port subxt-signer to no-std (such a pain)

Cargo.lock

@@ -1076,6 +1076,12 @@ dependencies = [
  "itertools 0.10.5",
 ]
 
+[[package]]
+name = "critical-section"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7059fff8937831a9ae6f0fe4d658ffabf58f2ca96aa9dec1c889f936f705f216"
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.5"
@@ -2732,6 +2738,10 @@ name = "once_cell"
 version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
+dependencies = [
+ "critical-section",
+ "portable-atomic",
+]
 
 [[package]]
 name = "oorandom"
@@ -2979,6 +2989,12 @@ dependencies = [
  "universal-hash",
 ]
 
+[[package]]
+name = "portable-atomic"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"
@@ -4622,9 +4638,11 @@ name = "subxt-signer"
 version = "0.34.0"
 dependencies = [
  "bip39",
+ "derive_more",
  "getrandom",
  "hex",
  "hmac 0.12.1",
+ "once_cell",
  "parity-scale-codec",
  "pbkdf2 0.12.2",
  "regex",
@@ -4636,7 +4654,6 @@ dependencies = [
  "sp-core-hashing",
  "sp-keyring",
  "subxt-core",
- "thiserror",
  "zeroize",
 ]
 

Cargo.toml

@@ -76,12 +76,13 @@ heck = "0.4.1"
 impl-serde = { version = "0.4.0", default-features = false }
 indoc = "2"
 jsonrpsee = { version = "0.21" }
+once_cell = { version = "1.19.0", default-features = false }
 pretty_assertions = "1.4.0"
 primitive-types = { version = "0.12.2", default-features = false }
 proc-macro-error = "1.0.4"
 proc-macro2 = "1.0.78"
 quote = "1.0.35"
-regex = "1.10.3"
+regex = { version = "1.10.3", default-features = false }
 scale-info = { version = "2.10.0", default-features = false }
 scale-value = { version = "0.13.0", default-features = false }
 scale-bits = { version = "0.4.0", default-features = false }
@@ -134,19 +135,19 @@ subxt-macro = { version = "0.34.0", path = "macro" }
 subxt-core = { version = "0.34.0", path = "core", default-features = false }
 subxt-metadata = { version = "0.34.0", path = "metadata", default-features = false }
 subxt-codegen = { version = "0.34.0", path = "codegen" }
-subxt-signer = { version = "0.34.0", path = "signer" }
+subxt-signer = { version = "0.34.0", path = "signer", default-features = false }
 subxt-lightclient = { version = "0.34.0", path = "lightclient", default-features = false }
 test-runtime = { path = "testing/test-runtime" }
 substrate-runner = { path = "testing/substrate-runner" }
 
 # subxt-signer deps that I expect aren't useful anywhere else:
-bip39 = "2.0.0"
-hmac = "0.12.1"
+bip39 = { version = "2.0.0", default-features = false }
+hmac = { version = "0.12.1", default-features = false }
 pbkdf2 = { version = "0.12.2", default-features = false }
-schnorrkel = "0.11.4"
-secp256k1 = "0.28.1"
+schnorrkel = { version = "0.11.4", default-features = false }
+secp256k1 = { version = "0.28.1", default-features = false }
 secrecy = "0.8.0"
-sha2 = "0.10.8"
+sha2 = { version = "0.10.8", default-features = false }
 zeroize = { version = "1", default-features = false }
 
 [profile.dev.package.smoldot-light]

core/src/lib.rs

@@ -30,6 +30,8 @@ pub use config::{
     PolkadotExtrinsicParams, SubstrateConfig, SubstrateExtrinsicParams,
 };
 
+pub use utils::{AccountId32, MultiAddress, MultiSignature, H160, H256, H512};
+
 pub use signer::Signer;
 
 pub use metadata::Metadata;

signer/Cargo.toml

@@ -15,7 +15,8 @@ description = "Sign extrinsics to be submitted by Subxt"
 keywords = ["parity", "subxt", "extrinsic", "signer"]
 
 [features]
-default = ["sr25519", "ecdsa", "subxt"]
+default = ["sr25519", "ecdsa", "subxt", "std"]
+std = []
 
 # Pick the signer implementation(s) you need by enabling the
 # corresponding features. Note: I had more difficulties getting
@@ -34,25 +35,28 @@ web = ["getrandom/js"]
 
 [dependencies]
 subxt-core = { workspace = true, optional = true, default-features = false }
-regex = { workspace = true }
+regex = { workspace = true, default-features = false }
 hex = { workspace = true }
 codec = { package = "parity-scale-codec", workspace = true, features = ["derive"] }
-sp-core-hashing = { workspace = true }
-thiserror = { workspace = true }
-pbkdf2 = { workspace = true }
-sha2 = { workspace = true }
-hmac = { workspace = true }
+sp-core-hashing = { workspace = true, default-features = false }
+derive_more = { workspace = true }
+pbkdf2 = { workspace = true, default-features = false }
+sha2 = { workspace = true, default-features = false }
+hmac = { workspace = true, default-features = false }
 zeroize = { workspace = true }
-bip39 = { workspace = true }
-schnorrkel = { workspace = true, optional = true }
-secp256k1 = { workspace = true, features = ["recovery", "global-context"], optional = true }
+bip39 = { workspace = true, default-features = false, features = ["unicode-normalization"] }
+schnorrkel = { workspace = true, optional = true, default-features = false }
+secp256k1 = { workspace = true, optional = true, default-features = false, features = ["alloc", "recovery"] } # features = ["recovery", "global-context"], 
 secrecy = { workspace = true }
 
+# We only pull this in because `std::sync::OnceLock` is not available in no-std contexts.
+once_cell = { workspace = true, default-features = false, features = ["alloc", "critical-section"] }
+
 # We only pull this in to enable the JS flag for schnorrkel to use.
 getrandom = { workspace = true, optional = true }
 
 [dev-dependencies]
-sp-core = { workspace = true, features = ["std"] }
+sp-core = { workspace = true, default-features = false }
 sp-keyring = { workspace = true }
 
 [package.metadata.cargo-machete]

signer/src/crypto/secret_uri.rs

@@ -3,6 +3,8 @@
 // see LICENSE for license details.
 
 use super::DeriveJunction;
+use alloc::vec::Vec;
+use derive_more::Display;
 use regex::Regex;
 use secrecy::SecretString;
 
@@ -88,7 +90,7 @@ pub struct SecretUri {
     pub junctions: Vec<DeriveJunction>,
 }
 
-impl std::str::FromStr for SecretUri {
+impl core::str::FromStr for SecretUri {
     type Err = SecretUriError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
@@ -115,10 +117,10 @@ impl std::str::FromStr for SecretUri {
 }
 
 /// This is returned if `FromStr` cannot parse a string into a `SecretUri`.
-#[derive(Debug, Copy, Clone, PartialEq, thiserror::Error)]
+#[derive(Debug, Copy, Clone, PartialEq, Display)]
 pub enum SecretUriError {
     /// Parsing the secret URI from a string failed; wrong format.
-    #[error("Invalid secret phrase format")]
+    #[display(fmt = "Invalid secret phrase format")]
     InvalidFormat,
 }
 

signer/src/crypto/seed_from_entropy.rs

@@ -2,6 +2,7 @@
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
+use alloc::string::String;
 use hmac::Hmac;
 use pbkdf2::pbkdf2;
 use sha2::Sha512;

signer/src/ecdsa.rs

@@ -6,10 +6,22 @@
 use codec::Encode;
 
 use crate::crypto::{seed_from_entropy, DeriveJunction, SecretUri};
+use core::str::FromStr;
+use derive_more::{Display, From};
 use hex::FromHex;
-use secp256k1::{ecdsa::RecoverableSignature, Message, SecretKey, SECP256K1};
+use secp256k1::{ecdsa::RecoverableSignature, All, Message, Secp256k1, SecretKey};
 use secrecy::ExposeSecret;
 
+struct GlobalSecp256K1Context;
+impl core::ops::Deref for GlobalSecp256K1Context {
+    type Target = Secp256k1<All>;
+
+    fn deref(&self) -> &Self::Target {
+        static ONCE: once_cell::sync::OnceCell<Secp256k1<All>> = once_cell::sync::OnceCell::new();
+        ONCE.get_or_init(|| Secp256k1::new())
+    }
+}
+
 const SEED_LENGTH: usize = 32;
 
 /// Seed bytes used to generate a key pair.
@@ -68,7 +80,7 @@ impl Keypair {
             let seed = Seed::from_hex(hex_str)?;
             Self::from_seed(seed)?
         } else {
-            let phrase = bip39::Mnemonic::parse(phrase.expose_secret().as_str())?;
+            let phrase = bip39::Mnemonic::from_str(phrase.expose_secret().as_str())?;
             let pass_str = password.as_ref().map(|p| p.expose_secret().as_str());
             Self::from_phrase(&phrase, pass_str)?
         };
@@ -91,8 +103,9 @@ impl Keypair {
     /// keypair.sign(b"Hello world!");
     /// ```
     pub fn from_phrase(mnemonic: &bip39::Mnemonic, password: Option<&str>) -> Result<Self, Error> {
-        let big_seed = seed_from_entropy(&mnemonic.to_entropy(), password.unwrap_or(""))
-            .ok_or(Error::InvalidSeed)?;
+        let (arr, len) = mnemonic.to_entropy_array();
+        let big_seed =
+            seed_from_entropy(&arr[0..len], password.unwrap_or("")).ok_or(Error::InvalidSeed)?;
 
         let seed: Seed = big_seed[..SEED_LENGTH]
             .try_into()
@@ -109,7 +122,8 @@ impl Keypair {
     pub fn from_seed(seed: Seed) -> Result<Self, Error> {
         let secret = SecretKey::from_slice(&seed).map_err(|_| Error::InvalidSeed)?;
         Ok(Self(secp256k1::Keypair::from_secret_key(
-            SECP256K1, &secret,
+            &GlobalSecp256K1Context,
+            &secret,
         )))
     }
 
@@ -161,9 +175,9 @@ impl Keypair {
         // From sp_core::ecdsa::sign_prehashed:
         let wrapped = Message::from_digest_slice(&message_hash).expect("Message is 32 bytes; qed");
         let recsig: RecoverableSignature =
-            SECP256K1.sign_ecdsa_recoverable(&wrapped, &self.0.secret_key());
+            GlobalSecp256K1Context.sign_ecdsa_recoverable(&wrapped, &self.0.secret_key());
         // From sp_core::ecdsa's `impl From<RecoverableSignature> for Signature`:
-        let (recid, sig) = recsig.serialize_compact();
+        let (recid, sig): (_, [u8; 64]) = recsig.serialize_compact();
         let mut signature_bytes: [u8; 65] = [0; 65];
         signature_bytes[..64].copy_from_slice(&sig);
         signature_bytes[64] = (recid.to_i32() & 0xFF) as u8;
@@ -192,31 +206,35 @@ pub fn verify<M: AsRef<[u8]>>(sig: &Signature, message: M, pubkey: &PublicKey) -
     };
     let message_hash = sp_core_hashing::blake2_256(message.as_ref());
     let wrapped = Message::from_digest_slice(&message_hash).expect("Message is 32 bytes; qed");
-    signature.verify(&wrapped, &public).is_ok()
+    GlobalSecp256K1Context
+        .verify_ecdsa(&wrapped, &signature, &public)
+        .is_ok()
 }
 
 /// An error handed back if creating a keypair fails.
-#[derive(Debug, PartialEq, thiserror::Error)]
+#[derive(Debug, PartialEq, Display, From)]
 pub enum Error {
     /// Invalid seed.
-    #[error("Invalid seed (was it the wrong length?)")]
+    #[display(fmt = "Invalid seed (was it the wrong length?)")]
+    #[from(ignore)]
     InvalidSeed,
     /// Invalid seed.
-    #[error("Invalid seed for ECDSA, contained soft junction")]
+    #[display(fmt = "Invalid seed for ECDSA, contained soft junction")]
+    #[from(ignore)]
     SoftJunction,
     /// Invalid phrase.
-    #[error("Cannot parse phrase: {0}")]
-    Phrase(#[from] bip39::Error),
+    #[display(fmt = "Cannot parse phrase: {_0}")]
+    Phrase(bip39::Error),
     /// Invalid hex.
-    #[error("Cannot parse hex string: {0}")]
-    Hex(#[from] hex::FromHexError),
+    #[display(fmt = "Cannot parse hex string: {_0}")]
+    Hex(hex::FromHexError),
 }
 
 /// Dev accounts, helpful for testing but not to be used in production,
 /// since the secret keys are known.
 pub mod dev {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     once_static_cloned! {
         /// Equivalent to `{DEV_PHRASE}//Alice`.
@@ -260,9 +278,9 @@ pub mod dev {
 mod subxt_compat {
     use super::*;
 
-    use subxt::config::Config;
-    use subxt::tx::Signer as SignerT;
-    use subxt::utils::{AccountId32, MultiAddress, MultiSignature};
+    use subxt_core::config::Config;
+    use subxt_core::utils::{AccountId32, MultiAddress, MultiSignature};
+    use subxt_core::Signer as SignerT;
 
     impl From<Signature> for MultiSignature {
         fn from(value: Signature) -> Self {

signer/src/lib.rs

@@ -14,6 +14,9 @@
 //! subxt transactions for chains supporting sr25519 signatures.
 
 #![cfg_attr(docsrs, feature(doc_cfg))]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+extern crate alloc;
 
 #[macro_use]
 mod utils;
@@ -40,9 +43,3 @@ pub use secrecy::{ExposeSecret, SecretString};
 // SecretUri's can be parsed from strings and used to generate key pairs.
 // DeriveJunctions are the "path" part of these SecretUris.
 pub use crypto::{DeriveJunction, SecretUri, SecretUriError, DEV_PHRASE};
-
-#[cfg(any(
-    all(feature = "web", feature = "native"),
-    not(any(feature = "web", feature = "native"))
-))]
-compile_error!("subxt-signer: exactly one of the 'web' and 'native' features should be used.");

signer/src/sr25519.rs

@@ -4,7 +4,11 @@
 
 //! An sr25519 keypair implementation.
 
+use core::str::FromStr;
+
 use crate::crypto::{seed_from_entropy, DeriveJunction, SecretUri};
+
+use derive_more::{Display, From};
 use hex::FromHex;
 use schnorrkel::{
     derive::{ChainCode, Derivation},
@@ -72,7 +76,7 @@ impl Keypair {
             let seed = Seed::from_hex(hex_str)?;
             Self::from_seed(seed)?
         } else {
-            let phrase = bip39::Mnemonic::parse(phrase.expose_secret().as_str())?;
+            let phrase = bip39::Mnemonic::from_str(phrase.expose_secret().as_str())?;
             let pass_str = password.as_ref().map(|p| p.expose_secret().as_str());
             Self::from_phrase(&phrase, pass_str)?
         };
@@ -95,8 +99,9 @@ impl Keypair {
     /// keypair.sign(b"Hello world!");
     /// ```
     pub fn from_phrase(mnemonic: &bip39::Mnemonic, password: Option<&str>) -> Result<Self, Error> {
-        let big_seed = seed_from_entropy(&mnemonic.to_entropy(), password.unwrap_or(""))
-            .ok_or(Error::InvalidSeed)?;
+        let (arr, len) = mnemonic.to_entropy_array();
+        let big_seed =
+            seed_from_entropy(&arr[0..len], password.unwrap_or("")).ok_or(Error::InvalidSeed)?;
 
         let seed: Seed = big_seed[..SEED_LENGTH]
             .try_into()
@@ -187,24 +192,25 @@ pub fn verify<M: AsRef<[u8]>>(sig: &Signature, message: M, pubkey: &PublicKey) -
 }
 
 /// An error handed back if creating a keypair fails.
-#[derive(Debug, thiserror::Error)]
+#[derive(Debug, Display, From)]
 pub enum Error {
     /// Invalid seed.
-    #[error("Invalid seed (was it the wrong length?)")]
+    #[display(fmt = "Invalid seed (was it the wrong length?)")]
+    #[from(ignore)]
     InvalidSeed,
     /// Invalid phrase.
-    #[error("Cannot parse phrase: {0}")]
-    Phrase(#[from] bip39::Error),
+    #[display(fmt = "Cannot parse phrase: {_0}")]
+    Phrase(bip39::Error),
     /// Invalid hex.
-    #[error("Cannot parse hex string: {0}")]
-    Hex(#[from] hex::FromHexError),
+    #[display(fmt = "Cannot parse hex string: {_0}")]
+    Hex(hex::FromHexError),
 }
 
 /// Dev accounts, helpful for testing but not to be used in production,
 /// since the secret keys are known.
 pub mod dev {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     once_static_cloned! {
         /// Equivalent to `{DEV_PHRASE}//Alice`.
@@ -249,9 +255,7 @@ pub mod dev {
 mod subxt_compat {
     use super::*;
 
-    use subxt::config::Config;
-    use subxt::tx::Signer as SignerT;
-    use subxt::utils::{AccountId32, MultiAddress, MultiSignature};
+    use subxt_core::{AccountId32, Config, MultiAddress, MultiSignature, Signer as SignerT};
 
     impl From<Signature> for MultiSignature {
         fn from(value: Signature) -> Self {

signer/src/utils.rs

@@ -19,7 +19,7 @@ macro_rules! once_static {
         $(
             $(#[$attr])*
             $vis fn $name() -> &'static $ty {
-                static VAR: std::sync::OnceLock<$ty> = std::sync::OnceLock::new();
+                static VAR: once_cell::sync::OnceCell<$ty> = once_cell::sync::OnceCell::new();
                 VAR.get_or_init(|| { $expr })
             }
         )+
@@ -33,7 +33,7 @@ macro_rules! once_static_cloned {
         $(
             $(#[$attr])*
             $vis fn $name() -> $ty {
-                static VAR: std::sync::OnceLock<$ty> = std::sync::OnceLock::new();
+                static VAR: once_cell::sync::OnceCell<$ty> = once_cell::sync::OnceCell::new();
                 VAR.get_or_init(|| { $expr }).clone()
             }
         )+

testing/no-std-tests/Cargo.lock

@@ -38,6 +38,22 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6107fe1be6682a68940da878d9e9f5e90ca5745b3dec9fd1bb393c8777d4f581"
 
+[[package]]
+name = "bip39"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93f2635620bf0b9d4576eb7bb9a38a55df78bd1205d26fa994b25911a69f212f"
+dependencies = [
+ "bitcoin_hashes",
+ "unicode-normalization",
+]
+
+[[package]]
+name = "bitcoin_hashes"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90064b8dee6815a6470d60bad07bbbaee885c0e12d04177138fa3291a01b7bc4"
+
 [[package]]
 name = "bitvec"
 version = "1.0.1"
@@ -91,6 +107,15 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
 
+[[package]]
+name = "cc"
+version = "1.0.83"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1174fb0b6ec23863f8b971027804a42614e347eafb0a95bf0b12cdae21fc4d0"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -118,6 +143,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "critical-section"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7059fff8937831a9ae6f0fe4d658ffabf58f2ca96aa9dec1c889f936f705f216"
+
 [[package]]
 name = "crunchy"
 version = "0.2.2"
@@ -134,6 +165,34 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "curve25519-dalek"
+version = "4.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e89b8c6a2e4b1f45971ad09761aafb85514a84744b67a95e32c3cc1352d1f65c"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "curve25519-dalek-derive",
+ "digest",
+ "fiat-crypto",
+ "platforms",
+ "rustc_version",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "curve25519-dalek-derive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f46882e17999c6cc590af592290432be3bce0428cb0d5f8b6715e4dc7b383eb3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.48",
+]
+
 [[package]]
 name = "darling"
 version = "0.14.4"
@@ -216,6 +275,12 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
+[[package]]
+name = "fiat-crypto"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27573eac26f4dd11e2b1916c3fe1baa56407c83c71a773a8ba17ec0bca03b6b7"
+
 [[package]]
 name = "fixed-hash"
 version = "0.8.0"
@@ -269,6 +334,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getrandom_or_panic"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ea1015b5a70616b688dc230cfe50c8af89d972cb132d5a622814d29773b10b9"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.3"
@@ -285,6 +359,15 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hmac"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c49c37c09c17a53d937dfbb742eb3a961d65a994e6bcdcf37e7399d0cc8ab5e"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "ident_case"
 version = "1.0.1"
@@ -363,11 +446,27 @@ version = "2.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "523dc4f511e55ab87b694dc30d0f820d60906ef06413f93d4d7a1385599cc149"
 
+[[package]]
+name = "merlin"
+version = "3.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "58c38e2799fc0978b65dfff8023ec7843e2330bb462f19198840b34b6582397d"
+dependencies = [
+ "byteorder",
+ "keccak",
+ "rand_core",
+ "zeroize",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
+dependencies = [
+ "critical-section",
+ "portable-atomic",
+]
 
 [[package]]
 name = "parity-scale-codec"
@@ -393,6 +492,27 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "pbkdf2"
+version = "0.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8ed6a7761f76e3b9f92dfb0a60a6a6477c61024b775147ff0973a02653abaf2"
+dependencies = [
+ "digest",
+]
+
+[[package]]
+name = "platforms"
+version = "3.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "626dec3cac7cc0e1577a2ec3fc496277ec2baa084bebad95bb6fdbfae235f84c"
+
+[[package]]
+name = "portable-atomic"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
+
 [[package]]
 name = "primitive-types"
 version = "0.12.2"
@@ -450,6 +570,37 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
 
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+
+[[package]]
+name = "regex"
+version = "1.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b62dbe01f0b06f9d8dc7d49e05a0785f153b00b2c227856282f671e0318c9b15"
+dependencies = [
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5bb987efffd3c6d0d8f5f89510bb458559eab11e4f869acb20bf845e016259cd"
+dependencies = [
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
+
 [[package]]
 name = "rustc_version"
 version = "0.4.0"
@@ -573,6 +724,50 @@ dependencies = [
  "scale-info",
 ]
 
+[[package]]
+name = "schnorrkel"
+version = "0.11.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8de18f6d8ba0aad7045f5feae07ec29899c1112584a38509a84ad7b04451eaa0"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "curve25519-dalek",
+ "getrandom_or_panic",
+ "merlin",
+ "rand_core",
+ "sha2",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "secp256k1"
+version = "0.28.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d24b59d129cdadea20aea4fb2352fa053712e5d713eee47d700cd4b2bc002f10"
+dependencies = [
+ "secp256k1-sys",
+]
+
+[[package]]
+name = "secp256k1-sys"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5d1746aae42c19d583c3c1a8c646bfad910498e2051c551a7f2e3c0c9fbb7eb"
+dependencies = [
+ "cc",
+]
+
+[[package]]
+name = "secrecy"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bd1c54ea06cfd2f6b63219704de0b9b4f72dcc2b8fdef820be6cd799780e91e"
+dependencies = [
+ "zeroize",
+]
+
 [[package]]
 name = "semver"
 version = "1.0.21"
@@ -703,6 +898,7 @@ dependencies = [
  "parity-scale-codec",
  "subxt-core",
  "subxt-metadata",
+ "subxt-signer",
 ]
 
 [[package]]
@@ -717,6 +913,27 @@ dependencies = [
  "sp-core-hashing",
 ]
 
+[[package]]
+name = "subxt-signer"
+version = "0.34.0"
+dependencies = [
+ "bip39",
+ "derive_more",
+ "hex",
+ "hmac",
+ "once_cell",
+ "parity-scale-codec",
+ "pbkdf2",
+ "regex",
+ "schnorrkel",
+ "secp256k1",
+ "secrecy",
+ "sha2",
+ "sp-core-hashing",
+ "subxt-core",
+ "zeroize",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -745,6 +962,21 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
+[[package]]
+name = "tinyvec"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87cc5ceb3875bb20c2890005a4e226a4651264a5c75edb2421b52861a0a0cb50"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.3"
@@ -808,6 +1040,15 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
 
+[[package]]
+name = "unicode-normalization"
+version = "0.1.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c5713f0fc4b5db668a2ac63cdb7bb4469d8c9fed047b1d0292cc7b0ce2ba921"
+dependencies = [
+ "tinyvec",
+]
+
 [[package]]
 name = "version_check"
 version = "0.9.4"
@@ -851,3 +1092,23 @@ dependencies = [
  "quote",
  "syn 2.0.48",
 ]
+
+[[package]]
+name = "zeroize"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "525b4ec142c6b68a2d10f01f7bbf6755599ca3f81ea53b8431b7dd348f5fdb2d"
+dependencies = [
+ "zeroize_derive",
+]
+
+[[package]]
+name = "zeroize_derive"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce36e65b0d2999d2aafac989fb249189a141aee1f53c612c1f37d72631959f69"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.48",
+]

testing/no-std-tests/Cargo.toml

@@ -8,6 +8,7 @@ resolver = "2"
 [dependencies]
 subxt-metadata = { path = "../../metadata", default-features = false }
 subxt-core = { path = "../../core", default-features = false }
+subxt-signer = { path = "../../signer", default-features = false, features = ["sr25519", "ecdsa", "subxt"] }
 codec = { package = "parity-scale-codec", version = "3.6.9", default-features = false, features = ["derive"] }
 libc = { version = "0.2", default-features = false }
 libc_alloc = { version = "1.0.6" }

testing/no-std-tests/src/main.rs

@@ -49,6 +49,14 @@ fn subxt_metadata_test() {
     subxt_metadata::Metadata::decode(&mut &METADATA[..]).expect("should be valid metadata");
 }
 
+fn subxt_signer_test() {
+    use subxt_signer::{ SecretUri, ecdsa::Keypair };
+    use core::str::FromStr;
+    let uri = SecretUri::from_str("//Alice").unwrap();
+    let keypair = Keypair::from_uri(&uri).unwrap();
+}
+
 fn subxt_core_test() {
     let _ = subxt_core::utils::Era::Immortal;
 }
+