Modularize PBEs (password-based encryption schemes)

1 files changed, 230 insertions, 0 deletions

diff --git a/src/pbe/pbes2/pbes2.cpp b/src/pbe/pbes2/pbes2.cpp
new file mode 100644
index 000000000..d3533f14f
--- /dev/null
+++ b/src/pbe/pbes2/pbes2.cpp
@@ -0,0 +1,230 @@
+/*************************************************
+* PKCS #5 PBES2 Source File                      *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/pbe_pkcs.h>
+#include <botan/libstate.h>
+#include <botan/der_enc.h>
+#include <botan/ber_dec.h>
+#include <botan/parsing.h>
+#include <botan/lookup.h>
+#include <botan/asn1_obj.h>
+#include <botan/oids.h>
+#include <algorithm>
+#include <memory>
+
+namespace Botan {
+
+/*************************************************
+* Encrypt some bytes using PBES2                 *
+*************************************************/
+void PBE_PKCS5v20::write(const byte input[], u32bit length)
+   {
+   while(length)
+      {
+      u32bit put = std::min(DEFAULT_BUFFERSIZE, length);
+      pipe.write(input, length);
+      flush_pipe(true);
+      length -= put;
+      }
+   }
+
+/*************************************************
+* Start encrypting with PBES2                    *
+*************************************************/
+void PBE_PKCS5v20::start_msg()
+   {
+   pipe.append(get_cipher(cipher, key, iv, direction));
+   pipe.start_msg();
+   if(pipe.message_count() > 1)
+      pipe.set_default_msg(pipe.default_msg() + 1);
+   }
+
+/*************************************************
+* Finish encrypting with PBES2                   *
+*************************************************/
+void PBE_PKCS5v20::end_msg()
+   {
+   pipe.end_msg();
+   flush_pipe(false);
+   pipe.reset();
+   }
+
+/*************************************************
+* Flush the pipe                                 *
+*************************************************/
+void PBE_PKCS5v20::flush_pipe(bool safe_to_skip)
+   {
+   if(safe_to_skip && pipe.remaining() < 64)
+      return;
+
+   SecureVector<byte> buffer(DEFAULT_BUFFERSIZE);
+   while(pipe.remaining())
+      {
+      u32bit got = pipe.read(buffer, buffer.size());
+      send(buffer, got);
+      }
+   }
+
+/*************************************************
+* Set the passphrase to use                      *
+*************************************************/
+void PBE_PKCS5v20::set_key(const std::string& passphrase)
+   {
+   std::auto_ptr<S2K> pbkdf(get_s2k("PBKDF2(" + digest + ")"));
+   pbkdf->set_iterations(iterations);
+   pbkdf->change_salt(salt, salt.size());
+   key = pbkdf->derive_key(key_length, passphrase).bits_of();
+   }
+
+/*************************************************
+* Create a new set of PBES2 parameters           *
+*************************************************/
+void PBE_PKCS5v20::new_params(RandomNumberGenerator& rng)
+   {
+   iterations = 2048;
+   key_length = max_keylength_of(cipher_algo);
+
+   salt.create(8);
+   rng.randomize(salt, salt.size());
+
+   iv.create(block_size_of(cipher_algo));
+   rng.randomize(iv, iv.size());
+   }
+
+/*************************************************
+* Encode PKCS#5 PBES2 parameters                 *
+*************************************************/
+MemoryVector<byte> PBE_PKCS5v20::encode_params() const
+   {
+   return DER_Encoder()
+      .start_cons(SEQUENCE)
+      .encode(
+         AlgorithmIdentifier("PKCS5.PBKDF2",
+            DER_Encoder()
+               .start_cons(SEQUENCE)
+                  .encode(salt, OCTET_STRING)
+                  .encode(iterations)
+                  .encode(key_length)
+               .end_cons()
+            .get_contents()
+            )
+         )
+      .encode(
+         AlgorithmIdentifier(cipher,
+            DER_Encoder()
+               .encode(iv, OCTET_STRING)
+            .get_contents()
+            )
+         )
+      .end_cons()
+      .get_contents();
+   }
+
+/*************************************************
+* Decode PKCS#5 PBES2 parameters                 *
+*************************************************/
+void PBE_PKCS5v20::decode_params(DataSource& source)
+   {
+   AlgorithmIdentifier kdf_algo, enc_algo;
+
+   BER_Decoder(source)
+      .start_cons(SEQUENCE)
+         .decode(kdf_algo)
+         .decode(enc_algo)
+         .verify_end()
+      .end_cons();
+
+   if(kdf_algo.oid == OIDS::lookup("PKCS5.PBKDF2"))
+      {
+      digest = "SHA-160";
+
+      BER_Decoder(kdf_algo.parameters)
+         .start_cons(SEQUENCE)
+            .decode(salt, OCTET_STRING)
+            .decode(iterations)
+            .decode_optional(key_length, INTEGER, UNIVERSAL)
+            .verify_end()
+         .end_cons();
+      }
+   else
+      throw Decoding_Error("PBE-PKCS5 v2.0: Unknown KDF algorithm " +
+                           kdf_algo.oid.as_string());
+
+   cipher = OIDS::lookup(enc_algo.oid);
+   std::vector<std::string> cipher_spec = split_on(cipher, '/');
+   if(cipher_spec.size() != 2)
+      throw Decoding_Error("PBE-PKCS5 v2.0: Invalid cipher spec " + cipher);
+   cipher_algo = global_state().deref_alias(cipher_spec[0]);
+
+   if(!known_cipher(cipher_algo) || cipher_spec[1] != "CBC")
+      throw Decoding_Error("PBE-PKCS5 v2.0: Don't know param format for " +
+                           cipher);
+
+   BER_Decoder(enc_algo.parameters).decode(iv, OCTET_STRING).verify_end();
+
+   if(key_length == 0)
+      key_length = max_keylength_of(cipher_algo);
+
+   if(salt.size() < 8)
+      throw Decoding_Error("PBE-PKCS5 v2.0: Encoded salt is too small");
+   }
+
+/*************************************************
+* Return an OID for PBES2                        *
+*************************************************/
+OID PBE_PKCS5v20::get_oid() const
+   {
+   return OIDS::lookup("PBE-PKCS5v20");
+   }
+
+/*************************************************
+* Check if this is a known PBES2 cipher          *
+*************************************************/
+bool PBE_PKCS5v20::known_cipher(const std::string& algo) const
+   {
+   if(algo == "AES-128" || algo == "AES-192" || algo == "AES-256")
+      return true;
+   if(algo == "DES" || algo == "TripleDES")
+      return true;
+   return false;
+   }
+
+/*************************************************
+* PKCS#5 v2.0 PBE Constructor                    *
+*************************************************/
+PBE_PKCS5v20::PBE_PKCS5v20(const std::string& d_algo,
+                           const std::string& c_algo) :
+   direction(ENCRYPTION),
+   digest(global_state().deref_alias(d_algo)),
+   cipher(c_algo)
+   {
+   std::vector<std::string> cipher_spec = split_on(cipher, '/');
+   if(cipher_spec.size() != 2)
+      throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher spec " + cipher);
+   cipher_algo = global_state().deref_alias(cipher_spec[0]);
+   const std::string cipher_mode = cipher_spec[1];
+
+   if(!have_block_cipher(cipher_algo))
+      throw Algorithm_Not_Found(cipher_algo);
+   if(!have_hash(digest))
+      throw Algorithm_Not_Found(digest);
+
+   if(!known_cipher(cipher_algo))
+      throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher " + cipher);
+   if(cipher_mode != "CBC")
+      throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher " + cipher);
+   if(digest != "SHA-160")
+      throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid digest " + digest);
+   }
+
+/*************************************************
+* PKCS#5 v2.0 PBE Constructor                    *
+*************************************************/
+PBE_PKCS5v20::PBE_PKCS5v20(DataSource& params) : direction(DECRYPTION)
+   {
+   decode_params(params);
+   }
+
+}