Time for an 2014 update…

Task/Bitcoin-address-validation/Ada/bitcoin-address-validation.ada

@@ -0,0 +1,128 @@
+with Ada.Exceptions, Interfaces;
+with Ada.Streams;
+use Ada.Exceptions, Interfaces;
+use Ada.Streams;
+
+package Bitcoin is
+    subtype BT_Raw_Addr is Stream_Element_Array(1..25);
+    subtype BT_Checksum is Stream_Element_Array(1..4);
+    subtype BT_Addr is String(1..34);
+    subtype Sha256String is String(1..64);
+    Invalid_Address_Error : Exception;
+
+    function Double_Sha256(S : Stream_Element_Array) return BT_Checksum;
+    function Is_Valid(A : BT_Raw_Addr) return Boolean;
+    procedure Base58_Decode(S : BT_Addr; A : out BT_Raw_Addr) ;
+private
+    Base58 : constant String := "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
+    function Hex_Val (C, C2 : Character) return Stream_Element;
+end Bitcoin;
+
+
+with GNAT.SHA256, Ada.Strings.Fixed;
+use  GNAT.SHA256, Ada.Strings.Fixed;
+
+package body Bitcoin is
+
+function Hex_Val (C, C2 : Character) return Stream_Element is
+    subtype Nibble is Integer range 0..15;
+    HEX : array (0..255) of Nibble := (
+          48=>0, 49=>1, 50=>2, 51=>3, 52=>4, 53=>5, 54=>6, 55=>7, 56=>8, 57=>9
+        , 65=>10, 66=>11, 67=>12, 68 =>13, 69 =>14, 70 =>15
+        , 97=>10, 98=>11, 99=>12, 100=>13, 101=>14, 102=>15
+        , Others=>0
+    );
+begin
+    return Stream_Element(HEX(Character'Pos(C)) * 16 + HEX(Character'Pos(C2)));
+end Hex_Val;
+
+function Double_Sha256(S : Stream_Element_Array) return BT_Checksum is
+    Ctx  : Context := Initial_Context;
+    D : Message_Digest;
+    S2 : Stream_Element_Array(1..32);
+    Ctx2 : Context := Initial_Context;
+    C : BT_Checksum;
+begin
+    Update(Ctx, S);
+    D := Digest(Ctx);
+    for I in S2'Range loop
+        S2(I) := Hex_Val(D(Integer(I)*2-1), D(Integer(I)*2));
+    end loop;
+    Update(Ctx2, S2);
+    D := Digest(Ctx2);
+    for I in C'Range loop
+        C(I) := Hex_Val(D(Integer(I)*2-1), D(Integer(I)*2));
+    end loop;
+    return C;
+
+end Double_Sha256;
+
+
+--------------------------------------------------------------------------------
+-- Summary of Base58:                                                         --
+-- We decode S into a 200 bit unsigned integer.                               --
+-- We could use a BigNum library, but choose to go without.                   --
+--------------------------------------------------------------------------------
+procedure Base58_Decode(S : BT_Addr; A : out BT_Raw_Addr) is
+begin
+    A := (Others => 0);
+    for I in S'Range loop
+        declare
+            P : Natural := Index(Base58, String(S(I..I)));
+            C : Natural;
+        begin
+            if P = 0 then
+                raise Invalid_Address_Error;
+            end if;
+            C := P - 1;
+            for J in reverse A'Range loop
+                C    := C + Natural(A(J)) * 58;
+                A(J) := Stream_Element(Unsigned_32(C) and 255);         -- 0x0F
+                C    := Natural(Shift_Right(Unsigned_32(C),8) and 255); -- 0xF0
+            end loop;
+            if C /= 0 then
+                raise Invalid_Address_Error;
+            end if;
+        end;
+    end loop;
+end Base58_Decode;
+
+
+function Is_Valid(A : BT_Raw_Addr) return Boolean is
+begin
+    return A(1) = 0 and A(22..25) = Double_Sha256(A(1..21));
+end Is_Valid;
+
+
+end Bitcoin;
+
+with Ada.Text_IO, Bitcoin;
+use Ada.Text_IO, Bitcoin;
+
+procedure Bitcoin_Addr_Validate is
+begin
+    declare
+        BTs : array (positive range <>) of BT_Addr := (
+              "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"  -- VALID
+            , "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9"  -- VALID
+            , "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X"  -- checksum changed, original data.
+            , "1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"  -- data changed, original checksum.
+            , "1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"  -- invalid chars
+        );
+    begin
+        for I in Bts'Range loop
+            declare
+                A : BT_Raw_Addr;
+                Valid : Boolean;
+            begin
+                Put(BTs(I) & " validity: ");
+                Base58_Decode(BTs(I), A);
+                Valid := Is_Valid(A);
+                Put_Line(Boolean'Image(Valid));
+            exception
+                when E : Invalid_Address_Error  =>
+                    Put_Line ("*** Error: Invalid BT address.");
+            end;
+        end loop;
+    end;
+end Bitcoin_Addr_Validate;

Task/Bitcoin-address-validation/Erlang/bitcoin-address-validation.erl

@@ -0,0 +1,17 @@
+-module( bitcoin_address ).
+
+-export( [task/0, validate/1] ).
+
+task() ->
+	io:fwrite( "Validate ~p~n", ["1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"] ),
+	io:fwrite( "~p~n", [validate("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i")] ),
+	io:fwrite( "Validate ~p~n", ["1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW622"] ),
+	io:fwrite( "~p~n", [validate("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW622")] ).
+
+validate( String ) ->
+	{length_25, <<Address:21/binary, Checksum:4/binary>>} = {length_25, base58:base58_to_binary( String )},
+	<<Version:1/binary, _/binary>> = Address,
+	{version_0, <<0>>} = {version_0, Version},
+	<<Four_bytes:4/binary, _T/binary>> = crypto:hash( sha256, crypto:hash(sha256, Address) ),
+	{checksum, Checksum} = {checksum, Four_bytes},
+	ok.

Task/Bitcoin-address-validation/Go/bitcoin-address-validation.go

@@ -44,7 +44,7 @@ func (a *A25) doubleSHA256() []byte {
 func (a *A25) ComputeChecksum() (c [4]byte) {
     copy(c[:], a.doubleSHA256())
     return
-}
+}/* {{header|Go}} */
 
 // Tmpl and Set58 are adapted from the C solution.
 // Go has big integers but this techinique seems better.