Constant AUTH_DIGEST_PLACEHOLDER

pub const AUTH_DIGEST_PLACEHOLDER: AuthDigest;

The placeholder used for the AuthDigest of pre-v5 transactions.

Consensus

For transaction versions before v5, a placeholder value consisting of 32 bytes of 0xFF is used in place of the authorizing data commitment. This is only used in the tree committed to by hashAuthDataRoot.

https://zips.z.cash/zip-0244#authorizing-data-commitment