Security

[ERussel]

Hello! Thank you for such useful implementation. I have several questions:

1. Is there any security audit conducted for the library as part of the w3f grant?

2. Looks like in sr25519_keypair_ed25519_to_uniform implementation missing secret_key_key[31] &= 0b0111_1111 operation. As I understand it protects against invalid value which still have nonzero probability. Am I missing something?

[TerenceGe]

Hello, thanks for the questions.

1. The people from W3F did review the code but I'm not sure if they have allocated resource for security auditing yet.
2. sr25519_keypair_ed25519_to_uniform is just used to convert ed25519 format keypair into uniform format, not to generate keypair. "secret_key_key[31] &= 0b0111_1111" is included in the keypair generation process:

   sr25519-donna/src/sr25519.c

   Line 39 in 013a3e0

   key[31] &= 0b1111111;