ring

Facts and the checks behind them

Nothing below is copied from documentation. The check content/libraries/verify/ring/run.sh ran ring 0.17.14 in the container image rust:1.99.1-trixie on October 20, 2026; the page must match what it printed, and each fact lists those lines.

• ECDSA signature encoding

  der-or-raw

  The algorithm constant chooses the encoding: *_FIXED signs and verifies 64-byte raw r‖s, *_ASN1 DER; a signature does not verify under the other constant.

  Recorded by the check

  fact ecdsa-signature-encoding = der-or-raw
  evidence ecdsa-signature-encoding: FIXED signs 64 bytes; ASN1 output starts with 0x30 (a DER SEQUENCE)
  evidence ecdsa-signature-encoding: a signature verifies under the other encoding's constant: false

• ECDSA nonce

  random

  Random nonce: two signatures of the same message differ, and there is no deterministic option.

  Recorded by the check

  fact ecdsa-nonce = random

• Low-S when signing

  either

  s is not normalized: high-S values appeared among 64 signatures.

  Recorded by the check

  fact ecdsa-low-s-sign = either

• High-S when verifying

  accepts-high-s

  The FIXED verifier accepted the signature with s replaced by n − s.

  Recorded by the check

  fact ecdsa-low-s-verify = accepts-high-s

• What the signing call hashes

  hashes-message

  The message is hashed as the algorithm says; there is no API for signing a precomputed digest.

  Recorded by the check

  fact ecdsa-prehash = hashes-message
  evidence ecdsa-prehash: the API has no entry point for signing a precomputed digest

• Malformed ECDSA signature

  returns-error

  verify() returns Err(Unspecified) for a malformed or wrong signature, with no detail.

  Recorded by the check

  fact ecdsa-malformed-signature = returns-error
  evidence ecdsa-malformed-signature: verify() of 3 bytes: Err(Unspecified)

• ECDSA curves

  P-256P-384

  P-256 and P-384 only.

  Recorded by the check

  fact ecdsa-curves = P-256, P-384
  evidence ecdsa-curves: ring defines ECDSA_P256_* and ECDSA_P384_* algorithms only

• EdDSA

  Ed25519

  Ed25519.

  Recorded by the check

  fact eddsa = Ed25519

• Ed25519 PKCS #8 v1 keys

  rejected-by-from-pkcs8

  A 48-byte PKCS#8 v1 Ed25519 key was refused by from_pkcs8 with VersionNotSupported; from_pkcs8_maybe_unchecked and from_seed_unchecked accepted it. generate_pkcs8 writes 83-byte v2 keys.

  Recorded by the check

  fact ed25519-pkcs8-v1 = rejected-by-from-pkcs8
  evidence ed25519-pkcs8-v1: generate_pkcs8 writes 83 bytes (PKCS#8 v2 with the public key); a 48-byte v1 key: from_pkcs8 Err(KeyRejected("VersionNotSupported")), from_pkcs8_maybe_unchecked ok true, from_seed_unchecked ok true

• Post-quantum algorithms

  none

  No post-quantum algorithms.

  Recorded by the check

  fact pqc = none

• Public key formats

  sec1-uncompressed

  Public keys are uncompressed SEC1 points (65 bytes for P-256); compressed points failed, and there is no SPKI, PEM or JWK parsing.

  Recorded by the check

  fact public-key-formats = sec1-uncompressed
  evidence public-key-formats: public_key() returns 65 bytes (uncompressed SEC1); no SPKI, PEM or JWK parsing

• Private key formats

  pkcs8-der

  Private keys load only from PKCS#8 DER.

  Recorded by the check

  fact private-key-formats = pkcs8-der

Usage

use ring::rand::SystemRandom;
use ring::signature::{self, EcdsaKeyPair, KeyPair, UnparsedPublicKey};

fn main() {
    let rng = SystemRandom::new();
    // ring only reads PKCS#8 DER private keys.
    let pkcs8 = EcdsaKeyPair::generate_pkcs8(&signature::ECDSA_P256_SHA256_FIXED_SIGNING, &rng).unwrap();
    let message = b"order #1042 approved";

    // The algorithm constant fixes the encoding: FIXED = raw r||s (JWS, WebCrypto),
    // ASN1 = DER (OpenSSL, Java). Verify with the matching constant.
    let fixed = EcdsaKeyPair::from_pkcs8(&signature::ECDSA_P256_SHA256_FIXED_SIGNING, pkcs8.as_ref(), &rng).unwrap();
    let raw = fixed.sign(&rng, message).unwrap();
    let public = fixed.public_key().as_ref(); // 65-byte uncompressed SEC1 point

    let ok = UnparsedPublicKey::new(&signature::ECDSA_P256_SHA256_FIXED, public).verify(message, raw.as_ref()).is_ok();
    let wrong = UnparsedPublicKey::new(&signature::ECDSA_P256_SHA256_ASN1, public).verify(message, raw.as_ref()).is_ok();
    println!("raw bytes: {}, verified: {ok}, verified as DER: {wrong}", raw.as_ref().len());
}