Commit 9c0d975a09

Frank Denis <124872+jedisct1@users.noreply.github.com>
2022-10-27 19:07:42
Revamp the ed25519 API (#13309)
1 parent 710e2e7
Changed files (3)
lib/std/crypto/25519/ed25519.zig
@@ -16,27 +16,227 @@ const WeakPublicKeyError = crypto.errors.WeakPublicKeyError;
 /// Ed25519 (EdDSA) signatures.
 pub const Ed25519 = struct {
     /// The underlying elliptic curve.
-    pub const Curve = @import("edwards25519.zig").Edwards25519;
-    /// Length (in bytes) of a seed required to create a key pair.
-    pub const seed_length = 32;
-    /// Length (in bytes) of a compressed secret key.
-    pub const secret_length = 64;
-    /// Length (in bytes) of a compressed public key.
-    pub const public_length = 32;
-    /// Length (in bytes) of a signature.
-    pub const signature_length = 64;
+    pub const Curve = std.crypto.ecc.Edwards25519;
+
     /// Length (in bytes) of optional random bytes, for non-deterministic signatures.
     pub const noise_length = 32;
 
     const CompressedScalar = Curve.scalar.CompressedScalar;
     const Scalar = Curve.scalar.Scalar;
 
+    /// An Ed25519 secret key.
+    pub const SecretKey = struct {
+        /// Length (in bytes) of a raw secret key.
+        pub const encoded_length = 64;
+
+        bytes: [encoded_length]u8,
+
+        /// Return the seed used to generate this secret key.
+        pub fn seed(self: SecretKey) [KeyPair.seed_length]u8 {
+            return self.bytes[0..KeyPair.seed_length].*;
+        }
+
+        /// Return the raw public key bytes corresponding to this secret key.
+        pub fn publicKeyBytes(self: SecretKey) [PublicKey.encoded_length]u8 {
+            return self.bytes[KeyPair.seed_length..].*;
+        }
+
+        /// Create a secret key from raw bytes.
+        pub fn fromBytes(bytes: [encoded_length]u8) !SecretKey {
+            return SecretKey{ .bytes = bytes };
+        }
+
+        /// Return the secret key as raw bytes.
+        pub fn toBytes(sk: SecretKey) [encoded_length]u8 {
+            return sk.bytes;
+        }
+
+        // Return the clamped secret scalar and prefix for this secret key
+        fn scalarAndPrefix(self: SecretKey) struct { scalar: CompressedScalar, prefix: [32]u8 } {
+            var az: [Sha512.digest_length]u8 = undefined;
+            var h = Sha512.init(.{});
+            h.update(&self.seed());
+            h.final(&az);
+
+            var s = az[0..32].*;
+            Curve.scalar.clamp(&s);
+
+            return .{ .scalar = s, .prefix = az[32..].* };
+        }
+    };
+
+    /// A Signer is used to incrementally compute a signature.
+    /// It can be obtained from a `KeyPair`, using the `signer()` function.
+    pub const Signer = struct {
+        h: Sha512,
+        scalar: CompressedScalar,
+        nonce: CompressedScalar,
+        r_bytes: [Curve.encoded_length]u8,
+
+        fn init(scalar: CompressedScalar, nonce: CompressedScalar, public_key: PublicKey) (IdentityElementError || KeyMismatchError || NonCanonicalError || WeakPublicKeyError)!Signer {
+            const r = try Curve.basePoint.mul(nonce);
+            const r_bytes = r.toBytes();
+
+            var t: [64]u8 = undefined;
+            mem.copy(u8, t[0..32], &r_bytes);
+            mem.copy(u8, t[32..], &public_key.bytes);
+            var h = Sha512.init(.{});
+            h.update(&t);
+
+            return Signer{ .h = h, .scalar = scalar, .nonce = nonce, .r_bytes = r_bytes };
+        }
+
+        /// Add new data to the message being signed.
+        pub fn update(self: *Signer, data: []const u8) void {
+            self.h.update(data);
+        }
+
+        /// Compute a signature over the entire message.
+        pub fn finalize(self: *Signer) Signature {
+            var hram64: [Sha512.digest_length]u8 = undefined;
+            self.h.final(&hram64);
+            const hram = Curve.scalar.reduce64(hram64);
+
+            const s = Curve.scalar.mulAdd(hram, self.scalar, self.nonce);
+
+            return Signature{ .r = self.r_bytes, .s = s };
+        }
+    };
+
+    /// An Ed25519 public key.
+    pub const PublicKey = struct {
+        /// Length (in bytes) of a raw public key.
+        pub const encoded_length = 32;
+
+        bytes: [encoded_length]u8,
+
+        /// Create a public key from raw bytes.
+        pub fn fromBytes(bytes: [encoded_length]u8) NonCanonicalError!PublicKey {
+            try Curve.rejectNonCanonical(bytes);
+            return PublicKey{ .bytes = bytes };
+        }
+
+        /// Convert a public key to raw bytes.
+        pub fn toBytes(pk: PublicKey) [encoded_length]u8 {
+            return pk.bytes;
+        }
+
+        fn signWithNonce(public_key: PublicKey, msg: []const u8, scalar: CompressedScalar, nonce: CompressedScalar) (IdentityElementError || NonCanonicalError || KeyMismatchError || WeakPublicKeyError)!Signature {
+            var st = try Signer.init(scalar, nonce, public_key);
+            st.update(msg);
+            return st.finalize();
+        }
+
+        fn computeNonceAndSign(public_key: PublicKey, msg: []const u8, noise: ?[noise_length]u8, scalar: CompressedScalar, prefix: []const u8) (IdentityElementError || NonCanonicalError || KeyMismatchError || WeakPublicKeyError)!Signature {
+            var h = Sha512.init(.{});
+            if (noise) |*z| {
+                h.update(z);
+            }
+            h.update(prefix);
+            h.update(msg);
+            var nonce64: [64]u8 = undefined;
+            h.final(&nonce64);
+
+            const nonce = Curve.scalar.reduce64(nonce64);
+
+            return public_key.signWithNonce(msg, scalar, nonce);
+        }
+    };
+
+    /// A Verifier is used to incrementally verify a signature.
+    /// It can be obtained from a `Signature`, using the `verifier()` function.
+    pub const Verifier = struct {
+        h: Sha512,
+        s: CompressedScalar,
+        a: Curve,
+        expected_r: Curve,
+
+        fn init(sig: Signature, public_key: PublicKey) (NonCanonicalError || EncodingError || IdentityElementError)!Verifier {
+            const r = sig.r;
+            const s = sig.s;
+            try Curve.scalar.rejectNonCanonical(s);
+            const a = try Curve.fromBytes(public_key.bytes);
+            try a.rejectIdentity();
+            try Curve.rejectNonCanonical(r);
+            const expected_r = try Curve.fromBytes(r);
+            try expected_r.rejectIdentity();
+
+            var h = Sha512.init(.{});
+            h.update(&r);
+            h.update(&public_key.bytes);
+
+            return Verifier{ .h = h, .s = s, .a = a, .expected_r = expected_r };
+        }
+
+        /// Add new content to the message to be verified.
+        pub fn update(self: *Verifier, msg: []const u8) void {
+            self.h.update(msg);
+        }
+
+        /// Verify that the signature is valid for the entire message.
+        pub fn verify(self: *Verifier) (SignatureVerificationError || WeakPublicKeyError || IdentityElementError)!void {
+            var hram64: [Sha512.digest_length]u8 = undefined;
+            self.h.final(&hram64);
+            const hram = Curve.scalar.reduce64(hram64);
+
+            const sb_ah = try Curve.basePoint.mulDoubleBasePublic(self.s, self.a.neg(), hram);
+            if (self.expected_r.sub(sb_ah).clearCofactor().rejectIdentity()) |_| {
+                return error.SignatureVerificationFailed;
+            } else |_| {}
+        }
+    };
+
+    /// An Ed25519 signature.
+    pub const Signature = struct {
+        /// Length (in bytes) of a raw signature.
+        pub const encoded_length = Curve.encoded_length + @sizeOf(CompressedScalar);
+
+        /// The R component of an EdDSA signature.
+        r: [Curve.encoded_length]u8,
+        /// The S component of an EdDSA signature.
+        s: CompressedScalar,
+
+        /// Return the raw signature (r, s) in little-endian format.
+        pub fn toBytes(self: Signature) [encoded_length]u8 {
+            var bytes: [encoded_length]u8 = undefined;
+            mem.copy(u8, bytes[0 .. encoded_length / 2], &self.r);
+            mem.copy(u8, bytes[encoded_length / 2 ..], &self.s);
+            return bytes;
+        }
+
+        /// Create a signature from a raw encoding of (r, s).
+        /// EdDSA always assumes little-endian.
+        pub fn fromBytes(bytes: [encoded_length]u8) Signature {
+            return Signature{
+                .r = bytes[0 .. encoded_length / 2].*,
+                .s = bytes[encoded_length / 2 ..].*,
+            };
+        }
+
+        /// Create a Verifier for incremental verification of a signature.
+        pub fn verifier(self: Signature, public_key: PublicKey) (NonCanonicalError || EncodingError || IdentityElementError)!Verifier {
+            return Verifier.init(self, public_key);
+        }
+
+        /// Verify the signature against a message and public key.
+        /// Return IdentityElement or NonCanonical if the public key or signature are not in the expected range,
+        /// or SignatureVerificationError if the signature is invalid for the given message and key.
+        pub fn verify(self: Signature, msg: []const u8, public_key: PublicKey) (IdentityElementError || NonCanonicalError || SignatureVerificationError || EncodingError || WeakPublicKeyError)!void {
+            var st = try Verifier.init(self, public_key);
+            st.update(msg);
+            return st.verify();
+        }
+    };
+
     /// An Ed25519 key pair.
     pub const KeyPair = struct {
+        /// Length (in bytes) of a seed required to create a key pair.
+        pub const seed_length = noise_length;
+
         /// Public part.
-        public_key: [public_length]u8,
-        /// Secret part. What we expose as a secret key is, under the hood, the concatenation of the seed and the public key.
-        secret_key: [secret_length]u8,
+        public_key: PublicKey,
+        /// Secret scalar.
+        secret_key: SecretKey,
 
         /// Derive a key pair from an optional secret seed.
         ///
@@ -56,120 +256,101 @@ pub const Ed25519 = struct {
             var h = Sha512.init(.{});
             h.update(&ss);
             h.final(&az);
-            const p = Curve.basePoint.clampedMul(az[0..32].*) catch return error.IdentityElement;
-            var sk: [secret_length]u8 = undefined;
-            mem.copy(u8, &sk, &ss);
-            const pk = p.toBytes();
-            mem.copy(u8, sk[seed_length..], &pk);
-
-            return KeyPair{ .public_key = pk, .secret_key = sk };
+            const pk_p = Curve.basePoint.clampedMul(az[0..32].*) catch return error.IdentityElement;
+            const pk_bytes = pk_p.toBytes();
+            var sk_bytes: [SecretKey.encoded_length]u8 = undefined;
+            mem.copy(u8, &sk_bytes, &ss);
+            mem.copy(u8, sk_bytes[seed_length..], &pk_bytes);
+            return KeyPair{
+                .public_key = PublicKey.fromBytes(pk_bytes) catch unreachable,
+                .secret_key = try SecretKey.fromBytes(sk_bytes),
+            };
         }
 
         /// Create a KeyPair from a secret key.
-        pub fn fromSecretKey(secret_key: [secret_length]u8) KeyPair {
+        pub fn fromSecretKey(secret_key: SecretKey) IdentityElementError!KeyPair {
+            const pk_p = try Curve.fromBytes(secret_key.publicKeyBytes());
+
+            // It is critical for EdDSA to use the correct public key.
+            // In order to enforce this, a SecretKey implicitly includes a copy of the public key.
+            // In Debug mode, we can still afford checking that the public key is correct for extra safety.
+            if (std.builtin.mode == .Debug) {
+                const recomputed_kp = try create(secret_key[0..seed_length].*);
+                debug.assert(recomputed_kp.public_key.p.toBytes() == pk_p.toBytes());
+            }
             return KeyPair{
+                .public_key = PublicKey{ .p = pk_p },
                 .secret_key = secret_key,
-                .public_key = secret_key[seed_length..].*,
             };
         }
-    };
 
-    /// Sign a message using a key pair, and optional random noise.
-    /// Having noise creates non-standard, non-deterministic signatures,
-    /// but has been proven to increase resilience against fault attacks.
-    pub fn sign(msg: []const u8, key_pair: KeyPair, noise: ?[noise_length]u8) (IdentityElementError || WeakPublicKeyError || KeyMismatchError)![signature_length]u8 {
-        const seed = key_pair.secret_key[0..seed_length];
-        const public_key = key_pair.secret_key[seed_length..];
-        if (!mem.eql(u8, public_key, &key_pair.public_key)) {
-            return error.KeyMismatch;
-        }
-        var az: [Sha512.digest_length]u8 = undefined;
-        var h = Sha512.init(.{});
-        h.update(seed);
-        h.final(&az);
-
-        h = Sha512.init(.{});
-        if (noise) |*z| {
-            h.update(z);
+        /// Sign a message using the key pair.
+        /// The noise can be null in order to create deterministic signatures.
+        /// If deterministic signatures are not required, the noise should be randomly generated instead.
+        /// This helps defend against fault attacks.
+        pub fn sign(key_pair: KeyPair, msg: []const u8, noise: ?[noise_length]u8) (IdentityElementError || NonCanonicalError || KeyMismatchError || WeakPublicKeyError)!Signature {
+            if (!mem.eql(u8, &key_pair.secret_key.publicKeyBytes(), &key_pair.public_key.toBytes())) {
+                return error.KeyMismatch;
+            }
+            const scalar_and_prefix = key_pair.secret_key.scalarAndPrefix();
+            return key_pair.public_key.computeNonceAndSign(
+                msg,
+                noise,
+                scalar_and_prefix.scalar,
+                &scalar_and_prefix.prefix,
+            );
         }
-        h.update(az[32..]);
-        h.update(msg);
-        var nonce64: [64]u8 = undefined;
-        h.final(&nonce64);
-        const nonce = Curve.scalar.reduce64(nonce64);
-        const r = try Curve.basePoint.mul(nonce);
-
-        var sig: [signature_length]u8 = undefined;
-        mem.copy(u8, sig[0..32], &r.toBytes());
-        mem.copy(u8, sig[32..], public_key);
-        h = Sha512.init(.{});
-        h.update(&sig);
-        h.update(msg);
-        var hram64: [Sha512.digest_length]u8 = undefined;
-        h.final(&hram64);
-        const hram = Curve.scalar.reduce64(hram64);
-
-        var x = az[0..32];
-        Curve.scalar.clamp(x);
-        const s = Curve.scalar.mulAdd(hram, x.*, nonce);
-        mem.copy(u8, sig[32..], s[0..]);
-        return sig;
-    }
 
-    /// Verify an Ed25519 signature given a message and a public key.
-    /// Returns error.SignatureVerificationFailed is the signature verification failed.
-    pub fn verify(sig: [signature_length]u8, msg: []const u8, public_key: [public_length]u8) (SignatureVerificationError || WeakPublicKeyError || EncodingError || NonCanonicalError || IdentityElementError)!void {
-        const r = sig[0..32];
-        const s = sig[32..64];
-        try Curve.scalar.rejectNonCanonical(s.*);
-        try Curve.rejectNonCanonical(public_key);
-        const a = try Curve.fromBytes(public_key);
-        try a.rejectIdentity();
-        try Curve.rejectNonCanonical(r.*);
-        const expected_r = try Curve.fromBytes(r.*);
-        try expected_r.rejectIdentity();
-
-        var h = Sha512.init(.{});
-        h.update(r);
-        h.update(&public_key);
-        h.update(msg);
-        var hram64: [Sha512.digest_length]u8 = undefined;
-        h.final(&hram64);
-        const hram = Curve.scalar.reduce64(hram64);
-
-        const sb_ah = try Curve.basePoint.mulDoubleBasePublic(s.*, a.neg(), hram);
-        if (expected_r.sub(sb_ah).clearCofactor().rejectIdentity()) |_| {
-            return error.SignatureVerificationFailed;
-        } else |_| {}
-    }
+        /// Create a Signer, that can be used for incremental signing.
+        /// Note that the signature is not deterministic.
+        /// The noise parameter, if set, should be something unique for each message,
+        /// such as a random nonce, or a counter.
+        pub fn signer(key_pair: KeyPair, noise: ?[noise_length]u8) (IdentityElementError || KeyMismatchError || NonCanonicalError || WeakPublicKeyError)!Signer {
+            if (!mem.eql(u8, &key_pair.secret_key.publicKeyBytes(), &key_pair.public_key.toBytes())) {
+                return error.KeyMismatch;
+            }
+            const scalar_and_prefix = key_pair.secret_key.scalarAndPrefix();
+            var h = Sha512.init(.{});
+            h.update(&scalar_and_prefix.prefix);
+            var noise2: [noise_length]u8 = undefined;
+            crypto.random.bytes(&noise2);
+            if (noise) |*z| {
+                h.update(z);
+            }
+            var nonce64: [64]u8 = undefined;
+            h.final(&nonce64);
+            const nonce = Curve.scalar.reduce64(nonce64);
+
+            return Signer.init(scalar_and_prefix.scalar, nonce, key_pair.public_key);
+        }
+    };
 
     /// A (signature, message, public_key) tuple for batch verification
     pub const BatchElement = struct {
-        sig: [signature_length]u8,
+        sig: Signature,
         msg: []const u8,
-        public_key: [public_length]u8,
+        public_key: PublicKey,
     };
 
     /// Verify several signatures in a single operation, much faster than verifying signatures one-by-one
     pub fn verifyBatch(comptime count: usize, signature_batch: [count]BatchElement) (SignatureVerificationError || IdentityElementError || WeakPublicKeyError || EncodingError || NonCanonicalError)!void {
-        var r_batch: [count][32]u8 = undefined;
-        var s_batch: [count][32]u8 = undefined;
+        var r_batch: [count]CompressedScalar = undefined;
+        var s_batch: [count]CompressedScalar = undefined;
         var a_batch: [count]Curve = undefined;
         var expected_r_batch: [count]Curve = undefined;
 
         for (signature_batch) |signature, i| {
-            const r = signature.sig[0..32];
-            const s = signature.sig[32..64];
-            try Curve.scalar.rejectNonCanonical(s.*);
-            try Curve.rejectNonCanonical(signature.public_key);
-            const a = try Curve.fromBytes(signature.public_key);
+            const r = signature.sig.r;
+            const s = signature.sig.s;
+            try Curve.scalar.rejectNonCanonical(s);
+            const a = try Curve.fromBytes(signature.public_key.bytes);
             try a.rejectIdentity();
-            try Curve.rejectNonCanonical(r.*);
-            const expected_r = try Curve.fromBytes(r.*);
+            try Curve.rejectNonCanonical(r);
+            const expected_r = try Curve.fromBytes(r);
             try expected_r.rejectIdentity();
             expected_r_batch[i] = expected_r;
-            r_batch[i] = r.*;
-            s_batch[i] = s.*;
+            r_batch[i] = r;
+            s_batch[i] = s;
             a_batch[i] = a;
         }
 
@@ -177,7 +358,7 @@ pub const Ed25519 = struct {
         for (signature_batch) |signature, i| {
             var h = Sha512.init(.{});
             h.update(&r_batch[i]);
-            h.update(&signature.public_key);
+            h.update(&signature.public_key.bytes);
             h.update(signature.msg);
             var hram64: [Sha512.digest_length]u8 = undefined;
             h.final(&hram64);
@@ -212,7 +393,7 @@ pub const Ed25519 = struct {
     }
 
     /// Ed25519 signatures with key blinding.
-    pub const BlindKeySignatures = struct {
+    pub const key_blinding = struct {
         /// Length (in bytes) of a blinding seed.
         pub const blind_seed_length = 32;
 
@@ -220,81 +401,69 @@ pub const Ed25519 = struct {
         pub const BlindSecretKey = struct {
             prefix: [64]u8,
             blind_scalar: CompressedScalar,
-            blind_public_key: CompressedScalar,
+            blind_public_key: BlindPublicKey,
+        };
+
+        /// A blind public key.
+        pub const BlindPublicKey = struct {
+            /// Public key equivalent, that can used for signature verification.
+            key: PublicKey,
+
+            /// Recover a public key from a blind version of it.
+            pub fn unblind(blind_public_key: BlindPublicKey, blind_seed: [blind_seed_length]u8, ctx: []const u8) (IdentityElementError || NonCanonicalError || EncodingError || WeakPublicKeyError)!PublicKey {
+                const blind_h = blindCtx(blind_seed, ctx);
+                const inv_blind_factor = Scalar.fromBytes(blind_h[0..32].*).invert().toBytes();
+                const pk_p = try (try Curve.fromBytes(blind_public_key.key.bytes)).mul(inv_blind_factor);
+                return PublicKey.fromBytes(pk_p.toBytes());
+            }
         };
 
         /// A blind key pair.
         pub const BlindKeyPair = struct {
-            blind_public_key: [public_length]u8,
+            blind_public_key: BlindPublicKey,
             blind_secret_key: BlindSecretKey,
-        };
 
-        /// Blind an existing key pair with a blinding seed and a context.
-        pub fn blind(key_pair: Ed25519.KeyPair, blind_seed: [blind_seed_length]u8, ctx: []const u8) !BlindKeyPair {
-            var h: [Sha512.digest_length]u8 = undefined;
-            Sha512.hash(key_pair.secret_key[0..32], &h, .{});
-            Curve.scalar.clamp(h[0..32]);
-            const scalar = Curve.scalar.reduce(h[0..32].*);
-
-            const blind_h = blindCtx(blind_seed, ctx);
-            const blind_factor = Curve.scalar.reduce(blind_h[0..32].*);
-
-            const blind_scalar = Curve.scalar.mul(scalar, blind_factor);
-            const blind_public_key = (Curve.basePoint.mul(blind_scalar) catch return error.IdentityElement).toBytes();
-
-            var prefix: [64]u8 = undefined;
-            mem.copy(u8, prefix[0..32], h[32..64]);
-            mem.copy(u8, prefix[32..64], blind_h[32..64]);
-
-            const blind_secret_key = .{
-                .prefix = prefix,
-                .blind_scalar = blind_scalar,
-                .blind_public_key = blind_public_key,
-            };
-            return BlindKeyPair{
-                .blind_public_key = blind_public_key,
-                .blind_secret_key = blind_secret_key,
-            };
-        }
-
-        /// Recover a public key from a blind version of it.
-        pub fn unblindPublicKey(blind_public_key: [public_length]u8, blind_seed: [blind_seed_length]u8, ctx: []const u8) ![public_length]u8 {
-            const blind_h = blindCtx(blind_seed, ctx);
-            const inv_blind_factor = Scalar.fromBytes(blind_h[0..32].*).invert().toBytes();
-            const public_key = try (try Curve.fromBytes(blind_public_key)).mul(inv_blind_factor);
-            return public_key.toBytes();
-        }
-
-        /// Sign a message using a blind key pair, and optional random noise.
-        /// Having noise creates non-standard, non-deterministic signatures,
-        /// but has been proven to increase resilience against fault attacks.
-        pub fn sign(msg: []const u8, key_pair: BlindKeyPair, noise: ?[noise_length]u8) ![signature_length]u8 {
-            var h = Sha512.init(.{});
-            if (noise) |*z| {
-                h.update(z);
+            /// Create an blind key pair from an existing key pair, a blinding seed and a context.
+            pub fn init(key_pair: Ed25519.KeyPair, blind_seed: [blind_seed_length]u8, ctx: []const u8) (NonCanonicalError || IdentityElementError)!BlindKeyPair {
+                var h: [Sha512.digest_length]u8 = undefined;
+                Sha512.hash(&key_pair.secret_key.seed(), &h, .{});
+                Curve.scalar.clamp(h[0..32]);
+                const scalar = Curve.scalar.reduce(h[0..32].*);
+
+                const blind_h = blindCtx(blind_seed, ctx);
+                const blind_factor = Curve.scalar.reduce(blind_h[0..32].*);
+
+                const blind_scalar = Curve.scalar.mul(scalar, blind_factor);
+                const blind_public_key = BlindPublicKey{
+                    .key = try PublicKey.fromBytes((Curve.basePoint.mul(blind_scalar) catch return error.IdentityElement).toBytes()),
+                };
+
+                var prefix: [64]u8 = undefined;
+                mem.copy(u8, prefix[0..32], h[32..64]);
+                mem.copy(u8, prefix[32..64], blind_h[32..64]);
+
+                const blind_secret_key = BlindSecretKey{
+                    .prefix = prefix,
+                    .blind_scalar = blind_scalar,
+                    .blind_public_key = blind_public_key,
+                };
+                return BlindKeyPair{
+                    .blind_public_key = blind_public_key,
+                    .blind_secret_key = blind_secret_key,
+                };
             }
-            h.update(&key_pair.blind_secret_key.prefix);
-            h.update(msg);
-            var nonce64: [64]u8 = undefined;
-            h.final(&nonce64);
 
-            const nonce = Curve.scalar.reduce64(nonce64);
-            const r = try Curve.basePoint.mul(nonce);
+            /// Sign a message using a blind key pair, and optional random noise.
+            /// Having noise creates non-standard, non-deterministic signatures,
+            /// but has been proven to increase resilience against fault attacks.
+            pub fn sign(key_pair: BlindKeyPair, msg: []const u8, noise: ?[noise_length]u8) (IdentityElementError || KeyMismatchError || NonCanonicalError || WeakPublicKeyError)!Signature {
+                const scalar = key_pair.blind_secret_key.blind_scalar;
+                const prefix = key_pair.blind_secret_key.prefix;
 
-            var sig: [signature_length]u8 = undefined;
-            mem.copy(u8, sig[0..32], &r.toBytes());
-            mem.copy(u8, sig[32..], &key_pair.blind_public_key);
-            h = Sha512.init(.{});
-            h.update(&sig);
-            h.update(msg);
-            var hram64: [Sha512.digest_length]u8 = undefined;
-            h.final(&hram64);
-            const hram = Curve.scalar.reduce64(hram64);
-
-            const s = Curve.scalar.mulAdd(hram, key_pair.blind_secret_key.blind_scalar, nonce);
-            mem.copy(u8, sig[32..], s[0..]);
-            return sig;
-        }
+                return (try PublicKey.fromBytes(key_pair.blind_public_key.key.bytes))
+                    .computeNonceAndSign(msg, noise, scalar, &prefix);
+            }
+        };
 
         /// Compute a blind context from a blinding seed and a context.
         fn blindCtx(blind_seed: [blind_seed_length]u8, ctx: []const u8) [Sha512.digest_length]u8 {
@@ -306,7 +475,13 @@ pub const Ed25519 = struct {
             hx.final(&blind_h);
             return blind_h;
         }
+
+        pub const sign = @compileError("deprecated; use BlindKeyPair.sign instead");
+        pub const unblindPublicKey = @compileError("deprecated; use BlindPublicKey.unblind instead");
     };
+
+    pub const sign = @compileError("deprecated; use KeyPair.sign instead");
+    pub const verify = @compileError("deprecated; use PublicKey.verify instead");
 };
 
 test "ed25519 key pair creation" {
@@ -314,8 +489,8 @@ test "ed25519 key pair creation" {
     _ = try fmt.hexToBytes(seed[0..], "8052030376d47112be7f73ed7a019293dd12ad910b654455798b4667d73de166");
     const key_pair = try Ed25519.KeyPair.create(seed);
     var buf: [256]u8 = undefined;
-    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&key_pair.secret_key)}), "8052030376D47112BE7F73ED7A019293DD12AD910B654455798B4667D73DE1662D6F7455D97B4A3A10D7293909D1A4F2058CB9A370E43FA8154BB280DB839083");
-    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&key_pair.public_key)}), "2D6F7455D97B4A3A10D7293909D1A4F2058CB9A370E43FA8154BB280DB839083");
+    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&key_pair.secret_key.toBytes())}), "8052030376D47112BE7F73ED7A019293DD12AD910B654455798B4667D73DE1662D6F7455D97B4A3A10D7293909D1A4F2058CB9A370E43FA8154BB280DB839083");
+    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&key_pair.public_key.toBytes())}), "2D6F7455D97B4A3A10D7293909D1A4F2058CB9A370E43FA8154BB280DB839083");
 }
 
 test "ed25519 signature" {
@@ -323,11 +498,11 @@ test "ed25519 signature" {
     _ = try fmt.hexToBytes(seed[0..], "8052030376d47112be7f73ed7a019293dd12ad910b654455798b4667d73de166");
     const key_pair = try Ed25519.KeyPair.create(seed);
 
-    const sig = try Ed25519.sign("test", key_pair, null);
+    const sig = try key_pair.sign("test", null);
     var buf: [128]u8 = undefined;
-    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&sig)}), "10A442B4A80CC4225B154F43BEF28D2472CA80221951262EB8E0DF9091575E2687CC486E77263C3418C757522D54F84B0359236ABBBD4ACD20DC297FDCA66808");
-    try Ed25519.verify(sig, "test", key_pair.public_key);
-    try std.testing.expectError(error.SignatureVerificationFailed, Ed25519.verify(sig, "TEST", key_pair.public_key));
+    try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&sig.toBytes())}), "10A442B4A80CC4225B154F43BEF28D2472CA80221951262EB8E0DF9091575E2687CC486E77263C3418C757522D54F84B0359236ABBBD4ACD20DC297FDCA66808");
+    try sig.verify("test", key_pair.public_key);
+    try std.testing.expectError(error.SignatureVerificationFailed, sig.verify("TEST", key_pair.public_key));
 }
 
 test "ed25519 batch verification" {
@@ -338,8 +513,8 @@ test "ed25519 batch verification" {
         var msg2: [32]u8 = undefined;
         crypto.random.bytes(&msg1);
         crypto.random.bytes(&msg2);
-        const sig1 = try Ed25519.sign(&msg1, key_pair, null);
-        const sig2 = try Ed25519.sign(&msg2, key_pair, null);
+        const sig1 = try key_pair.sign(&msg1, null);
+        const sig2 = try key_pair.sign(&msg2, null);
         var signature_batch = [_]Ed25519.BatchElement{
             Ed25519.BatchElement{
                 .sig = sig1,
@@ -355,9 +530,7 @@ test "ed25519 batch verification" {
         try Ed25519.verifyBatch(2, signature_batch);
 
         signature_batch[1].sig = sig1;
-        // TODO https://github.com/ziglang/zig/issues/12240
-        const sig_len = signature_batch.len;
-        try std.testing.expectError(error.SignatureVerificationFailed, Ed25519.verifyBatch(sig_len, signature_batch));
+        try std.testing.expectError(error.SignatureVerificationFailed, Ed25519.verifyBatch(signature_batch.len, signature_batch));
     }
 }
 
@@ -446,20 +619,25 @@ test "ed25519 test vectors" {
     for (entries) |entry| {
         var msg: [entry.msg_hex.len / 2]u8 = undefined;
         _ = try fmt.hexToBytes(&msg, entry.msg_hex);
-        var public_key: [32]u8 = undefined;
-        _ = try fmt.hexToBytes(&public_key, entry.public_key_hex);
-        var sig: [64]u8 = undefined;
-        _ = try fmt.hexToBytes(&sig, entry.sig_hex);
+        var public_key_bytes: [32]u8 = undefined;
+        _ = try fmt.hexToBytes(&public_key_bytes, entry.public_key_hex);
+        const public_key = Ed25519.PublicKey.fromBytes(public_key_bytes) catch |err| {
+            try std.testing.expectEqual(entry.expected.?, err);
+            continue;
+        };
+        var sig_bytes: [64]u8 = undefined;
+        _ = try fmt.hexToBytes(&sig_bytes, entry.sig_hex);
+        const sig = Ed25519.Signature.fromBytes(sig_bytes);
         if (entry.expected) |error_type| {
-            try std.testing.expectError(error_type, Ed25519.verify(sig, &msg, public_key));
+            try std.testing.expectError(error_type, sig.verify(&msg, public_key));
         } else {
-            try Ed25519.verify(sig, &msg, public_key);
+            try sig.verify(&msg, public_key);
         }
     }
 }
 
 test "ed25519 with blind keys" {
-    const BlindKeySignatures = Ed25519.BlindKeySignatures;
+    const BlindKeyPair = Ed25519.key_blinding.BlindKeyPair;
 
     // Create a standard Ed25519 key pair
     const kp = try Ed25519.KeyPair.create(null);
@@ -469,14 +647,30 @@ test "ed25519 with blind keys" {
     crypto.random.bytes(&blind);
 
     // Blind the key pair
-    const blind_kp = try BlindKeySignatures.blind(kp, blind, "ctx");
+    const blind_kp = try BlindKeyPair.init(kp, blind, "ctx");
 
     // Sign a message and check that it can be verified with the blind public key
     const msg = "test";
-    const sig = try BlindKeySignatures.sign(msg, blind_kp, null);
-    try Ed25519.verify(sig, msg, blind_kp.blind_public_key);
+    const sig = try blind_kp.sign(msg, null);
+    try sig.verify(msg, blind_kp.blind_public_key.key);
 
     // Unblind the public key
-    const pk = try BlindKeySignatures.unblindPublicKey(blind_kp.blind_public_key, blind, "ctx");
-    try std.testing.expectEqualSlices(u8, &pk, &kp.public_key);
+    const pk = try blind_kp.blind_public_key.unblind(blind, "ctx");
+    try std.testing.expectEqualSlices(u8, &pk.toBytes(), &kp.public_key.toBytes());
+}
+
+test "ed25519 signatures with streaming" {
+    const kp = try Ed25519.KeyPair.create(null);
+
+    var signer = try kp.signer(null);
+    signer.update("mes");
+    signer.update("sage");
+    const sig = signer.finalize();
+
+    try sig.verify("message", kp.public_key);
+
+    var verifier = try sig.verifier(kp.public_key);
+    verifier.update("mess");
+    verifier.update("age");
+    try verifier.verify();
 }
lib/std/crypto/25519/x25519.zig
@@ -44,9 +44,9 @@ pub const X25519 = struct {
 
         /// Create a key pair from an Ed25519 key pair
         pub fn fromEd25519(ed25519_key_pair: crypto.sign.Ed25519.KeyPair) (IdentityElementError || EncodingError)!KeyPair {
-            const seed = ed25519_key_pair.secret_key[0..32];
+            const seed = ed25519_key_pair.secret_key.seed();
             var az: [Sha512.digest_length]u8 = undefined;
-            Sha512.hash(seed, &az, .{});
+            Sha512.hash(&seed, &az, .{});
             var sk = az[0..32].*;
             Curve.scalar.clamp(&sk);
             const pk = try publicKeyFromEd25519(ed25519_key_pair.public_key);
@@ -64,8 +64,8 @@ pub const X25519 = struct {
     }
 
     /// Compute the X25519 equivalent to an Ed25519 public eky.
-    pub fn publicKeyFromEd25519(ed25519_public_key: [crypto.sign.Ed25519.public_length]u8) (IdentityElementError || EncodingError)![public_length]u8 {
-        const pk_ed = try crypto.ecc.Edwards25519.fromBytes(ed25519_public_key);
+    pub fn publicKeyFromEd25519(ed25519_public_key: crypto.sign.Ed25519.PublicKey) (IdentityElementError || EncodingError)![public_length]u8 {
+        const pk_ed = try crypto.ecc.Edwards25519.fromBytes(ed25519_public_key.bytes);
         const pk = try Curve.fromEdwards25519(pk_ed);
         return pk.toBytes();
     }
lib/std/crypto/benchmark.zig
@@ -130,7 +130,7 @@ pub fn benchmarkSignature(comptime Signature: anytype, comptime signatures_count
     {
         var i: usize = 0;
         while (i < signatures_count) : (i += 1) {
-            const sig = try Signature.sign(&msg, key_pair, null);
+            const sig = try key_pair.sign(&msg, null);
             mem.doNotOptimizeAway(&sig);
         }
     }
@@ -147,14 +147,14 @@ const signature_verifications = [_]Crypto{Crypto{ .ty = crypto.sign.Ed25519, .na
 pub fn benchmarkSignatureVerification(comptime Signature: anytype, comptime signatures_count: comptime_int) !u64 {
     const msg = [_]u8{0} ** 64;
     const key_pair = try Signature.KeyPair.create(null);
-    const sig = try Signature.sign(&msg, key_pair, null);
+    const sig = try key_pair.sign(&msg, null);
 
     var timer = try Timer.start();
     const start = timer.lap();
     {
         var i: usize = 0;
         while (i < signatures_count) : (i += 1) {
-            try Signature.verify(sig, &msg, key_pair.public_key);
+            try sig.verify(&msg, key_pair.public_key);
             mem.doNotOptimizeAway(&sig);
         }
     }
@@ -171,7 +171,7 @@ const batch_signature_verifications = [_]Crypto{Crypto{ .ty = crypto.sign.Ed2551
 pub fn benchmarkBatchSignatureVerification(comptime Signature: anytype, comptime signatures_count: comptime_int) !u64 {
     const msg = [_]u8{0} ** 64;
     const key_pair = try Signature.KeyPair.create(null);
-    const sig = try Signature.sign(&msg, key_pair, null);
+    const sig = try key_pair.sign(&msg, null);
 
     var batch: [64]Signature.BatchElement = undefined;
     for (batch) |*element| {
@@ -301,9 +301,13 @@ const CryptoPwhash = struct {
     params: *const anyopaque,
     name: []const u8,
 };
-const bcrypt_params = crypto.pwhash.bcrypt.Params{ .rounds_log = 12 };
+const bcrypt_params = crypto.pwhash.bcrypt.Params{ .rounds_log = 8 };
 const pwhashes = [_]CryptoPwhash{
-    .{ .ty = crypto.pwhash.bcrypt, .params = &bcrypt_params, .name = "bcrypt" },
+    .{
+        .ty = crypto.pwhash.bcrypt,
+        .params = &bcrypt_params,
+        .name = "bcrypt",
+    },
     .{
         .ty = crypto.pwhash.scrypt,
         .params = &crypto.pwhash.scrypt.Params.interactive,
@@ -323,7 +327,11 @@ fn benchmarkPwhash(
     comptime count: comptime_int,
 ) !f64 {
     const password = "testpass" ** 2;
-    const opts = .{ .allocator = allocator, .params = @ptrCast(*const ty.Params, params).*, .encoding = .phc };
+    const opts = .{
+        .allocator = allocator,
+        .params = @ptrCast(*const ty.Params, @alignCast(std.meta.alignment(ty.Params), params)).*,
+        .encoding = .phc,
+    };
     var buf: [256]u8 = undefined;
 
     var timer = try Timer.start();