| ... | ... | @@ -20,20 +20,20 @@ const Error = std.crypto.Error; |
| 20 | 20 | // pseudorandom function. See Appendix B.1 for further discussion.) |
| 21 | 21 | // PBKDF2 is recommended for new applications. |
| 22 | 22 | // |
| 23 | | // PBKDF2 (P, S, c, dkLen) |
| 23 | // PBKDF2 (P, S, c, dk_len) |
| 24 | 24 | // |
| 25 | | // Options: PRF underlying pseudorandom function (hLen |
| 25 | // Options: PRF underlying pseudorandom function (h_len |
| 26 | 26 | // denotes the length in octets of the |
| 27 | 27 | // pseudorandom function output) |
| 28 | 28 | // |
| 29 | 29 | // Input: P password, an octet string |
| 30 | 30 | // S salt, an octet string |
| 31 | 31 | // c iteration count, a positive integer |
| 32 | | // dkLen intended length in octets of the derived |
| 32 | // dk_len intended length in octets of the derived |
| 33 | 33 | // key, a positive integer, at most |
| 34 | | // (2^32 - 1) * hLen |
| 34 | // (2^32 - 1) * h_len |
| 35 | 35 | // |
| 36 | | // Output: DK derived key, a dkLen-octet string |
| 36 | // Output: DK derived key, a dk_len-octet string |
| 37 | 37 | |
| 38 | 38 | // Based on Apple's CommonKeyDerivation, based originally on code by Damien Bergamini. |
| 39 | 39 | |
| ... | ... | @@ -41,7 +41,7 @@ const Error = std.crypto.Error; |
| 41 | 41 | /// |
| 42 | 42 | /// PBKDF2 is defined in RFC 2898, and is a recommendation of NIST SP 800-132. |
| 43 | 43 | /// |
| 44 | | /// derivedKey: Slice of appropriate size for generated key. Generally 16 or 32 bytes in length. |
| 44 | /// dk: Slice of appropriate size for generated key. Generally 16 or 32 bytes in length. |
| 45 | 45 | /// May be uninitialized. All bytes will be overwritten. |
| 46 | 46 | /// Maximum size is `maxInt(u32) * Hash.digest_length` |
| 47 | 47 | /// It is a programming error to pass buffer longer than the maximum size. |
| ... | ... | @@ -52,43 +52,38 @@ const Error = std.crypto.Error; |
| 52 | 52 | /// |
| 53 | 53 | /// rounds: Iteration count. Must be greater than 0. Common values range from 1,000 to 100,000. |
| 54 | 54 | /// Larger iteration counts improve security by increasing the time required to compute |
| 55 | | /// the derivedKey. It is common to tune this parameter to achieve approximately 100ms. |
| 55 | /// the dk. It is common to tune this parameter to achieve approximately 100ms. |
| 56 | 56 | /// |
| 57 | 57 | /// Prf: Pseudo-random function to use. A common choice is `std.crypto.auth.hmac.HmacSha256`. |
| 58 | | pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds: u32, comptime Prf: type) Error!void { |
| 58 | pub fn pbkdf2(dk: []u8, password: []const u8, salt: []const u8, rounds: u32, comptime Prf: type) Error!void { |
| 59 | 59 | if (rounds < 1) return error.WeakParameters; |
| 60 | 60 | |
| 61 | | const dkLen = derivedKey.len; |
| 62 | | const hLen = Prf.mac_length; |
| 63 | | comptime std.debug.assert(hLen >= 1); |
| 61 | const dk_len = dk.len; |
| 62 | const h_len = Prf.mac_length; |
| 63 | comptime std.debug.assert(h_len >= 1); |
| 64 | 64 | |
| 65 | 65 | // FromSpec: |
| 66 | 66 | // |
| 67 | | // 1. If dkLen > maxInt(u32) * hLen, output "derived key too long" and |
| 67 | // 1. If dk_len > maxInt(u32) * h_len, output "derived key too long" and |
| 68 | 68 | // stop. |
| 69 | 69 | // |
| 70 | | if (comptime (maxInt(usize) > maxInt(u32) * hLen) and (dkLen > @as(usize, maxInt(u32) * hLen))) { |
| 71 | | // If maxInt(usize) is less than `maxInt(u32) * hLen` then dkLen is always inbounds |
| 70 | if (dk_len / h_len >= maxInt(u32)) { |
| 71 | // Counter starts at 1 and is 32 bit, so if we have to return more blocks, we would overflow |
| 72 | 72 | return error.OutputTooLong; |
| 73 | 73 | } |
| 74 | 74 | |
| 75 | 75 | // FromSpec: |
| 76 | 76 | // |
| 77 | | // 2. Let l be the number of hLen-long blocks of bytes in the derived key, |
| 77 | // 2. Let l be the number of h_len-long blocks of bytes in the derived key, |
| 78 | 78 | // rounding up, and let r be the number of bytes in the last |
| 79 | 79 | // block |
| 80 | 80 | // |
| 81 | 81 | |
| 82 | | // l will not overflow, proof: |
| 83 | | // let `L(dkLen, hLen) = (dkLen + hLen - 1) / hLen` |
| 84 | | // then `L^-1(l, hLen) = l*hLen - hLen + 1` |
| 85 | | // 1) L^-1(maxInt(u32), hLen) <= maxInt(u32)*hLen |
| 86 | | // 2) maxInt(u32)*hLen - hLen + 1 <= maxInt(u32)*hLen // subtract maxInt(u32)*hLen + 1 |
| 87 | | // 3) -hLen <= -1 // multiply by -1 |
| 88 | | // 4) hLen >= 1 |
| 89 | | const r_ = dkLen % hLen; |
| 90 | | const l = @intCast(u32, (dkLen / hLen) + @as(u1, if (r_ == 0) 0 else 1)); // original: (dkLen + hLen - 1) / hLen |
| 91 | | const r = if (r_ == 0) hLen else r_; |
| 82 | const blocks_count = @intCast(u32, std.math.divCeil(usize, dk_len, h_len) catch unreachable); |
| 83 | var r = dk_len % h_len; |
| 84 | if (r == 0) { |
| 85 | r = h_len; |
| 86 | } |
| 92 | 87 | |
| 93 | 88 | // FromSpec: |
| 94 | 89 | // |
| ... | ... | @@ -118,37 +113,38 @@ pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds: |
| 118 | 113 | // Here, INT (i) is a four-octet encoding of the integer i, most |
| 119 | 114 | // significant octet first. |
| 120 | 115 | // |
| 121 | | // 4. Concatenate the blocks and extract the first dkLen octets to |
| 116 | // 4. Concatenate the blocks and extract the first dk_len octets to |
| 122 | 117 | // produce a derived key DK: |
| 123 | 118 | // |
| 124 | 119 | // DK = T_1 || T_2 || ... || T_l<0..r-1> |
| 125 | | var block: u32 = 0; // Spec limits to u32 |
| 126 | | while (block < l) : (block += 1) { |
| 127 | | var prevBlock: [hLen]u8 = undefined; |
| 128 | | var newBlock: [hLen]u8 = undefined; |
| 120 | |
| 121 | var block: u32 = 0; |
| 122 | while (block < blocks_count) : (block += 1) { |
| 123 | var prev_block: [h_len]u8 = undefined; |
| 124 | var new_block: [h_len]u8 = undefined; |
| 129 | 125 | |
| 130 | 126 | // U_1 = PRF (P, S || INT (i)) |
| 131 | | const blockIndex = mem.toBytes(mem.nativeToBig(u32, block + 1)); // Block index starts at 0001 |
| 127 | const block_index = mem.toBytes(mem.nativeToBig(u32, block + 1)); // Block index starts at 0001 |
| 132 | 128 | var ctx = Prf.init(password); |
| 133 | 129 | ctx.update(salt); |
| 134 | | ctx.update(blockIndex[0..]); |
| 135 | | ctx.final(prevBlock[0..]); |
| 130 | ctx.update(block_index[0..]); |
| 131 | ctx.final(prev_block[0..]); |
| 136 | 132 | |
| 137 | 133 | // Choose portion of DK to write into (T_n) and initialize |
| 138 | | const offset = block * hLen; |
| 139 | | const blockLen = if (block != l - 1) hLen else r; |
| 140 | | const dkBlock: []u8 = derivedKey[offset..][0..blockLen]; |
| 141 | | mem.copy(u8, dkBlock, prevBlock[0..dkBlock.len]); |
| 134 | const offset = block * h_len; |
| 135 | const block_len = if (block != blocks_count - 1) h_len else r; |
| 136 | const dk_block: []u8 = dk[offset..][0..block_len]; |
| 137 | mem.copy(u8, dk_block, prev_block[0..dk_block.len]); |
| 142 | 138 | |
| 143 | 139 | var i: u32 = 1; |
| 144 | 140 | while (i < rounds) : (i += 1) { |
| 145 | 141 | // U_c = PRF (P, U_{c-1}) |
| 146 | | Prf.create(&newBlock, prevBlock[0..], password); |
| 147 | | mem.copy(u8, prevBlock[0..], newBlock[0..]); |
| 142 | Prf.create(&new_block, prev_block[0..], password); |
| 143 | mem.copy(u8, prev_block[0..], new_block[0..]); |
| 148 | 144 | |
| 149 | 145 | // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c |
| 150 | | for (dkBlock) |_, j| { |
| 151 | | dkBlock[j] ^= newBlock[j]; |
| 146 | for (dk_block) |_, j| { |
| 147 | dk_block[j] ^= new_block[j]; |
| 152 | 148 | } |
| 153 | 149 | } |
| 154 | 150 | } |
| ... | ... | @@ -158,49 +154,50 @@ const htest = @import("test.zig"); |
| 158 | 154 | const HmacSha1 = std.crypto.auth.hmac.HmacSha1; |
| 159 | 155 | |
| 160 | 156 | // RFC 6070 PBKDF2 HMAC-SHA1 Test Vectors |
| 157 | |
| 161 | 158 | test "RFC 6070 one iteration" { |
| 162 | 159 | const p = "password"; |
| 163 | 160 | const s = "salt"; |
| 164 | 161 | const c = 1; |
| 165 | | const dkLen = 20; |
| 162 | const dk_len = 20; |
| 166 | 163 | |
| 167 | | var derivedKey: [dkLen]u8 = undefined; |
| 164 | var dk: [dk_len]u8 = undefined; |
| 168 | 165 | |
| 169 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 166 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 170 | 167 | |
| 171 | 168 | const expected = "0c60c80f961f0e71f3a9b524af6012062fe037a6"; |
| 172 | 169 | |
| 173 | | htest.assertEqual(expected, derivedKey[0..]); |
| 170 | htest.assertEqual(expected, dk[0..]); |
| 174 | 171 | } |
| 175 | 172 | |
| 176 | 173 | test "RFC 6070 two iterations" { |
| 177 | 174 | const p = "password"; |
| 178 | 175 | const s = "salt"; |
| 179 | 176 | const c = 2; |
| 180 | | const dkLen = 20; |
| 177 | const dk_len = 20; |
| 181 | 178 | |
| 182 | | var derivedKey: [dkLen]u8 = undefined; |
| 179 | var dk: [dk_len]u8 = undefined; |
| 183 | 180 | |
| 184 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 181 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 185 | 182 | |
| 186 | 183 | const expected = "ea6c014dc72d6f8ccd1ed92ace1d41f0d8de8957"; |
| 187 | 184 | |
| 188 | | htest.assertEqual(expected, derivedKey[0..]); |
| 185 | htest.assertEqual(expected, dk[0..]); |
| 189 | 186 | } |
| 190 | 187 | |
| 191 | 188 | test "RFC 6070 4096 iterations" { |
| 192 | 189 | const p = "password"; |
| 193 | 190 | const s = "salt"; |
| 194 | 191 | const c = 4096; |
| 195 | | const dkLen = 20; |
| 192 | const dk_len = 20; |
| 196 | 193 | |
| 197 | | var derivedKey: [dkLen]u8 = undefined; |
| 194 | var dk: [dk_len]u8 = undefined; |
| 198 | 195 | |
| 199 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 196 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 200 | 197 | |
| 201 | 198 | const expected = "4b007901b765489abead49d926f721d065a429c1"; |
| 202 | 199 | |
| 203 | | htest.assertEqual(expected, derivedKey[0..]); |
| 200 | htest.assertEqual(expected, dk[0..]); |
| 204 | 201 | } |
| 205 | 202 | |
| 206 | 203 | test "RFC 6070 16,777,216 iterations" { |
| ... | ... | @@ -212,48 +209,48 @@ test "RFC 6070 16,777,216 iterations" { |
| 212 | 209 | const p = "password"; |
| 213 | 210 | const s = "salt"; |
| 214 | 211 | const c = 16777216; |
| 215 | | const dkLen = 20; |
| 212 | const dk_len = 20; |
| 216 | 213 | |
| 217 | | var derivedKey = [_]u8{0} ** dkLen; |
| 214 | var dk = [_]u8{0} ** dk_len; |
| 218 | 215 | |
| 219 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 216 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 220 | 217 | |
| 221 | 218 | const expected = "eefe3d61cd4da4e4e9945b3d6ba2158c2634e984"; |
| 222 | 219 | |
| 223 | | htest.assertEqual(expected, derivedKey[0..]); |
| 220 | htest.assertEqual(expected, dk[0..]); |
| 224 | 221 | } |
| 225 | 222 | |
| 226 | 223 | test "RFC 6070 multi-block salt and password" { |
| 227 | 224 | const p = "passwordPASSWORDpassword"; |
| 228 | 225 | const s = "saltSALTsaltSALTsaltSALTsaltSALTsalt"; |
| 229 | 226 | const c = 4096; |
| 230 | | const dkLen = 25; |
| 227 | const dk_len = 25; |
| 231 | 228 | |
| 232 | | var derivedKey: [dkLen]u8 = undefined; |
| 229 | var dk: [dk_len]u8 = undefined; |
| 233 | 230 | |
| 234 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 231 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 235 | 232 | |
| 236 | 233 | const expected = "3d2eec4fe41c849b80c8d83662c0e44a8b291a964cf2f07038"; |
| 237 | 234 | |
| 238 | | htest.assertEqual(expected, derivedKey[0..]); |
| 235 | htest.assertEqual(expected, dk[0..]); |
| 239 | 236 | } |
| 240 | 237 | |
| 241 | 238 | test "RFC 6070 embedded NUL" { |
| 242 | 239 | const p = "pass\x00word"; |
| 243 | 240 | const s = "sa\x00lt"; |
| 244 | 241 | const c = 4096; |
| 245 | | const dkLen = 16; |
| 242 | const dk_len = 16; |
| 246 | 243 | |
| 247 | | var derivedKey: [dkLen]u8 = undefined; |
| 244 | var dk: [dk_len]u8 = undefined; |
| 248 | 245 | |
| 249 | | try pbkdf2(&derivedKey, p, s, c, HmacSha1); |
| 246 | try pbkdf2(&dk, p, s, c, HmacSha1); |
| 250 | 247 | |
| 251 | 248 | const expected = "56fa6aa75548099dcc37d7f03425e0c3"; |
| 252 | 249 | |
| 253 | | htest.assertEqual(expected, derivedKey[0..]); |
| 250 | htest.assertEqual(expected, dk[0..]); |
| 254 | 251 | } |
| 255 | 252 | |
| 256 | | test "Very large dkLen" { |
| 253 | test "Very large dk_len" { |
| 257 | 254 | // This test allocates 8GB of memory and is expected to take several hours to run. |
| 258 | 255 | if (true) { |
| 259 | 256 | return error.SkipZigTest; |
| ... | ... | @@ -261,13 +258,13 @@ test "Very large dkLen" { |
| 261 | 258 | const p = "password"; |
| 262 | 259 | const s = "salt"; |
| 263 | 260 | const c = 1; |
| 264 | | const dkLen = 1 << 33; |
| 261 | const dk_len = 1 << 33; |
| 265 | 262 | |
| 266 | | var derivedKey = try std.testing.allocator.alloc(u8, dkLen); |
| 263 | var dk = try std.testing.allocator.alloc(u8, dk_len); |
| 267 | 264 | defer { |
| 268 | | std.testing.allocator.free(derivedKey); |
| 265 | std.testing.allocator.free(dk); |
| 269 | 266 | } |
| 270 | 267 | |
| 271 | | try pbkdf2(derivedKey, p, s, c, HmacSha1); |
| 272 | 268 | // Just verify this doesn't crash with an overflow |
| 269 | try pbkdf2(dk, p, s, c, HmacSha1); |
| 273 | 270 | } |
Andrew Kelley <andrew@ziglang.org> 2021-03-17 11:25:19-07:00
GitHub <noreply@github.com> 2021-03-17 11:25:19-07:00