contrib: keygen-html for generating keys in the browser
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld
parent
30cf5eb883
commit
bee819f289
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WireGuard Key Generation in JavaScript
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======================================
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Various people believe in JavaScript crypto, unfortunately. This small
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example helps them fuel their poor taste.
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It's possible to generate WireGuard keys (and thus configurations) in the
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browser. The webpage here simulates talking to a server to exchange keys
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and then generates a configuration file for the user to download.
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Bugs
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----
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Who knows how emscripten actually compiles this and whether or not it
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introduces interesting side-channel attacks.
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Secrets aren't zerored after use. Maybe you can get around this with
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some tricks taking advantage of browser allocator behavior and different
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processes, but it seems pretty hard.
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File diff suppressed because one or more lines are too long
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<script src="curve25519_generate.js"></script>
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<script>
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// License: GPLv2
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function generateWireguardKeypair()
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{
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var privateKey = Module._malloc(32);
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var publicKey = Module._malloc(32);
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Module._curve25519_generate_private(privateKey);
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Module._curve25519_generate_public(publicKey, privateKey);
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var privateBase64 = Module._malloc(45);
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var publicBase64 = Module._malloc(45);
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Module._key_to_base64(privateBase64, privateKey);
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Module._key_to_base64(publicBase64, publicKey);
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Module._free(privateKey);
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Module._free(publicKey);
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var keypair = {
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publicKey: Module.Pointer_stringify(publicBase64),
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privateKey: Module.Pointer_stringify(privateBase64)
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};
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Module._free(privateBase64);
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Module._free(publicBase64);
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return keypair;
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}
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function sendPubkeyToServer(pubkey, username, password)
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{
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alert("Sending " + username + ":" + password + " to server for new pubkey " + pubkey + "...");
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// send info to server
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var serverResponse = {
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publicKey: "6spHEFoJrp9pijbxjJoS6fHjZaAWQqtdFFO/OtpVe3w=",
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allowedIPs: [ "0.0.0.0/0", "::/0" ],
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endpoint: "demo.wireguard.com:63321",
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address: [ "192.168.18.42/32", "fd08:1234:1111::77/128" ],
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dns: [ "8.8.8.8", "8.8.4.4" ]
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}
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return serverResponse;
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}
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function downloadNewConfiguration()
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{
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var keypair = generateWireguardKeypair();
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var serverResponse = sendPubkeyToServer(keypair.publicKey, "zx2c4", "supersecretpassword");
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var config = [];
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config.push("[Interface]");
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config.push("PrivateKey = " + keypair.privateKey);
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config.push("Address = " + serverResponse.address.join(", "));
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config.push("DNS = " + serverResponse.dns.join(", "));
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config.push("");
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config.push("[Peer]");
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config.push("PublicKey = " + serverResponse.publicKey);
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config.push("AllowedIPs = " + serverResponse.allowedIPs.join(", "));
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config.push("Endpoint = " + serverResponse.endpoint);
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config.push("");
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config = config.join("\n");
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var blob = new Blob([config], { type: "text/plain" });
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var a = document.createElement("a");
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a.download = "demo0.conf";
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a.href = URL.createObjectURL(blob);
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a.style.display = "none";
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document.body.appendChild(a);
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a.click();
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document.body.removeChild(a);
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}
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</script>
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<a href="javascript:downloadNewConfiguration()">Download a WireGuard configuration file</a>
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@ -0,0 +1,914 @@
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/* License: GPLv2 */
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/* Build with emcc -O3 --memory-init-file 0 -o curve25519_generate.js curve25519_generate.c */
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#include <emscripten.h>
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typedef unsigned long long uint64_t;
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typedef long long int64_t;
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typedef int int32_t;
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typedef unsigned int uint32_t;
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typedef unsigned char uint8_t;
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typedef int64_t limb;
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/* Field element representation:
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*
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* Field elements are written as an array of signed, 64-bit limbs, least
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* significant first. The value of the field element is:
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* x[0] + 2^26·x[1] + x^51·x[2] + 2^102·x[3] + ...
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*
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* i.e. the limbs are 26, 25, 26, 25, ... bits wide.
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*/
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/* Sum two numbers: output += in */
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static void fsum(limb *output, const limb *in)
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{
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unsigned int i;
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for (i = 0; i < 10; i += 2) {
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output[0 + i] = output[0 + i] + in[0 + i];
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output[1 + i] = output[1 + i] + in[1 + i];
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}
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}
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/* Find the difference of two numbers: output = in - output
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* (note the order of the arguments!).
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*/
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static void fdifference(limb *output, const limb *in)
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{
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unsigned int i;
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for (i = 0; i < 10; ++i) {
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output[i] = in[i] - output[i];
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}
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}
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/* Multiply a number by a scalar: output = in * scalar */
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static void fscalar_product(limb *output, const limb *in, const limb scalar)
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{
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unsigned int i;
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for (i = 0; i < 10; ++i) {
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output[i] = in[i] * scalar;
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}
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}
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/* Multiply two numbers: output = in2 * in
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*
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* output must be distinct to both inputs. The inputs are reduced coefficient
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* form, the output is not.
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*
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* output[x] <= 14 * the largest product of the input limbs.
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*/
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static void fproduct(limb *output, const limb *in2, const limb *in)
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{
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output[0] = ((limb) ((int32_t) in2[0])) * ((int32_t) in[0]);
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output[1] = ((limb) ((int32_t) in2[0])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[0]);
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output[2] = 2 * ((limb) ((int32_t) in2[1])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[0]);
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output[3] = ((limb) ((int32_t) in2[1])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[0]);
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output[4] = ((limb) ((int32_t) in2[2])) * ((int32_t) in[2]) +
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2 * (((limb) ((int32_t) in2[1])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[1])) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[0]);
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output[5] = ((limb) ((int32_t) in2[2])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[0]);
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output[6] = 2 * (((limb) ((int32_t) in2[3])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[1])) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[0]);
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output[7] = ((limb) ((int32_t) in2[3])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[0]);
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output[8] = ((limb) ((int32_t) in2[4])) * ((int32_t) in[4]) +
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2 * (((limb) ((int32_t) in2[3])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[1])) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[0]);
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output[9] = ((limb) ((int32_t) in2[4])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[2]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[1]) +
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((limb) ((int32_t) in2[0])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[0]);
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output[10] = 2 * (((limb) ((int32_t) in2[5])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[1])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[1])) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[2]);
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output[11] = ((limb) ((int32_t) in2[5])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[4]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[3]) +
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((limb) ((int32_t) in2[2])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[2]);
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output[12] = ((limb) ((int32_t) in2[6])) * ((int32_t) in[6]) +
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2 * (((limb) ((int32_t) in2[5])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[3])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[3])) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[4]);
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output[13] = ((limb) ((int32_t) in2[6])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[7])) * ((int32_t) in[6]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[5]) +
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((limb) ((int32_t) in2[4])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[4]);
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output[14] = 2 * (((limb) ((int32_t) in2[7])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[5])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[5])) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[6]);
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output[15] = ((limb) ((int32_t) in2[7])) * ((int32_t) in[8]) +
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((limb) ((int32_t) in2[8])) * ((int32_t) in[7]) +
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((limb) ((int32_t) in2[6])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[6]);
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output[16] = ((limb) ((int32_t) in2[8])) * ((int32_t) in[8]) +
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2 * (((limb) ((int32_t) in2[7])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[7]));
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output[17] = ((limb) ((int32_t) in2[8])) * ((int32_t) in[9]) +
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((limb) ((int32_t) in2[9])) * ((int32_t) in[8]);
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output[18] = 2 * ((limb) ((int32_t) in2[9])) * ((int32_t) in[9]);
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}
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/* Reduce a long form to a short form by taking the input mod 2^255 - 19.
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*
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* On entry: |output[i]| < 14*2^54
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* On exit: |output[0..8]| < 280*2^54
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*/
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static void freduce_degree(limb *output)
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{
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/* Each of these shifts and adds ends up multiplying the value by 19.
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*
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* For output[0..8], the absolute entry value is < 14*2^54 and we add, at
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* most, 19*14*2^54 thus, on exit, |output[0..8]| < 280*2^54.
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*/
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output[8] += output[18] << 4;
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output[8] += output[18] << 1;
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output[8] += output[18];
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output[7] += output[17] << 4;
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output[7] += output[17] << 1;
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output[7] += output[17];
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output[6] += output[16] << 4;
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output[6] += output[16] << 1;
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output[6] += output[16];
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output[5] += output[15] << 4;
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output[5] += output[15] << 1;
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output[5] += output[15];
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output[4] += output[14] << 4;
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output[4] += output[14] << 1;
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output[4] += output[14];
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||||||
|
output[3] += output[13] << 4;
|
||||||
|
output[3] += output[13] << 1;
|
||||||
|
output[3] += output[13];
|
||||||
|
output[2] += output[12] << 4;
|
||||||
|
output[2] += output[12] << 1;
|
||||||
|
output[2] += output[12];
|
||||||
|
output[1] += output[11] << 4;
|
||||||
|
output[1] += output[11] << 1;
|
||||||
|
output[1] += output[11];
|
||||||
|
output[0] += output[10] << 4;
|
||||||
|
output[0] += output[10] << 1;
|
||||||
|
output[0] += output[10];
|
||||||
|
}
|
||||||
|
|
||||||
|
#if (-1 & 3) != 3
|
||||||
|
#error "This code only works on a two's complement system"
|
||||||
|
#endif
|
||||||
|
|
||||||
|
/* return v / 2^26, using only shifts and adds.
|
||||||
|
*
|
||||||
|
* On entry: v can take any value.
|
||||||
|
*/
|
||||||
|
static inline limb div_by_2_26(const limb v)
|
||||||
|
{
|
||||||
|
/* High word of v; no shift needed. */
|
||||||
|
const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
|
||||||
|
/* Set to all 1s if v was negative; else set to 0s. */
|
||||||
|
const int32_t sign = ((int32_t) highword) >> 31;
|
||||||
|
/* Set to 0x3ffffff if v was negative; else set to 0. */
|
||||||
|
const int32_t roundoff = ((uint32_t) sign) >> 6;
|
||||||
|
/* Should return v / (1<<26) */
|
||||||
|
return (v + roundoff) >> 26;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* return v / (2^25), using only shifts and adds.
|
||||||
|
*
|
||||||
|
* On entry: v can take any value.
|
||||||
|
*/
|
||||||
|
static inline limb div_by_2_25(const limb v)
|
||||||
|
{
|
||||||
|
/* High word of v; no shift needed*/
|
||||||
|
const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
|
||||||
|
/* Set to all 1s if v was negative; else set to 0s. */
|
||||||
|
const int32_t sign = ((int32_t) highword) >> 31;
|
||||||
|
/* Set to 0x1ffffff if v was negative; else set to 0. */
|
||||||
|
const int32_t roundoff = ((uint32_t) sign) >> 7;
|
||||||
|
/* Should return v / (1<<25) */
|
||||||
|
return (v + roundoff) >> 25;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Reduce all coefficients of the short form input so that |x| < 2^26.
|
||||||
|
*
|
||||||
|
* On entry: |output[i]| < 280*2^54
|
||||||
|
*/
|
||||||
|
static void freduce_coefficients(limb *output)
|
||||||
|
{
|
||||||
|
unsigned int i;
|
||||||
|
|
||||||
|
output[10] = 0;
|
||||||
|
|
||||||
|
for (i = 0; i < 10; i += 2) {
|
||||||
|
limb over = div_by_2_26(output[i]);
|
||||||
|
/* The entry condition (that |output[i]| < 280*2^54) means that over is, at
|
||||||
|
* most, 280*2^28 in the first iteration of this loop. This is added to the
|
||||||
|
* next limb and we can approximate the resulting bound of that limb by
|
||||||
|
* 281*2^54.
|
||||||
|
*/
|
||||||
|
output[i] -= over << 26;
|
||||||
|
output[i+1] += over;
|
||||||
|
|
||||||
|
/* For the first iteration, |output[i+1]| < 281*2^54, thus |over| <
|
||||||
|
* 281*2^29. When this is added to the next limb, the resulting bound can
|
||||||
|
* be approximated as 281*2^54.
|
||||||
|
*
|
||||||
|
* For subsequent iterations of the loop, 281*2^54 remains a conservative
|
||||||
|
* bound and no overflow occurs.
|
||||||
|
*/
|
||||||
|
over = div_by_2_25(output[i+1]);
|
||||||
|
output[i+1] -= over << 25;
|
||||||
|
output[i+2] += over;
|
||||||
|
}
|
||||||
|
/* Now |output[10]| < 281*2^29 and all other coefficients are reduced. */
|
||||||
|
output[0] += output[10] << 4;
|
||||||
|
output[0] += output[10] << 1;
|
||||||
|
output[0] += output[10];
|
||||||
|
|
||||||
|
output[10] = 0;
|
||||||
|
|
||||||
|
/* Now output[1..9] are reduced, and |output[0]| < 2^26 + 19*281*2^29
|
||||||
|
* So |over| will be no more than 2^16.
|
||||||
|
*/
|
||||||
|
{
|
||||||
|
limb over = div_by_2_26(output[0]);
|
||||||
|
|
||||||
|
output[0] -= over << 26;
|
||||||
|
output[1] += over;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Now output[0,2..9] are reduced, and |output[1]| < 2^25 + 2^16 < 2^26. The
|
||||||
|
* bound on |output[1]| is sufficient to meet our needs.
|
||||||
|
*/
|
||||||
|
}
|
||||||
|
|
||||||
|
/* A helpful wrapper around fproduct: output = in * in2.
|
||||||
|
*
|
||||||
|
* On entry: |in[i]| < 2^27 and |in2[i]| < 2^27.
|
||||||
|
*
|
||||||
|
* output must be distinct to both inputs. The output is reduced degree
|
||||||
|
* (indeed, one need only provide storage for 10 limbs) and |output[i]| < 2^26.
|
||||||
|
*/
|
||||||
|
static void fmul(limb *output, const limb *in, const limb *in2)
|
||||||
|
{
|
||||||
|
limb t[19];
|
||||||
|
|
||||||
|
fproduct(t, in, in2);
|
||||||
|
/* |t[i]| < 14*2^54 */
|
||||||
|
freduce_degree(t);
|
||||||
|
freduce_coefficients(t);
|
||||||
|
/* |t[i]| < 2^26 */
|
||||||
|
__builtin_memcpy(output, t, sizeof(limb) * 10);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Square a number: output = in**2
|
||||||
|
*
|
||||||
|
* output must be distinct from the input. The inputs are reduced coefficient
|
||||||
|
* form, the output is not.
|
||||||
|
*
|
||||||
|
* output[x] <= 14 * the largest product of the input limbs.
|
||||||
|
*/
|
||||||
|
static void fsquare_inner(limb *output, const limb *in)
|
||||||
|
{
|
||||||
|
output[0] = ((limb) ((int32_t) in[0])) * ((int32_t) in[0]);
|
||||||
|
output[1] = 2 * ((limb) ((int32_t) in[0])) * ((int32_t) in[1]);
|
||||||
|
output[2] = 2 * (((limb) ((int32_t) in[1])) * ((int32_t) in[1]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[2]));
|
||||||
|
output[3] = 2 * (((limb) ((int32_t) in[1])) * ((int32_t) in[2]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[3]));
|
||||||
|
output[4] = ((limb) ((int32_t) in[2])) * ((int32_t) in[2]) +
|
||||||
|
4 * ((limb) ((int32_t) in[1])) * ((int32_t) in[3]) +
|
||||||
|
2 * ((limb) ((int32_t) in[0])) * ((int32_t) in[4]);
|
||||||
|
output[5] = 2 * (((limb) ((int32_t) in[2])) * ((int32_t) in[3]) +
|
||||||
|
((limb) ((int32_t) in[1])) * ((int32_t) in[4]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[5]));
|
||||||
|
output[6] = 2 * (((limb) ((int32_t) in[3])) * ((int32_t) in[3]) +
|
||||||
|
((limb) ((int32_t) in[2])) * ((int32_t) in[4]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[6]) +
|
||||||
|
2 * ((limb) ((int32_t) in[1])) * ((int32_t) in[5]));
|
||||||
|
output[7] = 2 * (((limb) ((int32_t) in[3])) * ((int32_t) in[4]) +
|
||||||
|
((limb) ((int32_t) in[2])) * ((int32_t) in[5]) +
|
||||||
|
((limb) ((int32_t) in[1])) * ((int32_t) in[6]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[7]));
|
||||||
|
output[8] = ((limb) ((int32_t) in[4])) * ((int32_t) in[4]) +
|
||||||
|
2 * (((limb) ((int32_t) in[2])) * ((int32_t) in[6]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[8]) +
|
||||||
|
2 * (((limb) ((int32_t) in[1])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[3])) * ((int32_t) in[5])));
|
||||||
|
output[9] = 2 * (((limb) ((int32_t) in[4])) * ((int32_t) in[5]) +
|
||||||
|
((limb) ((int32_t) in[3])) * ((int32_t) in[6]) +
|
||||||
|
((limb) ((int32_t) in[2])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[1])) * ((int32_t) in[8]) +
|
||||||
|
((limb) ((int32_t) in[0])) * ((int32_t) in[9]));
|
||||||
|
output[10] = 2 * (((limb) ((int32_t) in[5])) * ((int32_t) in[5]) +
|
||||||
|
((limb) ((int32_t) in[4])) * ((int32_t) in[6]) +
|
||||||
|
((limb) ((int32_t) in[2])) * ((int32_t) in[8]) +
|
||||||
|
2 * (((limb) ((int32_t) in[3])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[1])) * ((int32_t) in[9])));
|
||||||
|
output[11] = 2 * (((limb) ((int32_t) in[5])) * ((int32_t) in[6]) +
|
||||||
|
((limb) ((int32_t) in[4])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[3])) * ((int32_t) in[8]) +
|
||||||
|
((limb) ((int32_t) in[2])) * ((int32_t) in[9]));
|
||||||
|
output[12] = ((limb) ((int32_t) in[6])) * ((int32_t) in[6]) +
|
||||||
|
2 * (((limb) ((int32_t) in[4])) * ((int32_t) in[8]) +
|
||||||
|
2 * (((limb) ((int32_t) in[5])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[3])) * ((int32_t) in[9])));
|
||||||
|
output[13] = 2 * (((limb) ((int32_t) in[6])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[5])) * ((int32_t) in[8]) +
|
||||||
|
((limb) ((int32_t) in[4])) * ((int32_t) in[9]));
|
||||||
|
output[14] = 2 * (((limb) ((int32_t) in[7])) * ((int32_t) in[7]) +
|
||||||
|
((limb) ((int32_t) in[6])) * ((int32_t) in[8]) +
|
||||||
|
2 * ((limb) ((int32_t) in[5])) * ((int32_t) in[9]));
|
||||||
|
output[15] = 2 * (((limb) ((int32_t) in[7])) * ((int32_t) in[8]) +
|
||||||
|
((limb) ((int32_t) in[6])) * ((int32_t) in[9]));
|
||||||
|
output[16] = ((limb) ((int32_t) in[8])) * ((int32_t) in[8]) +
|
||||||
|
4 * ((limb) ((int32_t) in[7])) * ((int32_t) in[9]);
|
||||||
|
output[17] = 2 * ((limb) ((int32_t) in[8])) * ((int32_t) in[9]);
|
||||||
|
output[18] = 2 * ((limb) ((int32_t) in[9])) * ((int32_t) in[9]);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* fsquare sets output = in^2.
|
||||||
|
*
|
||||||
|
* On entry: The |in| argument is in reduced coefficients form and |in[i]| <
|
||||||
|
* 2^27.
|
||||||
|
*
|
||||||
|
* On exit: The |output| argument is in reduced coefficients form (indeed, one
|
||||||
|
* need only provide storage for 10 limbs) and |out[i]| < 2^26.
|
||||||
|
*/
|
||||||
|
static void fsquare(limb *output, const limb *in)
|
||||||
|
{
|
||||||
|
limb t[19];
|
||||||
|
|
||||||
|
fsquare_inner(t, in);
|
||||||
|
/* |t[i]| < 14*2^54 because the largest product of two limbs will be <
|
||||||
|
* 2^(27+27) and fsquare_inner adds together, at most, 14 of those
|
||||||
|
* products.
|
||||||
|
*/
|
||||||
|
freduce_degree(t);
|
||||||
|
freduce_coefficients(t);
|
||||||
|
/* |t[i]| < 2^26 */
|
||||||
|
__builtin_memcpy(output, t, sizeof(limb) * 10);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Take a little-endian, 32-byte number and expand it into polynomial form */
|
||||||
|
static void fexpand(limb *output, const uint8_t *input)
|
||||||
|
{
|
||||||
|
#define F(n, start, shift, mask) \
|
||||||
|
output[n] = ((((limb) input[start + 0]) | \
|
||||||
|
((limb) input[start + 1]) << 8 | \
|
||||||
|
((limb) input[start + 2]) << 16 | \
|
||||||
|
((limb) input[start + 3]) << 24) >> shift) & mask;
|
||||||
|
F(0, 0, 0, 0x3ffffff);
|
||||||
|
F(1, 3, 2, 0x1ffffff);
|
||||||
|
F(2, 6, 3, 0x3ffffff);
|
||||||
|
F(3, 9, 5, 0x1ffffff);
|
||||||
|
F(4, 12, 6, 0x3ffffff);
|
||||||
|
F(5, 16, 0, 0x1ffffff);
|
||||||
|
F(6, 19, 1, 0x3ffffff);
|
||||||
|
F(7, 22, 3, 0x1ffffff);
|
||||||
|
F(8, 25, 4, 0x3ffffff);
|
||||||
|
F(9, 28, 6, 0x1ffffff);
|
||||||
|
#undef F
|
||||||
|
}
|
||||||
|
|
||||||
|
#if (-32 >> 1) != -16
|
||||||
|
#error "This code only works when >> does sign-extension on negative numbers"
|
||||||
|
#endif
|
||||||
|
|
||||||
|
/* int32_t_eq returns 0xffffffff iff a == b and zero otherwise. */
|
||||||
|
static int32_t int32_t_eq(int32_t a, int32_t b)
|
||||||
|
{
|
||||||
|
a = ~(a ^ b);
|
||||||
|
a &= a << 16;
|
||||||
|
a &= a << 8;
|
||||||
|
a &= a << 4;
|
||||||
|
a &= a << 2;
|
||||||
|
a &= a << 1;
|
||||||
|
return a >> 31;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* int32_t_gte returns 0xffffffff if a >= b and zero otherwise, where a and b are
|
||||||
|
* both non-negative.
|
||||||
|
*/
|
||||||
|
static int32_t int32_t_gte(int32_t a, int32_t b)
|
||||||
|
{
|
||||||
|
a -= b;
|
||||||
|
/* a >= 0 iff a >= b. */
|
||||||
|
return ~(a >> 31);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Take a fully reduced polynomial form number and contract it into a
|
||||||
|
* little-endian, 32-byte array.
|
||||||
|
*
|
||||||
|
* On entry: |input_limbs[i]| < 2^26
|
||||||
|
*/
|
||||||
|
static void fcontract(uint8_t *output, limb *input_limbs)
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
int j;
|
||||||
|
int32_t input[10];
|
||||||
|
int32_t mask;
|
||||||
|
|
||||||
|
/* |input_limbs[i]| < 2^26, so it's valid to convert to an int32_t. */
|
||||||
|
for (i = 0; i < 10; i++) {
|
||||||
|
input[i] = input_limbs[i];
|
||||||
|
}
|
||||||
|
|
||||||
|
for (j = 0; j < 2; ++j) {
|
||||||
|
for (i = 0; i < 9; ++i) {
|
||||||
|
if ((i & 1) == 1) {
|
||||||
|
/* This calculation is a time-invariant way to make input[i]
|
||||||
|
* non-negative by borrowing from the next-larger limb.
|
||||||
|
*/
|
||||||
|
const int32_t mask = input[i] >> 31;
|
||||||
|
const int32_t carry = -((input[i] & mask) >> 25);
|
||||||
|
|
||||||
|
input[i] = input[i] + (carry << 25);
|
||||||
|
input[i+1] = input[i+1] - carry;
|
||||||
|
} else {
|
||||||
|
const int32_t mask = input[i] >> 31;
|
||||||
|
const int32_t carry = -((input[i] & mask) >> 26);
|
||||||
|
|
||||||
|
input[i] = input[i] + (carry << 26);
|
||||||
|
input[i+1] = input[i+1] - carry;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/* There's no greater limb for input[9] to borrow from, but we can multiply
|
||||||
|
* by 19 and borrow from input[0], which is valid mod 2^255-19.
|
||||||
|
*/
|
||||||
|
{
|
||||||
|
const int32_t mask = input[9] >> 31;
|
||||||
|
const int32_t carry = -((input[9] & mask) >> 25);
|
||||||
|
|
||||||
|
input[9] = input[9] + (carry << 25);
|
||||||
|
input[0] = input[0] - (carry * 19);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* After the first iteration, input[1..9] are non-negative and fit within
|
||||||
|
* 25 or 26 bits, depending on position. However, input[0] may be
|
||||||
|
* negative.
|
||||||
|
*/
|
||||||
|
}
|
||||||
|
|
||||||
|
/* The first borrow-propagation pass above ended with every limb
|
||||||
|
except (possibly) input[0] non-negative.
|
||||||
|
If input[0] was negative after the first pass, then it was because of a
|
||||||
|
carry from input[9]. On entry, input[9] < 2^26 so the carry was, at most,
|
||||||
|
one, since (2**26-1) >> 25 = 1. Thus input[0] >= -19.
|
||||||
|
In the second pass, each limb is decreased by at most one. Thus the second
|
||||||
|
borrow-propagation pass could only have wrapped around to decrease
|
||||||
|
input[0] again if the first pass left input[0] negative *and* input[1]
|
||||||
|
through input[9] were all zero. In that case, input[1] is now 2^25 - 1,
|
||||||
|
and this last borrow-propagation step will leave input[1] non-negative. */
|
||||||
|
{
|
||||||
|
const int32_t mask = input[0] >> 31;
|
||||||
|
const int32_t carry = -((input[0] & mask) >> 26);
|
||||||
|
|
||||||
|
input[0] = input[0] + (carry << 26);
|
||||||
|
input[1] = input[1] - carry;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* All input[i] are now non-negative. However, there might be values between
|
||||||
|
* 2^25 and 2^26 in a limb which is, nominally, 25 bits wide.
|
||||||
|
*/
|
||||||
|
for (j = 0; j < 2; j++) {
|
||||||
|
for (i = 0; i < 9; i++) {
|
||||||
|
if ((i & 1) == 1) {
|
||||||
|
const int32_t carry = input[i] >> 25;
|
||||||
|
|
||||||
|
input[i] &= 0x1ffffff;
|
||||||
|
input[i+1] += carry;
|
||||||
|
} else {
|
||||||
|
const int32_t carry = input[i] >> 26;
|
||||||
|
|
||||||
|
input[i] &= 0x3ffffff;
|
||||||
|
input[i+1] += carry;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
{
|
||||||
|
const int32_t carry = input[9] >> 25;
|
||||||
|
|
||||||
|
input[9] &= 0x1ffffff;
|
||||||
|
input[0] += 19*carry;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/* If the first carry-chain pass, just above, ended up with a carry from
|
||||||
|
* input[9], and that caused input[0] to be out-of-bounds, then input[0] was
|
||||||
|
* < 2^26 + 2*19, because the carry was, at most, two.
|
||||||
|
*
|
||||||
|
* If the second pass carried from input[9] again then input[0] is < 2*19 and
|
||||||
|
* the input[9] -> input[0] carry didn't push input[0] out of bounds.
|
||||||
|
*/
|
||||||
|
|
||||||
|
/* It still remains the case that input might be between 2^255-19 and 2^255.
|
||||||
|
* In this case, input[1..9] must take their maximum value and input[0] must
|
||||||
|
* be >= (2^255-19) & 0x3ffffff, which is 0x3ffffed.
|
||||||
|
*/
|
||||||
|
mask = int32_t_gte(input[0], 0x3ffffed);
|
||||||
|
for (i = 1; i < 10; i++) {
|
||||||
|
if ((i & 1) == 1) {
|
||||||
|
mask &= int32_t_eq(input[i], 0x1ffffff);
|
||||||
|
} else {
|
||||||
|
mask &= int32_t_eq(input[i], 0x3ffffff);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/* mask is either 0xffffffff (if input >= 2^255-19) and zero otherwise. Thus
|
||||||
|
* this conditionally subtracts 2^255-19.
|
||||||
|
*/
|
||||||
|
input[0] -= mask & 0x3ffffed;
|
||||||
|
|
||||||
|
for (i = 1; i < 10; i++) {
|
||||||
|
if ((i & 1) == 1) {
|
||||||
|
input[i] -= mask & 0x1ffffff;
|
||||||
|
} else {
|
||||||
|
input[i] -= mask & 0x3ffffff;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
input[1] <<= 2;
|
||||||
|
input[2] <<= 3;
|
||||||
|
input[3] <<= 5;
|
||||||
|
input[4] <<= 6;
|
||||||
|
input[6] <<= 1;
|
||||||
|
input[7] <<= 3;
|
||||||
|
input[8] <<= 4;
|
||||||
|
input[9] <<= 6;
|
||||||
|
#define F(i, s) \
|
||||||
|
output[s+0] |= input[i] & 0xff; \
|
||||||
|
output[s+1] = (input[i] >> 8) & 0xff; \
|
||||||
|
output[s+2] = (input[i] >> 16) & 0xff; \
|
||||||
|
output[s+3] = (input[i] >> 24) & 0xff;
|
||||||
|
output[0] = 0;
|
||||||
|
output[16] = 0;
|
||||||
|
F(0, 0);
|
||||||
|
F(1, 3);
|
||||||
|
F(2, 6);
|
||||||
|
F(3, 9);
|
||||||
|
F(4, 12);
|
||||||
|
F(5, 16);
|
||||||
|
F(6, 19);
|
||||||
|
F(7, 22);
|
||||||
|
F(8, 25);
|
||||||
|
F(9, 28);
|
||||||
|
#undef F
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Input: Q, Q', Q-Q'
|
||||||
|
* Output: 2Q, Q+Q'
|
||||||
|
*
|
||||||
|
* x2 z3: long form
|
||||||
|
* x3 z3: long form
|
||||||
|
* x z: short form, destroyed
|
||||||
|
* xprime zprime: short form, destroyed
|
||||||
|
* qmqp: short form, preserved
|
||||||
|
*
|
||||||
|
* On entry and exit, the absolute value of the limbs of all inputs and outputs
|
||||||
|
* are < 2^26.
|
||||||
|
*/
|
||||||
|
static void fmonty(limb *x2, limb *z2, /* output 2Q */
|
||||||
|
limb *x3, limb *z3, /* output Q + Q' */
|
||||||
|
limb *x, limb *z, /* input Q */
|
||||||
|
limb *xprime, limb *zprime, /* input Q' */
|
||||||
|
|
||||||
|
const limb *qmqp /* input Q - Q' */)
|
||||||
|
{
|
||||||
|
limb origx[10], origxprime[10], zzz[19], xx[19], zz[19], xxprime[19],
|
||||||
|
zzprime[19], zzzprime[19], xxxprime[19];
|
||||||
|
|
||||||
|
__builtin_memcpy(origx, x, 10 * sizeof(limb));
|
||||||
|
fsum(x, z);
|
||||||
|
/* |x[i]| < 2^27 */
|
||||||
|
fdifference(z, origx); /* does x - z */
|
||||||
|
/* |z[i]| < 2^27 */
|
||||||
|
|
||||||
|
__builtin_memcpy(origxprime, xprime, sizeof(limb) * 10);
|
||||||
|
fsum(xprime, zprime);
|
||||||
|
/* |xprime[i]| < 2^27 */
|
||||||
|
fdifference(zprime, origxprime);
|
||||||
|
/* |zprime[i]| < 2^27 */
|
||||||
|
fproduct(xxprime, xprime, z);
|
||||||
|
/* |xxprime[i]| < 14*2^54: the largest product of two limbs will be <
|
||||||
|
* 2^(27+27) and fproduct adds together, at most, 14 of those products.
|
||||||
|
* (Approximating that to 2^58 doesn't work out.)
|
||||||
|
*/
|
||||||
|
fproduct(zzprime, x, zprime);
|
||||||
|
/* |zzprime[i]| < 14*2^54 */
|
||||||
|
freduce_degree(xxprime);
|
||||||
|
freduce_coefficients(xxprime);
|
||||||
|
/* |xxprime[i]| < 2^26 */
|
||||||
|
freduce_degree(zzprime);
|
||||||
|
freduce_coefficients(zzprime);
|
||||||
|
/* |zzprime[i]| < 2^26 */
|
||||||
|
__builtin_memcpy(origxprime, xxprime, sizeof(limb) * 10);
|
||||||
|
fsum(xxprime, zzprime);
|
||||||
|
/* |xxprime[i]| < 2^27 */
|
||||||
|
fdifference(zzprime, origxprime);
|
||||||
|
/* |zzprime[i]| < 2^27 */
|
||||||
|
fsquare(xxxprime, xxprime);
|
||||||
|
/* |xxxprime[i]| < 2^26 */
|
||||||
|
fsquare(zzzprime, zzprime);
|
||||||
|
/* |zzzprime[i]| < 2^26 */
|
||||||
|
fproduct(zzprime, zzzprime, qmqp);
|
||||||
|
/* |zzprime[i]| < 14*2^52 */
|
||||||
|
freduce_degree(zzprime);
|
||||||
|
freduce_coefficients(zzprime);
|
||||||
|
/* |zzprime[i]| < 2^26 */
|
||||||
|
__builtin_memcpy(x3, xxxprime, sizeof(limb) * 10);
|
||||||
|
__builtin_memcpy(z3, zzprime, sizeof(limb) * 10);
|
||||||
|
|
||||||
|
fsquare(xx, x);
|
||||||
|
/* |xx[i]| < 2^26 */
|
||||||
|
fsquare(zz, z);
|
||||||
|
/* |zz[i]| < 2^26 */
|
||||||
|
fproduct(x2, xx, zz);
|
||||||
|
/* |x2[i]| < 14*2^52 */
|
||||||
|
freduce_degree(x2);
|
||||||
|
freduce_coefficients(x2);
|
||||||
|
/* |x2[i]| < 2^26 */
|
||||||
|
fdifference(zz, xx); // does zz = xx - zz
|
||||||
|
/* |zz[i]| < 2^27 */
|
||||||
|
__builtin_memset(zzz + 10, 0, sizeof(limb) * 9);
|
||||||
|
fscalar_product(zzz, zz, 121665);
|
||||||
|
/* |zzz[i]| < 2^(27+17) */
|
||||||
|
/* No need to call freduce_degree here:
|
||||||
|
fscalar_product doesn't increase the degree of its input. */
|
||||||
|
freduce_coefficients(zzz);
|
||||||
|
/* |zzz[i]| < 2^26 */
|
||||||
|
fsum(zzz, xx);
|
||||||
|
/* |zzz[i]| < 2^27 */
|
||||||
|
fproduct(z2, zz, zzz);
|
||||||
|
/* |z2[i]| < 14*2^(26+27) */
|
||||||
|
freduce_degree(z2);
|
||||||
|
freduce_coefficients(z2);
|
||||||
|
/* |z2|i| < 2^26 */
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Conditionally swap two reduced-form limb arrays if 'iswap' is 1, but leave
|
||||||
|
* them unchanged if 'iswap' is 0. Runs in data-invariant time to avoid
|
||||||
|
* side-channel attacks.
|
||||||
|
*
|
||||||
|
* NOTE that this function requires that 'iswap' be 1 or 0; other values give
|
||||||
|
* wrong results. Also, the two limb arrays must be in reduced-coefficient,
|
||||||
|
* reduced-degree form: the values in a[10..19] or b[10..19] aren't swapped,
|
||||||
|
* and all all values in a[0..9],b[0..9] must have magnitude less than
|
||||||
|
* INT32_MAX.
|
||||||
|
*/
|
||||||
|
static void swap_conditional(limb a[static 19], limb b[static 19], limb iswap)
|
||||||
|
{
|
||||||
|
unsigned int i;
|
||||||
|
const int32_t swap = (int32_t) -iswap;
|
||||||
|
|
||||||
|
for (i = 0; i < 10; ++i) {
|
||||||
|
const int32_t x = swap & (((int32_t)a[i]) ^ ((int32_t)b[i]));
|
||||||
|
|
||||||
|
a[i] = ((int32_t)a[i]) ^ x;
|
||||||
|
b[i] = ((int32_t)b[i]) ^ x;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Calculates nQ where Q is the x-coordinate of a point on the curve
|
||||||
|
*
|
||||||
|
* resultx/resultz: the x coordinate of the resulting curve point (short form)
|
||||||
|
* n: a little endian, 32-byte number
|
||||||
|
* q: a point of the curve (short form)
|
||||||
|
*/
|
||||||
|
static void cmult(limb *resultx, limb *resultz, const uint8_t *n, const limb *q)
|
||||||
|
{
|
||||||
|
limb a[19] = {0}, b[19] = {1}, c[19] = {1}, d[19] = {0};
|
||||||
|
limb *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t;
|
||||||
|
limb e[19] = {0}, f[19] = {1}, g[19] = {0}, h[19] = {1};
|
||||||
|
limb *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h;
|
||||||
|
|
||||||
|
unsigned int i, j;
|
||||||
|
|
||||||
|
__builtin_memcpy(nqpqx, q, sizeof(limb) * 10);
|
||||||
|
|
||||||
|
for (i = 0; i < 32; ++i) {
|
||||||
|
uint8_t byte = n[31 - i];
|
||||||
|
|
||||||
|
for (j = 0; j < 8; ++j) {
|
||||||
|
const limb bit = byte >> 7;
|
||||||
|
|
||||||
|
swap_conditional(nqx, nqpqx, bit);
|
||||||
|
swap_conditional(nqz, nqpqz, bit);
|
||||||
|
fmonty(nqx2, nqz2,
|
||||||
|
nqpqx2, nqpqz2,
|
||||||
|
nqx, nqz,
|
||||||
|
nqpqx, nqpqz,
|
||||||
|
q);
|
||||||
|
swap_conditional(nqx2, nqpqx2, bit);
|
||||||
|
swap_conditional(nqz2, nqpqz2, bit);
|
||||||
|
|
||||||
|
t = nqx;
|
||||||
|
nqx = nqx2;
|
||||||
|
nqx2 = t;
|
||||||
|
t = nqz;
|
||||||
|
nqz = nqz2;
|
||||||
|
nqz2 = t;
|
||||||
|
t = nqpqx;
|
||||||
|
nqpqx = nqpqx2;
|
||||||
|
nqpqx2 = t;
|
||||||
|
t = nqpqz;
|
||||||
|
nqpqz = nqpqz2;
|
||||||
|
nqpqz2 = t;
|
||||||
|
|
||||||
|
byte <<= 1;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
__builtin_memcpy(resultx, nqx, sizeof(limb) * 10);
|
||||||
|
__builtin_memcpy(resultz, nqz, sizeof(limb) * 10);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void crecip(limb *out, const limb *z)
|
||||||
|
{
|
||||||
|
limb z2[10];
|
||||||
|
limb z9[10];
|
||||||
|
limb z11[10];
|
||||||
|
limb z2_5_0[10];
|
||||||
|
limb z2_10_0[10];
|
||||||
|
limb z2_20_0[10];
|
||||||
|
limb z2_50_0[10];
|
||||||
|
limb z2_100_0[10];
|
||||||
|
limb t0[10];
|
||||||
|
limb t1[10];
|
||||||
|
int i;
|
||||||
|
|
||||||
|
/* 2 */ fsquare(z2, z);
|
||||||
|
/* 4 */ fsquare(t1, z2);
|
||||||
|
/* 8 */ fsquare(t0, t1);
|
||||||
|
/* 9 */ fmul(z9, t0, z);
|
||||||
|
/* 11 */ fmul(z11, z9, z2);
|
||||||
|
/* 22 */ fsquare(t0, z11);
|
||||||
|
/* 2^5 - 2^0 = 31 */ fmul(z2_5_0, t0, z9);
|
||||||
|
|
||||||
|
/* 2^6 - 2^1 */ fsquare(t0, z2_5_0);
|
||||||
|
/* 2^7 - 2^2 */ fsquare(t1, t0);
|
||||||
|
/* 2^8 - 2^3 */ fsquare(t0, t1);
|
||||||
|
/* 2^9 - 2^4 */ fsquare(t1, t0);
|
||||||
|
/* 2^10 - 2^5 */ fsquare(t0, t1);
|
||||||
|
/* 2^10 - 2^0 */ fmul(z2_10_0, t0, z2_5_0);
|
||||||
|
|
||||||
|
/* 2^11 - 2^1 */ fsquare(t0, z2_10_0);
|
||||||
|
/* 2^12 - 2^2 */ fsquare(t1, t0);
|
||||||
|
/* 2^20 - 2^10 */ for (i = 2; i < 10; i += 2) { fsquare(t0, t1); fsquare(t1, t0); }
|
||||||
|
/* 2^20 - 2^0 */ fmul(z2_20_0, t1, z2_10_0);
|
||||||
|
|
||||||
|
/* 2^21 - 2^1 */ fsquare(t0, z2_20_0);
|
||||||
|
/* 2^22 - 2^2 */ fsquare(t1, t0);
|
||||||
|
/* 2^40 - 2^20 */ for (i = 2; i < 20; i += 2) { fsquare(t0, t1); fsquare(t1, t0); }
|
||||||
|
/* 2^40 - 2^0 */ fmul(t0, t1, z2_20_0);
|
||||||
|
|
||||||
|
/* 2^41 - 2^1 */ fsquare(t1, t0);
|
||||||
|
/* 2^42 - 2^2 */ fsquare(t0, t1);
|
||||||
|
/* 2^50 - 2^10 */ for (i = 2; i < 10; i += 2) { fsquare(t1, t0); fsquare(t0, t1); }
|
||||||
|
/* 2^50 - 2^0 */ fmul(z2_50_0, t0, z2_10_0);
|
||||||
|
|
||||||
|
/* 2^51 - 2^1 */ fsquare(t0, z2_50_0);
|
||||||
|
/* 2^52 - 2^2 */ fsquare(t1, t0);
|
||||||
|
/* 2^100 - 2^50 */ for (i = 2; i < 50; i += 2) { fsquare(t0, t1); fsquare(t1, t0); }
|
||||||
|
/* 2^100 - 2^0 */ fmul(z2_100_0, t1, z2_50_0);
|
||||||
|
|
||||||
|
/* 2^101 - 2^1 */ fsquare(t1, z2_100_0);
|
||||||
|
/* 2^102 - 2^2 */ fsquare(t0, t1);
|
||||||
|
/* 2^200 - 2^100 */ for (i = 2; i < 100; i += 2) { fsquare(t1, t0); fsquare(t0, t1); }
|
||||||
|
/* 2^200 - 2^0 */ fmul(t1, t0, z2_100_0);
|
||||||
|
|
||||||
|
/* 2^201 - 2^1 */ fsquare(t0, t1);
|
||||||
|
/* 2^202 - 2^2 */ fsquare(t1, t0);
|
||||||
|
/* 2^250 - 2^50 */ for (i = 2; i < 50; i += 2) { fsquare(t0, t1); fsquare(t1, t0); }
|
||||||
|
/* 2^250 - 2^0 */ fmul(t0, t1, z2_50_0);
|
||||||
|
|
||||||
|
/* 2^251 - 2^1 */ fsquare(t1, t0);
|
||||||
|
/* 2^252 - 2^2 */ fsquare(t0, t1);
|
||||||
|
/* 2^253 - 2^3 */ fsquare(t1, t0);
|
||||||
|
/* 2^254 - 2^4 */ fsquare(t0, t1);
|
||||||
|
/* 2^255 - 2^5 */ fsquare(t1, t0);
|
||||||
|
/* 2^255 - 21 */ fmul(out, t1, z11);
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline void curve25519_normalize_secret(uint8_t secret[static 32])
|
||||||
|
{
|
||||||
|
secret[0] &= 248;
|
||||||
|
secret[31] &= 127;
|
||||||
|
secret[31] |= 64;
|
||||||
|
}
|
||||||
|
static inline void curve25519(uint8_t mypublic[static 32], const uint8_t secret[static 32], const uint8_t basepoint[static 32])
|
||||||
|
{
|
||||||
|
limb bp[10], x[10], z[11], zmone[10];
|
||||||
|
uint8_t e[32];
|
||||||
|
|
||||||
|
__builtin_memcpy(e, secret, 32);
|
||||||
|
curve25519_normalize_secret(e);
|
||||||
|
|
||||||
|
fexpand(bp, basepoint);
|
||||||
|
cmult(x, z, e, bp);
|
||||||
|
crecip(zmone, z);
|
||||||
|
fmul(z, x, zmone);
|
||||||
|
fcontract(mypublic, z);
|
||||||
|
}
|
||||||
|
|
||||||
|
EMSCRIPTEN_KEEPALIVE void curve25519_generate_public(uint8_t public[static 32], const uint8_t private[static 32])
|
||||||
|
{
|
||||||
|
static const uint8_t basepoint[32] = { 9 };
|
||||||
|
|
||||||
|
curve25519(public, private, basepoint);
|
||||||
|
}
|
||||||
|
|
||||||
|
EMSCRIPTEN_KEEPALIVE void curve25519_generate_private(uint8_t private[static 32])
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
|
||||||
|
EM_ASM({
|
||||||
|
/* Same trick as libsodium */
|
||||||
|
var getRandomValue = function() {
|
||||||
|
var buf = new Uint32Array(1);
|
||||||
|
window.crypto.getRandomValues(buf);
|
||||||
|
return buf[0] >>> 0;
|
||||||
|
};
|
||||||
|
Module.getRandomValue = getRandomValue;
|
||||||
|
});
|
||||||
|
|
||||||
|
for (i = 0; i < 32; ++i)
|
||||||
|
private[i] = EM_ASM_INT_V({ return Module.getRandomValue(); });
|
||||||
|
curve25519_normalize_secret(private);
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline void encode_base64(char dest[4], const uint8_t src[3])
|
||||||
|
{
|
||||||
|
const uint8_t input[] = { (src[0] >> 2) & 63, ((src[0] << 4) | (src[1] >> 4)) & 63, ((src[1] << 2) | (src[2] >> 6)) & 63, src[2] & 63 };
|
||||||
|
|
||||||
|
for (unsigned int i = 0; i < 4; ++i)
|
||||||
|
dest[i] = input[i] + 'A'
|
||||||
|
+ (((25 - input[i]) >> 8) & 6)
|
||||||
|
- (((51 - input[i]) >> 8) & 75)
|
||||||
|
- (((61 - input[i]) >> 8) & 15)
|
||||||
|
+ (((62 - input[i]) >> 8) & 3);
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
EMSCRIPTEN_KEEPALIVE void key_to_base64(char base64[static 45], const uint8_t key[static 32])
|
||||||
|
{
|
||||||
|
unsigned int i;
|
||||||
|
|
||||||
|
for (i = 0; i < 32 / 3; ++i)
|
||||||
|
encode_base64(&base64[i * 4], &key[i * 3]);
|
||||||
|
encode_base64(&base64[i * 4], (const uint8_t[]){ key[i * 3 + 0], key[i * 3 + 1], 0 });
|
||||||
|
base64[45 - 2] = '=';
|
||||||
|
base64[45 - 1] = '\0';
|
||||||
|
}
|
||||||
Loading…
Reference in New Issue