	long l;
 
@@ -885,7 +885,8 @@ int ssl_cipher_id_cmp(SSL_CIPHER *a,SSL_CIPHER *b)
 		return((l > 0)?1:-1);
 	}
 
-int ssl_cipher_ptr_id_cmp(SSL_CIPHER **ap,SSL_CIPHER **bp)
+int ssl_cipher_ptr_id_cmp(const SSL_CIPHER * const *ap,
+			const SSL_CIPHER * const *bp)
 	{
 	long l;
 
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 9a52bab25..d70fff462 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -423,8 +423,9 @@ void ssl_sess_cert_free(SESS_CERT *sc);
 int ssl_set_peer_cert_type(SESS_CERT *c, int type);
 int ssl_get_new_session(SSL *s, int session);
 int ssl_get_prev_session(SSL *s, unsigned char *session,int len);
-int ssl_cipher_id_cmp(SSL_CIPHER *a,SSL_CIPHER *b);
-int ssl_cipher_ptr_id_cmp(SSL_CIPHER **ap,SSL_CIPHER **bp);
+int ssl_cipher_id_cmp(const SSL_CIPHER *a,const SSL_CIPHER *b);
+int ssl_cipher_ptr_id_cmp(const SSL_CIPHER * const *ap,
+			const SSL_CIPHER * const *bp);
 STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
 					       STACK_OF(SSL_CIPHER) **skp);
 int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p);