Add shared_ptr for DL_Group state

Add precomputations for mod-p math and g^x%p calcualations.

1 files changed, 119 insertions, 68 deletions

diff --git a/src/lib/pubkey/dl_group/dl_group.h b/src/lib/pubkey/dl_group/dl_group.h
index 24b829bd9..823c0ba95 100644
--- a/src/lib/pubkey/dl_group/dl_group.h
+++ b/src/lib/pubkey/dl_group/dl_group.h
@@ -1,6 +1,6 @@
 /*
 * Discrete Logarithm Group
-* (C) 1999-2008 Jack Lloyd
+* (C) 1999-2008,2018 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -12,31 +12,20 @@
 
 namespace Botan {
 
+class DL_Group_Data;
+
 /**
-* This class represents discrete logarithm groups. It holds a prime p,
-* a prime q = (p-1)/2 and g = x^((p-1)/q) mod p.
+* This class represents discrete logarithm groups. It holds a prime
+* modulus p, a generator g, and (optionally) a prime q which is a
+* factor of (p-1). In most cases g generates the order-q subgroup.
 */
 class BOTAN_PUBLIC_API(2,0) DL_Group final
    {
    public:
-
-      /**
-      * Get the prime p.
-      * @return prime p
-      */
-      const BigInt& get_p() const;
-
       /**
-      * Get the prime q.
-      * @return prime q
-      */
-      const BigInt& get_q() const;
-
-      /**
-      * Get the base g.
-      * @return base g
+      * Determine the prime creation for DL groups.
       */
-      const BigInt& get_g() const;
+      enum PrimeType { Strong, Prime_Subgroup, DSA_Kosherizer };
 
       /**
       * The DL group encoding format variants.
@@ -53,52 +42,11 @@ class BOTAN_PUBLIC_API(2,0) DL_Group final
       };
 
       /**
-      * Determine the prime creation for DL groups.
-      */
-      enum PrimeType { Strong, Prime_Subgroup, DSA_Kosherizer };
-
-      /**
-      * Perform validity checks on the group.
-      * @param rng the rng to use
-      * @param strong whether to perform stronger by lengthier tests
-      * @return true if the object is consistent, false otherwise
-      */
-      bool verify_group(RandomNumberGenerator& rng, bool strong) const;
-
-      /**
-      * Encode this group into a string using PEM encoding.
-      * @param format the encoding format
-      * @return string holding the PEM encoded group
-      */
-      std::string PEM_encode(Format format) const;
-
-      /**
-      * Encode this group into a string using DER encoding.
-      * @param format the encoding format
-      * @return string holding the DER encoded group
-      */
-      std::vector<uint8_t> DER_encode(Format format) const;
-
-      /**
-      * Decode a DER/BER encoded group into this instance.
-      * @param ber a vector containing the DER/BER encoded group
-      * @param format the format of the encoded group
-      */
-      void BER_decode(const std::vector<uint8_t>& ber,
-                      Format format);
-
-      /**
-      * Decode a PEM encoded group into this instance.
-      * @param pem the PEM encoding of the group
-      */
-      void PEM_decode(const std::string& pem);
-
-      /**
       * Construct a DL group with uninitialized internal value.
       * Use this constructor is you wish to set the groups values
       * from a DER or PEM encoded group.
       */
-      DL_Group();
+      DL_Group() = default;
 
       /**
       * Construct a DL group that is registered in the configuration.
@@ -137,7 +85,7 @@ class BOTAN_PUBLIC_API(2,0) DL_Group final
                size_t pbits = 1024, size_t qbits = 0);
 
       /**
-      * Create a DL group. The prime q will be determined according to p.
+      * Create a DL group.
       * @param p the prime p
       * @param g the base g
       */
@@ -152,16 +100,119 @@ class BOTAN_PUBLIC_API(2,0) DL_Group final
       DL_Group(const BigInt& p, const BigInt& q, const BigInt& g);
 
       /**
+      * Decode a BER-encoded DL group param
+      */
+      DL_Group(const uint8_t ber[], size_t ber_len, Format format);
+
+      /**
+      * Get the prime p.
+      * @return prime p
+      */
+      const BigInt& get_p() const;
+
+      /**
+      * Get the prime q, returns zero if q is not used
+      * @return prime q
+      */
+      const BigInt& get_q() const;
+
+      /**
+      * Get the base g.
+      * @return base g
+      */
+      const BigInt& get_g() const;
+
+      /**
+      * Perform validity checks on the group.
+      * @param rng the rng to use
+      * @param strong whether to perform stronger by lengthier tests
+      * @return true if the object is consistent, false otherwise
+      */
+      bool verify_group(RandomNumberGenerator& rng, bool strong) const;
+
+      /**
+      * Encode this group into a string using PEM encoding.
+      * @param format the encoding format
+      * @return string holding the PEM encoded group
+      */
+      std::string PEM_encode(Format format) const;
+
+      /**
+      * Encode this group into a string using DER encoding.
+      * @param format the encoding format
+      * @return string holding the DER encoded group
+      */
+      std::vector<uint8_t> DER_encode(Format format) const;
+
+      /*
+      * Reduce an integer modulo p
+      * @return x % p
+      */
+      BigInt mod_p(const BigInt& x) const;
+
+      /*
+      * Multiply and reduce an integer modulo p
+      * @return (x*y) % p
+      */
+      BigInt multiply_mod_p(const BigInt& x, const BigInt& y) const;
+
+      BigInt inverse_mod_p(const BigInt& x) const;
+
+      /*
+      * Modular exponentiation
+      * @return (g^x) % p
+      */
+      BigInt power_g_p(const BigInt& x) const;
+
+      /**
+      * Return the size of p in bits
+      * Same as get_p().bits()
+      */
+      size_t p_bits() const;
+
+      /**
+      * Return the size of p in bytes
+      * Same as get_p().bytes()
+      */
+      size_t p_bytes() const;
+
+      /**
+      * Decode a DER/BER encoded group into this instance.
+      * @param ber a vector containing the DER/BER encoded group
+      * @param format the format of the encoded group
+      */
+      void BOTAN_DEPRECATED("Use DL_Group(ber, Format)") BER_decode(const std::vector<uint8_t>& ber, Format format);
+
+      /**
+      * Decode a PEM encoded group into this instance.
+      * @param pem the PEM encoding of the group
+      */
+      void BOTAN_DEPRECATED("Use DL_Group(std::string)") PEM_decode(const std::string& pem);
+
+      /**
       * Return PEM representation of named DL group
       */
-      static std::string PEM_for_named_group(const std::string& name);
+      static std::string BOTAN_DEPRECATED("Use DL_Group(name).PEM_encode()")
+         PEM_for_named_group(const std::string& name);
+
+      /*
+      * For internal use only
+      */
+      static std::shared_ptr<DL_Group_Data> DL_group_info(const std::string& name);
+
    private:
-      static BigInt make_dsa_generator(const BigInt&, const BigInt&);
+      static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str,
+                                                               const char* q_str,
+                                                               const char* g_str);
+
+      static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str,
+                                                               const char* g_str);
+
+      static std::shared_ptr<DL_Group_Data>
+         BER_decode_DL_group(const uint8_t data[], size_t data_len, DL_Group::Format format);
 
-      void init_check() const;
-      void initialize(const BigInt&, const BigInt&, const BigInt&);
-      bool m_initialized;
-      BigInt m_p, m_q, m_g;
+      const DL_Group_Data& data() const;
+      std::shared_ptr<DL_Group_Data> m_data;
    };
 
 }