secp256k1-sys

• Update minimum supported rust compiler 1.22.
• Replace serialize_der function with SerializedSignature struct.
• Allow building without a standard library (no_std). std feature is on by default.
• Add human readable serialization to Signatures and SecretKeys.
• Stop displaying 0 bytes if a Signature is less than 72 bytes.
• Only compile recovery module if feature recovery is set (non-default).
• Update rand dependency from 0.4 to 0.6 and add rand_core 0.4 dependency.
• Relax cc dependency requirements.

• Overhaul API to remove context object when no precomputation is needed
• Add ThirtyTwoByteHash trait which allows infallible conversions to Messages
• Disallow 0-valued Message objects since signatures on them are forgeable for all keys
• Remove ops::Index implementations for Signature
• Remove depecated constants and unsafe ZERO_KEY constant

rust-secp256k1-sys 0.11.0

• A complete API overhaul to move many runtime errors into compiletime errors
• Update libsecp256k1 to 1e6f1f5ad5e7f1e3ef79313ec02023902bf8. Should be no visible changes.
• Remove PublicKey::new() and PublicKey::is_valid() since new was unsafe and it should now be impossible to create invalid PublicKey objects through the API
• Reintroduce serde support behind a feature gate using serde 1.0
• Clean up build process and various typos

• Fix incorrect FFI binding for secp256k1_pubkey_combine

• Patch out any instances of printf in upstream #663

• Add bindings to the ElligatorSwift implementation #627
• Update vendored lib secp256k1 to v0.4.0 #653
• Bump MSRV to 1.48 #595

• Implement insecure-erase.

• Update libsecp25k1 to v0.2.0

• Make comparison functions stable across library versions
• Add public methods cmp_fast_unstable and eq_fast_unstable for types that contain an inner array (see PR linked above).

• Bump MSRV to 1.41
• Re-implement Ord on PublicKey using upstream ordering function

• Fix WASM build

• Update MSRV to 1.29.0

• Update upstream to 670cdd3f8be25f81472b2d16dcd228b0d24a5c45
• Add missing return c_int to NonceFn
• Got wasm support working again
• Removed cc restriction, rustc 1.22 support now requires some downstream effort
• Exposed a reference to the underlying byte array for all byte-array-wrapping types
• Allow all-zeroes Message to be constructed
• Expose secp256k1_ec_pubkey_negate from upstream