ecdsa: provide a SigningKey::try_from_rng (#915)

Cargo.lock

@@ -369,7 +369,7 @@ checksum = "11157ac094ffbdde99aa67b23417ebdd801842852b500e395a45a9c0aac03e4a"
 [[package]]
 name = "elliptic-curve"
 version = "0.14.0-rc.1"
-source = "git+https://github.com/RustCrypto/traits.git#28b6e0d3231fa0fb31dc7f6bfdb62d6558bcfdf6"
+source = "git+https://github.com/RustCrypto/traits.git#27835aa66710bded06caef143284892dda83dda5"
 dependencies = [
  "base16ct",
  "crypto-bigint",
@@ -416,7 +416,7 @@ checksum = "658bd65b1cf4c852a3cc96f18a8ce7b5640f6b703f905c7d74532294c2a63984"
 [[package]]
 name = "ff"
 version = "0.13.0"
-source = "git+https://github.com/pinkforest/ff.git?branch=bump-rand-core#c734f7f21d6639bc6494dde538209d0770207c49"
+source = "git+https://github.com/zkcrypto/ff.git?branch=release-0.14.0#1bb634588722b1b7ce986d239c263e332bedda7f"
 dependencies = [
  "rand_core 0.9.2",
  "subtle",
@@ -1087,7 +1087,7 @@ dependencies = [
 [[package]]
 name = "signature"
 version = "2.3.0-pre.6"
-source = "git+https://github.com/RustCrypto/traits.git#28b6e0d3231fa0fb31dc7f6bfdb62d6558bcfdf6"
+source = "git+https://github.com/RustCrypto/traits.git#27835aa66710bded06caef143284892dda83dda5"
 dependencies = [
  "digest",
  "rand_core 0.9.2",

Cargo.toml

@@ -31,6 +31,7 @@ slh-dsa         = { path = "./slh-dsa" }
 
 # https://github.com/RustCrypto/traits/pull/1751
 # https://github.com/RustCrypto/traits/pull/1767
+# https://github.com/RustCrypto/traits/pull/1774
 elliptic-curve = { git = "https://github.com/RustCrypto/traits.git" }
 signature      = { git = "https://github.com/RustCrypto/traits.git" }
 
@@ -39,6 +40,10 @@ signature      = { git = "https://github.com/RustCrypto/traits.git" }
 crypto-bigint = { git = "https://github.com/RustCrypto/crypto-bigint.git" }
 
 # https://github.com/zkcrypto/ff/pull/122
-ff = { git = "https://github.com/pinkforest/ff.git", branch = "bump-rand-core" }
+# https://github.com/zkcrypto/ff/pull/126
+# https://github.com/zkcrypto/ff/pull/127
+# https://github.com/zkcrypto/ff/pull/130
+ff = { git = "https://github.com/zkcrypto/ff.git", branch = "release-0.14.0" }
+
 # https://github.com/zkcrypto/group/pull/56
 group = { git = "https://github.com/pinkforest/group.git", branch = "bump-rand-0.9" }

ecdsa/src/signing.rs

@@ -85,6 +85,13 @@ where
         NonZeroScalar::<C>::random(rng).into()
     }
 
+    /// Generate a cryptographically random [`SigningKey`].
+    pub fn try_from_rng<R: TryCryptoRng + ?Sized>(
+        rng: &mut R,
+    ) -> core::result::Result<Self, R::Error> {
+        Ok(NonZeroScalar::<C>::try_from_rng(rng)?.into())
+    }
+
     /// Initialize signing key from a raw scalar serialized as a byte array.
     pub fn from_bytes(bytes: &FieldBytes<C>) -> Result<Self> {
         SecretKey::<C>::from_bytes(bytes)