diff --git a/crypto/evp/evp_test.cc b/crypto/evp/evp_test.cc
index f71bd9f..ee165e5 100644
--- a/crypto/evp/evp_test.cc
+++ b/crypto/evp/evp_test.cc
@@ -610,7 +610,7 @@
 
     bool is_pss = t->HasInstruction("mgf");
     const EVP_MD *mgf1_md = nullptr;
-    int pss_salt_len = -1;
+    int pss_salt_len = RSA_PSS_SALTLEN_DIGEST;
     if (is_pss) {
       ASSERT_EQ("MGF1", t->GetInstructionOrDie("mgf"));
       mgf1_md = GetWycheproofDigest(t, "mgfSha", true);
diff --git a/crypto/evp/p_rsa.cc b/crypto/evp/p_rsa.cc
index 01eae68..4b47ee3 100644
--- a/crypto/evp/p_rsa.cc
+++ b/crypto/evp/p_rsa.cc
@@ -64,7 +64,7 @@
 
   rctx->nbits = 2048;
   rctx->pad_mode = RSA_PKCS1_PADDING;
-  rctx->saltlen = -2;
+  rctx->saltlen = RSA_PSS_SALTLEN_AUTO;
 
   ctx->data = rctx;
 
diff --git a/crypto/fipsmodule/rsa/padding.cc.inc b/crypto/fipsmodule/rsa/padding.cc.inc
index d86627f..2b9e20d 100644
--- a/crypto/fipsmodule/rsa/padding.cc.inc
+++ b/crypto/fipsmodule/rsa/padding.cc.inc
@@ -183,11 +183,11 @@
   //   -2      salt length is autorecovered from signature
   //   -N      reserved
   size_t hLen = EVP_MD_size(Hash);
-  if (sLen == -1) {
+  if (sLen == RSA_PSS_SALTLEN_DIGEST) {
     sLen = (int)hLen;
-  } else if (sLen == -2) {
-    sLen = -2;
-  } else if (sLen < -2) {
+  } else if (sLen == RSA_PSS_SALTLEN_AUTO) {
+    // Leave |sLen| negative.
+  } else if (sLen < 0) {
     OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_CHECK_FAILED);
     goto err;
   }
@@ -304,9 +304,9 @@
   //   -2  salt length is maximized
   //   -N  reserved
   size_t sLen;
-  if (sLenRequested == -1) {
+  if (sLenRequested == RSA_PSS_SALTLEN_DIGEST) {
     sLen = hLen;
-  } else if (sLenRequested == -2) {
+  } else if (sLenRequested == RSA_PSS_SALTLEN_AUTO) {
     sLen = emLen - hLen - 2;
   } else if (sLenRequested < 0) {
     OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_CHECK_FAILED);
diff --git a/crypto/fipsmodule/service_indicator/service_indicator.cc.inc b/crypto/fipsmodule/service_indicator/service_indicator.cc.inc
index 8b77013..d7ace3a 100644
--- a/crypto/fipsmodule/service_indicator/service_indicator.cc.inc
+++ b/crypto/fipsmodule/service_indicator/service_indicator.cc.inc
@@ -217,7 +217,8 @@
       const EVP_MD *mgf1_md;
       if (!EVP_PKEY_CTX_get_rsa_pss_saltlen(pctx, &salt_len) ||
           !EVP_PKEY_CTX_get_rsa_mgf1_md(pctx, &mgf1_md) ||
-          (salt_len != -1 && salt_len != (int)EVP_MD_size(pctx_md)) ||
+          (salt_len != RSA_PSS_SALTLEN_DIGEST &&
+           salt_len != (int)EVP_MD_size(pctx_md)) ||
           EVP_MD_type(mgf1_md) != md_type) {
         // Only PSS where saltLen == hashLen is tested with ACVP. Cases with
         // non-standard padding functions are also excluded.
diff --git a/crypto/fipsmodule/service_indicator/service_indicator_test.cc b/crypto/fipsmodule/service_indicator/service_indicator_test.cc
index c91b11b..571f806 100644
--- a/crypto/fipsmodule/service_indicator/service_indicator_test.cc
+++ b/crypto/fipsmodule/service_indicator/service_indicator_test.cc
@@ -1275,7 +1275,8 @@
         approved, EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
     ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
-        approved, EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1)));
+        approved,
+        EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
   }
   ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
@@ -1306,7 +1307,8 @@
         approved, EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
     ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
-        approved, EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1)));
+        approved,
+        EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
   }
   ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
@@ -1346,7 +1348,7 @@
                                  pkey.get()));
   if (test.use_pss) {
     ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING));
-    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1));
+    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST));
   }
   ASSERT_TRUE(EVP_DigestSign(md_ctx.get(), nullptr, &sig_len, nullptr, 0));
   signature.resize(sig_len);
@@ -1370,7 +1372,7 @@
     ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
         approved, EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
-    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1));
+    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST));
   }
   ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
       approved,
@@ -1391,7 +1393,7 @@
     ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
         approved, EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING)));
     EXPECT_EQ(approved, FIPSStatus::NOT_APPROVED);
-    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1));
+    ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST));
   }
   ASSERT_TRUE(CALL_SERVICE_AND_CHECK_APPROVED(
       approved,
diff --git a/crypto/x509/rsa_pss.cc b/crypto/x509/rsa_pss.cc
index 5449bef..689f64d 100644
--- a/crypto/x509/rsa_pss.cc
+++ b/crypto/x509/rsa_pss.cc
@@ -167,7 +167,7 @@
     return 0;
   }
   int md_len = (int)EVP_MD_size(sigmd);
-  if (saltlen == -1) {
+  if (saltlen == RSA_PSS_SALTLEN_DIGEST) {
     saltlen = md_len;
   } else if (saltlen != md_len) {
     OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
diff --git a/crypto/x509/x509_test.cc b/crypto/x509/x509_test.cc
index 6159d40..f8e2b4c 100644
--- a/crypto/x509/x509_test.cc
+++ b/crypto/x509/x509_test.cc
@@ -2206,7 +2206,8 @@
   ASSERT_TRUE(EVP_DigestSignInit(md_ctx.get(), &pkey_ctx, EVP_sha256(), NULL,
                                  pkey.get()));
   ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING));
-  ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1));
+  ASSERT_TRUE(
+      EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, RSA_PSS_SALTLEN_DIGEST));
   ASSERT_TRUE(SignatureRoundTrips(md_ctx.get(), pkey.get()));
 
   md_ctx.Reset();
@@ -2221,7 +2222,8 @@
   ASSERT_TRUE(EVP_DigestSignInit(md_ctx.get(), &pkey_ctx, EVP_sha1(), NULL,
                                  pkey.get()));
   ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING));
-  ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1));
+  ASSERT_TRUE(
+      EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, RSA_PSS_SALTLEN_DIGEST));
   bssl::UniquePtr<X509> cert = CertFromPEM(kLeafPEM);
   ASSERT_TRUE(cert);
   EXPECT_FALSE(X509_sign_ctx(cert.get(), md_ctx.get()));
@@ -2231,7 +2233,8 @@
   ASSERT_TRUE(EVP_DigestSignInit(md_ctx.get(), &pkey_ctx, EVP_sha256(), NULL,
                                  pkey.get()));
   ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING));
-  ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1));
+  ASSERT_TRUE(
+      EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, RSA_PSS_SALTLEN_DIGEST));
   ASSERT_TRUE(EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, EVP_sha512()));
   cert = CertFromPEM(kLeafPEM);
   ASSERT_TRUE(cert);
diff --git a/include/openssl/evp.h b/include/openssl/evp.h
index 88f0092..32d2084 100644
--- a/include/openssl/evp.h
+++ b/include/openssl/evp.h
@@ -686,16 +686,18 @@
                                                 int *out_padding);
 
 // EVP_PKEY_CTX_set_rsa_pss_saltlen sets the length of the salt in a PSS-padded
-// signature. A value of -1 cause the salt to be the same length as the digest
-// in the signature. A value of -2 causes the salt to be the maximum length
-// that will fit when signing and recovered from the signature when verifying.
-// Otherwise the value gives the size of the salt in bytes.
+// signature. A value of |RSA_PSS_SALTLEN_DIGEST| causes the salt to be the same
+// length as the digest in the signature. A value of |RSA_PSS_SALTLEN_AUTO|
+// causes the salt to be the maximum length that will fit when signing and
+// recovered from the signature when verifying. Otherwise the value gives the
+// size of the salt in bytes.
 //
-// If unsure, use -1.
+// If unsure, use |RSA_PSS_SALTLEN_DIGEST|.
 //
 // Returns one on success or zero on error.
 //
-// TODO(davidben): The default is currently -2. Switch it to -1.
+// TODO(davidben): The default is currently |RSA_PSS_SALTLEN_AUTO|. Switch it to
+// |RSA_PSS_SALTLEN_DIGEST|.
 OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx,
                                                     int salt_len);
 
diff --git a/include/openssl/rsa.h b/include/openssl/rsa.h
index c6c9fc4..c80aea8 100644
--- a/include/openssl/rsa.h
+++ b/include/openssl/rsa.h
@@ -301,6 +301,13 @@
                             size_t digest_len, uint8_t *out, unsigned *out_len,
                             RSA *rsa);
 
+// RSA_PSS_SALTLEN_DIGEST indicates a PSS salt length that matches the digest
+// length. This is recommended.
+#define RSA_PSS_SALTLEN_DIGEST (-1)
+// RSA_PSS_SALTLEN_AUTO indicates a maximum possible PSS salt length when
+// signing, and automatically detecting the salt length when verifying.
+#define RSA_PSS_SALTLEN_AUTO (-2)
+
 // RSA_sign_pss_mgf1 signs |digest_len| bytes from |digest| with the public key
 // from |rsa| using RSASSA-PSS with MGF1 as the mask generation function. It
 // writes, at most, |max_out| bytes of signature data to |out|. The |max_out|
@@ -311,9 +318,10 @@
 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
 // used.
 //
-// |salt_len| specifies the expected salt length in bytes. If |salt_len| is -1,
-// then the salt length is the same as the hash length. If -2, then the salt
-// length is maximal given the size of |rsa|. If unsure, use -1.
+// |salt_len| specifies the expected salt length in bytes. If |salt_len| is
+// |RSA_PSS_SALTLEN_DIGEST|, then the salt length is the same as the hash
+// length. If |RSA_PSS_SALTLEN_AUTO|, then the salt length is maximal given the
+// size of |rsa|. If unsure, use |RSA_PSS_SALTLEN_DIGEST|.
 //
 // WARNING: |digest| must be the result of hashing the data to be signed with
 // |md|. Passing unhashed inputs will not result in a secure signature scheme.
@@ -373,9 +381,9 @@
 // and the MGF1 hash, respectively. If |mgf1_md| is NULL, |md| is
 // used. |salt_len| specifies the expected salt length in bytes.
 //
-// If |salt_len| is -1, then the salt length is the same as the hash length. If
-// -2, then the salt length is recovered and all values accepted. If unsure, use
-// -1.
+// If |salt_len| is |RSA_PSS_SALTLEN_DIGEST|, then the salt length is the same
+// as the hash length. If |RSA_PSS_SALTLEN_AUTO|, then the salt length is
+// recovered and all values accepted. If unsure, use |RSA_PSS_SALTLEN_DIGEST|.
 //
 // WARNING: |digest| must be the result of hashing the data to be verified with
 // |md|. Passing unhashed input will not result in a secure signature scheme.
diff --git a/pki/verify_signed_data.cc b/pki/verify_signed_data.cc
index f53f039..668598c 100644
--- a/pki/verify_signed_data.cc
+++ b/pki/verify_signed_data.cc
@@ -273,7 +273,7 @@
     // also use the digest length as the salt length, which is specified with -1
     // in OpenSSL's API.
     if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
-        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1)) {
+        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)) {
       return false;
     }
   }
diff --git a/ssl/ssl_privkey.cc b/ssl/ssl_privkey.cc
index 70b9f03..46906f9 100644
--- a/ssl/ssl_privkey.cc
+++ b/ssl/ssl_privkey.cc
@@ -185,7 +185,7 @@
 
   if (alg->is_rsa_pss) {
     if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
-        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1 /* salt len = hash len */)) {
+        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)) {
       return false;
     }
   }
diff --git a/ssl/test/test_config.cc b/ssl/test/test_config.cc
index a847397..0f43d86 100644
--- a/ssl/test/test_config.cc
+++ b/ssl/test/test_config.cc
@@ -1242,7 +1242,7 @@
   // Configure additional signature parameters.
   if (SSL_is_signature_algorithm_rsa_pss(signature_algorithm)) {
     if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
-        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1 /* salt len = hash len */)) {
+        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)) {
       return ssl_private_key_failure;
     }
   }
diff --git a/util/fipstools/acvp/modulewrapper/modulewrapper.cc b/util/fipstools/acvp/modulewrapper/modulewrapper.cc
index 018aceb..80599d7 100644
--- a/util/fipstools/acvp/modulewrapper/modulewrapper.cc
+++ b/util/fipstools/acvp/modulewrapper/modulewrapper.cc
@@ -2043,7 +2043,7 @@
   size_t sig_len;
   if (UsePSS) {
     if (!RSA_sign_pss_mgf1(key, &sig_len, sig.data(), sig.size(), digest_buf,
-                           digest_len, md, md, -1)) {
+                           digest_len, md, md, RSA_PSS_SALTLEN_DIGEST)) {
       return false;
     }
   } else {
@@ -2087,8 +2087,8 @@
 
   uint8_t ok;
   if (UsePSS) {
-    ok = RSA_verify_pss_mgf1(key.get(), digest_buf, digest_len, md, md, -1,
-                             sig.data(), sig.size());
+    ok = RSA_verify_pss_mgf1(key.get(), digest_buf, digest_len, md, md,
+                             RSA_PSS_SALTLEN_DIGEST, sig.data(), sig.size());
   } else {
     ok = RSA_verify(EVP_MD_type(md), digest_buf, digest_len, sig.data(),
                     sig.size(), key.get());