From 766d04335d1825b9cc555c081839fb7583880665 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 12:49:10 +0200
Subject: [PATCH 01/20] =?UTF-8?q?Upgrade=20`libsecp256k1`=20from=20`0.3.5`?=
 =?UTF-8?q?=20=E2=9E=94=20`0.7.0`?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 crates/engine/Cargo.toml                              | 2 +-
 crates/engine/src/ext.rs                              | 4 ++--
 crates/env/Cargo.toml                                 | 2 +-
 crates/env/src/engine/experimental_off_chain/impls.rs | 4 ++--
 crates/env/src/engine/off_chain/impls.rs              | 4 ++--
 crates/eth_compatibility/Cargo.toml                   | 2 +-
 crates/eth_compatibility/src/lib.rs                   | 2 +-
 7 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/crates/engine/Cargo.toml b/crates/engine/Cargo.toml
index 4f700af06ec..85f26e05d70 100644
--- a/crates/engine/Cargo.toml
+++ b/crates/engine/Cargo.toml
@@ -23,7 +23,7 @@ sha3 = { version = "0.9" }
 blake2 = { version = "0.9" }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.3.5", default-features = false }
+libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
 
 [features]
 default = ["std"]
diff --git a/crates/engine/src/ext.rs b/crates/engine/src/ext.rs
index a302df6390a..a28957954cc 100644
--- a/crates/engine/src/ext.rs
+++ b/crates/engine/src/ext.rs
@@ -428,7 +428,7 @@ impl Engine {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result {
-        use secp256k1::{
+        use libsecp256k1::{
             recover,
             Message,
             RecoveryId,
@@ -443,7 +443,7 @@ impl Engine {
             signature[64]
         };
         let message = Message::parse(message_hash);
-        let signature = Signature::parse_slice(&signature[0..64])
+        let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
         let recovery_id = RecoveryId::parse(recovery_byte)
diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index 69bd6cd40ee..ff146457cfd 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -36,7 +36,7 @@ sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.3.5", default-features = false }
+libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
 
 # Only used in the off-chain environment.
 #
diff --git a/crates/env/src/engine/experimental_off_chain/impls.rs b/crates/env/src/engine/experimental_off_chain/impls.rs
index 375f85ab650..75a2a879318 100644
--- a/crates/env/src/engine/experimental_off_chain/impls.rs
+++ b/crates/env/src/engine/experimental_off_chain/impls.rs
@@ -255,7 +255,7 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use secp256k1::{
+        use libsecp256k1::{
             recover,
             Message,
             RecoveryId,
@@ -270,7 +270,7 @@ impl EnvBackend for EnvInstance {
             signature[64]
         };
         let message = Message::parse(message_hash);
-        let signature = Signature::parse_slice(&signature[0..64])
+        let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
         let recovery_id = RecoveryId::parse(recovery_byte)
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index b86631242b3..4e8deda5489 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -201,7 +201,7 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use secp256k1::{
+        use libsecp256k1::{
             recover,
             Message,
             RecoveryId,
@@ -216,7 +216,7 @@ impl EnvBackend for EnvInstance {
             signature[64]
         };
         let message = Message::parse(message_hash);
-        let signature = Signature::parse_slice(&signature[0..64])
+        let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
         let recovery_id = RecoveryId::parse(recovery_byte)
diff --git a/crates/eth_compatibility/Cargo.toml b/crates/eth_compatibility/Cargo.toml
index fa63f9f4db4..d6325d0c8b2 100644
--- a/crates/eth_compatibility/Cargo.toml
+++ b/crates/eth_compatibility/Cargo.toml
@@ -16,7 +16,7 @@ include = ["Cargo.toml", "src/**/*.rs", "/README.md", "/LICENSE"]
 
 [dependencies]
 ink_env = { version = "3.0.0-rc6", path = "../env", default-features = false }
-libsecp256k1 = { version = "0.3.5", default-features = false }
+libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
 
 [features]
 default = ["std"]
diff --git a/crates/eth_compatibility/src/lib.rs b/crates/eth_compatibility/src/lib.rs
index 4c27cad1ef3..b7144ea7411 100644
--- a/crates/eth_compatibility/src/lib.rs
+++ b/crates/eth_compatibility/src/lib.rs
@@ -92,7 +92,7 @@ impl ECDSAPublicKey {
     /// ```
     pub fn to_eth_address(&self) -> EthereumAddress {
         use ink_env::hash;
-        use secp256k1::PublicKey;
+        use libsecp256k1::PublicKey;
 
         // Transform compressed public key into uncompressed.
         let pub_key = PublicKey::parse_compressed(&self.0)

From 9610d3a1cb7cc2d633f2c06851013ddba54b3836 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 13:36:06 +0200
Subject: [PATCH 02/20] Include off-chain dependencies only when necessary

---
 crates/env/Cargo.toml | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index ff146457cfd..f3c6853d4d1 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -30,6 +30,7 @@ arrayref = "0.3"
 static_assertions = "1.1"
 sp-arithmetic = { version = "3.0", default-features = false }
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 # Hashes for the off-chain environment.
 sha2 = { version = "0.9", optional = true }
 sha3 = { version = "0.9", optional = true }
@@ -39,9 +40,6 @@ blake2 = { version = "0.9", optional = true }
 libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
 
 # Only used in the off-chain environment.
-#
-# Sadly couldn't be marked as dev-dependency.
-# Never use this crate outside the off-chain environment!
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }
 scale-info = { version = "1.0", default-features = false, features = ["derive"], optional = true }
 

From a32ce167ad7c0751fc2670abe954bb9699e65b7b Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 13:37:19 +0200
Subject: [PATCH 03/20] Include off-chain dependency only when necessary

---
 crates/storage/Cargo.toml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crates/storage/Cargo.toml b/crates/storage/Cargo.toml
index 4e7fb5ba3fc..2fb7b8238e0 100644
--- a/crates/storage/Cargo.toml
+++ b/crates/storage/Cargo.toml
@@ -27,6 +27,7 @@ scale-info = { version = "1.0", default-features = false, features = ["derive"],
 cfg-if = "1.0"
 array-init = { version = "2.0", default-features = false }
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 # Workaround: we actually just need criterion as a dev-dependency, but
 # there is an issue with a doubly included std lib when executing
 # `cargo check --no-default-features --target wasm32-unknown-unknown`.

From f4d895910e9bea629b1c40ed852341bd7231d62f Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 13:42:57 +0200
Subject: [PATCH 04/20] Include off-chain dependency only when necessary

---
 crates/eth_compatibility/Cargo.toml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/crates/eth_compatibility/Cargo.toml b/crates/eth_compatibility/Cargo.toml
index d6325d0c8b2..c744d921e32 100644
--- a/crates/eth_compatibility/Cargo.toml
+++ b/crates/eth_compatibility/Cargo.toml
@@ -16,6 +16,8 @@ include = ["Cargo.toml", "src/**/*.rs", "/README.md", "/LICENSE"]
 
 [dependencies]
 ink_env = { version = "3.0.0-rc6", path = "../env", default-features = false }
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
 
 [features]

From f339fdf74a1cb2b7281547aaec56d1a8cbd316fc Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 16:21:04 +0200
Subject: [PATCH 05/20] Switch to `secp256k1` for `eth_compatibility` crate

---
 crates/eth_compatibility/Cargo.toml | 4 ++--
 crates/eth_compatibility/src/lib.rs | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/crates/eth_compatibility/Cargo.toml b/crates/eth_compatibility/Cargo.toml
index c744d921e32..cebc5bf4e90 100644
--- a/crates/eth_compatibility/Cargo.toml
+++ b/crates/eth_compatibility/Cargo.toml
@@ -17,8 +17,8 @@ include = ["Cargo.toml", "src/**/*.rs", "/README.md", "/LICENSE"]
 [dependencies]
 ink_env = { version = "3.0.0-rc6", path = "../env", default-features = false }
 
-[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+secp256k1 = { version = "0.20.3", default-features = false }
 
 [features]
 default = ["std"]
diff --git a/crates/eth_compatibility/src/lib.rs b/crates/eth_compatibility/src/lib.rs
index b7144ea7411..b6676c92aeb 100644
--- a/crates/eth_compatibility/src/lib.rs
+++ b/crates/eth_compatibility/src/lib.rs
@@ -92,10 +92,10 @@ impl ECDSAPublicKey {
     /// ```
     pub fn to_eth_address(&self) -> EthereumAddress {
         use ink_env::hash;
-        use libsecp256k1::PublicKey;
+        use secp256k1::PublicKey;
 
         // Transform compressed public key into uncompressed.
-        let pub_key = PublicKey::parse_compressed(&self.0)
+        let pub_key = PublicKey::from_slice(&self.0)
             .expect("Unable to parse the compressed ECDSA public key");
         let uncompressed = pub_key.serialize();
 

From 1d4ff6dd9e89075265b646fc654ffc50cec0e76c Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Tue, 19 Oct 2021 19:37:51 +0200
Subject: [PATCH 06/20] Remove conditional dependency

---
 crates/eth_compatibility/Cargo.toml | 2 --
 1 file changed, 2 deletions(-)

diff --git a/crates/eth_compatibility/Cargo.toml b/crates/eth_compatibility/Cargo.toml
index cebc5bf4e90..b93c2416109 100644
--- a/crates/eth_compatibility/Cargo.toml
+++ b/crates/eth_compatibility/Cargo.toml
@@ -16,8 +16,6 @@ include = ["Cargo.toml", "src/**/*.rs", "/README.md", "/LICENSE"]
 
 [dependencies]
 ink_env = { version = "3.0.0-rc6", path = "../env", default-features = false }
-
-[target.'cfg(target_arch = "wasm32")'.dependencies]
 secp256k1 = { version = "0.20.3", default-features = false }
 
 [features]

From bf40498cd98b1ba99a5323e981bf6c551c91bb45 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Wed, 20 Oct 2021 07:41:33 +0200
Subject: [PATCH 07/20] Fix serialize

---
 crates/eth_compatibility/src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/eth_compatibility/src/lib.rs b/crates/eth_compatibility/src/lib.rs
index b6676c92aeb..3e853b8ea1a 100644
--- a/crates/eth_compatibility/src/lib.rs
+++ b/crates/eth_compatibility/src/lib.rs
@@ -97,7 +97,7 @@ impl ECDSAPublicKey {
         // Transform compressed public key into uncompressed.
         let pub_key = PublicKey::from_slice(&self.0)
             .expect("Unable to parse the compressed ECDSA public key");
-        let uncompressed = pub_key.serialize();
+        let uncompressed = pub_key.serialize_uncompressed();
 
         // Hash the uncompressed public key by Keccak256 algorithm.
         let mut hash = <hash::Keccak256 as hash::HashOutput>::Type::default();

From d22c6dafcfb80d50ca6f8557466ce00238b1be88 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Wed, 20 Oct 2021 08:31:16 +0200
Subject: [PATCH 08/20] Switch to `secp256k1` crate everywhere

---
 crates/engine/Cargo.toml   |  2 +-
 crates/engine/src/ext.rs   | 31 ++++++++------
 crates/engine/src/tests.rs | 82 ++++++++++++++++++++++++++++++++++++++
 crates/env/Cargo.toml      |  4 +-
 4 files changed, 104 insertions(+), 15 deletions(-)

diff --git a/crates/engine/Cargo.toml b/crates/engine/Cargo.toml
index 85f26e05d70..073d2c22a36 100644
--- a/crates/engine/Cargo.toml
+++ b/crates/engine/Cargo.toml
@@ -23,7 +23,7 @@ sha3 = { version = "0.9" }
 blake2 = { version = "0.9" }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
+secp256k1 = { version = "0.20.3", features = ["recovery"] }
 
 [features]
 default = ["std"]
diff --git a/crates/engine/src/ext.rs b/crates/engine/src/ext.rs
index a28957954cc..1d01f2d9a08 100644
--- a/crates/engine/src/ext.rs
+++ b/crates/engine/src/ext.rs
@@ -428,11 +428,13 @@ impl Engine {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result {
-        use libsecp256k1::{
-            recover,
+        use secp256k1::{
+            recovery::{
+                RecoverableSignature,
+                RecoveryId,
+            },
             Message,
-            RecoveryId,
-            Signature,
+            Secp256k1,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -442,17 +444,22 @@ impl Engine {
         } else {
             signature[64]
         };
-        let message = Message::parse(message_hash);
-        let signature = Signature::parse_standard_slice(&signature[0..64])
-            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
-
-        let recovery_id = RecoveryId::parse(recovery_byte)
+        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-
-        let pub_key = recover(&message, &signature, &recovery_id);
+        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
+            panic!("Unable to create the message from hash: {}", error)
+        });
+        let signature =
+            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
+                .unwrap_or_else(|error| {
+                    panic!("Unable to parse the signature: {}", error)
+                });
+
+        let secp = Secp256k1::new();
+        let pub_key = secp.recover(&message, &signature);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize_compressed();
+                *output = pub_key.serialize();
                 Ok(())
             }
             Err(_) => Err(Error::EcdsaRecoverFailed),
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 798f5287de7..97ffa823b71 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -16,6 +16,14 @@ use crate::ext::{
     Engine,
     Error,
 };
+use secp256k1::{
+    recovery::RecoverableSignature,
+    Message,
+    PublicKey,
+    Secp256k1,
+    SecretKey,
+};
+use std::convert::TryInto;
 
 /// The public methods of the `contracts` pallet write their result into an
 /// `output` buffer instead of returning them. Since we aim to emulate this
@@ -192,3 +200,77 @@ fn must_panic_when_buffer_too_small() {
     // then
     unreachable!("`get_storage` must already have panicked");
 }
+
+#[test]
+fn ecdsa_recovery_test_from_contracts_pallet() {
+    // given
+    let mut engine = Engine::new();
+    #[rustfmt::skip]
+    let signature: [u8; 65] = [
+        161, 234, 203,  74, 147, 96,  51, 212,   5, 174, 231,   9, 142,  48, 137, 201,
+        162, 118, 192,  67, 239, 16,  71, 216, 125,  86, 167, 139,  70,   7,  86, 241,
+         33,  87, 154, 251,  81, 29, 160,   4, 176, 239,  88, 211, 244, 232, 232,  52,
+        211, 234, 100, 115, 230, 47,  80,  44, 152, 166,  62,  50,   8,  13,  86, 175,
+         28,
+    ];
+    #[rustfmt::skip]
+    let message_hash: [u8; 32] = [
+        162, 28, 244, 179, 96, 76, 244, 178, 188,  83, 230, 248, 143, 106,  77, 117,
+        239, 95, 244, 171, 65, 95,  62, 153, 174, 166, 182,  28, 130,  73, 196, 208
+    ];
+
+    // when
+    let mut output = [0; 33];
+    engine
+        .ecdsa_recover(&signature, &message_hash, &mut output)
+        .expect("must work");
+
+    // then
+    #[rustfmt::skip]
+    const EXPECTED_COMPRESSED_PUBLIC_KEY: [u8; 33] = [
+          2, 121, 190, 102, 126, 249, 220, 187, 172, 85, 160,  98, 149, 206, 135, 11,
+          7,   2, 155, 252, 219,  45, 206,  40, 217, 89, 242, 129,  91,  22, 248, 23,
+        152,
+    ];
+    assert_eq!(output, EXPECTED_COMPRESSED_PUBLIC_KEY);
+}
+
+#[test]
+fn ecdsa_recovery_with_secp256k1_crate() {
+    // given
+    let mut engine = Engine::new();
+    let secp = Secp256k1::new();
+    let seckey = [
+        59, 148, 11, 85, 134, 130, 61, 253, 2, 174, 59, 70, 27, 180, 51, 107, 94, 203,
+        174, 253, 102, 39, 170, 146, 46, 252, 4, 143, 236, 12, 136, 28,
+    ];
+    let pubkey = PublicKey::from_slice(&[
+        2, 29, 21, 35, 7, 198, 183, 43, 14, 208, 65, 139, 14, 112, 205, 128, 231, 245,
+        41, 91, 141, 134, 245, 114, 45, 63, 82, 19, 251, 210, 57, 79, 54,
+    ])
+    .expect("pubkey creation failed");
+
+    let mut msg_hash = [0; 32];
+    crate::hashing::sha2_256(b"Some message", &mut msg_hash);
+
+    let msg = Message::from_slice(&msg_hash).expect("message creation failed");
+    let seckey = SecretKey::from_slice(&seckey).expect("secret key creation failed");
+    let recoverable_signature: RecoverableSignature =
+        secp.sign_recoverable(&msg, &seckey);
+
+    let recovery_id = recoverable_signature.serialize_compact().0.to_i32() as u8;
+    let mut signature = recoverable_signature.serialize_compact().1.to_vec();
+    signature.push(recovery_id);
+    let signature_with_recovery_id: [u8; 65] = signature
+        .try_into()
+        .expect("unable to create signature with recovery id");
+
+    // when
+    let mut output = [0; 33];
+    engine
+        .ecdsa_recover(&signature_with_recovery_id, &msg.as_ref(), &mut output)
+        .expect("ecdsa recovery failed");
+
+    // then
+    assert_eq!(output, pubkey.serialize());
+}
diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index f3c6853d4d1..3edcde5393a 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -15,7 +15,6 @@ categories = ["no-std", "embedded"]
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE"]
 
 [dependencies]
-ink_engine = { version = "3.0.0-rc6", path = "../engine/", default-features = false, optional = true }
 ink_metadata = { version = "3.0.0-rc6", path = "../metadata/", default-features = false, features = ["derive"], optional = true }
 ink_allocator = { version = "3.0.0-rc6", path = "../allocator/", default-features = false }
 ink_primitives = { version = "3.0.0-rc6", path = "../primitives/", default-features = false }
@@ -31,13 +30,14 @@ static_assertions = "1.1"
 sp-arithmetic = { version = "3.0", default-features = false }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+ink_engine = { version = "3.0.0-rc6", path = "../engine/", default-features = false, optional = true }
 # Hashes for the off-chain environment.
 sha2 = { version = "0.9", optional = true }
 sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.7.0", default-features = false, features = ["static-context"] }
+secp256k1 = { version = "0.20.3", features = ["recovery"] }
 
 # Only used in the off-chain environment.
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }

From 92d0577184a08dfaf753989847480d46e40e3699 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 12:34:00 +0200
Subject: [PATCH 09/20] Switch to `secp256k1` crate everywhere

---
 .../engine/experimental_off_chain/impls.rs    | 31 ++++++++++-------
 crates/env/src/engine/off_chain/impls.rs      | 33 +++++++++++--------
 2 files changed, 39 insertions(+), 25 deletions(-)

diff --git a/crates/env/src/engine/experimental_off_chain/impls.rs b/crates/env/src/engine/experimental_off_chain/impls.rs
index 75a2a879318..dea1c6d0139 100644
--- a/crates/env/src/engine/experimental_off_chain/impls.rs
+++ b/crates/env/src/engine/experimental_off_chain/impls.rs
@@ -255,11 +255,13 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use libsecp256k1::{
-            recover,
+        use secp256k1::{
+            recovery::{
+                RecoverableSignature,
+                RecoveryId,
+            },
             Message,
-            RecoveryId,
-            Signature,
+            Secp256k1,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -269,17 +271,22 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let message = Message::parse(message_hash);
-        let signature = Signature::parse_standard_slice(&signature[0..64])
-            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
-
-        let recovery_id = RecoveryId::parse(recovery_byte)
+        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-
-        let pub_key = recover(&message, &signature, &recovery_id);
+        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
+            panic!("Unable to create the message from hash: {}", error)
+        });
+        let signature =
+            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
+                .unwrap_or_else(|error| {
+                    panic!("Unable to parse the signature: {}", error)
+                });
+
+        let secp = Secp256k1::new();
+        let pub_key = secp.recover(&message, &signature);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize_compressed();
+                *output = pub_key.serialize();
                 Ok(())
             }
             Err(_) => Err(crate::Error::EcdsaRecoverFailed),
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 4e8deda5489..27ba2bb05de 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -201,11 +201,13 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use libsecp256k1::{
-            recover,
+        use secp256k1::{
+            recovery::{
+                RecoverableSignature,
+                RecoveryId,
+            },
             Message,
-            RecoveryId,
-            Signature,
+            Secp256k1,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -215,20 +217,25 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let message = Message::parse(message_hash);
-        let signature = Signature::parse_standard_slice(&signature[0..64])
-            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
-
-        let recovery_id = RecoveryId::parse(recovery_byte)
+        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-
-        let pub_key = recover(&message, &signature, &recovery_id);
+        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
+            panic!("Unable to create the message from hash: {}", error)
+        });
+        let signature =
+            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
+                .unwrap_or_else(|error| {
+                    panic!("Unable to parse the signature: {}", error)
+                });
+
+        let secp = Secp256k1::new();
+        let pub_key = secp.recover(&message, &signature);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize_compressed();
+                *output = pub_key.serialize();
                 Ok(())
             }
-            Err(_) => Err(Error::EcdsaRecoverFailed),
+            Err(_) => Err(crate::Error::EcdsaRecoverFailed),
         }
     }
 

From 6f4e16e96adfa60f693cca64499ad1e9603325af Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 13:15:31 +0200
Subject: [PATCH 10/20] Fix compilation for `wasm32` target

---
 crates/env/Cargo.toml               | 3 ++-
 crates/eth_compatibility/src/lib.rs | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index 3edcde5393a..68b5255736c 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -31,13 +31,14 @@ sp-arithmetic = { version = "3.0", default-features = false }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ink_engine = { version = "3.0.0-rc6", path = "../engine/", default-features = false, optional = true }
+
 # Hashes for the off-chain environment.
 sha2 = { version = "0.9", optional = true }
 sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-secp256k1 = { version = "0.20.3", features = ["recovery"] }
+secp256k1 = { version = "0.20.3", default-features = false, features = ["recovery"] }
 
 # Only used in the off-chain environment.
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }
diff --git a/crates/eth_compatibility/src/lib.rs b/crates/eth_compatibility/src/lib.rs
index 3e853b8ea1a..1439f8f3098 100644
--- a/crates/eth_compatibility/src/lib.rs
+++ b/crates/eth_compatibility/src/lib.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #![no_std]
+
 use ink_env::{
     DefaultEnvironment,
     Environment,

From a30a790d557025a4e4ab88c90e11b7c08a5a2105 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 13:44:17 +0200
Subject: [PATCH 11/20] Ensure enabled features are not merged for targets

---
 Cargo.toml            | 1 +
 crates/env/Cargo.toml | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 554092d4a5e..48f592ff034 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,4 +1,5 @@
 [workspace]
+resolver = "2"
 members = [
     "crates/metadata",
     "crates/allocator",
diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index 68b5255736c..a517358c8db 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -29,6 +29,9 @@ arrayref = "0.3"
 static_assertions = "1.1"
 sp-arithmetic = { version = "3.0", default-features = false }
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+secp256k1 = { version = "0.20.3", default-features = false }
+
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ink_engine = { version = "3.0.0-rc6", path = "../engine/", default-features = false, optional = true }
 
@@ -38,7 +41,7 @@ sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-secp256k1 = { version = "0.20.3", default-features = false, features = ["recovery"] }
+secp256k1 = { version = "0.20.3", features = ["recovery"] }
 
 # Only used in the off-chain environment.
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }

From 17369999a02867ab0d270dc428488f8e1ccf9148 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 13:53:50 +0200
Subject: [PATCH 12/20] Make clippy happy

---
 crates/engine/src/tests.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 97ffa823b71..f687ad3d136 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -268,7 +268,7 @@ fn ecdsa_recovery_with_secp256k1_crate() {
     // when
     let mut output = [0; 33];
     engine
-        .ecdsa_recover(&signature_with_recovery_id, &msg.as_ref(), &mut output)
+        .ecdsa_recover(&signature_with_recovery_id, msg.as_ref(), &mut output)
         .expect("ecdsa recovery failed");
 
     // then

From f12e024d01554f0d62ceb97bdae117c4848f03b7 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 14:24:42 +0200
Subject: [PATCH 13/20] Use resolver `2` in all examples

---
 examples/contract-terminate/Cargo.toml    | 1 +
 examples/contract-transfer/Cargo.toml     | 1 +
 examples/delegator/Cargo.toml             | 1 +
 examples/delegator/accumulator/Cargo.toml | 1 +
 examples/delegator/adder/Cargo.toml       | 1 +
 examples/delegator/subber/Cargo.toml      | 1 +
 examples/dns/Cargo.toml                   | 1 +
 examples/erc1155/Cargo.toml               | 1 +
 examples/erc20/Cargo.toml                 | 1 +
 examples/erc721/Cargo.toml                | 1 +
 examples/flipper/Cargo.toml               | 1 +
 examples/incrementer/Cargo.toml           | 1 +
 examples/multisig/Cargo.toml              | 1 +
 examples/rand-extension/Cargo.toml        | 1 +
 examples/trait-erc20/Cargo.toml           | 1 +
 examples/trait-flipper/Cargo.toml         | 1 +
 examples/trait-incrementer/Cargo.toml     | 1 +
 17 files changed, 17 insertions(+)

diff --git a/examples/contract-terminate/Cargo.toml b/examples/contract-terminate/Cargo.toml
index 39d89d74061..4f4feb74df4 100644
--- a/examples/contract-terminate/Cargo.toml
+++ b/examples/contract-terminate/Cargo.toml
@@ -3,6 +3,7 @@ name = "contract_terminate"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/contract-transfer/Cargo.toml b/examples/contract-transfer/Cargo.toml
index 3d6a2cc0cfc..d7ef695a187 100644
--- a/examples/contract-transfer/Cargo.toml
+++ b/examples/contract-transfer/Cargo.toml
@@ -3,6 +3,7 @@ name = "contract_transfer"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/delegator/Cargo.toml b/examples/delegator/Cargo.toml
index 087684226cf..1899b35750e 100644
--- a/examples/delegator/Cargo.toml
+++ b/examples/delegator/Cargo.toml
@@ -3,6 +3,7 @@ name = "delegator"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/delegator/accumulator/Cargo.toml b/examples/delegator/accumulator/Cargo.toml
index 03ce8203287..cee48a893a5 100644
--- a/examples/delegator/accumulator/Cargo.toml
+++ b/examples/delegator/accumulator/Cargo.toml
@@ -3,6 +3,7 @@ name = "accumulator"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../../crates/primitives", default-features = false }
diff --git a/examples/delegator/adder/Cargo.toml b/examples/delegator/adder/Cargo.toml
index 043d9808013..5778bb5c65e 100644
--- a/examples/delegator/adder/Cargo.toml
+++ b/examples/delegator/adder/Cargo.toml
@@ -3,6 +3,7 @@ name = "adder"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../../crates/primitives", default-features = false }
diff --git a/examples/delegator/subber/Cargo.toml b/examples/delegator/subber/Cargo.toml
index 3470808961a..a068e3758c4 100644
--- a/examples/delegator/subber/Cargo.toml
+++ b/examples/delegator/subber/Cargo.toml
@@ -3,6 +3,7 @@ name = "subber"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../../crates/primitives", default-features = false }
diff --git a/examples/dns/Cargo.toml b/examples/dns/Cargo.toml
index 438690c768d..bb433e83345 100644
--- a/examples/dns/Cargo.toml
+++ b/examples/dns/Cargo.toml
@@ -3,6 +3,7 @@ name = "dns"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/erc1155/Cargo.toml b/examples/erc1155/Cargo.toml
index 957e8409921..9bf2c452f2f 100644
--- a/examples/erc1155/Cargo.toml
+++ b/examples/erc1155/Cargo.toml
@@ -3,6 +3,7 @@ name = "erc1155"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/erc20/Cargo.toml b/examples/erc20/Cargo.toml
index 8430850f5d9..2e5663c508d 100644
--- a/examples/erc20/Cargo.toml
+++ b/examples/erc20/Cargo.toml
@@ -3,6 +3,7 @@ name = "erc20"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/erc721/Cargo.toml b/examples/erc721/Cargo.toml
index 068e9d81013..58e04f0197a 100644
--- a/examples/erc721/Cargo.toml
+++ b/examples/erc721/Cargo.toml
@@ -3,6 +3,7 @@ name = "erc721"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/flipper/Cargo.toml b/examples/flipper/Cargo.toml
index 22fb07ef367..3047165a5e4 100644
--- a/examples/flipper/Cargo.toml
+++ b/examples/flipper/Cargo.toml
@@ -3,6 +3,7 @@ name = "flipper"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/incrementer/Cargo.toml b/examples/incrementer/Cargo.toml
index 3f834cc9e89..a3756e22336 100644
--- a/examples/incrementer/Cargo.toml
+++ b/examples/incrementer/Cargo.toml
@@ -3,6 +3,7 @@ name = "incrementer"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/multisig/Cargo.toml b/examples/multisig/Cargo.toml
index f324ce3782d..3458a958502 100755
--- a/examples/multisig/Cargo.toml
+++ b/examples/multisig/Cargo.toml
@@ -3,6 +3,7 @@ name = "multisig"
 version = "3.0.0-rc5"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/rand-extension/Cargo.toml b/examples/rand-extension/Cargo.toml
index d17f4f985b8..3872c400e4d 100755
--- a/examples/rand-extension/Cargo.toml
+++ b/examples/rand-extension/Cargo.toml
@@ -3,6 +3,7 @@ name = "rand_extension"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/trait-erc20/Cargo.toml b/examples/trait-erc20/Cargo.toml
index 85200db8a7a..0b4efc6f67a 100644
--- a/examples/trait-erc20/Cargo.toml
+++ b/examples/trait-erc20/Cargo.toml
@@ -3,6 +3,7 @@ name = "trait_erc20"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/trait-flipper/Cargo.toml b/examples/trait-flipper/Cargo.toml
index 60563b6e504..ed049aaf45b 100644
--- a/examples/trait-flipper/Cargo.toml
+++ b/examples/trait-flipper/Cargo.toml
@@ -3,6 +3,7 @@ name = "trait_flipper"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }
diff --git a/examples/trait-incrementer/Cargo.toml b/examples/trait-incrementer/Cargo.toml
index 3e54410fe05..f92aa54e422 100644
--- a/examples/trait-incrementer/Cargo.toml
+++ b/examples/trait-incrementer/Cargo.toml
@@ -3,6 +3,7 @@ name = "trait-incrementer"
 version = "3.0.0-rc6"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
+resolver = "2"
 
 [dependencies]
 ink_primitives = { version = "3.0.0-rc6", path = "../../crates/primitives", default-features = false }

From f3c5161fde3aa9bee915641519e7b3260ad54c82 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 16:43:55 +0200
Subject: [PATCH 14/20] Switch to `libsecp256k1` 0.7.0

---
 crates/engine/Cargo.toml                      |  2 +-
 crates/engine/src/ext.rs                      | 30 +++++++----------
 crates/engine/src/tests.rs                    | 23 +++++--------
 crates/env/Cargo.toml                         |  4 +--
 .../engine/experimental_off_chain/impls.rs    | 33 ++++++++-----------
 crates/env/src/engine/off_chain/impls.rs      | 32 +++++++-----------
 crates/eth_compatibility/Cargo.toml           |  2 +-
 crates/eth_compatibility/src/lib.rs           |  6 ++--
 8 files changed, 52 insertions(+), 80 deletions(-)

diff --git a/crates/engine/Cargo.toml b/crates/engine/Cargo.toml
index 073d2c22a36..95cd6e4fa64 100644
--- a/crates/engine/Cargo.toml
+++ b/crates/engine/Cargo.toml
@@ -23,7 +23,7 @@ sha3 = { version = "0.9" }
 blake2 = { version = "0.9" }
 
 # ECDSA for the off-chain environment.
-secp256k1 = { version = "0.20.3", features = ["recovery"] }
+libsecp256k1 = { version = "0.7.0", features = ["lazy-static-context"] }
 
 [features]
 default = ["std"]
diff --git a/crates/engine/src/ext.rs b/crates/engine/src/ext.rs
index 1d01f2d9a08..73e4a1c26e9 100644
--- a/crates/engine/src/ext.rs
+++ b/crates/engine/src/ext.rs
@@ -428,13 +428,11 @@ impl Engine {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result {
-        use secp256k1::{
-            recovery::{
-                RecoverableSignature,
-                RecoveryId,
-            },
+        use libsecp256k1::{
+            recover,
             Message,
-            Secp256k1,
+            RecoveryId,
+            Signature,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -444,22 +442,16 @@ impl Engine {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
+        let recovery_id = RecoveryId::parse(recovery_byte)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
-            panic!("Unable to create the message from hash: {}", error)
-        });
-        let signature =
-            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
-                .unwrap_or_else(|error| {
-                    panic!("Unable to parse the signature: {}", error)
-                });
-
-        let secp = Secp256k1::new();
-        let pub_key = secp.recover(&message, &signature);
+        let message = Message::parse(message_hash);
+        let signature = Signature::parse_standard_slice(&signature[0..64])
+            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
+
+        let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize();
+                *output = pub_key.serialize_compressed();
                 Ok(())
             }
             Err(_) => Err(Error::EcdsaRecoverFailed),
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index f687ad3d136..524468685a2 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -16,11 +16,9 @@ use crate::ext::{
     Engine,
     Error,
 };
-use secp256k1::{
-    recovery::RecoverableSignature,
+use libsecp256k1::{
     Message,
     PublicKey,
-    Secp256k1,
     SecretKey,
 };
 use std::convert::TryInto;
@@ -239,12 +237,11 @@ fn ecdsa_recovery_test_from_contracts_pallet() {
 fn ecdsa_recovery_with_secp256k1_crate() {
     // given
     let mut engine = Engine::new();
-    let secp = Secp256k1::new();
     let seckey = [
         59, 148, 11, 85, 134, 130, 61, 253, 2, 174, 59, 70, 27, 180, 51, 107, 94, 203,
         174, 253, 102, 39, 170, 146, 46, 252, 4, 143, 236, 12, 136, 28,
     ];
-    let pubkey = PublicKey::from_slice(&[
+    let pubkey = PublicKey::parse_compressed(&[
         2, 29, 21, 35, 7, 198, 183, 43, 14, 208, 65, 139, 14, 112, 205, 128, 231, 245,
         41, 91, 141, 134, 245, 114, 45, 63, 82, 19, 251, 210, 57, 79, 54,
     ])
@@ -253,14 +250,12 @@ fn ecdsa_recovery_with_secp256k1_crate() {
     let mut msg_hash = [0; 32];
     crate::hashing::sha2_256(b"Some message", &mut msg_hash);
 
-    let msg = Message::from_slice(&msg_hash).expect("message creation failed");
-    let seckey = SecretKey::from_slice(&seckey).expect("secret key creation failed");
-    let recoverable_signature: RecoverableSignature =
-        secp.sign_recoverable(&msg, &seckey);
+    let msg = Message::parse(&msg_hash);
+    let seckey = SecretKey::parse(&seckey).expect("secret key creation failed");
+    let (signature, recovery_id) = libsecp256k1::sign(&msg, &seckey);
 
-    let recovery_id = recoverable_signature.serialize_compact().0.to_i32() as u8;
-    let mut signature = recoverable_signature.serialize_compact().1.to_vec();
-    signature.push(recovery_id);
+    let mut signature = signature.serialize().to_vec();
+    signature.push(recovery_id.serialize());
     let signature_with_recovery_id: [u8; 65] = signature
         .try_into()
         .expect("unable to create signature with recovery id");
@@ -268,9 +263,9 @@ fn ecdsa_recovery_with_secp256k1_crate() {
     // when
     let mut output = [0; 33];
     engine
-        .ecdsa_recover(&signature_with_recovery_id, msg.as_ref(), &mut output)
+        .ecdsa_recover(&signature_with_recovery_id, &msg.serialize(), &mut output)
         .expect("ecdsa recovery failed");
 
     // then
-    assert_eq!(output, pubkey.serialize());
+    assert_eq!(output, pubkey.serialize_compressed());
 }
diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index a517358c8db..cf21d59331a 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -30,7 +30,7 @@ static_assertions = "1.1"
 sp-arithmetic = { version = "3.0", default-features = false }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-secp256k1 = { version = "0.20.3", default-features = false }
+libsecp256k1 = { version = "0.7.0", default-features = false }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ink_engine = { version = "3.0.0-rc6", path = "../engine/", default-features = false, optional = true }
@@ -41,7 +41,7 @@ sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-secp256k1 = { version = "0.20.3", features = ["recovery"] }
+libsecp256k1 = { version = "0.7.0", features = ["lazy-static-context"] }
 
 # Only used in the off-chain environment.
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }
diff --git a/crates/env/src/engine/experimental_off_chain/impls.rs b/crates/env/src/engine/experimental_off_chain/impls.rs
index dea1c6d0139..9eac160dadf 100644
--- a/crates/env/src/engine/experimental_off_chain/impls.rs
+++ b/crates/env/src/engine/experimental_off_chain/impls.rs
@@ -34,6 +34,7 @@ use crate::{
     Clear,
     EnvBackend,
     Environment,
+    Error,
     RentParams,
     RentStatus,
     Result,
@@ -255,13 +256,11 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use secp256k1::{
-            recovery::{
-                RecoverableSignature,
-                RecoveryId,
-            },
+        use libsecp256k1::{
+            recover,
             Message,
-            Secp256k1,
+            RecoveryId,
+            Signature,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -271,25 +270,19 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
+        let recovery_id = RecoveryId::parse(recovery_byte)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
-            panic!("Unable to create the message from hash: {}", error)
-        });
-        let signature =
-            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
-                .unwrap_or_else(|error| {
-                    panic!("Unable to parse the signature: {}", error)
-                });
-
-        let secp = Secp256k1::new();
-        let pub_key = secp.recover(&message, &signature);
+        let message = Message::parse(message_hash);
+        let signature = Signature::parse_standard_slice(&signature[0..64])
+            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
+
+        let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize();
+                *output = pub_key.serialize_compressed();
                 Ok(())
             }
-            Err(_) => Err(crate::Error::EcdsaRecoverFailed),
+            Err(_) => Err(Error::EcdsaRecoverFailed),
         }
     }
 
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 27ba2bb05de..529cf1baa57 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -201,13 +201,11 @@ impl EnvBackend for EnvInstance {
         message_hash: &[u8; 32],
         output: &mut [u8; 33],
     ) -> Result<()> {
-        use secp256k1::{
-            recovery::{
-                RecoverableSignature,
-                RecoveryId,
-            },
+        use libsecp256k1::{
+            recover,
             Message,
-            Secp256k1,
+            RecoveryId,
+            Signature,
         };
 
         // In most implementations, the v is just 0 or 1 internally, but 27 was added
@@ -217,25 +215,19 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::from_i32(recovery_byte as i32)
+        let recovery_id = RecoveryId::parse(recovery_byte)
             .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
-        let message = Message::from_slice(message_hash).unwrap_or_else(|error| {
-            panic!("Unable to create the message from hash: {}", error)
-        });
-        let signature =
-            RecoverableSignature::from_compact(&signature[0..64], recovery_id)
-                .unwrap_or_else(|error| {
-                    panic!("Unable to parse the signature: {}", error)
-                });
-
-        let secp = Secp256k1::new();
-        let pub_key = secp.recover(&message, &signature);
+        let message = Message::parse(message_hash);
+        let signature = Signature::parse_standard_slice(&signature[0..64])
+            .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
+
+        let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {
-                *output = pub_key.serialize();
+                *output = pub_key.serialize_compressed();
                 Ok(())
             }
-            Err(_) => Err(crate::Error::EcdsaRecoverFailed),
+            Err(_) => Err(Error::EcdsaRecoverFailed),
         }
     }
 
diff --git a/crates/eth_compatibility/Cargo.toml b/crates/eth_compatibility/Cargo.toml
index b93c2416109..85359c81567 100644
--- a/crates/eth_compatibility/Cargo.toml
+++ b/crates/eth_compatibility/Cargo.toml
@@ -16,7 +16,7 @@ include = ["Cargo.toml", "src/**/*.rs", "/README.md", "/LICENSE"]
 
 [dependencies]
 ink_env = { version = "3.0.0-rc6", path = "../env", default-features = false }
-secp256k1 = { version = "0.20.3", default-features = false }
+libsecp256k1 = { version = "0.7.0", default-features = false }
 
 [features]
 default = ["std"]
diff --git a/crates/eth_compatibility/src/lib.rs b/crates/eth_compatibility/src/lib.rs
index 1439f8f3098..827384ed3b2 100644
--- a/crates/eth_compatibility/src/lib.rs
+++ b/crates/eth_compatibility/src/lib.rs
@@ -93,12 +93,12 @@ impl ECDSAPublicKey {
     /// ```
     pub fn to_eth_address(&self) -> EthereumAddress {
         use ink_env::hash;
-        use secp256k1::PublicKey;
+        use libsecp256k1::PublicKey;
 
         // Transform compressed public key into uncompressed.
-        let pub_key = PublicKey::from_slice(&self.0)
+        let pub_key = PublicKey::parse_compressed(&self.0)
             .expect("Unable to parse the compressed ECDSA public key");
-        let uncompressed = pub_key.serialize_uncompressed();
+        let uncompressed = pub_key.serialize();
 
         // Hash the uncompressed public key by Keccak256 algorithm.
         let mut hash = <hash::Keccak256 as hash::HashOutput>::Type::default();

From c68fcbe9de8837c4ffaf5b22c3ca8568f4c9a56a Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 17:53:35 +0200
Subject: [PATCH 15/20] Use default features

---
 crates/engine/Cargo.toml | 2 +-
 crates/env/Cargo.toml    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/engine/Cargo.toml b/crates/engine/Cargo.toml
index 95cd6e4fa64..ffbdfd290ed 100644
--- a/crates/engine/Cargo.toml
+++ b/crates/engine/Cargo.toml
@@ -23,7 +23,7 @@ sha3 = { version = "0.9" }
 blake2 = { version = "0.9" }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.7.0", features = ["lazy-static-context"] }
+libsecp256k1 = { version = "0.7.0" }
 
 [features]
 default = ["std"]
diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index cf21d59331a..cb4666e694b 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -41,7 +41,7 @@ sha3 = { version = "0.9", optional = true }
 blake2 = { version = "0.9", optional = true }
 
 # ECDSA for the off-chain environment.
-libsecp256k1 = { version = "0.7.0", features = ["lazy-static-context"] }
+libsecp256k1 = { version = "0.7.0" }
 
 # Only used in the off-chain environment.
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }

From b5ee0914d4828556ba032e7b93e960fa4bc30a89 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 17:55:15 +0200
Subject: [PATCH 16/20] Bring comment back

---
 crates/env/Cargo.toml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/crates/env/Cargo.toml b/crates/env/Cargo.toml
index cb4666e694b..2d1cbaabee9 100644
--- a/crates/env/Cargo.toml
+++ b/crates/env/Cargo.toml
@@ -44,6 +44,9 @@ blake2 = { version = "0.9", optional = true }
 libsecp256k1 = { version = "0.7.0" }
 
 # Only used in the off-chain environment.
+#
+# Sadly couldn't be marked as dev-dependency.
+# Never use this crate outside the off-chain environment!
 rand = { version = "0.8", default-features = false, features = ["alloc"], optional = true }
 scale-info = { version = "1.0", default-features = false, features = ["derive"], optional = true }
 

From 2186ceb7cd9e6fb136edcb2c47e46fc1343655a1 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 18:04:50 +0200
Subject: [PATCH 17/20] Reduce diff

---
 crates/engine/src/ext.rs                              | 5 +++--
 crates/env/src/engine/experimental_off_chain/impls.rs | 5 +++--
 crates/env/src/engine/off_chain/impls.rs              | 5 +++--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/crates/engine/src/ext.rs b/crates/engine/src/ext.rs
index 73e4a1c26e9..a28957954cc 100644
--- a/crates/engine/src/ext.rs
+++ b/crates/engine/src/ext.rs
@@ -442,12 +442,13 @@ impl Engine {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::parse(recovery_byte)
-            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
         let message = Message::parse(message_hash);
         let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
+        let recovery_id = RecoveryId::parse(recovery_byte)
+            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
+
         let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {
diff --git a/crates/env/src/engine/experimental_off_chain/impls.rs b/crates/env/src/engine/experimental_off_chain/impls.rs
index 9eac160dadf..3cdc5979e76 100644
--- a/crates/env/src/engine/experimental_off_chain/impls.rs
+++ b/crates/env/src/engine/experimental_off_chain/impls.rs
@@ -270,12 +270,13 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::parse(recovery_byte)
-            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
         let message = Message::parse(message_hash);
         let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
+        let recovery_id = RecoveryId::parse(recovery_byte)
+            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
+
         let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {
diff --git a/crates/env/src/engine/off_chain/impls.rs b/crates/env/src/engine/off_chain/impls.rs
index 529cf1baa57..4e8deda5489 100644
--- a/crates/env/src/engine/off_chain/impls.rs
+++ b/crates/env/src/engine/off_chain/impls.rs
@@ -215,12 +215,13 @@ impl EnvBackend for EnvInstance {
         } else {
             signature[64]
         };
-        let recovery_id = RecoveryId::parse(recovery_byte)
-            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
         let message = Message::parse(message_hash);
         let signature = Signature::parse_standard_slice(&signature[0..64])
             .unwrap_or_else(|error| panic!("Unable to parse the signature: {}", error));
 
+        let recovery_id = RecoveryId::parse(recovery_byte)
+            .unwrap_or_else(|error| panic!("Unable to parse the recovery id: {}", error));
+
         let pub_key = recover(&message, &signature, &recovery_id);
         match pub_key {
             Ok(pub_key) => {

From da18644d5903730043bbf052fea7ad0102584ef8 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 19:11:54 +0200
Subject: [PATCH 18/20] Remove unnecessary import

---
 crates/engine/src/tests.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 524468685a2..b8fd7179d50 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -21,7 +21,6 @@ use libsecp256k1::{
     PublicKey,
     SecretKey,
 };
-use std::convert::TryInto;
 
 /// The public methods of the `contracts` pallet write their result into an
 /// `output` buffer instead of returning them. Since we aim to emulate this

From f9f4b78a2d421e3d08bdb971b225c5439e4e14dc Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 20:28:35 +0200
Subject: [PATCH 19/20] Update rustfmt config to edition 2018

---
 .rustfmt.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.rustfmt.toml b/.rustfmt.toml
index 0e0e77b53ca..422da2beabf 100644
--- a/.rustfmt.toml
+++ b/.rustfmt.toml
@@ -43,7 +43,7 @@ trailing_comma = "Vertical"
 match_block_trailing_comma = false
 blank_lines_upper_bound = 1
 blank_lines_lower_bound = 0
-edition = "2018" # changed
+edition = "2021" # changed
 version = "One"
 merge_derives = true
 use_try_shorthand = true # changed

From ffbb1e8d98d5de39806dfb7c975d19e43237a689 Mon Sep 17 00:00:00 2001
From: Michael Mueller <mich@elmueller.net>
Date: Thu, 21 Oct 2021 20:28:48 +0200
Subject: [PATCH 20/20] Use resolver `2` for workspace

---
 Cargo.toml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Cargo.toml b/Cargo.toml
index 554092d4a5e..48f592ff034 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,4 +1,5 @@
 [workspace]
+resolver = "2"
 members = [
     "crates/metadata",
     "crates/allocator",