| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/incubator-teaclave-crates-c8106113f74feefc/ede1f68/ring/src/ec/suite_b.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>suite_b.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../ring/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../ring/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="comment">// Copyright 2016 Brian Smith. |
| // |
| // Permission to use, copy, modify, and/or distribute this software for any |
| // purpose with or without fee is hereby granted, provided that the above |
| // copyright notice and this permission notice appear in all copies. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES |
| // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
| // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| |
| </span><span class="doccomment">//! Elliptic curve operations on P-256 & P-384. |
| |
| </span><span class="kw">use </span><span class="self">self</span>::ops::<span class="kw-2">*</span>; |
| <span class="kw">use crate</span>::{arithmetic::montgomery::<span class="kw-2">*</span>, cpu, ec, error, io::der, limb::LimbMask, pkcs8}; |
| |
| <span class="comment">// NIST SP 800-56A Step 3: "If q is an odd prime p, verify that |
| // yQ**2 = xQ**3 + axQ + b in GF(p), where the arithmetic is performed modulo |
| // p." |
| // |
| // That is, verify that (x, y) is on the curve, which is true iif: |
| // |
| // y**2 == x**3 + a*x + b (mod q) |
| // |
| // Or, equivalently, but more efficiently: |
| // |
| // y**2 == (x**2 + a)*x + b (mod q) |
| // |
| </span><span class="kw">fn </span>verify_affine_point_is_on_the_curve( |
| ops: <span class="kw-2">&</span>CommonOps, |
| (x, y): (<span class="kw-2">&</span>Elem<R>, <span class="kw-2">&</span>Elem<R>), |
| ) -> <span class="prelude-ty">Result</span><(), error::Unspecified> { |
| verify_affine_point_is_on_the_curve_scaled(ops, (x, y), <span class="kw-2">&</span>ops.a, <span class="kw-2">&</span>ops.b) |
| } |
| |
| <span class="comment">// Use `verify_affine_point_is_on_the_curve` instead of this function whenever |
| // the affine coordinates are available or will become available. This function |
| // should only be used then the affine coordinates are never calculated. See |
| // the notes for `verify_affine_point_is_on_the_curve_scaled`. |
| // |
| // The value `z**2` is returned on success because it is useful for ECDSA |
| // verification. |
| // |
| // This function also verifies that the point is not at infinity. |
| </span><span class="kw">fn </span>verify_jacobian_point_is_on_the_curve( |
| ops: <span class="kw-2">&</span>CommonOps, |
| p: <span class="kw-2">&</span>Point, |
| ) -> <span class="prelude-ty">Result</span><Elem<R>, error::Unspecified> { |
| <span class="kw">let </span>z = ops.point_z(p); |
| |
| <span class="comment">// Verify that the point is not at infinity. |
| </span>ops.elem_verify_is_not_zero(<span class="kw-2">&</span>z)<span class="question-mark">?</span>; |
| |
| <span class="kw">let </span>x = ops.point_x(p); |
| <span class="kw">let </span>y = ops.point_y(p); |
| |
| <span class="comment">// We are given Jacobian coordinates (x, y, z). So, we have: |
| // |
| // (x/z**2, y/z**3) == (x', y'), |
| // |
| // where (x', y') are the affine coordinates. The curve equation is: |
| // |
| // y'**2 == x'**3 + a*x' + b == (x'**2 + a)*x' + b |
| // |
| // Substituting our Jacobian coordinates, we get: |
| // |
| // / y \**2 / / x \**2 \ / x \ |
| // | ---- | == | | ---- | + a | * | ---- | + b |
| // \ z**3 / \ \ z**2 / / \ z**2 / |
| // |
| // Simplify: |
| // |
| // y**2 / x**2 \ x |
| // ---- == | ---- + a | * ---- + b |
| // z**6 \ z**4 / z**2 |
| // |
| // Multiply both sides by z**6: |
| // |
| // z**6 / x**2 \ z**6 |
| // ---- * y**2 == | ---- + a | * ---- * x + (z**6) * b |
| // z**6 \ z**4 / z**2 |
| // |
| // Simplify: |
| // |
| // / x**2 \ |
| // y**2 == | ---- + a | * z**4 * x + (z**6) * b |
| // \ z**4 / |
| // |
| // Distribute z**4: |
| // |
| // / z**4 \ |
| // y**2 == | ---- * x**2 + z**4 * a | * x + (z**6) * b |
| // \ z**4 / |
| // |
| // Simplify: |
| // |
| // y**2 == (x**2 + z**4 * a) * x + (z**6) * b |
| // |
| </span><span class="kw">let </span>z2 = ops.elem_squared(<span class="kw-2">&</span>z); |
| <span class="kw">let </span>z4 = ops.elem_squared(<span class="kw-2">&</span>z2); |
| <span class="kw">let </span>z4_a = ops.elem_product(<span class="kw-2">&</span>z4, <span class="kw-2">&</span>ops.a); |
| <span class="kw">let </span>z6 = ops.elem_product(<span class="kw-2">&</span>z4, <span class="kw-2">&</span>z2); |
| <span class="kw">let </span>z6_b = ops.elem_product(<span class="kw-2">&</span>z6, <span class="kw-2">&</span>ops.b); |
| verify_affine_point_is_on_the_curve_scaled(ops, (<span class="kw-2">&</span>x, <span class="kw-2">&</span>y), <span class="kw-2">&</span>z4_a, <span class="kw-2">&</span>z6_b)<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(z2) |
| } |
| |
| <span class="comment">// Handles the common logic of point-is-on-the-curve checks for both affine and |
| // Jacobian cases. |
| // |
| // When doing the check that the point is on the curve after a computation, |
| // to avoid fault attacks or mitigate potential bugs, it is better for security |
| // to use `verify_affine_point_is_on_the_curve` on the affine coordinates, |
| // because it provides some protection against faults that occur in the |
| // computation of the inverse of `z`. See the paper and presentation "Fault |
| // Attacks on Projective-to-Affine Coordinates Conversion" by Diana Maimuţ, |
| // Cédric Murdica, David Naccache, Mehdi Tibouchi. That presentation concluded |
| // simply "Check the validity of the result after conversion to affine |
| // coordinates." (It seems like a good idea to verify that |
| // z_inv * z == 1 mod q too). |
| // |
| // In the case of affine coordinates (x, y), `a_scaled` and `b_scaled` are |
| // `a` and `b`, respectively. In the case of Jacobian coordinates (x, y, z), |
| // the computation and comparison is the same, except `a_scaled` and `b_scaled` |
| // are (z**4 * a) and (z**6 * b), respectively. Thus, performance is another |
| // reason to prefer doing the check on the affine coordinates, as Jacobian |
| // computation requires 3 extra multiplications and 2 extra squarings. |
| // |
| // An example of a fault attack that isn't mitigated by a point-on-the-curve |
| // check after multiplication is given in "Sign Change Fault Attacks On |
| // Elliptic Curve Cryptosystems" by Johannes Blömer, Martin Otto, and |
| // Jean-Pierre Seifert. |
| </span><span class="kw">fn </span>verify_affine_point_is_on_the_curve_scaled( |
| ops: <span class="kw-2">&</span>CommonOps, |
| (x, y): (<span class="kw-2">&</span>Elem<R>, <span class="kw-2">&</span>Elem<R>), |
| a_scaled: <span class="kw-2">&</span>Elem<R>, |
| b_scaled: <span class="kw-2">&</span>Elem<R>, |
| ) -> <span class="prelude-ty">Result</span><(), error::Unspecified> { |
| <span class="kw">let </span>lhs = ops.elem_squared(y); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>rhs = ops.elem_squared(x); |
| ops.elem_add(<span class="kw-2">&mut </span>rhs, a_scaled); |
| ops.elem_mul(<span class="kw-2">&mut </span>rhs, x); |
| ops.elem_add(<span class="kw-2">&mut </span>rhs, b_scaled); |
| |
| <span class="kw">if </span>ops.elems_are_equal(<span class="kw-2">&</span>lhs, <span class="kw-2">&</span>rhs) != LimbMask::True { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(error::Unspecified); |
| } |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>key_pair_from_pkcs8( |
| curve: <span class="kw-2">&</span><span class="lifetime">'static </span>ec::Curve, |
| template: <span class="kw-2">&</span>pkcs8::Template, |
| input: untrusted::Input, |
| cpu_features: cpu::Features, |
| ) -> <span class="prelude-ty">Result</span><ec::KeyPair, error::KeyRejected> { |
| <span class="kw">let </span>(ec_private_key, <span class="kw">_</span>) = pkcs8::unwrap_key(template, pkcs8::Version::V1Only, input)<span class="question-mark">?</span>; |
| <span class="kw">let </span>(private_key, public_key) = |
| ec_private_key.read_all(error::KeyRejected::invalid_encoding(), |input| { |
| <span class="comment">// https://tools.ietf.org/html/rfc5915#section-3 |
| </span>der::nested( |
| input, |
| der::Tag::Sequence, |
| error::KeyRejected::invalid_encoding(), |
| |input| key_pair_from_pkcs8_(template, input), |
| ) |
| })<span class="question-mark">?</span>; |
| key_pair_from_bytes(curve, private_key, public_key, cpu_features) |
| } |
| |
| <span class="kw">fn </span>key_pair_from_pkcs8_<<span class="lifetime">'a</span>>( |
| template: <span class="kw-2">&</span>pkcs8::Template, |
| input: <span class="kw-2">&mut </span>untrusted::Reader<<span class="lifetime">'a</span>>, |
| ) -> <span class="prelude-ty">Result</span><(untrusted::Input<<span class="lifetime">'a</span>>, untrusted::Input<<span class="lifetime">'a</span>>), error::KeyRejected> { |
| <span class="kw">let </span>version = der::small_nonnegative_integer(input) |
| .map_err(|error::Unspecified| error::KeyRejected::invalid_encoding())<span class="question-mark">?</span>; |
| <span class="kw">if </span>version != <span class="number">1 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(error::KeyRejected::version_not_supported()); |
| } |
| |
| <span class="kw">let </span>private_key = der::expect_tag_and_get_value(input, der::Tag::OctetString) |
| .map_err(|error::Unspecified| error::KeyRejected::invalid_encoding())<span class="question-mark">?</span>; |
| |
| <span class="comment">// [0] parameters (optional). |
| </span><span class="kw">if </span>input.peek(u8::from(der::Tag::ContextSpecificConstructed0)) { |
| <span class="kw">let </span>actual_alg_id = |
| der::expect_tag_and_get_value(input, der::Tag::ContextSpecificConstructed0) |
| .map_err(|error::Unspecified| error::KeyRejected::invalid_encoding())<span class="question-mark">?</span>; |
| <span class="kw">if </span>actual_alg_id != template.curve_oid() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(error::KeyRejected::wrong_algorithm()); |
| } |
| } |
| |
| <span class="comment">// [1] publicKey. The RFC says it is optional, but we require it |
| // to be present. |
| </span><span class="kw">let </span>public_key = der::nested( |
| input, |
| der::Tag::ContextSpecificConstructed1, |
| error::Unspecified, |
| der::bit_string_with_no_unused_bits, |
| ) |
| .map_err(|error::Unspecified| error::KeyRejected::invalid_encoding())<span class="question-mark">?</span>; |
| |
| <span class="prelude-val">Ok</span>((private_key, public_key)) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>key_pair_from_bytes( |
| curve: <span class="kw-2">&</span><span class="lifetime">'static </span>ec::Curve, |
| private_key_bytes: untrusted::Input, |
| public_key_bytes: untrusted::Input, |
| cpu_features: cpu::Features, |
| ) -> <span class="prelude-ty">Result</span><ec::KeyPair, error::KeyRejected> { |
| <span class="kw">let </span>seed = ec::Seed::from_bytes(curve, private_key_bytes, cpu_features) |
| .map_err(|error::Unspecified| error::KeyRejected::invalid_component())<span class="question-mark">?</span>; |
| |
| <span class="kw">let </span>r = ec::KeyPair::derive(seed) |
| .map_err(|error::Unspecified| error::KeyRejected::unexpected_error())<span class="question-mark">?</span>; |
| <span class="kw">if </span>public_key_bytes != <span class="kw-2">*</span>r.public_key().as_ref() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(error::KeyRejected::inconsistent_components()); |
| } |
| |
| <span class="prelude-val">Ok</span>(r) |
| } |
| |
| <span class="kw">pub mod </span>curve; |
| <span class="kw">pub mod </span>ecdh; |
| <span class="kw">pub mod </span>ecdsa; |
| |
| <span class="kw">mod </span>ops; |
| |
| <span class="kw">mod </span>private_key; |
| <span class="kw">mod </span>public_key; |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="ring" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
