Initial 1.0.0

git-svn-id: svn://svn.code.sf.net/p/axtls/code/axTLS@2 9a5d90b5-6617-0410-8a86-bb477d3ed2e3

ssl/BigIntConfig.in

@@ -0,0 +1,132 @@
+#
+# For a description of the syntax of this configuration file,
+# see scripts/config/Kconfig-language.txt
+#
+
+menu "BigInt Options"
+    depends on !CONFIG_SSL_SKELETON_MODE
+
+choice
+    prompt "Reduction Algorithm"
+    default CONFIG_BIGINT_BARRETT 
+
+config CONFIG_BIGINT_CLASSICAL
+    bool "Classical"
+    help
+        Classical uses standard division. It has no limitations and is
+        theoretically the slowest due to the divisions used. For this particular
+        implementation it is surprisingly quite fast.
+
+config CONFIG_BIGINT_MONTGOMERY
+    bool "Montgomery"
+    help
+        Montgomery uses simple addition and multiplication to achieve its
+        performance. In this implementation it is slower than classical, 
+        and it has the limitation that 0 <= x, y < m, and so is not used 
+        when CRT is active.
+
+        This option will not be normally selected.
+
+config CONFIG_BIGINT_BARRETT
+    bool "Barrett"
+    help
+        Barrett performs expensive precomputation before reduction and partial
+        multiplies for computational speed. It can't be used with some of the
+        calculations when CRT is used, and so defaults to classical when this
+        occurs.
+
+        It is about 40% faster than Classical/Montgomery with the expense of
+        about 2kB, and so this option is normally selected.
+
+endchoice
+
+config CONFIG_BIGINT_CRT
+    bool "Chinese Remainder Theorem (CRT)"
+    default y
+    help 
+        Allow the Chinese Remainder Theorem (CRT) to be used.
+
+        Uses a number of extra coefficients from the private key to improve the
+        performance of a decryption. This feature is one of the most 
+        significant performance improvements (it reduces a decryption time by 
+        over 3 times).
+
+        This option should be selected.
+
+config CONFIG_BIGINT_KARATSUBA
+    bool "Karatsuba Multiplication"
+    default n
+    help
+        Allow Karasuba multiplication to be used.
+ 
+        Uses 3 multiplications (plus a number of additions/subtractions) 
+        instead of 4. Multiplications are O(N^2) but addition/subtraction 
+        is O(N) hence for large numbers is beneficial. For this project, the 
+        effect was only useful for 4096 bit keys. As these aren't likely to 
+        be used, the feature is disabled by default. 
+        
+        It costs about 2kB to enable it.
+
+config MUL_KARATSUBA_THRESH
+    int "Karatsuba Multiplication Theshold"
+    default 20
+    depends on CONFIG_BIGINT_KARATSUBA
+    help
+        The minimum number of components needed before Karasuba muliplication
+        is used.
+ 
+        This is very dependent on the speed/implementation of bi_add()/
+        bi_subtract(). There is a bit of trial and error here and will be
+        at a different point for different architectures.
+
+config SQU_KARATSUBA_THRESH
+    int "Karatsuba Square Threshold"
+    default 40
+    depends on CONFIG_BIGINT_KARATSUBA && CONFIG_BIGINT_SQUARE
+    help    
+        The minimum number of components needed before Karatsuba squaring
+        is used.
+ 
+        This is very dependent on the speed/implementation of bi_add()/
+        bi_subtract(). There is a bit of trial and error here and will be
+        at a different point for different architectures.
+
+config CONFIG_BIGINT_SLIDING_WINDOW
+    bool "Sliding Window Exponentiation"
+    default y
+    help
+        Allow Sliding-Window Exponentiation to be used.
+ 
+        Potentially processes more than 1 bit at a time when doing 
+        exponentiation. The sliding-window technique reduces the number of 
+        precomputations compared to other precomputed techniques.
+
+        It results in a considerable performance improvement with it enabled
+        (it halves the decryption time) and so should be selected.
+
+config CONFIG_BIGINT_SQUARE
+    bool "Square Algorithm"
+    default y
+    help
+        Allow squaring to be used instead of a multiplication.
+ 
+        Squaring is theoretically 50% faster than a standard multiply 
+        (but is actually about 25% faster). 
+
+        It gives a 20% speed improvement and so should be selected.
+
+config CONFIG_BIGINT_CHECK_ON
+    bool "BigInt Integrity Checking"
+    default n if !CONFIG_DEBUG
+    default y if CONFIG_DEBUG
+    help
+        This is used when developing bigint algorithms. It performs a sanity
+        check on all operations at the expense of speed.
+        
+        This option is only selected when developing and should normally be
+        turned off.
+
+endmenu
+
+
+