One-Step Key Derivation Method with KMAC

doc/api_ref/kdf.rst

@@ -158,19 +158,20 @@ e.g. ``X9.42-PRF(KeyWrap.TripleDES)``, ``X9.42-PRF(1.2.840.113549.1.9.16.3.7)``
 SP800-56A
 ~~~~~~~~~~
 
-KDF from NIST SP 800-56A.
+KDF from NIST SP 800-56Ar2 or One-Step KDF of SP 800-56Cr2.
 
 Available if ``BOTAN_HAS_SP800_56A`` is defined.
 
 Algorithm specification names:
 
 - ``SP800-56A(<HashFunction>)``, e.g. ``SP800-56A(SHA-256)``
 - ``SP800-56A(HMAC(<HashFunction>))``, e.g. ``SP800-56A(HMAC(SHA-256))``
+- ``SP800-56A(KMAC-128)`` or ``SP800-56A(KMAC-256)``
 
 SP800-56C
 ~~~~~~~~~~
 
-KDF from NIST SP 800-56C.
+Two-Step KDF from NIST SP 800-56Cr2.
 
 Available if ``BOTAN_HAS_SP800_56C`` is defined.
 

src/lib/kdf/kdf.cpp

@@ -42,11 +42,11 @@
 #endif
 
 #if defined(BOTAN_HAS_SP800_56A)
-   #include <botan/internal/sp800_56a.h>
+   #include <botan/internal/sp800_56c_one_step.h>
 #endif
 
 #if defined(BOTAN_HAS_SP800_56C)
-   #include <botan/internal/sp800_56c.h>
+   #include <botan/internal/sp800_56c_two_step.h>
 #endif
 
 namespace Botan {
@@ -160,10 +160,16 @@ std::unique_ptr<KDF> KDF::create(std::string_view algo_spec, std::string_view pr
 #if defined(BOTAN_HAS_SP800_56A)
    if(req.algo_name() == "SP800-56A" && req.arg_count() == 1) {
       if(auto hash = HashFunction::create(req.arg(0))) {
-         return std::make_unique<SP800_56A_Hash>(std::move(hash));
+         return std::make_unique<SP800_56C_One_Step_Hash>(std::move(hash));
+      }
+      if(req.arg(0) == "KMAC-128") {
+         return std::make_unique<SP800_56C_One_Step_KMAC128>();
+      }
+      if(req.arg(0) == "KMAC-256") {
+         return std::make_unique<SP800_56C_One_Step_KMAC256>();
       }
       if(auto mac = MessageAuthenticationCode::create(req.arg(0))) {
-         return std::make_unique<SP800_56A_HMAC>(std::move(mac));
+         return std::make_unique<SP800_56C_One_Step_HMAC>(std::move(mac));
       }
    }
 #endif
@@ -173,11 +179,11 @@ std::unique_ptr<KDF> KDF::create(std::string_view algo_spec, std::string_view pr
       std::unique_ptr<KDF> exp(kdf_create_mac_or_hash<SP800_108_Feedback>(req.arg(0)));
       if(exp) {
          if(auto mac = MessageAuthenticationCode::create(req.arg(0))) {
-            return std::make_unique<SP800_56C>(std::move(mac), std::move(exp));
+            return std::make_unique<SP800_56C_Two_Step>(std::move(mac), std::move(exp));
          }
 
          if(auto mac = MessageAuthenticationCode::create(fmt("HMAC({})", req.arg(0)))) {
-            return std::make_unique<SP800_56C>(std::move(mac), std::move(exp));
+            return std::make_unique<SP800_56C_Two_Step>(std::move(mac), std::move(exp));
          }
       }
    }

src/lib/kdf/sp800_56a/info.txt

@@ -8,4 +8,5 @@ name -> "NIST SP800-56A"
 
 <requires>
 hmac
+kmac
 </requires>

src/lib/kdf/sp800_56a/sp800_56c_one_step.cpp

@@ -0,0 +1,192 @@
+/*
+* KDF defined in NIST SP 800-56a revision 2 (Single-step key-derivation function)
+* or in NIST SP 800-56C revision 2 (Section 4 - One-Step KDM)
+*
+* (C) 2017 Ribose Inc. Written by Krzysztof Kwiatkowski.
+* (C) 2024 Fabian Albert - Rohde & Schwarz Cybersecurity
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/sp800_56c_one_step.h>
+
+#include <botan/exceptn.h>
+#include <botan/internal/bit_ops.h>
+#include <botan/internal/fmt.h>
+#include <botan/internal/kmac.h>
+
+#include <functional>
+
+namespace Botan {
+
+namespace {
+/**
+ * @brief One-Step Key Derivation as defined in SP800-56Cr2 Section 4
+ */
+void kdm_internal(std::span<uint8_t> output_buffer,
+                  std::span<const uint8_t> z,
+                  std::span<const uint8_t> fixed_info,
+                  Buffered_Computation& h,
+                  const std::function<void(Buffered_Computation*)>& reset_h_callback) {
+   size_t l = output_buffer.size() * 8;
+   // 1. If L > 0, then set reps = ceil(L / H_outputBits); otherwise,
+   //    output an error indicator and exit this process without
+   //    performing the remaining actions (i.e., omit steps 2 through 8).
+   BOTAN_ARG_CHECK(l > 0, "Zero KDM output length");
+   size_t reps = ceil_division(l, h.output_length() * 8);
+
+   // 2. If reps > (2^32 − 1), then output an error indicator and exit this
+   //    process without performing the remaining actions
+   //    (i.e., omit steps 3 through 8).
+   BOTAN_ARG_CHECK(reps <= 0xFFFFFFFF, "Too large KDM output length");
+
+   // 3. Initialize a big-endian 4-byte unsigned integer counter as
+   //    0x00000000, corresponding to a 32-bit binary representation of
+   //    the number zero.
+   uint32_t counter = 0;
+
+   // 4. If counter || Z || FixedInfo is more than max_H_inputBits bits
+   //    long, then output an error indicator and exit this process
+   //    without performing any of the remaining actions (i.e., omit
+   //    steps 5 through 8). => SHA3 and KMAC are unlimited
+
+   // 5. Initialize Result(0) as an empty bit string
+   //    (i.e., the null string).
+   secure_vector<uint8_t> result;
+
+   // 6. For i = 1 to reps, do the following:
+   for(size_t i = 1; i <= reps; i++) {
+      // 6.1. Increment counter by 1.
+      counter++;
+      // Reset the hash/MAC object. For MAC, also set the key (salt) and IV.
+      reset_h_callback(&h);
+
+      // 6.2 Compute K(i) = H(counter || Z || FixedInfo).
+      h.update_be(counter);
+      h.update(z);
+      h.update(fixed_info);
+      auto k_i = h.final();
+
+      // 6.3. Set Result(i) = Result(i−1) || K(i).
+      result.insert(result.end(), k_i.begin(), k_i.end());
+   }
+
+   // 7. Set DerivedKeyingMaterial equal to the leftmost L bits of Result(reps).
+   copy_mem(output_buffer, std::span(result).subspan(0, output_buffer.size()));
+}
+
+}  // namespace
+
+void SP800_56C_One_Step_Hash::kdf(uint8_t key[],
+                                  size_t key_len,
+                                  const uint8_t secret[],
+                                  size_t secret_len,
+                                  const uint8_t salt[],
+                                  size_t salt_len,
+                                  const uint8_t label[],
+                                  size_t label_len) const {
+   BOTAN_UNUSED(salt);
+   BOTAN_ARG_CHECK(salt_len == 0, "SP800_56A_Hash does not support a non-empty salt");
+
+   kdm_internal({key, key_len}, {secret, secret_len}, {label, label_len}, *m_hash, [](Buffered_Computation* kdf) {
+      HashFunction* hash = dynamic_cast<HashFunction*>(kdf);
+      BOTAN_ASSERT_NONNULL(hash);
+      hash->clear();
+   });
+}
+
+std::string SP800_56C_One_Step_Hash::name() const {
+   return fmt("SP800-56A({})", m_hash->name());
+}
+
+std::unique_ptr<KDF> SP800_56C_One_Step_Hash::new_object() const {
+   return std::make_unique<SP800_56C_One_Step_Hash>(m_hash->new_object());
+}
+
+SP800_56C_One_Step_HMAC::SP800_56C_One_Step_HMAC(std::unique_ptr<MessageAuthenticationCode> mac) :
+      m_mac(std::move(mac)) {
+   // TODO: we need a MessageAuthenticationCode::is_hmac
+   if(!m_mac->name().starts_with("HMAC(")) {
+      throw Algorithm_Not_Found("Only HMAC can be used with SP800_56A_HMAC");
+   }
+}
+
+void SP800_56C_One_Step_HMAC::kdf(uint8_t key[],
+                                  size_t key_len,
+                                  const uint8_t secret[],
+                                  size_t secret_len,
+                                  const uint8_t salt[],
+                                  size_t salt_len,
+                                  const uint8_t label[],
+                                  size_t label_len) const {
+   kdm_internal({key, key_len}, {secret, secret_len}, {label, label_len}, *m_mac, [&](Buffered_Computation* kdf) {
+      MessageAuthenticationCode* kdf_mac = dynamic_cast<MessageAuthenticationCode*>(kdf);
+      BOTAN_ASSERT_NONNULL(kdf_mac);
+      kdf_mac->clear();
+      // 4.1 Option 2 and 3 - An implementation dependent byte string, salt,
+      //     whose (non-null) value may be optionally provided in
+      //     OtherInput, serves as the HMAC#/KMAC# key ..
+
+      // SP 800-56A specifies if the salt is empty then a block of zeros
+      // equal to the hash's underlying block size are used. However this
+      // is equivalent to setting a zero-length key, so the same call
+      // works for either case.
+      kdf_mac->set_key(std::span{salt, salt_len});
+   });
+}
+
+std::string SP800_56C_One_Step_HMAC::name() const {
+   return fmt("SP800-56A({})", m_mac->name());
+}
+
+std::unique_ptr<KDF> SP800_56C_One_Step_HMAC::new_object() const {
+   return std::make_unique<SP800_56C_One_Step_HMAC>(m_mac->new_object());
+}
+
+// Option 3 - KMAC
+void SP800_56A_One_Step_KMAC_Abstract::kdf(uint8_t key[],
+                                           size_t key_len,
+                                           const uint8_t secret[],
+                                           size_t secret_len,
+                                           const uint8_t salt[],
+                                           size_t salt_len,
+                                           const uint8_t label[],
+                                           size_t label_len) const {
+   auto mac = create_kmac_instance(key_len);
+   kdm_internal({key, key_len}, {secret, secret_len}, {label, label_len}, *mac, [&](Buffered_Computation* kdf) {
+      MessageAuthenticationCode* kdf_mac = dynamic_cast<MessageAuthenticationCode*>(kdf);
+      BOTAN_ASSERT_NONNULL(kdf_mac);
+      kdf_mac->clear();
+      // 4.1 Option 2 and 3 - An implementation dependent byte string, salt,
+      //     whose (non-null) value may be optionally provided in
+      //     OtherInput, serves as the HMAC#/KMAC# key ..
+
+      // SP 800-56A specifies if the salt is empty then a block of zeros
+      // equal to the hash's underlying block size are used. However this
+      // is equivalent to setting a zero-length key, so the same call
+      // works for either case.
+      kdf_mac->set_key(std::span{salt, salt_len});
+
+      // 4.1 Option 2 and 3 - An implementation dependent byte string, salt,
+      //     whose (non-null) value may be optionally provided in
+      //     OtherInput, serves as the HMAC#/KMAC# key ...
+      kdf_mac->set_key(std::span{salt, salt_len});
+
+      // 4.1 Option 3 - The "customization string" S shall be the byte string
+      //     01001011 || 01000100 || 01000110, which represents the sequence
+      //     of characters 'K', 'D', and 'F' in 8-bit ASCII.
+      kdf_mac->start(std::array<uint8_t, 3>{'K', 'D', 'F'});
+   });
+}
+
+std::unique_ptr<MessageAuthenticationCode> SP800_56C_One_Step_KMAC128::create_kmac_instance(
+   size_t output_byte_len) const {
+   return std::make_unique<KMAC128>(output_byte_len * 8);
+}
+
+std::unique_ptr<MessageAuthenticationCode> SP800_56C_One_Step_KMAC256::create_kmac_instance(
+   size_t output_byte_len) const {
+   return std::make_unique<KMAC256>(output_byte_len * 8);
+}
+
+}  // namespace Botan