authorgravatar for git@vexu.euVeikka Tuominen <git@vexu.eu> 2020-05-16 13:20:14+03:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2020-05-16 13:20:14+03:00
loge2a0f5741df8b00290c0900122c4aca6ccdf6a2d
treef0157942e291b158c883e97a53098e19dc35794e
parent6c10075dd3f26f7793e76f2540a5c853edb6d3a0
parent130435a17a14faba805a41da2d9ddb24c01c396c
signature Signed by PGP key 4AEE18F83AFDEB23

Merge pull request #5189 from zigazeljko/patch-1

Split AES struct into AESEncrypt and AESDecrypt

1 files changed, 66 insertions(+), 8 deletions(-)

lib/std/crypto/aes.zig+66-8
......@@ -130,21 +130,55 @@ fn AES(comptime keysize: usize) type {
130130 return struct {
131131 const Self = @This();
132132
133 pub const Encrypt = AESEncrypt(keysize);
134 pub const Decrypt = AESDecrypt(keysize);
135
133136 const nn = (keysize / 8) + 28;
134 enc: [nn]u32,
135 dec: [nn]u32,
137 enc: Encrypt,
138 dec: Decrypt,
136139
137140 pub fn init(key: [keysize / 8]u8) Self {
138141 var ctx: Self = undefined;
139 expandKey(&key, ctx.enc[0..], ctx.dec[0..]);
142 ctx.enc = Encrypt.init(key);
143 ctx.dec = ctx.enc.toDecrypt();
140144 return ctx;
141145 }
142146
143147 pub fn encrypt(ctx: Self, dst: []u8, src: []const u8) void {
144 encryptBlock(ctx.enc[0..], dst, src);
148 ctx.enc.encrypt(dst, src);
145149 }
146150 pub fn decrypt(ctx: Self, dst: []u8, src: []const u8) void {
147 decryptBlock(ctx.dec[0..], dst, src);
151 ctx.dec.decrypt(dst, src);
152 }
153 pub fn ctr(ctx: Self, dst: []u8, src: []const u8, iv: [16]u8) void {
154 ctx.enc.ctr(dst, src, iv);
155 }
156 };
157}
158
159fn AESEncrypt(comptime keysize: usize) type {
160 return struct {
161 const Self = @This();
162
163 const Decrypt = AESDecrypt(keysize);
164
165 const nn = (keysize / 8) + 28;
166 enc: [nn]u32,
167
168 pub fn init(key: [keysize / 8]u8) Self {
169 var ctx: Self = undefined;
170 expandKeyEncrypt(&key, ctx.enc[0..]);
171 return ctx;
172 }
173
174 pub fn toDecrypt(ctx: Self) Decrypt {
175 var dec: Decrypt = undefined;
176 expandKeyDecrypt(ctx.enc[0..], dec.dec[0..]);
177 return dec;
178 }
179
180 pub fn encrypt(ctx: Self, dst: []u8, src: []const u8) void {
181 encryptBlock(ctx.enc[0..], dst, src);
148182 }
149183 pub fn ctr(ctx: Self, dst: []u8, src: []const u8, iv: [16]u8) void {
150184 std.debug.assert(dst.len >= src.len);
......@@ -163,6 +197,27 @@ fn AES(comptime keysize: usize) type {
163197 };
164198}
165199
200fn AESDecrypt(comptime keysize: usize) type {
201 return struct {
202 const Self = @This();
203
204 const nn = (keysize / 8) + 28;
205 dec: [nn]u32,
206
207 pub fn init(key: [keysize / 8]u8) Self {
208 var ctx: Self = undefined;
209 var enc: [nn]u32 = undefined;
210 expandKeyEncrypt(key[0..], enc[0..]);
211 expandKeyDecrypt(enc[0..], ctx.dec[0..]);
212 return ctx;
213 }
214
215 pub fn decrypt(ctx: Self, dst: []u8, src: []const u8) void {
216 decryptBlock(ctx.dec[0..], dst, src);
217 }
218 };
219}
220
166221test "ctr" {
167222 // NIST SP 800-38A pp 55-58
168223 {
......@@ -247,7 +302,7 @@ test "decrypt" {
247302}
248303
249304// Key expansion algorithm. See FIPS-197, Figure 11.
250fn expandKey(key: []const u8, enc: []u32, dec: []u32) void {
305fn expandKeyEncrypt(key: []const u8, enc: []u32) void {
251306 var i: usize = 0;
252307 var nk = key.len / 4;
253308 while (i < nk) : (i += 1) {
......@@ -262,9 +317,11 @@ fn expandKey(key: []const u8, enc: []u32, dec: []u32) void {
262317 }
263318 enc[i] = enc[i - nk] ^ t;
264319 }
320}
265321
322fn expandKeyDecrypt(enc: []const u32, dec: []u32) void {
323 var i: usize = 0;
266324 var n = enc.len;
267 i = 0;
268325 while (i < n) : (i += 4) {
269326 var ei = n - i - 4;
270327 var j: usize = 0;
......@@ -308,7 +365,8 @@ test "expand key" {
308365 };
309366 var enc: [exp_enc.len]u32 = undefined;
310367 var dec: [exp_dec.len]u32 = undefined;
311 expandKey(key[0..], enc[0..], dec[0..]);
368 expandKeyEncrypt(key[0..], enc[0..]);
369 expandKeyDecrypt(enc[0..], dec[0..]);
312370 testing.expectEqualSlices(u32, exp_enc[0..], enc[0..]);
313371 testing.expectEqualSlices(u32, exp_dec[0..], dec[0..]);
314372}