Modify interfaces of KDF and PBKDF to write output to an array, with

higher level functions on interface handling returning a vector.

2 files changed, 25 insertions, 24 deletions

diff --git a/src/lib/kdf/prf_x942/prf_x942.cpp b/src/lib/kdf/prf_x942/prf_x942.cpp
index 30bf737a9..5ca0f01ff 100644
--- a/src/lib/kdf/prf_x942/prf_x942.cpp
+++ b/src/lib/kdf/prf_x942/prf_x942.cpp
@@ -9,7 +9,7 @@
 #include <botan/prf_x942.h>
 #include <botan/der_enc.h>
 #include <botan/oids.h>
-#include <botan/sha160.h>
+#include <botan/hash.h>
 #include <botan/loadstor.h>
 #include <algorithm>
 
@@ -31,24 +31,22 @@ std::vector<byte> encode_x942_int(u32bit n)
 
 }
 
-/*
-* X9.42 PRF
-*/
-secure_vector<byte> X942_PRF::derive(size_t key_len,
-                                    const byte secret[], size_t secret_len,
-                                    const byte salt[], size_t salt_len) const
+size_t X942_PRF::kdf(byte key[], size_t key_len,
+                     const byte secret[], size_t secret_len,
+                     const byte salt[], size_t salt_len) const
    {
-   SHA_160 hash;
-   const OID kek_algo(key_wrap_oid);
+   std::unique_ptr<HashFunction> hash(make_a<HashFunction>("SHA-160"));
+   const OID kek_algo(m_key_wrap_oid);
 
-   secure_vector<byte> key;
+   secure_vector<byte> h;
+   size_t offset = 0;
    u32bit counter = 1;
 
-   while(key.size() != key_len && counter)
+   while(offset != key_len && counter)
       {
-      hash.update(secret, secret_len);
+      hash->update(secret, secret_len);
 
-      hash.update(
+      hash->update(
          DER_Encoder().start_cons(SEQUENCE)
 
             .start_cons(SEQUENCE)
@@ -70,14 +68,15 @@ secure_vector<byte> X942_PRF::derive(size_t key_len,
          .end_cons().get_contents()
          );
 
-      secure_vector<byte> digest = hash.final();
-      const size_t needed = std::min(digest.size(), key_len - key.size());
-      key += std::make_pair(&digest[0], needed);
+      hash->final(h);
+      const size_t copied = std::min(h.size(), key_len - offset);
+      copy_mem(&key[offset], &h[0], copied);
+      offset += copied;
 
       ++counter;
       }
 
-   return key;
+   return offset;
    }
 
 /*
@@ -86,9 +85,9 @@ secure_vector<byte> X942_PRF::derive(size_t key_len,
 X942_PRF::X942_PRF(const std::string& oid)
    {
    if(OIDS::have_oid(oid))
-      key_wrap_oid = OIDS::lookup(oid).as_string();
+      m_key_wrap_oid = OIDS::lookup(oid).as_string();
    else
-      key_wrap_oid = oid;
+      m_key_wrap_oid = oid;
    }
 
 }
diff --git a/src/lib/kdf/prf_x942/prf_x942.h b/src/lib/kdf/prf_x942/prf_x942.h
index d2678c127..242a83150 100644
--- a/src/lib/kdf/prf_x942/prf_x942.h
+++ b/src/lib/kdf/prf_x942/prf_x942.h
@@ -18,15 +18,17 @@ namespace Botan {
 class BOTAN_DLL X942_PRF : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t, const byte[], size_t,
-                                const byte[], size_t) const;
+      std::string name() const { return "X942_PRF(" + m_key_wrap_oid + ")"; }
 
-      std::string name() const { return "X942_PRF(" + key_wrap_oid + ")"; }
-      KDF* clone() const { return new X942_PRF(key_wrap_oid); }
+      KDF* clone() const { return new X942_PRF(m_key_wrap_oid); }
+
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
 
       X942_PRF(const std::string& oid);
    private:
-      std::string key_wrap_oid;
+      std::string m_key_wrap_oid;
    };
 
 }