mirror of
https://codeberg.org/ziglang/zig.git
synced 2025-12-06 05:44:20 +00:00
d29871977f
We already have a LICENSE file that covers the Zig Standard Library. We no longer need to remind everyone that the license is MIT in every single file. Previously this was introduced to clarify the situation for a fork of Zig that made Zig's LICENSE file harder to find, and replaced it with their own license that required annual payments to their company. However that fork now appears to be dead. So there is no need to reinforce the copyright notice in every single file.
478 lines
18 KiB
Zig
478 lines
18 KiB
Zig
const std = @import("../../std.zig");
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const mem = std.mem;
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const debug = std.debug;
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const Vector = std.meta.Vector;
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const BlockVec = Vector(2, u64);
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/// A single AES block.
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pub const Block = struct {
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pub const block_length: usize = 16;
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/// Internal representation of a block.
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repr: BlockVec,
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/// Convert a byte sequence into an internal representation.
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pub inline fn fromBytes(bytes: *const [16]u8) Block {
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const repr = mem.bytesToValue(BlockVec, bytes);
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return Block{ .repr = repr };
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}
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/// Convert the internal representation of a block into a byte sequence.
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pub inline fn toBytes(block: Block) [16]u8 {
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return mem.toBytes(block.repr);
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}
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/// XOR the block with a byte sequence.
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pub inline fn xorBytes(block: Block, bytes: *const [16]u8) [16]u8 {
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const x = block.repr ^ fromBytes(bytes).repr;
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return mem.toBytes(x);
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}
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const zero = Vector(2, u64){ 0, 0 };
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/// Encrypt a block with a round key.
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pub inline fn encrypt(block: Block, round_key: Block) Block {
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return Block{
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.repr = asm (
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\\ mov %[out].16b, %[in].16b
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\\ aese %[out].16b, %[zero].16b
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\\ aesmc %[out].16b, %[out].16b
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\\ eor %[out].16b, %[out].16b, %[rk].16b
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: [out] "=&x" (-> BlockVec)
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: [in] "x" (block.repr),
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[rk] "x" (round_key.repr),
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[zero] "x" (zero)
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),
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};
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}
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/// Encrypt a block with the last round key.
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pub inline fn encryptLast(block: Block, round_key: Block) Block {
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return Block{
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.repr = asm (
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\\ mov %[out].16b, %[in].16b
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\\ aese %[out].16b, %[zero].16b
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\\ eor %[out].16b, %[out].16b, %[rk].16b
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: [out] "=&x" (-> BlockVec)
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: [in] "x" (block.repr),
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[rk] "x" (round_key.repr),
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[zero] "x" (zero)
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),
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};
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}
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/// Decrypt a block with a round key.
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pub inline fn decrypt(block: Block, inv_round_key: Block) Block {
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return Block{
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.repr = asm (
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\\ mov %[out].16b, %[in].16b
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\\ aesd %[out].16b, %[zero].16b
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\\ aesimc %[out].16b, %[out].16b
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\\ eor %[out].16b, %[out].16b, %[rk].16b
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: [out] "=&x" (-> BlockVec)
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: [in] "x" (block.repr),
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[rk] "x" (inv_round_key.repr),
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[zero] "x" (zero)
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),
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};
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}
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/// Decrypt a block with the last round key.
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pub inline fn decryptLast(block: Block, inv_round_key: Block) Block {
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return Block{
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.repr = asm (
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\\ mov %[out].16b, %[in].16b
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\\ aesd %[out].16b, %[zero].16b
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\\ eor %[out].16b, %[out].16b, %[rk].16b
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: [out] "=&x" (-> BlockVec)
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: [in] "x" (block.repr),
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[rk] "x" (inv_round_key.repr),
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[zero] "x" (zero)
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),
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};
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}
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/// Apply the bitwise XOR operation to the content of two blocks.
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pub inline fn xorBlocks(block1: Block, block2: Block) Block {
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return Block{ .repr = block1.repr ^ block2.repr };
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}
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/// Apply the bitwise AND operation to the content of two blocks.
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pub inline fn andBlocks(block1: Block, block2: Block) Block {
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return Block{ .repr = block1.repr & block2.repr };
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}
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/// Apply the bitwise OR operation to the content of two blocks.
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pub inline fn orBlocks(block1: Block, block2: Block) Block {
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return Block{ .repr = block1.repr | block2.repr };
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}
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/// Perform operations on multiple blocks in parallel.
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pub const parallel = struct {
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/// The recommended number of AES encryption/decryption to perform in parallel for the chosen implementation.
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pub const optimal_parallel_blocks = 8;
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/// Encrypt multiple blocks in parallel, each their own round key.
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pub inline fn encryptParallel(comptime count: usize, blocks: [count]Block, round_keys: [count]Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].encrypt(round_keys[i]);
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}
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return out;
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}
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/// Decrypt multiple blocks in parallel, each their own round key.
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pub inline fn decryptParallel(comptime count: usize, blocks: [count]Block, round_keys: [count]Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].decrypt(round_keys[i]);
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}
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return out;
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}
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/// Encrypt multiple blocks in parallel with the same round key.
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pub inline fn encryptWide(comptime count: usize, blocks: [count]Block, round_key: Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].encrypt(round_key);
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}
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return out;
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}
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/// Decrypt multiple blocks in parallel with the same round key.
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pub inline fn decryptWide(comptime count: usize, blocks: [count]Block, round_key: Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].decrypt(round_key);
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}
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return out;
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}
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/// Encrypt multiple blocks in parallel with the same last round key.
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pub inline fn encryptLastWide(comptime count: usize, blocks: [count]Block, round_key: Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].encryptLast(round_key);
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}
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return out;
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}
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/// Decrypt multiple blocks in parallel with the same last round key.
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pub inline fn decryptLastWide(comptime count: usize, blocks: [count]Block, round_key: Block) [count]Block {
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comptime var i = 0;
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var out: [count]Block = undefined;
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inline while (i < count) : (i += 1) {
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out[i] = blocks[i].decryptLast(round_key);
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}
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return out;
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}
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};
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};
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fn KeySchedule(comptime Aes: type) type {
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std.debug.assert(Aes.rounds == 10 or Aes.rounds == 14);
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const rounds = Aes.rounds;
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return struct {
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const Self = @This();
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const zero = Vector(2, u64){ 0, 0 };
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const mask1 = @Vector(16, u8){ 13, 14, 15, 12, 13, 14, 15, 12, 13, 14, 15, 12, 13, 14, 15, 12 };
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const mask2 = @Vector(16, u8){ 12, 13, 14, 15, 12, 13, 14, 15, 12, 13, 14, 15, 12, 13, 14, 15 };
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round_keys: [rounds + 1]Block,
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fn drc128(comptime rc: u8, t: BlockVec) BlockVec {
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var v1: BlockVec = undefined;
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var v2: BlockVec = undefined;
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var v3: BlockVec = undefined;
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var v4: BlockVec = undefined;
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return asm (
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\\ movi %[v2].4s, %[rc]
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\\ tbl %[v4].16b, {%[t].16b}, %[mask].16b
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\\ ext %[r].16b, %[zero].16b, %[t].16b, #12
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\\ aese %[v4].16b, %[zero].16b
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\\ eor %[v2].16b, %[r].16b, %[v2].16b
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\\ ext %[r].16b, %[zero].16b, %[r].16b, #12
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\\ eor %[v1].16b, %[v2].16b, %[t].16b
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\\ ext %[v3].16b, %[zero].16b, %[r].16b, #12
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\\ eor %[v1].16b, %[v1].16b, %[r].16b
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\\ eor %[r].16b, %[v1].16b, %[v3].16b
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\\ eor %[r].16b, %[r].16b, %[v4].16b
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: [r] "=&x" (-> BlockVec),
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[v1] "=&x" (v1),
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[v2] "=&x" (v2),
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[v3] "=&x" (v3),
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[v4] "=&x" (v4)
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: [rc] "N" (rc),
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[t] "x" (t),
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[zero] "x" (zero),
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[mask] "x" (mask1)
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);
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}
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fn drc256(comptime second: bool, comptime rc: u8, t: BlockVec, tx: BlockVec) BlockVec {
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var v1: BlockVec = undefined;
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var v2: BlockVec = undefined;
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var v3: BlockVec = undefined;
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var v4: BlockVec = undefined;
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return asm (
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\\ movi %[v2].4s, %[rc]
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\\ tbl %[v4].16b, {%[t].16b}, %[mask].16b
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\\ ext %[r].16b, %[zero].16b, %[tx].16b, #12
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\\ aese %[v4].16b, %[zero].16b
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\\ eor %[v1].16b, %[tx].16b, %[r].16b
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\\ ext %[r].16b, %[zero].16b, %[r].16b, #12
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\\ eor %[v1].16b, %[v1].16b, %[r].16b
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\\ ext %[v3].16b, %[zero].16b, %[r].16b, #12
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\\ eor %[v1].16b, %[v1].16b, %[v2].16b
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\\ eor %[v1].16b, %[v1].16b, %[v3].16b
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\\ eor %[r].16b, %[v1].16b, %[v4].16b
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: [r] "=&x" (-> BlockVec),
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[v1] "=&x" (v1),
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[v2] "=&x" (v2),
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[v3] "=&x" (v3),
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[v4] "=&x" (v4)
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: [rc] "N" (if (second) @as(u8, 0) else rc),
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[t] "x" (t),
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[tx] "x" (tx),
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[zero] "x" (zero),
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[mask] "x" (if (second) mask2 else mask1)
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);
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}
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fn expand128(t1: *Block) Self {
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var round_keys: [11]Block = undefined;
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const rcs = [_]u8{ 1, 2, 4, 8, 16, 32, 64, 128, 27, 54 };
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inline for (rcs) |rc, round| {
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round_keys[round] = t1.*;
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t1.repr = drc128(rc, t1.repr);
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}
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round_keys[rcs.len] = t1.*;
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return Self{ .round_keys = round_keys };
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}
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fn expand256(t1: *Block, t2: *Block) Self {
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var round_keys: [15]Block = undefined;
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const rcs = [_]u8{ 1, 2, 4, 8, 16, 32 };
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round_keys[0] = t1.*;
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inline for (rcs) |rc, round| {
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round_keys[round * 2 + 1] = t2.*;
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t1.repr = drc256(false, rc, t2.repr, t1.repr);
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round_keys[round * 2 + 2] = t1.*;
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t2.repr = drc256(true, rc, t1.repr, t2.repr);
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}
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round_keys[rcs.len * 2 + 1] = t2.*;
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t1.repr = drc256(false, 64, t2.repr, t1.repr);
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round_keys[rcs.len * 2 + 2] = t1.*;
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return Self{ .round_keys = round_keys };
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}
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/// Invert the key schedule.
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pub fn invert(key_schedule: Self) Self {
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const round_keys = &key_schedule.round_keys;
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var inv_round_keys: [rounds + 1]Block = undefined;
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inv_round_keys[0] = round_keys[rounds];
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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inv_round_keys[i] = Block{
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.repr = asm (
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\\ aesimc %[inv_rk].16b, %[rk].16b
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: [inv_rk] "=x" (-> BlockVec)
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: [rk] "x" (round_keys[rounds - i].repr)
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),
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};
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}
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inv_round_keys[rounds] = round_keys[0];
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return Self{ .round_keys = inv_round_keys };
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}
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};
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}
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/// A context to perform encryption using the standard AES key schedule.
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pub fn AesEncryptCtx(comptime Aes: type) type {
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std.debug.assert(Aes.key_bits == 128 or Aes.key_bits == 256);
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const rounds = Aes.rounds;
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return struct {
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const Self = @This();
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pub const block = Aes.block;
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pub const block_length = block.block_length;
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key_schedule: KeySchedule(Aes),
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/// Create a new encryption context with the given key.
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pub fn init(key: [Aes.key_bits / 8]u8) Self {
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var t1 = Block.fromBytes(key[0..16]);
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const key_schedule = if (Aes.key_bits == 128) ks: {
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break :ks KeySchedule(Aes).expand128(&t1);
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} else ks: {
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var t2 = Block.fromBytes(key[16..32]);
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break :ks KeySchedule(Aes).expand256(&t1, &t2);
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};
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return Self{
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.key_schedule = key_schedule,
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};
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}
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/// Encrypt a single block.
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pub fn encrypt(ctx: Self, dst: *[16]u8, src: *const [16]u8) void {
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const round_keys = ctx.key_schedule.round_keys;
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var t = Block.fromBytes(src).xorBlocks(round_keys[0]);
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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t = t.encrypt(round_keys[i]);
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}
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t = t.encryptLast(round_keys[rounds]);
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dst.* = t.toBytes();
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}
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/// Encrypt+XOR a single block.
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pub fn xor(ctx: Self, dst: *[16]u8, src: *const [16]u8, counter: [16]u8) void {
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const round_keys = ctx.key_schedule.round_keys;
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var t = Block.fromBytes(&counter).xorBlocks(round_keys[0]);
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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t = t.encrypt(round_keys[i]);
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}
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t = t.encryptLast(round_keys[rounds]);
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dst.* = t.xorBytes(src);
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}
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/// Encrypt multiple blocks, possibly leveraging parallelization.
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pub fn encryptWide(ctx: Self, comptime count: usize, dst: *[16 * count]u8, src: *const [16 * count]u8) void {
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const round_keys = ctx.key_schedule.round_keys;
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var ts: [count]Block = undefined;
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comptime var j = 0;
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inline while (j < count) : (j += 1) {
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ts[j] = Block.fromBytes(src[j * 16 .. j * 16 + 16][0..16]).xorBlocks(round_keys[0]);
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}
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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ts = Block.parallel.encryptWide(count, ts, round_keys[i]);
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}
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ts = Block.parallel.encryptLastWide(count, ts, round_keys[i]);
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j = 0;
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inline while (j < count) : (j += 1) {
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dst[16 * j .. 16 * j + 16].* = ts[j].toBytes();
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}
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}
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/// Encrypt+XOR multiple blocks, possibly leveraging parallelization.
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pub fn xorWide(ctx: Self, comptime count: usize, dst: *[16 * count]u8, src: *const [16 * count]u8, counters: [16 * count]u8) void {
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const round_keys = ctx.key_schedule.round_keys;
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var ts: [count]Block = undefined;
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comptime var j = 0;
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inline while (j < count) : (j += 1) {
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ts[j] = Block.fromBytes(counters[j * 16 .. j * 16 + 16][0..16]).xorBlocks(round_keys[0]);
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}
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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ts = Block.parallel.encryptWide(count, ts, round_keys[i]);
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}
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ts = Block.parallel.encryptLastWide(count, ts, round_keys[i]);
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j = 0;
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inline while (j < count) : (j += 1) {
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dst[16 * j .. 16 * j + 16].* = ts[j].xorBytes(src[16 * j .. 16 * j + 16]);
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}
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}
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};
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}
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/// A context to perform decryption using the standard AES key schedule.
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pub fn AesDecryptCtx(comptime Aes: type) type {
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std.debug.assert(Aes.key_bits == 128 or Aes.key_bits == 256);
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const rounds = Aes.rounds;
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return struct {
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const Self = @This();
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pub const block = Aes.block;
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pub const block_length = block.block_length;
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key_schedule: KeySchedule(Aes),
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/// Create a decryption context from an existing encryption context.
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pub fn initFromEnc(ctx: AesEncryptCtx(Aes)) Self {
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return Self{
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.key_schedule = ctx.key_schedule.invert(),
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};
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}
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/// Create a new decryption context with the given key.
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pub fn init(key: [Aes.key_bits / 8]u8) Self {
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const enc_ctx = AesEncryptCtx(Aes).init(key);
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return initFromEnc(enc_ctx);
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}
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/// Decrypt a single block.
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pub fn decrypt(ctx: Self, dst: *[16]u8, src: *const [16]u8) void {
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const inv_round_keys = ctx.key_schedule.round_keys;
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var t = Block.fromBytes(src).xorBlocks(inv_round_keys[0]);
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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t = t.decrypt(inv_round_keys[i]);
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}
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t = t.decryptLast(inv_round_keys[rounds]);
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dst.* = t.toBytes();
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}
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/// Decrypt multiple blocks, possibly leveraging parallelization.
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pub fn decryptWide(ctx: Self, comptime count: usize, dst: *[16 * count]u8, src: *const [16 * count]u8) void {
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const inv_round_keys = ctx.key_schedule.round_keys;
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var ts: [count]Block = undefined;
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comptime var j = 0;
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inline while (j < count) : (j += 1) {
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ts[j] = Block.fromBytes(src[j * 16 .. j * 16 + 16][0..16]).xorBlocks(inv_round_keys[0]);
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}
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comptime var i = 1;
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inline while (i < rounds) : (i += 1) {
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ts = Block.parallel.decryptWide(count, ts, inv_round_keys[i]);
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}
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ts = Block.parallel.decryptLastWide(count, ts, inv_round_keys[i]);
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j = 0;
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inline while (j < count) : (j += 1) {
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dst[16 * j .. 16 * j + 16].* = ts[j].toBytes();
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}
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}
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};
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}
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/// AES-128 with the standard key schedule.
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pub const Aes128 = struct {
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pub const key_bits: usize = 128;
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pub const rounds = ((key_bits - 64) / 32 + 8);
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pub const block = Block;
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|
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/// Create a new context for encryption.
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pub fn initEnc(key: [key_bits / 8]u8) AesEncryptCtx(Aes128) {
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return AesEncryptCtx(Aes128).init(key);
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}
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|
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/// Create a new context for decryption.
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pub fn initDec(key: [key_bits / 8]u8) AesDecryptCtx(Aes128) {
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return AesDecryptCtx(Aes128).init(key);
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}
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};
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|
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/// AES-256 with the standard key schedule.
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pub const Aes256 = struct {
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pub const key_bits: usize = 256;
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pub const rounds = ((key_bits - 64) / 32 + 8);
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pub const block = Block;
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|
|
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/// Create a new context for encryption.
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|
pub fn initEnc(key: [key_bits / 8]u8) AesEncryptCtx(Aes256) {
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return AesEncryptCtx(Aes256).init(key);
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|
}
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|
|
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/// Create a new context for decryption.
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|
pub fn initDec(key: [key_bits / 8]u8) AesDecryptCtx(Aes256) {
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return AesDecryptCtx(Aes256).init(key);
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|
}
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|
};
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