No STD

Removes the mutability from PublicKey::as_uncompressed_bytes(&mut self) as it is not required.

Also adds a compilation option without std to allow for no std compilations.

Small IKMs

Modifies SecretKey::key_generate() to return a Result. The error case will arise if IKM is less than 32 bytes.

Splitting Zero

Add an additional check to ensure that if an aggregate public key sums to infinity that it will be considered invalid.

Windows Naming

The Apache Milagro submodule has been updated such that it no longer uses files names with characters that are illegal in windows (e.g. :).

Stricter AggregatePublicKey and Subgroup Checks

Updates

• Subgroup checks for public keys now occur during deserialisation (alternatively use PublicKey::from_bytes_unchecked())
• Subgroup checks for signatures still occur during verification
• AggregatePublicKey has been restricted to prevent adding the point at infinity by removing
  • is_empty
  • from_bytes()
  • new()
  • default()

Secret Key Non-Zero

BLSv4

• Reject Secret Keys that are zero.
• Reject infinity public keys in fast_aggregate_verify().

BLS v04

• Match BLS Signatures Standards version 4
  • Disallows SecretKey = 0; PublicKey = infinity in generation and validation.
• Match Hash to Curve Standards version 9
  • No significant changes

Hash to Curve v07

Updates the underlying hash to curve function to hash-to-curve-v07.

This involves pushing much of the code upstream to Apache Milagro Crypto Library - Rust.

Tight Keys

SecretKeys have been restricted to 32 bytes.

BLS v02

Updates to match BLS-signatures-v02

Matches BLS v02 naming however still linked hash-to-curve-05