trezor-firmware/core/src/storage/recovery_shares.py

from storage import common
from trezor.crypto import slip39

# Mnemonics stored during SLIP-39 recovery process.
# Each mnemonic is stored under key = index.


def set(index: int, group_index: int, mnemonic: str) -> None:
    common.set(
        common.APP_RECOVERY_SHARES,
        index + group_index * slip39.MAX_SHARE_COUNT,
        mnemonic.encode(),
    )


def get(index: int, group_index: int) -> str | None:
    m = common.get(
        common.APP_RECOVERY_SHARES, index + group_index * slip39.MAX_SHARE_COUNT
    )
    if m:
        return m.decode()
    return None


def fetch_group(group_index: int) -> list[str]:
    mnemonics = []
    for index in range(slip39.MAX_SHARE_COUNT):
        m = get(index, group_index)
        if m:
            mnemonics.append(m)

    return mnemonics


def delete() -> None:
    for index in range(slip39.MAX_SHARE_COUNT * slip39.MAX_GROUP_COUNT):
        common.delete(common.APP_RECOVERY_SHARES, index)