calculate verifiers and multiplier just like in py srpfeature-py_srp_compat

Some other parts are still missing. Main issue was using hashes of hex representation rather that hashes of byte arrays

3 files changed, 15 insertions, 17 deletions

diff --git a/lib/ruby-srp.rb b/lib/ruby-srp.rb
index 7cbe06f..d5d6cf3 100644
--- a/lib/ruby-srp.rb
+++ b/lib/ruby-srp.rb
@@ -10,6 +10,7 @@ $:.unshift File.dirname(__FILE__)
 module SRP
   autoload :Client, 'srp/client'
   autoload :Authentication, 'srp/authentication'
+  autoload :Util, 'srp/util'
   class WrongPassword < StandardError
   end
 end
diff --git a/lib/srp/client.rb b/lib/srp/client.rb
index 484d12b..37f37d7 100644
--- a/lib/srp/client.rb
+++ b/lib/srp/client.rb
@@ -7,10 +7,10 @@ module SRP
 
     attr_reader :salt, :verifier
 
-    def initialize(username, password)
+    def initialize(username, password, salt = nil)
       @username = username
       @password = password
-      @salt = "5d3055e0acd3ddcfc15".hex # bigrand(10).hex
+      @salt = salt.hex || bigrand(4).hex
       @multiplier = multiplier # let's cache it
       calculate_verifier
     end
@@ -27,15 +27,15 @@ module SRP
 
     protected
     def calculate_verifier
-      x = calculate_x(@username, @password, @salt)
-      @verifier = modpow(GENERATOR, x, PRIME_N)
+      x = calculate_x
+      @verifier = modpow(GENERATOR, x, BIG_PRIME_N)
       @verifier
     end
 
-    def calculate_x(username, password, salt)
-      shex = '%x' % [salt]
-      spad = "" # if shex.length.odd? then '0' else '' end
-      sha256_str(spad + shex + sha256_str([username, password].join(':'))).hex
+    def calculate_x
+      shex = '%x' % [@salt]
+      inner = sha256_str([@username, @password].join(':'))
+      sha256_str([shex].pack('H*') + [inner].pack('H*')).hex
     end
 
     def calculate_client_s(x, a, bb, u)
diff --git a/lib/srp/util.rb b/lib/srp/util.rb
index bf4c248..66bd9e7 100644
--- a/lib/srp/util.rb
+++ b/lib/srp/util.rb
@@ -10,7 +10,7 @@ module SRP
 115b8b692e0e045692cf280b436735c77a5a9e8a9e7ed56c965f87db5b2a2ece3
     EOS
 
-    BIG_PRIME_N = <<-EOS # 1024 bits modulus (N)
+    BIG_PRIME_N = <<-EOS.split.join.hex # 1024 bits modulus (N)
 eeaf0ab9adb38dd69c33f80afa8fc5e86072618775ff3c0b9ea2314c9c25657
 6d674df7496ea81d3383b4813d692c6e0e0d5d8e250b98be48e495c1d6089da
 d15dc7d7b46154d6b6ce8ef4ad69b15d4982559b297bcf1885c529f566660e5
@@ -43,21 +43,18 @@ d15dc7d7b46154d6b6ce8ef4ad69b15d4982559b297bcf1885c529f566660e5
     end
 
     def multiplier
-      return "c46d46600d87fef149bd79b81119842f3c20241fda67d06ef412d8f6d9479c58".hex % PRIME_N
       @k ||= calculate_multiplier
     end
 
     protected
 
     def calculate_multiplier
-      n = PRIME_N
+      n = BIG_PRIME_N
       g = GENERATOR
-      nhex = '%x' % [n]
-      nlen = nhex.length + (nhex.length.odd? ? 1 : 0 )
-      ghex = '%x' % [g]
-      hashin = '0' * (nlen - nhex.length) + nhex \
-        + '0' * (nlen - ghex.length) + ghex
-      sha256_hex(hashin).hex % n
+      nhex = '%x' % n
+      ghex = '0%x' % g
+      hashin = [nhex].pack('H*') + [ghex].pack('H*')
+      sha256_str(hashin).hex
     end
 
     def calculate_m(aa, bb, s)