[ON HOLD] wip: Reference implementation of message encryption

[dhedey]

Summary

Work in progress implementation of message encryption - currently only working for Curve25519.

Details

Still to-do:

• There is a version clash where curve25519-dalek 3.x requires zeroize version = ">=1, <1.4": https://github.com/dalek-cryptography/curve25519-dalek/blob/3.2.1/Cargo.toml BUT other crypto libraries such as https://github.com/RustCrypto/elliptic-curves/blob/master/k256/Cargo.toml require later versions. As they're both on major version 1.x, Cargo just errors. Instead, I suggest we get rid of x25519_dalek (as it's really not adding much) and update to curve25519-dalek v4 for this which has a more sane feature/dependency list.
• Implement Secp256k1 handling when the above zeroize issue is resolved - possibly with k256 = { version = "0.13.1", default-features = false, features= ["arithmetic", "ecdh", "alloc"], optional = true } (although that might only support ECDH not static DH, so will need some investigation)
• Ensure the test vectors align with other implementations
  • Looks to be that they used x25519 keys rather than ed25519 keys - see also: https://crypto.stackexchange.com/a/68129
• Better handling of zeroizing private keys

Testing

More to come:

• Secp256k1 impl and testing
• Test vectors

Update Recommendations

For dApp Developers

N/A

For Internal Integrators

Toolkit

When ready, can be used by the toolkit to implement message encryption as part of intent construction -- assuming OsRng is exposed the toolkit appropriately in the given runtime. (EG it might error in WASM unless a secure RNG is linked in, which depends on how the WASM is run).

[github-actions]

Benchmark for 66f75f2

Click to view benchmark

Test	Base	PR	%
Decimal::add/0	2.8±0.04ns	2.8±0.04ns	0.00%
Decimal::div/0	222.0±0.68ns	220.1±0.40ns	-0.86%
Decimal::from_string/0	261.1±0.70ns	265.1±2.31ns	+1.53%
Decimal::mul/0	182.0±0.34ns	180.9±0.70ns	-0.60%
Decimal::pow/0	919.2±1.55ns	914.9±6.60ns	-0.47%
Decimal::root/0	12.2±0.05µs	12.2±0.26µs	0.00%
Decimal::sub/0	0.7±0.03ns	0.7±0.01ns	0.00%
Decimal::to_string/0	604.5±1.33ns	614.1±2.60ns	+1.59%
Decompile Intent Natively/Prepare NotarizedTransaction	2.3±0.01ms	2.3±0.01ms	0.00%
Decompile Intent Natively/Prepare NotarizedTransaction and Decompile	6.9±0.15ms	6.9±0.02ms	0.00%
Decompile Intent Natively/Prepare NotarizedTransaction, Decompile, then Recompile	27.1±0.97ms	25.8±0.07ms	-4.80%
PreciseDecimal::add/0	7.6±0.06ns	7.6±0.63ns	0.00%
PreciseDecimal::div/0	705.4±1.97ns	705.1±4.27ns	-0.04%
PreciseDecimal::from_string/0	632.2±1.50ns	634.4±2.40ns	+0.35%
PreciseDecimal::mul/0	705.5±2.55ns	711.1±1.53ns	+0.79%
PreciseDecimal::pow/0	3.7±0.03µs	3.7±0.08µs	0.00%
PreciseDecimal::root/0	95.7±0.56µs	96.4±0.20µs	+0.73%
PreciseDecimal::sub/0	7.2±0.01ns	7.3±0.49ns	+1.39%
PreciseDecimal::to_string/0	1511.8±5.69ns	1528.9±92.86ns	+1.13%
Radiswap::run	3.9±0.02ms	3.9±0.02ms	0.00%
Schema::validate_payload	251.9±1.20µs	250.1±0.89µs	-0.71%
SpinLoop::run	161.1±4.00ms	156.5±1.07ms	-2.86%
Transfer::run	1552.8±6.31µs	1543.9±28.80µs	-0.57%
Validation::validate_manifest	46.2±0.11µs	46.3±0.27µs	+0.22%
Validation::verify_ecdsa	82.2±0.19µs	82.2±0.20µs	0.00%
Validation::verify_ed25519	51.9±0.22µs	51.8±0.34µs	-0.19%
WASM::instantiate_wasm	3.1±0.20ms	3.0±0.02ms	-3.23%
WASM::instantiate_wasm_preloaded	76.3±0.16µs	77.4±0.11µs	+1.44%
WASM::validate_wasm	15.8±0.08ms	15.9±0.40ms	+0.63%