48 lines
1.8 KiB
Ada
48 lines
1.8 KiB
Ada
-- Copyright (C) 2015 Daniel Otte <bg@nerilex.org>
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--
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-- This program is free software: you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation, either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program. If not, see <http://www.gnu.org/licenses/>.
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package body TDES is
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procedure Initialize(Context : out Context_T; Key : in u8_Array) is
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begin
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if Key'Length = 16 then
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DES.Initialize(Context.Ctx1, Key(Key'First + 0 .. Key'First + 7));
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DES.Initialize(Context.Ctx2, Key(Key'First + 8 .. Key'First + 15));
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DES.Initialize(Context.Ctx3, Key(Key'First + 0 .. Key'First + 7));
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elsif Key'Length = 24 then
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DES.Initialize(Context.Ctx1, Key(Key'First + 0 .. Key'First + 7));
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DES.Initialize(Context.Ctx2, Key(Key'First + 8 .. Key'First + 15));
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DES.Initialize(Context.Ctx3, Key(Key'First + 16 .. Key'First + 23));
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else
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raise Invalid_Key_Size;
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end if;
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end;
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procedure Encrypt(Context : in Context_T; Block: in out Block_64_Bit) is
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begin
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DES.Encrypt(Context.Ctx1, Block);
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DES.Decrypt(Context.Ctx2, Block);
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DES.Encrypt(Context.Ctx3, Block);
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end Encrypt;
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procedure Decrypt(Context : in Context_T; Block: in out Block_64_Bit) is
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begin
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DES.Decrypt(Context.Ctx3, Block);
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DES.Encrypt(Context.Ctx2, Block);
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DES.Decrypt(Context.Ctx1, Block);
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end Decrypt;
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end TDES;
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