Create proto file for the Sphincs Digital Signature Algorithm and add ProtoToSubtle/SubtleToProto functions for corresponding enums.

PiperOrigin-RevId: 394650844

10 files changed, 428 insertions, 124 deletions

diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_sign.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_sign.cc
index 4ee019276..9aa46c167 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_sign.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_sign.cc
@@ -41,6 +41,11 @@ util::StatusOr<std::unique_ptr<PublicKeySign>> SphincsSign::New(
     return key_size;
   }
 
+  util::Status valid_parameters = ValidateParams(key.GetParams());
+  if (!valid_parameters.ok()) {
+    return valid_parameters;
+  }
+
   return {absl::WrapUnique(new SphincsSign(std::move(key)))};
 }
 
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_sign_test.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_sign_test.cc
index 7ee91e6b6..c338de236 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_sign_test.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_sign_test.cc
@@ -79,7 +79,7 @@ struct SphincsTestCase {
   std::string test_name;
   SphincsHashType hash_type;
   SphincsVariant variant;
-  SphincsSignatureLengthType sig_length_type;
+  SphincsSignatureType sig_length_type;
   int32_t private_key_size;
   int32_t signature_length;
 };
@@ -197,155 +197,155 @@ INSTANTIATE_TEST_SUITE_P(
     SphincsSignTests, SphincsSignTest,
     testing::ValuesIn<SphincsTestCase>(
         {{"SPHINCSHARAKA128FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSHARAKA192FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSHARAKA256FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSSHA256128FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHA256192FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHA256256FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256128FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256192FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256256FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_BYTES}}),
     [](const testing::TestParamInfo<SphincsSignTest::ParamType>& info) {
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.cc
index 956c5500b..90efdf7f0 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.cc
@@ -23,6 +23,7 @@
 #include "absl/strings/str_format.h"
 #include "tink/experimental/pqcrypto/signature/subtle/sphincs_helper_pqclean.h"
 #include "tink/util/secret_data.h"
+#include "tink/util/status.h"
 #include "tink/util/statusor.h"
 
 namespace crypto {
@@ -31,16 +32,16 @@ namespace subtle {
 
 crypto::tink::util::StatusOr<SphincsKeyPair> GenerateSphincsKeyPair(
     SphincsParamsPqclean params) {
-  util::Status key_size_status =
-      ValidatePrivateKeySize(params.private_key_size);
-  if (!key_size_status.ok()) {
-    return key_size_status;
+  // Check if parameters are valid.
+  util::Status valid_parameters = ValidateParams(params);
+  if (!valid_parameters.ok()) {
+    return valid_parameters;
   }
 
-  util::StatusOr<int32> key_size_index_or =
+  util::StatusOr<int32> key_size_index =
       SphincsKeySizeToIndex(params.private_key_size);
-  if (!key_size_index_or.ok()) {
-    return key_size_index_or.status();
+  if (!key_size_index.ok()) {
+    return key_size_index.status();
   }
 
   std::string public_key;
@@ -48,8 +49,8 @@ crypto::tink::util::StatusOr<SphincsKeyPair> GenerateSphincsKeyPair(
   private_key.resize(params.private_key_size);
 
   const SphincsHelperPqclean &sphincs_helper_pqclean =
-      GetSphincsHelperPqclean(params.hash_type, params.variant,
-                              *key_size_index_or, params.sig_length_type);
+      GetSphincsHelperPqclean(params.hash_type, params.variant, *key_size_index,
+                              params.sig_length_type);
   public_key.resize(sphincs_helper_pqclean.GetPublicKeySize());
 
   if (0 != sphincs_helper_pqclean.Keygen(
@@ -112,6 +113,42 @@ crypto::tink::util::StatusOr<int32> SphincsKeySizeToIndex(int32 key_size) {
   }
 }
 
+crypto::tink::util::Status ValidateParams(SphincsParamsPqclean params) {
+  switch (params.hash_type) {
+    case SphincsHashType::HARAKA:
+    case SphincsHashType::SHA256:
+    case SphincsHashType::SHAKE256: {
+      break;
+    }
+    default: {
+      return util::Status(util::error::INVALID_ARGUMENT, "Invalid hash type");
+    }
+  }
+
+  switch (params.variant) {
+    case SphincsVariant::ROBUST:
+    case SphincsVariant::SIMPLE: {
+      break;
+    }
+    default: {
+      return util::Status(util::error::INVALID_ARGUMENT, "Invalid variant");
+    }
+  }
+
+  switch (params.sig_length_type) {
+    case SphincsSignatureType::FAST_SIGNING:
+    case SphincsSignatureType::SMALL_SIGNATURE: {
+      break;
+    }
+    default: {
+      return util::Status(util::error::INVALID_ARGUMENT,
+                          "Invalid signature type");
+    }
+  }
+
+  return ValidatePrivateKeySize(params.private_key_size);
+}
+
 }  // namespace subtle
 }  // namespace tink
 }  // namespace crypto
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.h b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.h
index 38f5f0fc5..62670f948 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.h
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.h
@@ -43,22 +43,25 @@ enum SphincsHashType {
   HARAKA = 0,
   SHA256 = 1,
   SHAKE256 = 2,
+  UNKNOWN_HASH_TYPE = 3,
 };
 
 enum SphincsVariant {
   ROBUST = 0,
   SIMPLE = 1,
+  UNKNOWN_VARIANT = 3,
 };
 
-enum SphincsSignatureLengthType {
-  F = 0,
-  S = 1,
+enum SphincsSignatureType {
+  FAST_SIGNING = 0,
+  SMALL_SIGNATURE = 1,
+  UNKNOWN_SIG_TYPE = 3,
 };
 
 struct SphincsParamsPqclean {
   SphincsHashType hash_type;
   SphincsVariant variant;
-  SphincsSignatureLengthType sig_length_type;
+  SphincsSignatureType sig_length_type;
   int32 private_key_size;
 };
 
@@ -129,6 +132,10 @@ crypto::tink::util::Status ValidatePrivateKeySize(int32 key_size);
 // Validates whether the public key size is safe to use for sphincs signature.
 crypto::tink::util::Status ValidatePublicKeySize(int32 key_size);
 
+// Validates whether the parameters are safe to use for sphincs signature.
+crypto::tink::util::Status ValidateParams(SphincsParamsPqclean params);
+
+
 // Convert the sphincs private key size to the appropiate index in the
 // pqclean functions array.
 crypto::tink::util::StatusOr<int32> SphincsKeySizeToIndex(int32 key_size);
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils_test.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils_test.cc
index 928b77d07..a55ccec4f 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils_test.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils_test.cc
@@ -77,7 +77,7 @@ struct SphincsUtilsTestCase {
   std::string test_name;
   SphincsHashType hash_type;
   SphincsVariant variant;
-  SphincsSignatureLengthType sig_length_type;
+  SphincsSignatureType sig_length_type;
   int32_t private_key_size;
   int32_t public_key_size;
 };
@@ -148,159 +148,205 @@ TEST(SphincsUtilsTest, InvalidPublicKeySize) {
   }
 }
 
+TEST_P(SphincsUtilsTest, ValidParams) {
+  const SphincsUtilsTestCase& test_case = GetParam();
+
+  SphincsParamsPqclean params = {
+      .hash_type = test_case.hash_type,
+      .variant = test_case.variant,
+      .sig_length_type = test_case.sig_length_type,
+      .private_key_size = test_case.private_key_size,
+  };
+
+  EXPECT_TRUE(ValidateParams(params).ok());
+}
+
+TEST(SphincsUtilsTest, InvalidHashType) {
+    SphincsParamsPqclean params = {
+      .hash_type = SphincsHashType::UNKNOWN_HASH_TYPE,
+      .variant = SphincsVariant::ROBUST,
+      .sig_length_type = SphincsSignatureType::FAST_SIGNING,
+      .private_key_size = kSphincsPrivateKeySize64,
+  };
+
+  EXPECT_FALSE(ValidateParams(params).ok());
+}
+
+TEST(SphincsUtilsTest, InvalidVariant) {
+    SphincsParamsPqclean params = {
+      .hash_type = SphincsHashType::HARAKA,
+      .variant = SphincsVariant::UNKNOWN_VARIANT,
+      .sig_length_type = SphincsSignatureType::FAST_SIGNING,
+      .private_key_size = kSphincsPrivateKeySize64,
+  };
+
+  EXPECT_FALSE(ValidateParams(params).ok());
+}
+
+TEST(SphincsUtilsTest, InvalidSignatureType) {
+    SphincsParamsPqclean params = {
+      .hash_type = SphincsHashType::HARAKA,
+      .variant = SphincsVariant::ROBUST,
+      .sig_length_type = SphincsSignatureType::UNKNOWN_SIG_TYPE,
+      .private_key_size = kSphincsPrivateKeySize64,
+  };
+
+  EXPECT_FALSE(ValidateParams(params).ok());
+}
+
 INSTANTIATE_TEST_SUITE_P(
     SphincsUtilsTests, SphincsUtilsTest,
     testing::ValuesIn<SphincsUtilsTestCase>(
         {{"SPHINCSHARAKA128FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA128SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA128FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA128SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSHARAKA192FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA192SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA192FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA192SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSHARAKA256FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA256SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA256FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSHARAKA256SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHA256128FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256128SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256128FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256128SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHA256192FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256192SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256192FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256192SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHA256256FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256256SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256256FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHA256256SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHAKE256128FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256128SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256128FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256128SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHAKE256192FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256192SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256192FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256192SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
 
          {"SPHINCSSHAKE256256FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256256SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256256FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES},
          {"SPHINCSSHAKE256256SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_PUBLICKEYBYTES}}),
     [](const testing::TestParamInfo<SphincsUtilsTest::ParamType>& info) {
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_verify.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_verify.cc
index 2906601db..77c55f006 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_verify.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_verify.cc
@@ -41,6 +41,11 @@ util::StatusOr<std::unique_ptr<PublicKeyVerify>> SphincsVerify::New(
     return key_size;
   }
 
+  util::Status valid_parameters = ValidateParams(public_key.GetParams());
+  if (!valid_parameters.ok()) {
+    return valid_parameters;
+  }
+
   return {absl::WrapUnique<SphincsVerify>(
       new SphincsVerify(std::move(public_key)))};
 }
diff --git a/cc/experimental/pqcrypto/signature/subtle/sphincs_verify_test.cc b/cc/experimental/pqcrypto/signature/subtle/sphincs_verify_test.cc
index 869c314df..660a2a5d8 100644
--- a/cc/experimental/pqcrypto/signature/subtle/sphincs_verify_test.cc
+++ b/cc/experimental/pqcrypto/signature/subtle/sphincs_verify_test.cc
@@ -80,7 +80,7 @@ struct SphincsTestCase {
   std::string test_name;
   SphincsHashType hash_type;
   SphincsVariant variant;
-  SphincsSignatureLengthType sig_length_type;
+  SphincsSignatureType sig_length_type;
   int32_t private_key_size;
   int32_t signature_length;
 };
@@ -276,155 +276,155 @@ INSTANTIATE_TEST_SUITE_P(
     SphincsVerifyTests, SphincsVerifyTest,
     testing::ValuesIn<SphincsTestCase>(
         {{"SPHINCSHARAKA128FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA128SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA128SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSHARAKA192FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA192SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA192SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSHARAKA256FROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256SROBUST", SphincsHashType::HARAKA,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SROBUST_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256FSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256FSIMPLE_AESNI_CRYPTO_BYTES},
          {"SPHINCSHARAKA256SSIMPLE", SphincsHashType::HARAKA,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSHARAKA256SSIMPLE_AESNI_CRYPTO_BYTES},
 
          {"SPHINCSSHA256128FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256128SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256128SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHA256192FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256192SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256192SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHA256256FROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256SROBUST", SphincsHashType::SHA256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256FSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHA256256SSIMPLE", SphincsHashType::SHA256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHA256256SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256128FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256128SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256128SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256192FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256192SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256192SSIMPLE_AVX2_CRYPTO_BYTES},
 
          {"SPHINCSSHAKE256256FROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::F,
+          SphincsVariant::ROBUST, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256SROBUST", SphincsHashType::SHAKE256,
-          SphincsVariant::ROBUST, SphincsSignatureLengthType::S,
+          SphincsVariant::ROBUST, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SROBUST_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256FSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::F,
+          SphincsVariant::SIMPLE, SphincsSignatureType::FAST_SIGNING,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256FSIMPLE_AVX2_CRYPTO_BYTES},
          {"SPHINCSSHAKE256256SSIMPLE", SphincsHashType::SHAKE256,
-          SphincsVariant::SIMPLE, SphincsSignatureLengthType::S,
+          SphincsVariant::SIMPLE, SphincsSignatureType::SMALL_SIGNATURE,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_SECRETKEYBYTES,
           PQCLEAN_SPHINCSSHAKE256256SSIMPLE_AVX2_CRYPTO_BYTES}}),
     [](const testing::TestParamInfo<SphincsVerifyTest::ParamType>& info) {
diff --git a/cc/experimental/pqcrypto/signature/util/enums.cc b/cc/experimental/pqcrypto/signature/util/enums.cc
index 166a37556..c6593f77b 100644
--- a/cc/experimental/pqcrypto/signature/util/enums.cc
+++ b/cc/experimental/pqcrypto/signature/util/enums.cc
@@ -48,6 +48,86 @@ subtle::DilithiumSeedExpansion EnumsPqcrypto::ProtoToSubtle(
   }
 }
 
+// static
+pb::SphincsHashType EnumsPqcrypto::SubtleToProto(subtle::SphincsHashType type) {
+  switch (type) {
+    case subtle::SphincsHashType::HARAKA:
+      return pb::SphincsHashType::HARAKA;
+    case subtle::SphincsHashType::SHA256:
+      return pb::SphincsHashType::SHA256;
+    case subtle::SphincsHashType::SHAKE256:
+      return pb::SphincsHashType::SHAKE256;
+    default:
+      return pb::SphincsHashType::UNKNOWN_HASH_TYPE;
+  }
+}
+
+// static
+subtle::SphincsHashType EnumsPqcrypto::ProtoToSubtle(pb::SphincsHashType type) {
+  switch (type) {
+    case pb::SphincsHashType::HARAKA:
+      return subtle::SphincsHashType::HARAKA;
+    case pb::SphincsHashType::SHA256:
+      return subtle::SphincsHashType::SHA256;
+    case pb::SphincsHashType::SHAKE256:
+      return subtle::SphincsHashType::SHAKE256;
+    default:
+      return subtle::SphincsHashType::UNKNOWN_HASH_TYPE;
+  }
+}
+
+// static
+pb::SphincsVariant EnumsPqcrypto::SubtleToProto(
+    subtle::SphincsVariant variant) {
+  switch (variant) {
+    case subtle::SphincsVariant::ROBUST:
+      return pb::SphincsVariant::ROBUST;
+    case subtle::SphincsVariant::SIMPLE:
+      return pb::SphincsVariant::SIMPLE;
+    default:
+      return pb::SphincsVariant::UNKNOWN_VARIANT;
+  }
+}
+
+// static
+subtle::SphincsVariant EnumsPqcrypto::ProtoToSubtle(
+    pb::SphincsVariant variant) {
+  switch (variant) {
+    case pb::SphincsVariant::ROBUST:
+      return subtle::SphincsVariant::ROBUST;
+    case pb::SphincsVariant::SIMPLE:
+      return subtle::SphincsVariant::SIMPLE;
+    default:
+      return subtle::SphincsVariant::UNKNOWN_VARIANT;
+  }
+}
+
+// static
+pb::SphincsSignatureType EnumsPqcrypto::SubtleToProto(
+    subtle::SphincsSignatureType type) {
+  switch (type) {
+    case subtle::SphincsSignatureType::FAST_SIGNING:
+      return pb::SphincsSignatureType::FAST_SIGNING;
+    case subtle::SphincsSignatureType::SMALL_SIGNATURE:
+      return pb::SphincsSignatureType::SMALL_SIGNATURE;
+    default:
+      return pb::SphincsSignatureType::UNKNOWN_SIG_TYPE;
+  }
+}
+
+// static
+subtle::SphincsSignatureType EnumsPqcrypto::ProtoToSubtle(
+    pb::SphincsSignatureType type) {
+  switch (type) {
+    case pb::SphincsSignatureType::FAST_SIGNING:
+      return subtle::SphincsSignatureType::FAST_SIGNING;
+    case pb::SphincsSignatureType::SMALL_SIGNATURE:
+      return subtle::SphincsSignatureType::SMALL_SIGNATURE;
+    default:
+      return subtle::SphincsSignatureType::UNKNOWN_SIG_TYPE;
+  }
+}
+
 }  // namespace util
 }  // namespace tink
 }  // namespace crypto
diff --git a/cc/experimental/pqcrypto/signature/util/enums.h b/cc/experimental/pqcrypto/signature/util/enums.h
index 3b8d438ff..e72b8e335 100644
--- a/cc/experimental/pqcrypto/signature/util/enums.h
+++ b/cc/experimental/pqcrypto/signature/util/enums.h
@@ -19,8 +19,10 @@
 
 #include "absl/strings/string_view.h"
 #include "tink/experimental/pqcrypto/signature/subtle/dilithium_key.h"
+#include "tink/experimental/pqcrypto/signature/subtle/sphincs_subtle_utils.h"
 #include "tink/util/statusor.h"
 #include "proto/experimental/pqcrypto/dilithium.pb.h"
+#include "proto/experimental/pqcrypto/sphincs.pb.h"
 #include "proto/tink.pb.h"
 
 namespace crypto {
@@ -37,6 +39,27 @@ class EnumsPqcrypto {
 
   static crypto::tink::subtle::DilithiumSeedExpansion ProtoToSubtle(
       google::crypto::tink::DilithiumSeedExpansion expansion);
+
+  // SphincsHashType.
+  static google::crypto::tink::SphincsHashType SubtleToProto(
+      crypto::tink::subtle::SphincsHashType type);
+
+  static crypto::tink::subtle::SphincsHashType ProtoToSubtle(
+      google::crypto::tink::SphincsHashType type);
+
+  // SphincsVariant.
+  static google::crypto::tink::SphincsVariant SubtleToProto(
+      crypto::tink::subtle::SphincsVariant variant);
+
+  static crypto::tink::subtle::SphincsVariant ProtoToSubtle(
+      google::crypto::tink::SphincsVariant variant);
+
+  // SphincsSignatureType.
+  static google::crypto::tink::SphincsSignatureType SubtleToProto(
+      crypto::tink::subtle::SphincsSignatureType type);
+
+  static crypto::tink::subtle::SphincsSignatureType ProtoToSubtle(
+      google::crypto::tink::SphincsSignatureType type);
 };
 
 }  // namespace util
diff --git a/cc/experimental/pqcrypto/signature/util/enums_test.cc b/cc/experimental/pqcrypto/signature/util/enums_test.cc
index 7f0e6731a..1327fe834 100644
--- a/cc/experimental/pqcrypto/signature/util/enums_test.cc
+++ b/cc/experimental/pqcrypto/signature/util/enums_test.cc
@@ -64,6 +64,107 @@ TEST_F(EnumsTest, DilithiumSeedExpansion) {
   EXPECT_EQ(3, count);
 }
 
+TEST_F(EnumsTest, SphincsHashType) {
+  EXPECT_EQ(pb::SphincsHashType::HARAKA,
+            EnumsPqcrypto::SubtleToProto(subtle::SphincsHashType::HARAKA));
+  EXPECT_EQ(pb::SphincsHashType::SHA256,
+            EnumsPqcrypto::SubtleToProto(subtle::SphincsHashType::SHA256));
+  EXPECT_EQ(pb::SphincsHashType::SHAKE256,
+            EnumsPqcrypto::SubtleToProto(subtle::SphincsHashType::SHAKE256));
+  EXPECT_EQ(
+      pb::SphincsHashType::UNKNOWN_HASH_TYPE,
+      EnumsPqcrypto::SubtleToProto(subtle::SphincsHashType::UNKNOWN_HASH_TYPE));
+
+  EXPECT_EQ(subtle::SphincsHashType::HARAKA,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsHashType::HARAKA));
+  EXPECT_EQ(subtle::SphincsHashType::SHA256,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsHashType::SHA256));
+  EXPECT_EQ(subtle::SphincsHashType::SHAKE256,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsHashType::SHAKE256));
+  EXPECT_EQ(
+      subtle::SphincsHashType::UNKNOWN_HASH_TYPE,
+      EnumsPqcrypto::ProtoToSubtle(pb::SphincsHashType::UNKNOWN_HASH_TYPE));
+
+  // Check that enum conversion covers the entire range of the proto-enum.
+  int count = 0;
+  for (int int_type = static_cast<int>(pb::SphincsHashType_MIN);
+       int_type <= static_cast<int>(pb::SphincsHashType_MAX); int_type++) {
+    if (pb::SphincsHashType_IsValid(int_type)) {
+      pb::SphincsHashType type = static_cast<pb::SphincsHashType>(int_type);
+      EXPECT_EQ(type, EnumsPqcrypto::SubtleToProto(
+                          EnumsPqcrypto::ProtoToSubtle(type)));
+      count++;
+    }
+  }
+  EXPECT_EQ(4, count);
+}
+
+TEST_F(EnumsTest, SphincsVariant) {
+  EXPECT_EQ(pb::SphincsVariant::ROBUST,
+            EnumsPqcrypto::SubtleToProto(subtle::SphincsVariant::ROBUST));
+  EXPECT_EQ(pb::SphincsVariant::SIMPLE,
+            EnumsPqcrypto::SubtleToProto(subtle::SphincsVariant::SIMPLE));
+  EXPECT_EQ(
+      pb::SphincsVariant::UNKNOWN_VARIANT,
+      EnumsPqcrypto::SubtleToProto(subtle::SphincsVariant::UNKNOWN_VARIANT));
+
+  EXPECT_EQ(subtle::SphincsVariant::ROBUST,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsVariant::ROBUST));
+  EXPECT_EQ(subtle::SphincsVariant::SIMPLE,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsVariant::SIMPLE));
+  EXPECT_EQ(subtle::SphincsVariant::UNKNOWN_VARIANT,
+            EnumsPqcrypto::ProtoToSubtle(pb::SphincsVariant::UNKNOWN_VARIANT));
+
+  // Check that enum conversion covers the entire range of the proto-enum.
+  int count = 0;
+  for (int int_type = static_cast<int>(pb::SphincsVariant_MIN);
+       int_type <= static_cast<int>(pb::SphincsVariant_MAX); int_type++) {
+    if (pb::SphincsVariant_IsValid(int_type)) {
+      pb::SphincsVariant type = static_cast<pb::SphincsVariant>(int_type);
+      EXPECT_EQ(type, EnumsPqcrypto::SubtleToProto(
+                          EnumsPqcrypto::ProtoToSubtle(type)));
+      count++;
+    }
+  }
+  EXPECT_EQ(3, count);
+}
+
+TEST_F(EnumsTest, SphincsSignatureType) {
+  EXPECT_EQ(
+      pb::SphincsSignatureType::FAST_SIGNING,
+      EnumsPqcrypto::SubtleToProto(subtle::SphincsSignatureType::FAST_SIGNING));
+  EXPECT_EQ(pb::SphincsSignatureType::SMALL_SIGNATURE,
+            EnumsPqcrypto::SubtleToProto(
+                subtle::SphincsSignatureType::SMALL_SIGNATURE));
+  EXPECT_EQ(pb::SphincsSignatureType::UNKNOWN_SIG_TYPE,
+            EnumsPqcrypto::SubtleToProto(
+                subtle::SphincsSignatureType::UNKNOWN_SIG_TYPE));
+
+  EXPECT_EQ(
+      subtle::SphincsSignatureType::FAST_SIGNING,
+      EnumsPqcrypto::ProtoToSubtle(pb::SphincsSignatureType::FAST_SIGNING));
+  EXPECT_EQ(
+      subtle::SphincsSignatureType::SMALL_SIGNATURE,
+      EnumsPqcrypto::ProtoToSubtle(pb::SphincsSignatureType::SMALL_SIGNATURE));
+  EXPECT_EQ(
+      subtle::SphincsSignatureType::UNKNOWN_SIG_TYPE,
+      EnumsPqcrypto::ProtoToSubtle(pb::SphincsSignatureType::UNKNOWN_SIG_TYPE));
+
+  // Check that enum conversion covers the entire range of the proto-enum.
+  int count = 0;
+  for (int int_type = static_cast<int>(pb::SphincsSignatureType_MIN);
+       int_type <= static_cast<int>(pb::SphincsSignatureType_MAX); int_type++) {
+    if (pb::SphincsSignatureType_IsValid(int_type)) {
+      pb::SphincsSignatureType type =
+          static_cast<pb::SphincsSignatureType>(int_type);
+      EXPECT_EQ(type, EnumsPqcrypto::SubtleToProto(
+                          EnumsPqcrypto::ProtoToSubtle(type)));
+      count++;
+    }
+  }
+  EXPECT_EQ(3, count);
+}
+
 }  // namespace
 }  // namespace tink
 }  // namespace crypto