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authorlloyd <[email protected]>2015-02-05 07:44:25 +0000
committerlloyd <[email protected]>2015-02-05 07:44:25 +0000
commitcb0f83ae63c4555cbdd0607e3a5f6e9260c0d19c (patch)
tree4981027a25fa8074177b97c3a3ca7431f3337deb /src/lib/misc/srp6/srp6.cpp
parent2c14faf0aa1cfe0f8d70af1938dcad5b4d6d3b59 (diff)
Clean up root dir, remove some unneeded dependencies
Diffstat (limited to 'src/lib/misc/srp6/srp6.cpp')
-rw-r--r--src/lib/misc/srp6/srp6.cpp157
1 files changed, 157 insertions, 0 deletions
diff --git a/src/lib/misc/srp6/srp6.cpp b/src/lib/misc/srp6/srp6.cpp
new file mode 100644
index 000000000..d3f7338bd
--- /dev/null
+++ b/src/lib/misc/srp6/srp6.cpp
@@ -0,0 +1,157 @@
+/*
+* SRP-6a (RFC 5054 compatatible)
+* (C) 2011,2012 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/srp6.h>
+#include <botan/dl_group.h>
+#include <botan/numthry.h>
+#include <botan/lookup.h>
+
+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(get_hash(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(get_hash(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();
+
+ m_p_bytes = p.bytes();
+ m_v = v;
+ m_b = BigInt(rng, 256);
+ m_p = p;
+ m_hash_id = hash_id;
+
+ const BigInt k = hash_seq(hash_id, m_p_bytes, p, g);
+
+ m_B = (v*k + power_mod(g, m_b, p)) % p;
+
+ return m_B;
+ }
+
+SymmetricKey SRP6_Server_Session::step2(const BigInt& A)
+ {
+ if(A <= 0 || A >= m_p)
+ throw std::runtime_error("Invalid SRP parameter from client");
+
+ const BigInt u = hash_seq(m_hash_id, m_p_bytes, A, m_B);
+
+ const BigInt S = power_mod(A * power_mod(m_v, u, m_p), m_b, m_p);
+
+ return BigInt::encode_1363(S, m_p_bytes);
+ }
+
+}