diff --git a/doc/admin/conf_files/krb5_conf.rst b/doc/admin/conf_files/krb5_conf.rst
index 1d2aa7f..3a8b9cf 100644
--- a/doc/admin/conf_files/krb5_conf.rst
+++ b/doc/admin/conf_files/krb5_conf.rst
@@ -331,6 +331,12 @@ The libdefaults section may contain any of the following relations:
     qualification of shortnames, set this relation to the empty string
     with ``qualify_shortname = ""``.  (New in release 1.18.)
 
+**radius_md5_fips_override**
+    Downstream-only option to enable use of MD5 in RADIUS
+    communication (libkrad).  This allows for local (or protected
+    tunnel) communication with a RADIUS server that doesn't use krad
+    (e.g., freeradius) while in FIPS mode.
+
 **rdns**
     If this flag is true, reverse name lookup will be used in addition
     to forward name lookup to canonicalizing hostnames for use in
diff --git a/src/lib/crypto/krb/prng.c b/src/lib/crypto/krb/prng.c
index cb9ca9b..f0e9984 100644
--- a/src/lib/crypto/krb/prng.c
+++ b/src/lib/crypto/krb/prng.c
@@ -26,6 +26,8 @@
 
 #include "crypto_int.h"
 
+#include <openssl/rand.h>
+
 krb5_error_code KRB5_CALLCONV
 krb5_c_random_seed(krb5_context context, krb5_data *data)
 {
@@ -99,9 +101,16 @@ krb5_boolean
 k5_get_os_entropy(unsigned char *buf, size_t len, int strong)
 {
     const char *device;
-#if defined(__linux__) && defined(SYS_getrandom)
     int r;
 
+    /* A wild FIPS mode appeared! */
+    if (FIPS_mode()) {
+        /* The return codes on this API are not good */
+        r = RAND_bytes(buf, len);
+        return r == 1;
+    }
+
+#if defined(__linux__) && defined(SYS_getrandom)
     while (len > 0) {
         /*
          * Pull from the /dev/urandom pool, but require it to have been seeded.
diff --git a/src/lib/crypto/openssl/enc_provider/camellia.c b/src/lib/crypto/openssl/enc_provider/camellia.c
index 2da6913..f79679a 100644
--- a/src/lib/crypto/openssl/enc_provider/camellia.c
+++ b/src/lib/crypto/openssl/enc_provider/camellia.c
@@ -304,6 +304,9 @@ krb5int_camellia_cbc_mac(krb5_key key, const krb5_crypto_iov *data,
     unsigned char blockY[CAMELLIA_BLOCK_SIZE], blockB[CAMELLIA_BLOCK_SIZE];
     struct iov_cursor cursor;
 
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     if (output->length < CAMELLIA_BLOCK_SIZE)
         return KRB5_BAD_MSIZE;
 
@@ -331,6 +334,9 @@ static krb5_error_code
 krb5int_camellia_init_state (const krb5_keyblock *key, krb5_keyusage usage,
                              krb5_data *state)
 {
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     state->length = 16;
     state->data = (void *) malloc(16);
     if (state->data == NULL)
diff --git a/src/lib/crypto/openssl/enc_provider/rc4.c b/src/lib/crypto/openssl/enc_provider/rc4.c
index a65d57b..6ccaca9 100644
--- a/src/lib/crypto/openssl/enc_provider/rc4.c
+++ b/src/lib/crypto/openssl/enc_provider/rc4.c
@@ -66,6 +66,9 @@ k5_arcfour_docrypt(krb5_key key, const krb5_data *state, krb5_crypto_iov *data,
     EVP_CIPHER_CTX *ctx = NULL;
     struct arcfour_state *arcstate;
 
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     arcstate = (state != NULL) ? (void *)state->data : NULL;
     if (arcstate != NULL) {
         ctx = arcstate->ctx;
@@ -113,7 +116,12 @@ k5_arcfour_docrypt(krb5_key key, const krb5_data *state, krb5_crypto_iov *data,
 static void
 k5_arcfour_free_state(krb5_data *state)
 {
-    struct arcfour_state *arcstate = (void *)state->data;
+    struct arcfour_state *arcstate;
+
+    if (FIPS_mode())
+        return;
+
+    arcstate = (void *) state->data;
 
     EVP_CIPHER_CTX_free(arcstate->ctx);
     free(arcstate);
@@ -125,6 +133,9 @@ k5_arcfour_init_state(const krb5_keyblock *key,
 {
     struct arcfour_state *arcstate;
 
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     /*
      * The cipher state here is a saved pointer to a struct arcfour_state
      * object, rather than a flat byte array as in most enc providers.  The
diff --git a/src/lib/crypto/openssl/hash_provider/hash_evp.c b/src/lib/crypto/openssl/hash_provider/hash_evp.c
index 1e0fb8f..2eb5139 100644
--- a/src/lib/crypto/openssl/hash_provider/hash_evp.c
+++ b/src/lib/crypto/openssl/hash_provider/hash_evp.c
@@ -49,6 +49,11 @@ hash_evp(const EVP_MD *type, const krb5_crypto_iov *data, size_t num_data,
     if (ctx == NULL)
         return ENOMEM;
 
+    if (type == EVP_md4() || type == EVP_md5()) {
+        /* See comments below in hash_md4() and hash_md5(). */
+        EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
+    }
+
     ok = EVP_DigestInit_ex(ctx, type, NULL);
     for (i = 0; i < num_data; i++) {
         if (!SIGN_IOV(&data[i]))
@@ -64,12 +69,19 @@ hash_evp(const EVP_MD *type, const krb5_crypto_iov *data, size_t num_data,
 static krb5_error_code
 hash_md4(const krb5_crypto_iov *data, size_t num_data, krb5_data *output)
 {
+    /*
+     * MD4 is needed in FIPS mode to perform key generation for RC4 keys used
+     * by IPA.  These keys are only used along a (separately) secured channel
+     * for legacy reasons when performing trusts to Active Directory.
+     */
     return hash_evp(EVP_md4(), data, num_data, output);
 }
 
 static krb5_error_code
 hash_md5(const krb5_crypto_iov *data, size_t num_data, krb5_data *output)
 {
+    /* MD5 is needed in FIPS mode for communication with RADIUS servers.  This
+     * is gated in libkrad by libdefaults->radius_md5_fips_override. */
     return hash_evp(EVP_md5(), data, num_data, output);
 }
 
diff --git a/src/lib/crypto/openssl/hmac.c b/src/lib/crypto/openssl/hmac.c
index 7dc59dc..769a50c 100644
--- a/src/lib/crypto/openssl/hmac.c
+++ b/src/lib/crypto/openssl/hmac.c
@@ -103,7 +103,11 @@ map_digest(const struct krb5_hash_provider *hash)
         return EVP_sha256();
     else if (!strncmp(hash->hash_name, "SHA-384",7))
         return EVP_sha384();
-    else if (!strncmp(hash->hash_name, "MD5", 3))
+
+    if (FIPS_mode())
+        return NULL;
+
+    if (!strncmp(hash->hash_name, "MD5", 3))
         return EVP_md5();
     else if (!strncmp(hash->hash_name, "MD4", 3))
         return EVP_md4();
diff --git a/src/lib/krad/attr.c b/src/lib/krad/attr.c
index 9c13d9d..42d354a 100644
--- a/src/lib/krad/attr.c
+++ b/src/lib/krad/attr.c
@@ -38,7 +38,8 @@
 typedef krb5_error_code
 (*attribute_transform_fn)(krb5_context ctx, const char *secret,
                           const unsigned char *auth, const krb5_data *in,
-                          unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+                          unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+                          krb5_boolean *is_fips);
 
 typedef struct {
     const char *name;
@@ -51,12 +52,14 @@ typedef struct {
 static krb5_error_code
 user_password_encode(krb5_context ctx, const char *secret,
                      const unsigned char *auth, const krb5_data *in,
-                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+                     krb5_boolean *is_fips);
 
 static krb5_error_code
 user_password_decode(krb5_context ctx, const char *secret,
                      const unsigned char *auth, const krb5_data *in,
-                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+                     krb5_boolean *ignored);
 
 static const attribute_record attributes[UCHAR_MAX] = {
     {"User-Name", 1, MAX_ATTRSIZE, NULL, NULL},
@@ -128,7 +131,8 @@ static const attribute_record attributes[UCHAR_MAX] = {
 static krb5_error_code
 user_password_encode(krb5_context ctx, const char *secret,
                      const unsigned char *auth, const krb5_data *in,
-                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
+                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+                     krb5_boolean *is_fips)
 {
     const unsigned char *indx;
     krb5_error_code retval;
@@ -154,8 +158,15 @@ user_password_encode(krb5_context ctx, const char *secret,
     for (blck = 0, indx = auth; blck * BLOCKSIZE < len; blck++) {
         memcpy(tmp.data + seclen, indx, BLOCKSIZE);
 
-        retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &tmp,
-                                      &sum);
+        if (kr_use_fips(ctx)) {
+            /* Skip encryption here.  Taint so that we won't pass it out of
+             * the machine by accident. */
+            *is_fips = TRUE;
+            sum.contents = calloc(1, BLOCKSIZE);
+        } else {
+            retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &tmp,
+                                          &sum);
+        }
         if (retval != 0) {
             zap(tmp.data, tmp.length);
             zap(outbuf, len);
@@ -180,7 +191,8 @@ user_password_encode(krb5_context ctx, const char *secret,
 static krb5_error_code
 user_password_decode(krb5_context ctx, const char *secret,
                      const unsigned char *auth, const krb5_data *in,
-                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
+                     unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+                     krb5_boolean *is_fips)
 {
     const unsigned char *indx;
     krb5_error_code retval;
@@ -204,8 +216,15 @@ user_password_decode(krb5_context ctx, const char *secret,
     for (blck = 0, indx = auth; blck * BLOCKSIZE < in->length; blck++) {
         memcpy(tmp.data + seclen, indx, BLOCKSIZE);
 
-        retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0,
-                                      &tmp, &sum);
+        if (kr_use_fips(ctx)) {
+            /* Skip encryption here.  Taint so that we won't pass it out of
+             * the machine by accident. */
+            *is_fips = TRUE;
+            sum.contents = calloc(1, BLOCKSIZE);
+        } else {
+            retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0,
+                                          &tmp, &sum);
+        }
         if (retval != 0) {
             zap(tmp.data, tmp.length);
             zap(outbuf, in->length);
@@ -248,7 +267,7 @@ krb5_error_code
 kr_attr_encode(krb5_context ctx, const char *secret,
                const unsigned char *auth, krad_attr type,
                const krb5_data *in, unsigned char outbuf[MAX_ATTRSIZE],
-               size_t *outlen)
+               size_t *outlen, krb5_boolean *is_fips)
 {
     krb5_error_code retval;
 
@@ -265,7 +284,8 @@ kr_attr_encode(krb5_context ctx, const char *secret,
         return 0;
     }
 
-    return attributes[type - 1].encode(ctx, secret, auth, in, outbuf, outlen);
+    return attributes[type - 1].encode(ctx, secret, auth, in, outbuf, outlen,
+                                       is_fips);
 }
 
 krb5_error_code
@@ -274,6 +294,7 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
                unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
 {
     krb5_error_code retval;
+    krb5_boolean ignored;
 
     retval = kr_attr_valid(type, in);
     if (retval != 0)
@@ -288,7 +309,8 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
         return 0;
     }
 
-    return attributes[type - 1].decode(ctx, secret, auth, in, outbuf, outlen);
+    return attributes[type - 1].decode(ctx, secret, auth, in, outbuf, outlen,
+                                       &ignored);
 }
 
 krad_attr
diff --git a/src/lib/krad/attrset.c b/src/lib/krad/attrset.c
index 03c6137..d89982a 100644
--- a/src/lib/krad/attrset.c
+++ b/src/lib/krad/attrset.c
@@ -167,7 +167,8 @@ krad_attrset_copy(const krad_attrset *set, krad_attrset **copy)
 krb5_error_code
 kr_attrset_encode(const krad_attrset *set, const char *secret,
                   const unsigned char *auth,
-                  unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen)
+                  unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen,
+                  krb5_boolean *is_fips)
 {
     unsigned char buffer[MAX_ATTRSIZE];
     krb5_error_code retval;
@@ -181,7 +182,7 @@ kr_attrset_encode(const krad_attrset *set, const char *secret,
 
     K5_TAILQ_FOREACH(a, &set->list, list) {
         retval = kr_attr_encode(set->ctx, secret, auth, a->type, &a->attr,
-                                buffer, &attrlen);
+                                buffer, &attrlen, is_fips);
         if (retval != 0)
             return retval;
 
diff --git a/src/lib/krad/internal.h b/src/lib/krad/internal.h
index 996a893..312dc82 100644
--- a/src/lib/krad/internal.h
+++ b/src/lib/krad/internal.h
@@ -39,6 +39,8 @@
 #include <sys/socket.h>
 #include <netdb.h>
 
+#include <openssl/crypto.h>
+
 #ifndef UCHAR_MAX
 #define UCHAR_MAX 255
 #endif
@@ -49,6 +51,13 @@
 
 typedef struct krad_remote_st krad_remote;
 
+struct krad_packet_st {
+    char buffer[KRAD_PACKET_SIZE_MAX];
+    krad_attrset *attrset;
+    krb5_data pkt;
+    krb5_boolean is_fips;
+};
+
 /* Validate constraints of an attribute. */
 krb5_error_code
 kr_attr_valid(krad_attr type, const krb5_data *data);
@@ -57,7 +66,8 @@ kr_attr_valid(krad_attr type, const krb5_data *data);
 krb5_error_code
 kr_attr_encode(krb5_context ctx, const char *secret, const unsigned char *auth,
                krad_attr type, const krb5_data *in,
-               unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+               unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+               krb5_boolean *is_fips);
 
 /* Decode an attribute. */
 krb5_error_code
@@ -69,7 +79,8 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
 krb5_error_code
 kr_attrset_encode(const krad_attrset *set, const char *secret,
                   const unsigned char *auth,
-                  unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen);
+                  unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen,
+                  krb5_boolean *is_fips);
 
 /* Decode attributes from a buffer. */
 krb5_error_code
@@ -152,4 +163,17 @@ gai_error_code(int err)
     }
 }
 
+static inline krb5_boolean
+kr_use_fips(krb5_context ctx)
+{
+    int val = 0;
+
+    if (!FIPS_mode())
+        return 0;
+
+    profile_get_boolean(ctx->profile, "libdefaults",
+                        "radius_md5_fips_override", NULL, 0, &val);
+    return !val;
+}
+
 #endif /* INTERNAL_H_ */
diff --git a/src/lib/krad/packet.c b/src/lib/krad/packet.c
index c597174..fc2d248 100644
--- a/src/lib/krad/packet.c
+++ b/src/lib/krad/packet.c
@@ -53,12 +53,6 @@ typedef unsigned char uchar;
 #define pkt_auth(p) ((uchar *)offset(&(p)->pkt, OFFSET_AUTH))
 #define pkt_attr(p) ((unsigned char *)offset(&(p)->pkt, OFFSET_ATTR))
 
-struct krad_packet_st {
-    char buffer[KRAD_PACKET_SIZE_MAX];
-    krad_attrset *attrset;
-    krb5_data pkt;
-};
-
 typedef struct {
     uchar x[(UCHAR_MAX + 1) / 8];
 } idmap;
@@ -187,8 +181,14 @@ auth_generate_response(krb5_context ctx, const char *secret,
     memcpy(data.data + response->pkt.length, secret, strlen(secret));
 
     /* Hash it. */
-    retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &data,
-                                  &hash);
+    if (kr_use_fips(ctx)) {
+        /* This checksum does very little security-wise anyway, so don't
+         * taint. */
+        hash.contents = calloc(1, AUTH_FIELD_SIZE);
+    } else {
+        retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &data,
+                                      &hash);
+    }
     free(data.data);
     if (retval != 0)
         return retval;
@@ -276,7 +276,7 @@ krad_packet_new_request(krb5_context ctx, const char *secret, krad_code code,
 
     /* Encode the attributes. */
     retval = kr_attrset_encode(set, secret, pkt_auth(pkt), pkt_attr(pkt),
-                               &attrset_len);
+                               &attrset_len, &pkt->is_fips);
     if (retval != 0)
         goto error;
 
@@ -314,7 +314,7 @@ krad_packet_new_response(krb5_context ctx, const char *secret, krad_code code,
 
     /* Encode the attributes. */
     retval = kr_attrset_encode(set, secret, pkt_auth(request), pkt_attr(pkt),
-                               &attrset_len);
+                               &attrset_len, &pkt->is_fips);
     if (retval != 0)
         goto error;
 
@@ -451,6 +451,8 @@ krad_packet_decode_response(krb5_context ctx, const char *secret,
 const krb5_data *
 krad_packet_encode(const krad_packet *pkt)
 {
+    if (pkt->is_fips)
+        return NULL;
     return &pkt->pkt;
 }
 
diff --git a/src/lib/krad/remote.c b/src/lib/krad/remote.c
index 437f7e9..0f90443 100644
--- a/src/lib/krad/remote.c
+++ b/src/lib/krad/remote.c
@@ -263,7 +263,7 @@ on_io_write(krad_remote *rr)
     request *r;
 
     K5_TAILQ_FOREACH(r, &rr->list, list) {
-        tmp = krad_packet_encode(r->request);
+        tmp = &r->request->pkt;
 
         /* If the packet has already been sent, do nothing. */
         if (r->sent == tmp->length)
@@ -359,7 +359,7 @@ on_io_read(krad_remote *rr)
     if (req != NULL) {
         K5_TAILQ_FOREACH(r, &rr->list, list) {
             if (r->request == req &&
-                r->sent == krad_packet_encode(req)->length) {
+                r->sent == req->pkt.length) {
                 request_finish(r, 0, rsp);
                 break;
             }
@@ -455,6 +455,12 @@ kr_remote_send(krad_remote *rr, krad_code code, krad_attrset *attrs,
                                      (krad_packet_iter_cb)iterator, &r, &tmp);
     if (retval != 0)
         goto error;
+    else if (tmp->is_fips && rr->info->ai_family != AF_LOCAL &&
+        rr->info->ai_family != AF_UNIX) {
+        /* This would expose cleartext passwords, so abort. */
+        retval = ESOCKTNOSUPPORT;
+        goto error;
+    }
 
     K5_TAILQ_FOREACH(r, &rr->list, list) {
         if (r->request == tmp) {
diff --git a/src/lib/krad/t_attr.c b/src/lib/krad/t_attr.c
index eb2a780..4d285ad 100644
--- a/src/lib/krad/t_attr.c
+++ b/src/lib/krad/t_attr.c
@@ -50,6 +50,7 @@ main()
     const char *tmp;
     krb5_data in;
     size_t len;
+    krb5_boolean is_fips = FALSE;
 
     noerror(krb5_init_context(&ctx));
 
@@ -73,7 +74,7 @@ main()
     in = string2data((char *)decoded);
     retval = kr_attr_encode(ctx, secret, auth,
                             krad_attr_name2num("User-Password"),
-                            &in, outbuf, &len);
+                            &in, outbuf, &len, &is_fips);
     insist(retval == 0);
     insist(len == sizeof(encoded));
     insist(memcmp(outbuf, encoded, len) == 0);
diff --git a/src/lib/krad/t_attrset.c b/src/lib/krad/t_attrset.c
index 7928335..0f95762 100644
--- a/src/lib/krad/t_attrset.c
+++ b/src/lib/krad/t_attrset.c
@@ -49,6 +49,7 @@ main()
     krb5_context ctx;
     size_t len = 0, encode_len;
     krb5_data tmp;
+    krb5_boolean is_fips = FALSE;
 
     noerror(krb5_init_context(&ctx));
     noerror(krad_attrset_new(ctx, &set));
@@ -62,7 +63,8 @@ main()
     noerror(krad_attrset_add(set, krad_attr_name2num("User-Password"), &tmp));
 
     /* Encode attrset. */
-    noerror(kr_attrset_encode(set, "foo", auth, buffer, &encode_len));
+    noerror(kr_attrset_encode(set, "foo", auth, buffer, &encode_len,
+                              &is_fips));
     krad_attrset_free(set);
 
     /* Manually encode User-Name. */
diff --git a/src/plugins/preauth/spake/spake_client.c b/src/plugins/preauth/spake/spake_client.c
index 00734a1..a3ce22b 100644
--- a/src/plugins/preauth/spake/spake_client.c
+++ b/src/plugins/preauth/spake/spake_client.c
@@ -38,6 +38,8 @@
 #include "groups.h"
 #include <krb5/clpreauth_plugin.h>
 
+#include <openssl/crypto.h>
+
 typedef struct reqstate_st {
     krb5_pa_spake *msg;         /* set in prep_questions, used in process */
     krb5_keyblock *initial_key;
@@ -375,6 +377,10 @@ clpreauth_spake_initvt(krb5_context context, int maj_ver, int min_ver,
 
     if (maj_ver != 1)
         return KRB5_PLUGIN_VER_NOTSUPP;
+
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     vt = (krb5_clpreauth_vtable)vtable;
     vt->name = "spake";
     vt->pa_type_list = pa_types;
diff --git a/src/plugins/preauth/spake/spake_kdc.c b/src/plugins/preauth/spake/spake_kdc.c
index 88c964c..c7df039 100644
--- a/src/plugins/preauth/spake/spake_kdc.c
+++ b/src/plugins/preauth/spake/spake_kdc.c
@@ -41,6 +41,8 @@
 
 #include <krb5/kdcpreauth_plugin.h>
 
+#include <openssl/crypto.h>
+
 /*
  * The SPAKE kdcpreauth module uses a secure cookie containing the following
  * concatenated fields (all integer fields are big-endian):
@@ -571,6 +573,10 @@ kdcpreauth_spake_initvt(krb5_context context, int maj_ver, int min_ver,
 
     if (maj_ver != 1)
         return KRB5_PLUGIN_VER_NOTSUPP;
+
+    if (FIPS_mode())
+        return KRB5_CRYPTO_INTERNAL;
+
     vt = (krb5_kdcpreauth_vtable)vtable;
     vt->name = "spake";
     vt->pa_type_list = pa_types;