diff --git a/src/libsodium/crypto_pwhash/crypto_pwhash.c b/src/libsodium/crypto_pwhash/crypto_pwhash.c
index b65b7209..c2e7b22c 100644
--- a/src/libsodium/crypto_pwhash/crypto_pwhash.c
+++ b/src/libsodium/crypto_pwhash/crypto_pwhash.c
@@ -1,6 +1,20 @@
 
+#include <errno.h>
+
 #include "crypto_pwhash.h"
 
+int
+crypto_pwhash_alg_argon2i13(void)
+{
+    return crypto_pwhash_ALG_ARGON2I13;
+}
+
+int
+crypto_pwhash_alg_default(void)
+{
+    return crypto_pwhash_ALG_ARGON2I13;
+}
+
 size_t
 crypto_pwhash_saltbytes(void)
 {
@@ -59,10 +73,12 @@ int
 crypto_pwhash(unsigned char * const out, unsigned long long outlen,
               const char * const passwd, unsigned long long passwdlen,
               const unsigned char * const salt,
-              unsigned long long opslimit, size_t memlimit,
-              const struct crypto_pwhash_options *options)
+              unsigned long long opslimit, size_t memlimit, int alg)
 {
-    (void) options;
+    if (alg != crypto_pwhash_ALG_ARGON2I13) {
+        errno = EINVAL;
+        return -1;
+    }
     return crypto_pwhash_argon2i(out, outlen, passwd, passwdlen, salt,
                                  opslimit, memlimit);
 }
diff --git a/src/libsodium/include/sodium/crypto_pwhash.h b/src/libsodium/include/sodium/crypto_pwhash.h
index 78d01928..a5048d8c 100644
--- a/src/libsodium/include/sodium/crypto_pwhash.h
+++ b/src/libsodium/include/sodium/crypto_pwhash.h
@@ -13,6 +13,14 @@
 extern "C" {
 #endif
 
+#define crypto_pwhash_ALG_ARGON2I13 1
+SODIUM_EXPORT
+int crypto_pwhash_alg_argon2i13(void);
+
+#define crypto_pwhash_ALG_DEFAULT crypto_pwhash_ALG_ARGON2I13
+SODIUM_EXPORT
+int crypto_pwhash_alg_default(void);
+
 #define crypto_pwhash_SALTBYTES crypto_pwhash_argon2i_SALTBYTES
 SODIUM_EXPORT
 size_t crypto_pwhash_saltbytes(void);
@@ -49,14 +57,11 @@ size_t crypto_pwhash_opslimit_sensitive(void);
 SODIUM_EXPORT
 size_t crypto_pwhash_memlimit_sensitive(void);
 
-typedef struct crypto_pwhash_options crypto_pwhash_options;
-
 SODIUM_EXPORT
 int crypto_pwhash(unsigned char * const out, unsigned long long outlen,
                   const char * const passwd, unsigned long long passwdlen,
                   const unsigned char * const salt,
-                  unsigned long long opslimit, size_t memlimit,
-                  const crypto_pwhash_options *options)
+                  unsigned long long opslimit, size_t memlimit, int alg)
             __attribute__ ((warn_unused_result));
 
 SODIUM_EXPORT
diff --git a/test/default/pwhash.c b/test/default/pwhash.c
index 2e04f8df..708c09db 100644
--- a/test/default/pwhash.c
+++ b/test/default/pwhash.c
@@ -92,7 +92,7 @@ static void tv(void)
         if (crypto_pwhash(out, (unsigned long long) tests[i].outlen,
                           passwd, tests[i].passwdlen,
                           (const unsigned char *) salt, tests[i].opslimit,
-                          tests[i].memlimit, NULL) != 0) {
+                          tests[i].memlimit, crypto_pwhash_alg_default()) != 0) {
             printf("[tv] pwhash failure (maybe intentional): [%u]\n", (unsigned int) i);
             continue;
         }
@@ -142,7 +142,7 @@ static void tv2(void)
         if (crypto_pwhash(out, (unsigned long long) tests[i].outlen,
                           passwd, tests[i].passwdlen,
                           (const unsigned char *) salt, tests[i].opslimit,
-                          tests[i].memlimit, NULL) != 0) {
+                          tests[i].memlimit, crypto_pwhash_alg_default()) != 0) {
             printf("[tv2] pwhash failure: [%u]\n", (unsigned int) i);
             continue;
         }
@@ -151,23 +151,27 @@ static void tv2(void)
     } while (++i < (sizeof tests) / (sizeof tests[0]));
 
     if (crypto_pwhash(out, sizeof out, "password", strlen("password"),
-                      salt, 3, 1, NULL) != -1) {
+                      salt, 3, 1ULL << 12, 0) != -1) {
+        printf("[tv2] pwhash should have failed (0)\n");
+    }
+    if (crypto_pwhash(out, sizeof out, "password", strlen("password"),
+                      salt, 3, 1, crypto_pwhash_alg_default()) != -1) {
         printf("[tv2] pwhash should have failed (1)\n");
     }
     if (crypto_pwhash(out, sizeof out, "password", strlen("password"),
-                      salt, 3, 1ULL << 12, NULL) != -1) {
+                      salt, 3, 1ULL << 12, crypto_pwhash_alg_default()) != -1) {
         printf("[tv2] pwhash should have failed (2)\n");
     }
     if (crypto_pwhash(out, sizeof out, "password", strlen("password"),
-                      salt, 2, 1ULL << 12, NULL) != -1) {
+                      salt, 2, 1ULL << 12, crypto_pwhash_alg_default()) != -1) {
         printf("[tv2] pwhash should have failed (3)\n");
     }
     if (crypto_pwhash(out, 0x100000000ULL, "password", strlen("password"),
-                      salt, 3, 1ULL << 12, NULL) != -1) {
+                      salt, 3, 1ULL << 12, crypto_pwhash_alg_default()) != -1) {
         printf("[tv2] pwhash with a long output length should have failed\n");
     }
     if (crypto_pwhash(out, sizeof out, "password", 0x100000000ULL,
-                      salt, 3, 1ULL << 12, NULL) != -1) {
+                      salt, 3, 1ULL << 12, crypto_pwhash_alg_default()) != -1) {
         printf("[tv2] pwhash with a long password length should have failed\n");
     }
 }
@@ -349,6 +353,8 @@ int main(void)
            crypto_pwhash_memlimit_moderate());
     assert(crypto_pwhash_argon2i_memlimit_sensitive() ==
            crypto_pwhash_memlimit_sensitive());
+    assert(crypto_pwhash_alg_argon2i13() == crypto_pwhash_ALG_ARGON2I13);
+    assert(crypto_pwhash_alg_argon2i13() == crypto_pwhash_alg_default());
 
     sodium_free(salt);
     sodium_free(str_out);