Shuffle things around. Add NIST X.509 test to build.

23 files changed, 1741 insertions, 0 deletions

diff --git a/lib/constructs/aont/info.txt b/lib/constructs/aont/info.txt
new file mode 100644
index 000000000..fb66d4129
--- /dev/null
+++ b/lib/constructs/aont/info.txt
@@ -0,0 +1,8 @@
+define PACKAGE_TRANSFORM 20131128
+
+<requires>
+block
+ctr
+rng
+filters
+</requires>
diff --git a/lib/constructs/aont/package.cpp b/lib/constructs/aont/package.cpp
new file mode 100644
index 000000000..1adee90e8
--- /dev/null
+++ b/lib/constructs/aont/package.cpp
@@ -0,0 +1,120 @@
+/*
+* Rivest's Package Tranform
+*
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/package.h>
+#include <botan/filters.h>
+#include <botan/ctr.h>
+#include <botan/get_byte.h>
+#include <botan/internal/xor_buf.h>
+
+namespace Botan {
+
+void aont_package(RandomNumberGenerator& rng,
+                  BlockCipher* cipher,
+                  const byte input[], size_t input_len,
+                  byte output[])
+   {
+   const size_t BLOCK_SIZE = cipher->block_size();
+
+   if(!cipher->valid_keylength(BLOCK_SIZE))
+      throw Invalid_Argument("AONT::package: Invalid cipher");
+
+   // The all-zero string which is used both as the CTR IV and as K0
+   const std::string all_zeros(BLOCK_SIZE*2, '0');
+
+   SymmetricKey package_key(rng, BLOCK_SIZE);
+
+   Pipe pipe(new StreamCipher_Filter(new CTR_BE(cipher), package_key));
+
+   pipe.process_msg(input, input_len);
+   pipe.read(output, pipe.remaining());
+
+   // Set K0 (the all zero key)
+   cipher->set_key(SymmetricKey(all_zeros));
+
+   secure_vector<byte> buf(BLOCK_SIZE);
+
+   const size_t blocks =
+      (input_len + BLOCK_SIZE - 1) / BLOCK_SIZE;
+
+   byte* final_block = output + input_len;
+   clear_mem(final_block, BLOCK_SIZE);
+
+   // XOR the hash blocks into the final block
+   for(size_t i = 0; i != blocks; ++i)
+      {
+      const size_t left = std::min<size_t>(BLOCK_SIZE,
+                                           input_len - BLOCK_SIZE * i);
+
+      zeroise(buf);
+      copy_mem(&buf[0], output + (BLOCK_SIZE * i), left);
+
+      for(size_t j = 0; j != sizeof(i); ++j)
+         buf[BLOCK_SIZE - 1 - j] ^= get_byte(sizeof(i)-1-j, i);
+
+      cipher->encrypt(&buf[0]);
+
+      xor_buf(&final_block[0], &buf[0], BLOCK_SIZE);
+      }
+
+   // XOR the random package key into the final block
+   xor_buf(&final_block[0], package_key.begin(), BLOCK_SIZE);
+   }
+
+void aont_unpackage(BlockCipher* cipher,
+                    const byte input[], size_t input_len,
+                    byte output[])
+   {
+   const size_t BLOCK_SIZE = cipher->block_size();
+
+   if(!cipher->valid_keylength(BLOCK_SIZE))
+      throw Invalid_Argument("AONT::unpackage: Invalid cipher");
+
+   if(input_len < BLOCK_SIZE)
+      throw Invalid_Argument("AONT::unpackage: Input too short");
+
+   // The all-zero string which is used both as the CTR IV and as K0
+   const std::string all_zeros(BLOCK_SIZE*2, '0');
+
+   cipher->set_key(SymmetricKey(all_zeros));
+
+   secure_vector<byte> package_key(BLOCK_SIZE);
+   secure_vector<byte> buf(BLOCK_SIZE);
+
+   // Copy the package key (masked with the block hashes)
+   copy_mem(&package_key[0],
+            input + (input_len - BLOCK_SIZE),
+            BLOCK_SIZE);
+
+   const size_t blocks = ((input_len - 1) / BLOCK_SIZE);
+
+   // XOR the blocks into the package key bits
+   for(size_t i = 0; i != blocks; ++i)
+      {
+      const size_t left = std::min<size_t>(BLOCK_SIZE,
+                                           input_len - BLOCK_SIZE * (i+1));
+
+      zeroise(buf);
+      copy_mem(&buf[0], input + (BLOCK_SIZE * i), left);
+
+      for(size_t j = 0; j != sizeof(i); ++j)
+         buf[BLOCK_SIZE - 1 - j] ^= get_byte(sizeof(i)-1-j, i);
+
+      cipher->encrypt(&buf[0]);
+
+      xor_buf(&package_key[0], &buf[0], BLOCK_SIZE);
+      }
+
+   Pipe pipe(new StreamCipher_Filter(new CTR_BE(cipher), package_key));
+
+   pipe.process_msg(input, input_len - BLOCK_SIZE);
+
+   pipe.read(output, pipe.remaining());
+   }
+
+}
diff --git a/lib/constructs/aont/package.h b/lib/constructs/aont/package.h
new file mode 100644
index 000000000..52d1c2190
--- /dev/null
+++ b/lib/constructs/aont/package.h
@@ -0,0 +1,44 @@
+/*
+* Rivest's Package Tranform
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AONT_PACKAGE_TRANSFORM_H__
+#define BOTAN_AONT_PACKAGE_TRANSFORM_H__
+
+#include <botan/block_cipher.h>
+#include <botan/rng.h>
+
+namespace Botan {
+
+/**
+* Rivest's Package Tranform
+* @param rng the random number generator to use
+* @param cipher the block cipher to use
+* @param input the input data buffer
+* @param input_len the length of the input data in bytes
+* @param output the output data buffer (must be at least
+*        input_len + cipher->BLOCK_SIZE bytes long)
+*/
+void BOTAN_DLL aont_package(RandomNumberGenerator& rng,
+                            BlockCipher* cipher,
+                            const byte input[], size_t input_len,
+                            byte output[]);
+
+/**
+* Rivest's Package Tranform (Inversion)
+* @param cipher the block cipher to use
+* @param input the input data buffer
+* @param input_len the length of the input data in bytes
+* @param output the output data buffer (must be at least
+*        input_len - cipher->BLOCK_SIZE bytes long)
+*/
+void BOTAN_DLL aont_unpackage(BlockCipher* cipher,
+                              const byte input[], size_t input_len,
+                              byte output[]);
+
+}
+
+#endif
diff --git a/lib/constructs/cryptobox/cryptobox.cpp b/lib/constructs/cryptobox/cryptobox.cpp
new file mode 100644
index 000000000..aa2369c6c
--- /dev/null
+++ b/lib/constructs/cryptobox/cryptobox.cpp
@@ -0,0 +1,163 @@
+/*
+* Cryptobox Message Routines
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/cryptobox.h>
+#include <botan/filters.h>
+#include <botan/pipe.h>
+#include <botan/lookup.h>
+#include <botan/sha2_64.h>
+#include <botan/hmac.h>
+#include <botan/pbkdf2.h>
+#include <botan/pem.h>
+#include <botan/get_byte.h>
+#include <botan/mem_ops.h>
+
+namespace Botan {
+
+namespace CryptoBox {
+
+namespace {
+
+/*
+First 24 bits of SHA-256("Botan Cryptobox"), followed by 8 0 bits
+for later use as flags, etc if needed
+*/
+const u32bit CRYPTOBOX_VERSION_CODE = 0xEFC22400;
+
+const size_t VERSION_CODE_LEN = 4;
+const size_t CIPHER_KEY_LEN = 32;
+const size_t CIPHER_IV_LEN = 16;
+const size_t MAC_KEY_LEN = 32;
+const size_t MAC_OUTPUT_LEN = 20;
+const size_t PBKDF_SALT_LEN = 10;
+const size_t PBKDF_ITERATIONS = 8 * 1024;
+
+const size_t PBKDF_OUTPUT_LEN = CIPHER_KEY_LEN + CIPHER_IV_LEN + MAC_KEY_LEN;
+
+}
+
+std::string encrypt(const byte input[], size_t input_len,
+                    const std::string& passphrase,
+                    RandomNumberGenerator& rng)
+   {
+   secure_vector<byte> pbkdf_salt(PBKDF_SALT_LEN);
+   rng.randomize(&pbkdf_salt[0], pbkdf_salt.size());
+
+   PKCS5_PBKDF2 pbkdf(new HMAC(new SHA_512));
+
+   OctetString master_key = pbkdf.derive_key(
+      PBKDF_OUTPUT_LEN,
+      passphrase,
+      &pbkdf_salt[0],
+      pbkdf_salt.size(),
+      PBKDF_ITERATIONS);
+
+   const byte* mk = master_key.begin();
+
+   SymmetricKey cipher_key(&mk[0], CIPHER_KEY_LEN);
+   SymmetricKey mac_key(&mk[CIPHER_KEY_LEN], MAC_KEY_LEN);
+   InitializationVector iv(&mk[CIPHER_KEY_LEN + MAC_KEY_LEN], CIPHER_IV_LEN);
+
+   Pipe pipe(get_cipher("Serpent/CTR-BE", cipher_key, iv, ENCRYPTION),
+             new Fork(
+                nullptr,
+                new MAC_Filter(new HMAC(new SHA_512),
+                               mac_key, MAC_OUTPUT_LEN)));
+
+   pipe.process_msg(input, input_len);
+
+   /*
+   Output format is:
+      version # (4 bytes)
+      salt (10 bytes)
+      mac (20 bytes)
+      ciphertext
+   */
+   const size_t ciphertext_len = pipe.remaining(0);
+
+   std::vector<byte> out_buf(VERSION_CODE_LEN +
+                             PBKDF_SALT_LEN +
+                             MAC_OUTPUT_LEN +
+                             ciphertext_len);
+
+   for(size_t i = 0; i != VERSION_CODE_LEN; ++i)
+     out_buf[i] = get_byte(i, CRYPTOBOX_VERSION_CODE);
+
+   copy_mem(&out_buf[VERSION_CODE_LEN], &pbkdf_salt[0],  PBKDF_SALT_LEN);
+
+   pipe.read(&out_buf[VERSION_CODE_LEN + PBKDF_SALT_LEN], MAC_OUTPUT_LEN, 1);
+   pipe.read(&out_buf[VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN],
+             ciphertext_len, 0);
+
+   return PEM_Code::encode(out_buf, "BOTAN CRYPTOBOX MESSAGE");
+   }
+
+std::string decrypt(const byte input[], size_t input_len,
+                    const std::string& passphrase)
+   {
+   DataSource_Memory input_src(input, input_len);
+   secure_vector<byte> ciphertext =
+      PEM_Code::decode_check_label(input_src,
+                                   "BOTAN CRYPTOBOX MESSAGE");
+
+   if(ciphertext.size() < (VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN))
+      throw Decoding_Error("Invalid CryptoBox input");
+
+   for(size_t i = 0; i != VERSION_CODE_LEN; ++i)
+      if(ciphertext[i] != get_byte(i, CRYPTOBOX_VERSION_CODE))
+         throw Decoding_Error("Bad CryptoBox version");
+
+   const byte* pbkdf_salt = &ciphertext[VERSION_CODE_LEN];
+
+   PKCS5_PBKDF2 pbkdf(new HMAC(new SHA_512));
+
+   OctetString master_key = pbkdf.derive_key(
+      PBKDF_OUTPUT_LEN,
+      passphrase,
+      pbkdf_salt,
+      PBKDF_SALT_LEN,
+      PBKDF_ITERATIONS);
+
+   const byte* mk = master_key.begin();
+
+   SymmetricKey cipher_key(&mk[0], CIPHER_KEY_LEN);
+   SymmetricKey mac_key(&mk[CIPHER_KEY_LEN], MAC_KEY_LEN);
+   InitializationVector iv(&mk[CIPHER_KEY_LEN + MAC_KEY_LEN], CIPHER_IV_LEN);
+
+   Pipe pipe(new Fork(
+                get_cipher("Serpent/CTR-BE", cipher_key, iv, DECRYPTION),
+                new MAC_Filter(new HMAC(new SHA_512),
+                               mac_key, MAC_OUTPUT_LEN)));
+
+   const size_t ciphertext_offset =
+      VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN;
+
+   pipe.process_msg(&ciphertext[ciphertext_offset],
+                    ciphertext.size() - ciphertext_offset);
+
+   byte computed_mac[MAC_OUTPUT_LEN];
+   pipe.read(computed_mac, MAC_OUTPUT_LEN, 1);
+
+   if(!same_mem(computed_mac,
+                &ciphertext[VERSION_CODE_LEN + PBKDF_SALT_LEN],
+                MAC_OUTPUT_LEN))
+      throw Decoding_Error("CryptoBox integrity failure");
+
+   return pipe.read_all_as_string(0);
+   }
+
+std::string decrypt(const std::string& input,
+                    const std::string& passphrase)
+   {
+   return decrypt(reinterpret_cast<const byte*>(&input[0]),
+                  input.size(),
+                  passphrase);
+   }
+
+}
+
+}
diff --git a/lib/constructs/cryptobox/cryptobox.h b/lib/constructs/cryptobox/cryptobox.h
new file mode 100644
index 000000000..7a363f72d
--- /dev/null
+++ b/lib/constructs/cryptobox/cryptobox.h
@@ -0,0 +1,55 @@
+/*
+* Cryptobox Message Routines
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_CRYPTOBOX_H__
+#define BOTAN_CRYPTOBOX_H__
+
+#include <string>
+#include <botan/rng.h>
+#include <botan/symkey.h>
+
+namespace Botan {
+
+/**
+* This namespace holds various high-level crypto functions
+*/
+namespace CryptoBox {
+
+/**
+* Encrypt a message using a passphrase
+* @param input the input data
+* @param input_len the length of input in bytes
+* @param passphrase the passphrase used to encrypt the message
+* @param rng a ref to a random number generator, such as AutoSeeded_RNG
+*/
+BOTAN_DLL std::string encrypt(const byte input[], size_t input_len,
+                              const std::string& passphrase,
+                              RandomNumberGenerator& rng);
+
+
+/**
+* Decrypt a message encrypted with CryptoBox::encrypt
+* @param input the input data
+* @param input_len the length of input in bytes
+* @param passphrase the passphrase used to encrypt the message
+*/
+BOTAN_DLL std::string decrypt(const byte input[], size_t input_len,
+                              const std::string& passphrase);
+
+/**
+* Decrypt a message encrypted with CryptoBox::encrypt
+* @param input the input data
+* @param passphrase the passphrase used to encrypt the message
+*/
+BOTAN_DLL std::string decrypt(const std::string& input,
+                              const std::string& passphrase);
+
+}
+
+}
+
+#endif
diff --git a/lib/constructs/cryptobox/info.txt b/lib/constructs/cryptobox/info.txt
new file mode 100644
index 000000000..b7bf6e4e8
--- /dev/null
+++ b/lib/constructs/cryptobox/info.txt
@@ -0,0 +1,13 @@
+define CRYPTO_BOX 20131128
+
+<requires>
+filters
+ctr
+hmac
+rng
+serpent
+sha2_64
+base64
+pbkdf2
+pem
+</requires>
diff --git a/lib/constructs/cryptobox_psk/cryptobox_psk.cpp b/lib/constructs/cryptobox_psk/cryptobox_psk.cpp
new file mode 100644
index 000000000..f22e43b43
--- /dev/null
+++ b/lib/constructs/cryptobox_psk/cryptobox_psk.cpp
@@ -0,0 +1,134 @@
+/*
+* Cryptobox Message Routines
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/cryptobox_psk.h>
+#include <botan/pipe.h>
+#include <botan/lookup.h>
+#include <botan/loadstor.h>
+#include <memory>
+
+namespace Botan {
+
+namespace CryptoBox {
+
+namespace {
+
+const u32bit CRYPTOBOX_MAGIC = 0x571B0E4F;
+const std::string CRYPTOBOX_CIPHER = "AES-256/CBC";
+const std::string CRYPTOBOX_MAC = "HMAC(SHA-256)";
+const std::string CRYPTOBOX_KDF = "KDF2(SHA-256)";
+
+const size_t MAGIC_LENGTH = 4;
+const size_t KEY_KDF_SALT_LENGTH = 10;
+const size_t MAC_KEY_LENGTH = 32;
+const size_t CIPHER_KEY_LENGTH = 32;
+const size_t CIPHER_IV_LENGTH = 16;
+const size_t MAC_OUTPUT_LENGTH = 32;
+
+}
+
+std::vector<byte> encrypt(const byte input[], size_t input_len,
+                          const SymmetricKey& master_key,
+                          RandomNumberGenerator& rng)
+   {
+   std::unique_ptr<KDF> kdf(get_kdf(CRYPTOBOX_KDF));
+
+   const secure_vector<byte> cipher_key_salt =
+      rng.random_vec(KEY_KDF_SALT_LENGTH);
+
+   const secure_vector<byte> mac_key_salt =
+      rng.random_vec(KEY_KDF_SALT_LENGTH);
+
+   SymmetricKey cipher_key =
+      kdf->derive_key(CIPHER_KEY_LENGTH,
+                      master_key.bits_of(),
+                      cipher_key_salt);
+
+   SymmetricKey mac_key =
+      kdf->derive_key(MAC_KEY_LENGTH,
+                      master_key.bits_of(),
+                      mac_key_salt);
+
+   InitializationVector cipher_iv(rng, 16);
+
+   std::unique_ptr<MessageAuthenticationCode> mac(get_mac(CRYPTOBOX_MAC));
+   mac->set_key(mac_key);
+
+   Pipe pipe(get_cipher(CRYPTOBOX_CIPHER, cipher_key, cipher_iv, ENCRYPTION));
+   pipe.process_msg(input, input_len);
+   secure_vector<byte> ctext = pipe.read_all(0);
+
+   std::vector<byte> out(MAGIC_LENGTH);
+   store_be(CRYPTOBOX_MAGIC, &out[0]);
+   out += cipher_key_salt;
+   out += mac_key_salt;
+   out += cipher_iv.bits_of();
+   out += ctext;
+
+   mac->update(out);
+
+   out += mac->final();
+   return out;
+   }
+
+secure_vector<byte> decrypt(const byte input[], size_t input_len,
+                            const SymmetricKey& master_key)
+   {
+   const size_t MIN_CTEXT_SIZE = 16; // due to using CBC with padding
+
+   const size_t MIN_POSSIBLE_LENGTH =
+      MAGIC_LENGTH +
+      2 * KEY_KDF_SALT_LENGTH +
+      CIPHER_IV_LENGTH +
+      MIN_CTEXT_SIZE +
+      MAC_OUTPUT_LENGTH;
+
+   if(input_len < MIN_POSSIBLE_LENGTH)
+      throw Decoding_Error("Encrypted input too short to be valid");
+
+   if(load_be<u32bit>(input, 0) != CRYPTOBOX_MAGIC)
+      throw Decoding_Error("Unknown header value in cryptobox");
+
+   std::unique_ptr<KDF> kdf(get_kdf(CRYPTOBOX_KDF));
+
+   const byte* cipher_key_salt = &input[MAGIC_LENGTH];
+
+   const byte* mac_key_salt = &input[MAGIC_LENGTH + KEY_KDF_SALT_LENGTH];
+
+   SymmetricKey mac_key = kdf->derive_key(MAC_KEY_LENGTH,
+                                          master_key.bits_of(),
+                                          mac_key_salt,
+                                          KEY_KDF_SALT_LENGTH);
+
+   std::unique_ptr<MessageAuthenticationCode> mac(get_mac(CRYPTOBOX_MAC));
+   mac->set_key(mac_key);
+
+   mac->update(&input[0], input_len - MAC_OUTPUT_LENGTH);
+   secure_vector<byte> computed_mac = mac->final();
+
+   if(!same_mem(&input[input_len - MAC_OUTPUT_LENGTH], &computed_mac[0], computed_mac.size()))
+      throw Decoding_Error("MAC verification failed");
+
+   SymmetricKey cipher_key =
+      kdf->derive_key(CIPHER_KEY_LENGTH,
+                      master_key.bits_of(),
+                      cipher_key_salt, KEY_KDF_SALT_LENGTH);
+
+   InitializationVector cipher_iv(&input[MAGIC_LENGTH+2*KEY_KDF_SALT_LENGTH],
+                                  CIPHER_IV_LENGTH);
+
+   const size_t CTEXT_OFFSET = MAGIC_LENGTH + 2 * KEY_KDF_SALT_LENGTH + CIPHER_IV_LENGTH;
+
+   Pipe pipe(get_cipher(CRYPTOBOX_CIPHER, cipher_key, cipher_iv, DECRYPTION));
+   pipe.process_msg(&input[CTEXT_OFFSET],
+                    input_len - (MAC_OUTPUT_LENGTH + CTEXT_OFFSET));
+   return pipe.read_all();
+   }
+
+}
+
+}
diff --git a/lib/constructs/cryptobox_psk/cryptobox_psk.h b/lib/constructs/cryptobox_psk/cryptobox_psk.h
new file mode 100644
index 000000000..2f16ee461
--- /dev/null
+++ b/lib/constructs/cryptobox_psk/cryptobox_psk.h
@@ -0,0 +1,47 @@
+/*
+* Cryptobox Message Routines
+* (C) 2009,2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_CRYPTOBOX_PSK_H__
+#define BOTAN_CRYPTOBOX_PSK_H__
+
+#include <string>
+#include <botan/rng.h>
+#include <botan/symkey.h>
+
+namespace Botan {
+
+/**
+* This namespace holds various high-level crypto functions
+*/
+namespace CryptoBox {
+
+/**
+* Encrypt a message using a shared secret key
+* @param input the input data
+* @param input_len the length of input in bytes
+* @param key the key used to encrypt the message
+* @param rng a ref to a random number generator, such as AutoSeeded_RNG
+*/
+BOTAN_DLL std::vector<byte> encrypt(const byte input[], size_t input_len,
+                                    const SymmetricKey& key,
+                                    RandomNumberGenerator& rng);
+
+/**
+* Encrypt a message using a shared secret key
+* @param input the input data
+* @param input_len the length of input in bytes
+* @param key the key used to encrypt the message
+* @param rng a ref to a random number generator, such as AutoSeeded_RNG
+*/
+BOTAN_DLL secure_vector<byte> decrypt(const byte input[], size_t input_len,
+                                      const SymmetricKey& key);
+
+}
+
+}
+
+#endif
diff --git a/lib/constructs/cryptobox_psk/info.txt b/lib/constructs/cryptobox_psk/info.txt
new file mode 100644
index 000000000..03f7525f5
--- /dev/null
+++ b/lib/constructs/cryptobox_psk/info.txt
@@ -0,0 +1,10 @@
+define CRYPTOBOX_PSK 20131128
+
+<requires>
+aes
+cbc
+hmac
+kdf2
+rng
+sha2_64
+</requires>
diff --git a/lib/constructs/fpe_fe1/fpe_fe1.cpp b/lib/constructs/fpe_fe1/fpe_fe1.cpp
new file mode 100644
index 000000000..b22d3a8df
--- /dev/null
+++ b/lib/constructs/fpe_fe1/fpe_fe1.cpp
@@ -0,0 +1,193 @@
+/*
+* Format Preserving Encryption using the scheme FE1 from the paper
+* "Format-Preserving Encryption" by Bellare, Rogaway, et al
+*    (http://eprint.iacr.org/2009/251)
+*
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/fpe_fe1.h>
+#include <botan/numthry.h>
+#include <botan/hmac.h>
+#include <botan/sha2_32.h>
+#include <stdexcept>
+
+namespace Botan {
+
+namespace FPE {
+
+namespace {
+
+// Normally FPE is for SSNs, CC#s, etc, nothing too big
+const size_t MAX_N_BYTES = 128/8;
+
+/*
+* Factor n into a and b which are as close together as possible.
+* Assumes n is composed mostly of small factors which is the case for
+* typical uses of FPE (typically, n is a power of 10)
+*
+* Want a >= b since the safe number of rounds is 2+log_a(b); if a >= b
+* then this is always 3
+*/
+void factor(BigInt n, BigInt& a, BigInt& b)
+   {
+   a = 1;
+   b = 1;
+
+   size_t n_low_zero = low_zero_bits(n);
+
+   a <<= (n_low_zero / 2);
+   b <<= n_low_zero - (n_low_zero / 2);
+   n >>= n_low_zero;
+
+   for(size_t i = 0; i != PRIME_TABLE_SIZE; ++i)
+      {
+      while(n % PRIMES[i] == 0)
+         {
+         a *= PRIMES[i];
+         if(a > b)
+            std::swap(a, b);
+         n /= PRIMES[i];
+         }
+      }
+
+   if(a > b)
+      std::swap(a, b);
+   a *= n;
+   if(a < b)
+      std::swap(a, b);
+
+   if(a <= 1 || b <= 1)
+      throw std::runtime_error("Could not factor n for use in FPE");
+   }
+
+/*
+* According to a paper by Rogaway, Bellare, etc, the min safe number
+* of rounds to use for FPE is 2+log_a(b). If a >= b then log_a(b) <= 1
+* so 3 rounds is safe. The FPE factorization routine should always
+* return a >= b, so just confirm that and return 3.
+*/
+size_t rounds(const BigInt& a, const BigInt& b)
+   {
+   if(a < b)
+      throw std::logic_error("FPE rounds: a < b");
+   return 3;
+   }
+
+/*
+* A simple round function based on HMAC(SHA-256)
+*/
+class FPE_Encryptor
+   {
+   public:
+      FPE_Encryptor(const SymmetricKey& key,
+                    const BigInt& n,
+                    const std::vector<byte>& tweak);
+
+      ~FPE_Encryptor() { delete mac; }
+
+      BigInt operator()(size_t i, const BigInt& R);
+
+   private:
+      MessageAuthenticationCode* mac;
+      std::vector<byte> mac_n_t;
+   };
+
+FPE_Encryptor::FPE_Encryptor(const SymmetricKey& key,
+                             const BigInt& n,
+                             const std::vector<byte>& tweak)
+   {
+   mac = new HMAC(new SHA_256);
+   mac->set_key(key);
+
+   std::vector<byte> n_bin = BigInt::encode(n);
+
+   if(n_bin.size() > MAX_N_BYTES)
+      throw std::runtime_error("N is too large for FPE encryption");
+
+   mac->update_be(static_cast<u32bit>(n_bin.size()));
+   mac->update(&n_bin[0], n_bin.size());
+
+   mac->update_be(static_cast<u32bit>(tweak.size()));
+   mac->update(&tweak[0], tweak.size());
+
+   mac_n_t = unlock(mac->final());
+   }
+
+BigInt FPE_Encryptor::operator()(size_t round_no, const BigInt& R)
+   {
+   secure_vector<byte> r_bin = BigInt::encode_locked(R);
+
+   mac->update(mac_n_t);
+   mac->update_be(static_cast<u32bit>(round_no));
+
+   mac->update_be(static_cast<u32bit>(r_bin.size()));
+   mac->update(&r_bin[0], r_bin.size());
+
+   secure_vector<byte> X = mac->final();
+   return BigInt(&X[0], X.size());
+   }
+
+}
+
+/*
+* Generic Z_n FPE encryption, FE1 scheme
+*/
+BigInt fe1_encrypt(const BigInt& n, const BigInt& X0,
+                   const SymmetricKey& key,
+                   const std::vector<byte>& tweak)
+   {
+   FPE_Encryptor F(key, n, tweak);
+
+   BigInt a, b;
+   factor(n, a, b);
+
+   const size_t r = rounds(a, b);
+
+   BigInt X = X0;
+
+   for(size_t i = 0; i != r; ++i)
+      {
+      BigInt L = X / b;
+      BigInt R = X % b;
+
+      BigInt W = (L + F(i, R)) % a;
+      X = a * R + W;
+      }
+
+   return X;
+   }
+
+/*
+* Generic Z_n FPE decryption, FD1 scheme
+*/
+BigInt fe1_decrypt(const BigInt& n, const BigInt& X0,
+                   const SymmetricKey& key,
+                   const std::vector<byte>& tweak)
+   {
+   FPE_Encryptor F(key, n, tweak);
+
+   BigInt a, b;
+   factor(n, a, b);
+
+   const size_t r = rounds(a, b);
+
+   BigInt X = X0;
+
+   for(size_t i = 0; i != r; ++i)
+      {
+      BigInt W = X % a;
+      BigInt R = X / a;
+
+      BigInt L = (W - F(r-i-1, R)) % a;
+      X = b * L + R;
+      }
+
+   return X;
+   }
+
+}
+
+}
diff --git a/lib/constructs/fpe_fe1/fpe_fe1.h b/lib/constructs/fpe_fe1/fpe_fe1.h
new file mode 100644
index 000000000..66e7f1cfa
--- /dev/null
+++ b/lib/constructs/fpe_fe1/fpe_fe1.h
@@ -0,0 +1,44 @@
+/*
+* Format Preserving Encryption (FE1 scheme)
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_FPE_FE1_H__
+#define BOTAN_FPE_FE1_H__
+
+#include <botan/bigint.h>
+#include <botan/symkey.h>
+
+namespace Botan {
+
+namespace FPE {
+
+/**
+* Encrypt X from and onto the group Z_n using key and tweak
+* @param n the modulus
+* @param X the plaintext as a BigInt
+* @param key a random key
+* @param tweak will modify the ciphertext (think of as an IV)
+*/
+BigInt BOTAN_DLL fe1_encrypt(const BigInt& n, const BigInt& X,
+                             const SymmetricKey& key,
+                             const std::vector<byte>& tweak);
+
+/**
+* Decrypt X from and onto the group Z_n using key and tweak
+* @param n the modulus
+* @param X the ciphertext as a BigInt
+* @param key is the key used for encryption
+* @param tweak the same tweak used for encryption
+*/
+BigInt BOTAN_DLL fe1_decrypt(const BigInt& n, const BigInt& X,
+                             const SymmetricKey& key,
+                             const std::vector<byte>& tweak);
+
+}
+
+}
+
+#endif
diff --git a/lib/constructs/fpe_fe1/info.txt b/lib/constructs/fpe_fe1/info.txt
new file mode 100644
index 000000000..42264e54e
--- /dev/null
+++ b/lib/constructs/fpe_fe1/info.txt
@@ -0,0 +1,7 @@
+define FPE_FE1 20131128
+
+<requires>
+hmac
+sha2_32
+bigint
+</requires>
diff --git a/lib/constructs/rfc3394/info.txt b/lib/constructs/rfc3394/info.txt
new file mode 100644
index 000000000..4b62b16e3
--- /dev/null
+++ b/lib/constructs/rfc3394/info.txt
@@ -0,0 +1 @@
+define RFC3394_KEYWRAP 20131128
diff --git a/lib/constructs/rfc3394/rfc3394.cpp b/lib/constructs/rfc3394/rfc3394.cpp
new file mode 100644
index 000000000..cfe95f40b
--- /dev/null
+++ b/lib/constructs/rfc3394/rfc3394.cpp
@@ -0,0 +1,122 @@
+/*
+* AES Key Wrap (RFC 3394)
+* (C) 2011 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/rfc3394.h>
+#include <botan/algo_factory.h>
+#include <botan/block_cipher.h>
+#include <botan/loadstor.h>
+#include <botan/exceptn.h>
+#include <botan/internal/xor_buf.h>
+#include <memory>
+
+namespace Botan {
+
+namespace {
+
+BlockCipher* make_aes(size_t keylength,
+                      Algorithm_Factory& af)
+   {
+   if(keylength == 16)
+      return af.make_block_cipher("AES-128");
+   else if(keylength == 24)
+      return af.make_block_cipher("AES-192");
+   else if(keylength == 32)
+      return af.make_block_cipher("AES-256");
+   else
+      throw std::invalid_argument("Bad KEK length for NIST keywrap");
+   }
+
+}
+
+secure_vector<byte> rfc3394_keywrap(const secure_vector<byte>& key,
+                                    const SymmetricKey& kek,
+                                    Algorithm_Factory& af)
+   {
+   if(key.size() % 8 != 0)
+      throw std::invalid_argument("Bad input key size for NIST key wrap");
+
+   std::unique_ptr<BlockCipher> aes(make_aes(kek.length(), af));
+   aes->set_key(kek);
+
+   const size_t n = key.size() / 8;
+
+   secure_vector<byte> R((n + 1) * 8);
+   secure_vector<byte> A(16);
+
+   for(size_t i = 0; i != 8; ++i)
+      A[i] = 0xA6;
+
+   copy_mem(&R[8], &key[0], key.size());
+
+   for(size_t j = 0; j <= 5; ++j)
+      {
+      for(size_t i = 1; i <= n; ++i)
+         {
+         const u32bit t = (n * j) + i;
+
+         copy_mem(&A[8], &R[8*i], 8);
+
+         aes->encrypt(&A[0]);
+         copy_mem(&R[8*i], &A[8], 8);
+
+         byte t_buf[4] = { 0 };
+         store_be(t, t_buf);
+         xor_buf(&A[4], &t_buf[0], 4);
+         }
+      }
+
+   copy_mem(&R[0], &A[0], 8);
+
+   return R;
+   }
+
+secure_vector<byte> rfc3394_keyunwrap(const secure_vector<byte>& key,
+                                     const SymmetricKey& kek,
+                                     Algorithm_Factory& af)
+   {
+   if(key.size() < 16 || key.size() % 8 != 0)
+      throw std::invalid_argument("Bad input key size for NIST key unwrap");
+
+   std::unique_ptr<BlockCipher> aes(make_aes(kek.length(), af));
+   aes->set_key(kek);
+
+   const size_t n = (key.size() - 8) / 8;
+
+   secure_vector<byte> R(n * 8);
+   secure_vector<byte> A(16);
+
+   for(size_t i = 0; i != 8; ++i)
+      A[i] = key[i];
+
+   copy_mem(&R[0], &key[8], key.size() - 8);
+
+   for(size_t j = 0; j <= 5; ++j)
+      {
+      for(size_t i = n; i != 0; --i)
+         {
+         const u32bit t = (5 - j) * n + i;
+
+         byte t_buf[4] = { 0 };
+         store_be(t, t_buf);
+
+         xor_buf(&A[4], &t_buf[0], 4);
+
+         copy_mem(&A[8], &R[8*(i-1)], 8);
+
+         aes->decrypt(&A[0]);
+
+         copy_mem(&R[8*(i-1)], &A[8], 8);
+         }
+      }
+
+   if(load_be<u64bit>(&A[0], 0) != 0xA6A6A6A6A6A6A6A6)
+      throw Integrity_Failure("NIST key unwrap failed");
+
+   return R;
+   }
+
+}
diff --git a/lib/constructs/rfc3394/rfc3394.h b/lib/constructs/rfc3394/rfc3394.h
new file mode 100644
index 000000000..febd5207e
--- /dev/null
+++ b/lib/constructs/rfc3394/rfc3394.h
@@ -0,0 +1,45 @@
+/*
+* AES Key Wrap (RFC 3394)
+* (C) 2011 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AES_KEY_WRAP_H__
+#define BOTAN_AES_KEY_WRAP_H__
+
+#include <botan/symkey.h>
+
+namespace Botan {
+
+class Algorithm_Factory;
+
+/**
+* Encrypt a key under a key encryption key using the algorithm
+* described in RFC 3394
+*
+* @param key the plaintext key to encrypt
+* @param kek the key encryption key
+* @param af an algorithm factory
+* @return key encrypted under kek
+*/
+secure_vector<byte> BOTAN_DLL rfc3394_keywrap(const secure_vector<byte>& key,
+                                             const SymmetricKey& kek,
+                                             Algorithm_Factory& af);
+
+/**
+* Decrypt a key under a key encryption key using the algorithm
+* described in RFC 3394
+*
+* @param key the encrypted key to decrypt
+* @param kek the key encryption key
+* @param af an algorithm factory
+* @return key decrypted under kek
+*/
+secure_vector<byte> BOTAN_DLL rfc3394_keyunwrap(const secure_vector<byte>& key,
+                                               const SymmetricKey& kek,
+                                               Algorithm_Factory& af);
+
+}
+
+#endif
diff --git a/lib/constructs/srp6/info.txt b/lib/constructs/srp6/info.txt
new file mode 100644
index 000000000..1d1c4ba96
--- /dev/null
+++ b/lib/constructs/srp6/info.txt
@@ -0,0 +1,7 @@
+define SRP6 20131128
+
+<requires>
+bigint
+hash
+dl_group
+</requires>
diff --git a/lib/constructs/srp6/srp6.cpp b/lib/constructs/srp6/srp6.cpp
new file mode 100644
index 000000000..7bc879350
--- /dev/null
+++ b/lib/constructs/srp6/srp6.cpp
@@ -0,0 +1,163 @@
+/*
+* SRP-6a (RFC 5054 compatatible)
+* (C) 2011,2012 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/srp6.h>
+#include <botan/dl_group.h>
+#include <botan/libstate.h>
+#include <botan/numthry.h>
+#include <memory>
+
+namespace Botan {
+
+namespace {
+
+BigInt hash_seq(const std::string& hash_id,
+                size_t pad_to,
+                const BigInt& in1,
+                const BigInt& in2)
+   {
+   std::unique_ptr<HashFunction> hash_fn(
+      global_state().algorithm_factory().make_hash_function(hash_id));
+
+   hash_fn->update(BigInt::encode_1363(in1, pad_to));
+   hash_fn->update(BigInt::encode_1363(in2, pad_to));
+
+   return BigInt::decode(hash_fn->final());
+   }
+
+BigInt compute_x(const std::string& hash_id,
+                 const std::string& identifier,
+                 const std::string& password,
+                 const std::vector<byte>& salt)
+   {
+   std::unique_ptr<HashFunction> hash_fn(
+      global_state().algorithm_factory().make_hash_function(hash_id));
+
+   hash_fn->update(identifier);
+   hash_fn->update(":");
+   hash_fn->update(password);
+
+   secure_vector<byte> inner_h = hash_fn->final();
+
+   hash_fn->update(salt);
+   hash_fn->update(inner_h);
+
+   secure_vector<byte> outer_h = hash_fn->final();
+
+   return BigInt::decode(outer_h);
+   }
+
+}
+
+std::string srp6_group_identifier(const BigInt& N, const BigInt& g)
+   {
+   /*
+   This function assumes that only one 'standard' SRP parameter set has
+   been defined for a particular bitsize. As of this writing that is the case.
+   */
+   try
+      {
+      const std::string group_name = "modp/srp/" + std::to_string(N.bits());
+
+      DL_Group group(group_name);
+
+      if(group.get_p() == N && group.get_g() == g)
+         return group_name;
+
+      throw std::runtime_error("Unknown SRP params");
+      }
+   catch(...)
+      {
+      throw Invalid_Argument("Bad SRP group parameters");
+      }
+   }
+
+std::pair<BigInt, SymmetricKey>
+srp6_client_agree(const std::string& identifier,
+                  const std::string& password,
+                  const std::string& group_id,
+                  const std::string& hash_id,
+                  const std::vector<byte>& salt,
+                  const BigInt& B,
+                  RandomNumberGenerator& rng)
+   {
+   DL_Group group(group_id);
+   const BigInt& g = group.get_g();
+   const BigInt& p = group.get_p();
+
+   const size_t p_bytes = group.get_p().bytes();
+
+   if(B <= 0 || B >= p)
+      throw std::runtime_error("Invalid SRP parameter from server");
+
+   BigInt k = hash_seq(hash_id, p_bytes, p, g);
+
+   BigInt a(rng, 256);
+
+   BigInt A = power_mod(g, a, p);
+
+   BigInt u = hash_seq(hash_id, p_bytes, A, B);
+
+   const BigInt x = compute_x(hash_id, identifier, password, salt);
+
+   BigInt S = power_mod((B - (k * power_mod(g, x, p))) % p, (a + (u * x)), p);
+
+   SymmetricKey Sk(BigInt::encode_1363(S, p_bytes));
+
+   return std::make_pair(A, Sk);
+   }
+
+BigInt generate_srp6_verifier(const std::string& identifier,
+                              const std::string& password,
+                              const std::vector<byte>& salt,
+                              const std::string& group_id,
+                              const std::string& hash_id)
+   {
+   const BigInt x = compute_x(hash_id, identifier, password, salt);
+
+   DL_Group group(group_id);
+   return power_mod(group.get_g(), x, group.get_p());
+   }
+
+BigInt SRP6_Server_Session::step1(const BigInt& v,
+                                  const std::string& group_id,
+                                  const std::string& hash_id,
+                                  RandomNumberGenerator& rng)
+   {
+   DL_Group group(group_id);
+   const BigInt& g = group.get_g();
+   const BigInt& p = group.get_p();
+
+   p_bytes = p.bytes();
+
+   BigInt k = hash_seq(hash_id, p_bytes, p, g);
+
+   BigInt b(rng, 256);
+
+   B = (v*k + power_mod(g, b, p)) % p;
+
+   this->v = v;
+   this->b = b;
+   this->p = p;
+   this->hash_id = hash_id;
+
+   return B;
+   }
+
+SymmetricKey SRP6_Server_Session::step2(const BigInt& A)
+   {
+   if(A <= 0 || A >= p)
+      throw std::runtime_error("Invalid SRP parameter from client");
+
+   BigInt u = hash_seq(hash_id, p_bytes, A, B);
+
+   BigInt S = power_mod(A * power_mod(v, u, p), b, p);
+
+   return BigInt::encode_1363(S, p_bytes);
+   }
+
+}
diff --git a/lib/constructs/srp6/srp6.h b/lib/constructs/srp6/srp6.h
new file mode 100644
index 000000000..6f3960be1
--- /dev/null
+++ b/lib/constructs/srp6/srp6.h
@@ -0,0 +1,97 @@
+/*
+* SRP-6a (RFC 5054 compatatible)
+* (C) 2011,2012 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_RFC5054_SRP6_H__
+#define BOTAN_RFC5054_SRP6_H__
+
+#include <botan/bigint.h>
+#include <botan/hash.h>
+#include <botan/rng.h>
+#include <botan/symkey.h>
+#include <string>
+
+namespace Botan {
+
+/**
+* SRP6a Client side
+* @param username the username we are attempting login for
+* @param password the password we are attempting to use
+* @param group_id specifies the shared SRP group
+* @param hash_id specifies a secure hash function
+* @param salt is the salt value sent by the server
+* @param B is the server's public value
+* @param rng is a random number generator
+*
+* @return (A,K) the client public key and the shared secret key
+*/
+std::pair<BigInt,SymmetricKey>
+BOTAN_DLL srp6_client_agree(const std::string& username,
+                            const std::string& password,
+                            const std::string& group_id,
+                            const std::string& hash_id,
+                            const std::vector<byte>& salt,
+                            const BigInt& B,
+                            RandomNumberGenerator& rng);
+
+/**
+* Generate a new SRP-6 verifier
+* @param identifier a username or other client identifier
+* @param password the secret used to authenticate user
+* @param salt a randomly chosen value, at least 128 bits long
+* @param group_id specifies the shared SRP group
+* @param hash_id specifies a secure hash function
+*/
+BigInt BOTAN_DLL generate_srp6_verifier(const std::string& identifier,
+                                        const std::string& password,
+                                        const std::vector<byte>& salt,
+                                        const std::string& group_id,
+                                        const std::string& hash_id);
+
+/**
+* Return the group id for this SRP param set, or else thrown an
+* exception
+* @param N the group modulus
+* @param g the group generator
+* @return group identifier
+*/
+std::string BOTAN_DLL srp6_group_identifier(const BigInt& N, const BigInt& g);
+
+/**
+* Represents a SRP-6a server session
+*/
+class BOTAN_DLL SRP6_Server_Session
+   {
+   public:
+      /**
+      * Server side step 1
+      * @param v the verification value saved from client registration
+      * @param group_id the SRP group id
+      * @param hash_id the SRP hash in use
+      * @param rng a random number generator
+      * @return SRP-6 B value
+      */
+      BigInt step1(const BigInt& v,
+                   const std::string& group_id,
+                   const std::string& hash_id,
+                   RandomNumberGenerator& rng);
+
+      /**
+      * Server side step 2
+      * @param A the client's value
+      * @return shared symmetric key
+      */
+      SymmetricKey step2(const BigInt& A);
+
+   private:
+      std::string hash_id;
+      BigInt B, b, v, S, p;
+      size_t p_bytes;
+   };
+
+}
+
+#endif
diff --git a/lib/constructs/srp6/srp6_files.cpp b/lib/constructs/srp6/srp6_files.cpp
new file mode 100644
index 000000000..4df2986f3
--- /dev/null
+++ b/lib/constructs/srp6/srp6_files.cpp
@@ -0,0 +1,69 @@
+/*
+* SRP-6a File Handling
+* (C) 2011 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/srp6_files.h>
+#include <botan/parsing.h>
+#include <botan/base64.h>
+#include <fstream>
+
+namespace Botan {
+
+SRP6_Authenticator_File::SRP6_Authenticator_File(const std::string& filename)
+   {
+   std::ifstream in(filename.c_str());
+
+   if(!in)
+      return; // no entries
+
+   while(in.good())
+      {
+      std::string line;
+      std::getline(in, line);
+
+      std::vector<std::string> parts = split_on(line, ':');
+
+      if(parts.size() != 4)
+         throw Decoding_Error("Invalid line in SRP authenticator file");
+
+      std::string username = parts[0];
+      BigInt v = BigInt::decode(base64_decode(parts[1]));
+      std::vector<byte> salt = unlock(base64_decode(parts[2]));
+      BigInt group_id_idx = BigInt::decode(base64_decode(parts[3]));
+
+      std::string group_id;
+
+      if(group_id_idx == 1)
+         group_id = "modp/srp/1024";
+      else if(group_id_idx == 2)
+         group_id = "modp/srp/1536";
+      else if(group_id_idx == 3)
+         group_id = "modp/srp/2048";
+      else
+         continue; // unknown group, ignored
+
+      entries[username] = SRP6_Data(v, salt, group_id);
+      }
+   }
+
+bool SRP6_Authenticator_File::lookup_user(const std::string& username,
+                                          BigInt& v,
+                                          std::vector<byte>& salt,
+                                          std::string& group_id) const
+   {
+   std::map<std::string, SRP6_Data>::const_iterator i = entries.find(username);
+
+   if(i == entries.end())
+      return false;
+
+   v = i->second.v;
+   salt = i->second.salt;
+   group_id = i->second.group_id;
+
+   return true;
+   }
+
+}
diff --git a/lib/constructs/srp6/srp6_files.h b/lib/constructs/srp6/srp6_files.h
new file mode 100644
index 000000000..4e0d3ff02
--- /dev/null
+++ b/lib/constructs/srp6/srp6_files.h
@@ -0,0 +1,53 @@
+/*
+* SRP-6a File Handling
+* (C) 2011 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_SRP6A_FILES_H__
+#define BOTAN_SRP6A_FILES_H__
+
+#include <botan/bigint.h>
+#include <string>
+#include <map>
+
+namespace Botan {
+
+/**
+* A GnuTLS compatible SRP6 authenticator file
+*/
+class BOTAN_DLL SRP6_Authenticator_File
+   {
+   public:
+      /**
+      * @param filename will be opened and processed as a SRP
+      * authenticator file
+      */
+      SRP6_Authenticator_File(const std::string& filename);
+
+      bool lookup_user(const std::string& username,
+                       BigInt& v,
+                       std::vector<byte>& salt,
+                       std::string& group_id) const;
+   private:
+      struct SRP6_Data
+         {
+         SRP6_Data() {}
+
+         SRP6_Data(const BigInt& v,
+                   const std::vector<byte>& salt,
+                   const std::string& group_id) :
+            v(v), salt(salt), group_id(group_id) {}
+
+         BigInt v;
+         std::vector<byte> salt;
+         std::string group_id;
+         };
+
+      std::map<std::string, SRP6_Data> entries;
+   };
+
+}
+
+#endif
diff --git a/lib/constructs/tss/info.txt b/lib/constructs/tss/info.txt
new file mode 100644
index 000000000..0c86bebbe
--- /dev/null
+++ b/lib/constructs/tss/info.txt
@@ -0,0 +1,8 @@
+define THRESHOLD_SECRET_SHARING 20131128
+
+<requires>
+hash
+rng
+filters
+hex
+</requires>
diff --git a/lib/constructs/tss/tss.cpp b/lib/constructs/tss/tss.cpp
new file mode 100644
index 000000000..2024b39ec
--- /dev/null
+++ b/lib/constructs/tss/tss.cpp
@@ -0,0 +1,262 @@
+/*
+* RTSS (threshold secret sharing)
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/tss.h>
+#include <botan/loadstor.h>
+#include <botan/pipe.h>
+#include <botan/hex.h>
+#include <botan/sha2_32.h>
+#include <botan/sha160.h>
+#include <memory>
+
+namespace Botan {
+
+namespace {
+
+/**
+Table for GF(2^8) arithmetic (exponentials)
+*/
+const byte RTSS_EXP[256] = {
+0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72,
+0x96, 0xA1, 0xF8, 0x13, 0x35, 0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73,
+0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA, 0xE5,
+0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70,
+0x90, 0xAB, 0xE6, 0x31, 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44,
+0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD, 0x4C, 0xD4,
+0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18,
+0x28, 0x78, 0x88, 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F,
+0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A, 0xB5, 0xC4, 0x57,
+0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6,
+0x61, 0xA3, 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F,
+0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0, 0xFB, 0x16, 0x3A, 0x4E,
+0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F,
+0x41, 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED,
+0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75, 0x9F, 0xBA, 0xD5, 0x64, 0xAC,
+0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80,
+0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F,
+0xB1, 0xC8, 0x43, 0xC5, 0x54, 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4,
+0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA, 0x45,
+0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42,
+0xC6, 0x51, 0xF3, 0x0E, 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D,
+0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17, 0x39, 0x4B,
+0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7,
+0x52, 0xF6, 0x01 };
+
+/**
+Table for GF(2^8) arithmetic (logarithms)
+*/
+const byte RTSS_LOG[] = {
+0x90, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1A, 0xC6, 0x4B, 0xC7, 0x1B,
+0x68, 0x33, 0xEE, 0xDF, 0x03, 0x64, 0x04, 0xE0, 0x0E, 0x34, 0x8D,
+0x81, 0xEF, 0x4C, 0x71, 0x08, 0xC8, 0xF8, 0x69, 0x1C, 0xC1, 0x7D,
+0xC2, 0x1D, 0xB5, 0xF9, 0xB9, 0x27, 0x6A, 0x4D, 0xE4, 0xA6, 0x72,
+0x9A, 0xC9, 0x09, 0x78, 0x65, 0x2F, 0x8A, 0x05, 0x21, 0x0F, 0xE1,
+0x24, 0x12, 0xF0, 0x82, 0x45, 0x35, 0x93, 0xDA, 0x8E, 0x96, 0x8F,
+0xDB, 0xBD, 0x36, 0xD0, 0xCE, 0x94, 0x13, 0x5C, 0xD2, 0xF1, 0x40,
+0x46, 0x83, 0x38, 0x66, 0xDD, 0xFD, 0x30, 0xBF, 0x06, 0x8B, 0x62,
+0xB3, 0x25, 0xE2, 0x98, 0x22, 0x88, 0x91, 0x10, 0x7E, 0x6E, 0x48,
+0xC3, 0xA3, 0xB6, 0x1E, 0x42, 0x3A, 0x6B, 0x28, 0x54, 0xFA, 0x85,
+0x3D, 0xBA, 0x2B, 0x79, 0x0A, 0x15, 0x9B, 0x9F, 0x5E, 0xCA, 0x4E,
+0xD4, 0xAC, 0xE5, 0xF3, 0x73, 0xA7, 0x57, 0xAF, 0x58, 0xA8, 0x50,
+0xF4, 0xEA, 0xD6, 0x74, 0x4F, 0xAE, 0xE9, 0xD5, 0xE7, 0xE6, 0xAD,
+0xE8, 0x2C, 0xD7, 0x75, 0x7A, 0xEB, 0x16, 0x0B, 0xF5, 0x59, 0xCB,
+0x5F, 0xB0, 0x9C, 0xA9, 0x51, 0xA0, 0x7F, 0x0C, 0xF6, 0x6F, 0x17,
+0xC4, 0x49, 0xEC, 0xD8, 0x43, 0x1F, 0x2D, 0xA4, 0x76, 0x7B, 0xB7,
+0xCC, 0xBB, 0x3E, 0x5A, 0xFB, 0x60, 0xB1, 0x86, 0x3B, 0x52, 0xA1,
+0x6C, 0xAA, 0x55, 0x29, 0x9D, 0x97, 0xB2, 0x87, 0x90, 0x61, 0xBE,
+0xDC, 0xFC, 0xBC, 0x95, 0xCF, 0xCD, 0x37, 0x3F, 0x5B, 0xD1, 0x53,
+0x39, 0x84, 0x3C, 0x41, 0xA2, 0x6D, 0x47, 0x14, 0x2A, 0x9E, 0x5D,
+0x56, 0xF2, 0xD3, 0xAB, 0x44, 0x11, 0x92, 0xD9, 0x23, 0x20, 0x2E,
+0x89, 0xB4, 0x7C, 0xB8, 0x26, 0x77, 0x99, 0xE3, 0xA5, 0x67, 0x4A,
+0xED, 0xDE, 0xC5, 0x31, 0xFE, 0x18, 0x0D, 0x63, 0x8C, 0x80, 0xC0,
+0xF7, 0x70, 0x07 };
+
+byte gfp_mul(byte x, byte y)
+   {
+   if(x == 0 || y == 0)
+      return 0;
+   return RTSS_EXP[(RTSS_LOG[x] + RTSS_LOG[y]) % 255];
+   }
+
+byte rtss_hash_id(const std::string& hash_name)
+   {
+   if(hash_name == "SHA-160")
+      return 1;
+   else if(hash_name == "SHA-256")
+      return 2;
+   else
+      throw Invalid_Argument("RTSS only supports SHA-1 and SHA-256");
+   }
+
+HashFunction* get_rtss_hash_by_id(byte id)
+   {
+   if(id == 1)
+      return new SHA_160;
+   else if(id == 2)
+      return new SHA_256;
+   else
+      throw Decoding_Error("Bad RTSS hash identifier");
+   }
+
+}
+
+RTSS_Share::RTSS_Share(const std::string& hex_input)
+   {
+   contents = hex_decode_locked(hex_input);
+   }
+
+byte RTSS_Share::share_id() const
+   {
+   if(!initialized())
+      throw Invalid_State("RTSS_Share::share_id not initialized");
+
+   return contents[20];
+   }
+
+std::string RTSS_Share::to_string() const
+   {
+   return hex_encode(&contents[0], contents.size());
+   }
+
+std::vector<RTSS_Share>
+RTSS_Share::split(byte M, byte N,
+                  const byte S[], u16bit S_len,
+                  const byte identifier[16],
+                  RandomNumberGenerator& rng)
+   {
+   if(M == 0 || N == 0 || M > N)
+      throw Encoding_Error("RTSS_Share::split: M == 0 or N == 0 or M > N");
+
+   SHA_256 hash; // always use SHA-256 when generating shares
+
+   std::vector<RTSS_Share> shares(N);
+
+   // Create RTSS header in each share
+   for(byte i = 0; i != N; ++i)
+      {
+      shares[i].contents += std::make_pair(identifier, 16);
+      shares[i].contents += rtss_hash_id(hash.name());
+      shares[i].contents += M;
+      shares[i].contents += get_byte(0, S_len);
+      shares[i].contents += get_byte(1, S_len);
+      }
+
+   // Choose sequential values for X starting from 1
+   for(byte i = 0; i != N; ++i)
+      shares[i].contents.push_back(i+1);
+
+   // secret = S || H(S)
+   secure_vector<byte> secret(S, S + S_len);
+   secret += hash.process(S, S_len);
+
+   for(size_t i = 0; i != secret.size(); ++i)
+      {
+      std::vector<byte> coefficients(M-1);
+      rng.randomize(&coefficients[0], coefficients.size());
+
+      for(byte j = 0; j != N; ++j)
+         {
+         const byte X = j + 1;
+
+         byte sum = secret[i];
+         byte X_i = X;
+
+         for(size_t k = 0; k != coefficients.size(); ++k)
+            {
+            sum ^= gfp_mul(X_i, coefficients[k]);
+            X_i  = gfp_mul(X_i, X);
+            }
+
+         shares[j].contents.push_back(sum);
+         }
+      }
+
+   return shares;
+   }
+
+secure_vector<byte>
+RTSS_Share::reconstruct(const std::vector<RTSS_Share>& shares)
+   {
+   const size_t RTSS_HEADER_SIZE = 20;
+
+   for(size_t i = 0; i != shares.size(); ++i)
+      {
+      if(shares[i].size() != shares[0].size())
+         throw Decoding_Error("Different sized RTSS shares detected");
+      if(shares[i].share_id() == 0)
+         throw Decoding_Error("Invalid (id = 0) RTSS share detected");
+      if(shares[i].size() < RTSS_HEADER_SIZE)
+         throw Decoding_Error("Missing or malformed RTSS header");
+
+      if(!same_mem(&shares[0].contents[0],
+                   &shares[i].contents[0], RTSS_HEADER_SIZE))
+         throw Decoding_Error("Different RTSS headers detected");
+      }
+
+   if(shares.size() < shares[0].contents[17])
+      throw Decoding_Error("Insufficient shares to do TSS reconstruction");
+
+   u16bit secret_len = make_u16bit(shares[0].contents[18],
+                                   shares[0].contents[19]);
+
+   byte hash_id = shares[0].contents[16];
+
+   std::unique_ptr<HashFunction> hash(get_rtss_hash_by_id(hash_id));
+
+   if(shares[0].size() != secret_len + hash->output_length() + RTSS_HEADER_SIZE + 1)
+      throw Decoding_Error("Bad RTSS length field in header");
+
+   std::vector<byte> V(shares.size());
+   secure_vector<byte> secret;
+
+   for(size_t i = RTSS_HEADER_SIZE + 1; i != shares[0].size(); ++i)
+      {
+      for(size_t j = 0; j != V.size(); ++j)
+         V[j] = shares[j].contents[i];
+
+      byte r = 0;
+      for(size_t k = 0; k != shares.size(); ++k)
+         {
+         // L_i function:
+         byte r2 = 1;
+         for(size_t l = 0; l != shares.size(); ++l)
+            {
+            if(k == l)
+               continue;
+
+            byte share_k = shares[k].share_id();
+            byte share_l = shares[l].share_id();
+
+            if(share_k == share_l)
+               throw Decoding_Error("Duplicate shares found in RTSS recovery");
+
+            byte div = RTSS_EXP[(255 +
+                                 RTSS_LOG[share_l] -
+                                 RTSS_LOG[share_k ^ share_l]) % 255];
+
+            r2 = gfp_mul(r2, div);
+            }
+
+         r ^= gfp_mul(V[k], r2);
+         }
+      secret.push_back(r);
+      }
+
+   if(secret.size() != secret_len + hash->output_length())
+      throw Decoding_Error("Bad length in RTSS output");
+
+   hash->update(&secret[0], secret_len);
+   secure_vector<byte> hash_check = hash->final();
+
+   if(!same_mem(&hash_check[0],
+                &secret[secret_len], hash->output_length()))
+      throw Decoding_Error("RTSS hash check failed");
+
+   return secure_vector<byte>(&secret[0], &secret[secret_len]);
+   }
+
+}
diff --git a/lib/constructs/tss/tss.h b/lib/constructs/tss/tss.h
new file mode 100644
index 000000000..4664af317
--- /dev/null
+++ b/lib/constructs/tss/tss.h
@@ -0,0 +1,76 @@
+/*
+* RTSS (threshold secret sharing)
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_RTSS_H__
+#define BOTAN_RTSS_H__
+
+#include <botan/secmem.h>
+#include <botan/hash.h>
+#include <botan/rng.h>
+#include <vector>
+
+namespace Botan {
+
+/**
+* A split secret, using the format from draft-mcgrew-tss-03
+*/
+class BOTAN_DLL RTSS_Share
+   {
+   public:
+      /**
+      * @param M the number of shares needed to reconstruct
+      * @param N the number of shares generated
+      * @param secret the secret to split
+      * @param secret_len the length of the secret
+      * @param identifier the 16 byte share identifier
+      * @param rng the random number generator to use
+      */
+      static std::vector<RTSS_Share>
+         split(byte M, byte N,
+               const byte secret[], u16bit secret_len,
+               const byte identifier[16],
+               RandomNumberGenerator& rng);
+
+      /**
+      * @param shares the list of shares
+      */
+      static secure_vector<byte>
+        reconstruct(const std::vector<RTSS_Share>& shares);
+
+      RTSS_Share() {}
+
+      /**
+      * @param hex_input the share encoded in hexadecimal
+      */
+      RTSS_Share(const std::string& hex_input);
+
+      /**
+      * @return hex representation
+      */
+      std::string to_string() const;
+
+      /**
+      * @return share identifier
+      */
+      byte share_id() const;
+
+      /**
+      * @return size of this share in bytes
+      */
+      size_t size() const { return contents.size(); }
+
+      /**
+      * @return if this TSS share was initialized or not
+      */
+      bool initialized() const { return (contents.size() > 0); }
+   private:
+      secure_vector<byte> contents;
+   };
+
+}
+
+#endif