Skip to content

Support working with ed25519 seeds in addition to raw keypairs. #1055

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
aqua wants to merge 3 commits into
base: dev
Choose a base branch
from
+57 −12
Open

Support working with ed25519 seeds in addition to raw keypairs. #1055

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
a2df373
Support working with ed25519 seeds in addition to raw keypairs.
Nov 3, 2025
c086bd9
Merge branch 'dev' of https://github.com/meshcore-dev/MeshCore into e…
Apr 26, 2026
eb33284
Allow set prv.seed remotely
Apr 28, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
36 changes: 26 additions & 10 deletions src/Identity.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,6 @@ LocalIdentity::LocalIdentity(const char* prv_hex, const char* pub_hex) : Identit
}

LocalIdentity::LocalIdentity(RNG* rng) {
uint8_t seed[SEED_SIZE];
rng->random(seed, SEED_SIZE);
ed25519_create_keypair(pub_key, prv_key, seed);
}
Expand Down Expand Up @@ -95,12 +94,17 @@ bool LocalIdentity::validatePrivateKey(const uint8_t prv[64]) {
bool LocalIdentity::readFrom(Stream& s) {
bool success = (s.readBytes(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
success = success && (s.readBytes(prv_key, PRV_KEY_SIZE) == PRV_KEY_SIZE);
memset(seed, 0, SEED_SIZE);
if (success) {
s.readBytes(seed, SEED_SIZE);
}
return success;
}

bool LocalIdentity::writeTo(Stream& s) const {
bool success = (s.write(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
success = success && (s.write(prv_key, PRV_KEY_SIZE) == PRV_KEY_SIZE);
success = success && (s.write(seed, SEED_SIZE) == SEED_SIZE);
return success;
}

Expand All @@ -109,26 +113,38 @@ void LocalIdentity::printTo(Stream& s) const {
s.print("prv_key: "); Utils::printHex(s, prv_key, PRV_KEY_SIZE); s.println();
}

size_t LocalIdentity::writeTo(uint8_t* dest, size_t max_len) {
size_t LocalIdentity::writePubkeyTo(uint8_t* dest, size_t max_len) {
if (max_len < PUB_KEY_SIZE) return 0; // not big enough
memcpy(dest, pub_key, PUB_KEY_SIZE);
return PUB_KEY_SIZE;
}

size_t LocalIdentity::writePrvkeyTo(uint8_t* dest, size_t max_len) {
if (max_len < PRV_KEY_SIZE) return 0; // not big enough
memcpy(dest, prv_key, PRV_KEY_SIZE);
return PRV_KEY_SIZE;
}

if (max_len < PRV_KEY_SIZE + PUB_KEY_SIZE) { // only room for prv_key
memcpy(dest, prv_key, PRV_KEY_SIZE);
return PRV_KEY_SIZE;
}
memcpy(dest, prv_key, PRV_KEY_SIZE); // otherwise can fit prv + pub keys
memcpy(&dest[PRV_KEY_SIZE], pub_key, PUB_KEY_SIZE);
return PRV_KEY_SIZE + PUB_KEY_SIZE;
size_t LocalIdentity::writeSeedTo(uint8_t* dest, size_t max_len) {
if (max_len < SEED_SIZE) return 0; // not big enough
memcpy(dest, seed, SEED_SIZE);
return SEED_SIZE;
}

void LocalIdentity::readFrom(const uint8_t* src, size_t len) {
if (len == PRV_KEY_SIZE + PUB_KEY_SIZE) { // has prv + pub keys
memcpy(prv_key, src, PRV_KEY_SIZE);
memcpy(pub_key, &src[PRV_KEY_SIZE], PUB_KEY_SIZE);
memset(seed, 0, SEED_SIZE);
} else if (len == PRV_KEY_SIZE) {
memcpy(prv_key, src, PRV_KEY_SIZE);
// now need to re-calculate the pub_key
ed25519_derive_pub(pub_key, prv_key);
memset(seed, 0, SEED_SIZE);
} else if (len == SEED_SIZE) {
memcpy(seed, src, SEED_SIZE);
// re-generate the keypair from the given seed
ed25519_create_keypair(pub_key, prv_key, seed);
}
}

Expand All @@ -140,4 +156,4 @@ void LocalIdentity::calcSharedSecret(uint8_t* secret, const uint8_t* other_pub_k
ed25519_key_exchange(secret, other_pub_key, prv_key);
}

}
}
15 changes: 14 additions & 1 deletion src/Identity.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ class Identity {
*/
class LocalIdentity : public Identity {
uint8_t prv_key[PRV_KEY_SIZE];
uint8_t seed[SEED_SIZE];
public:
LocalIdentity();
LocalIdentity(const char* prv_hex, const char* pub_hex);
Expand Down Expand Up @@ -90,7 +91,19 @@ class LocalIdentity : public Identity {
bool readFrom(Stream& s);
bool writeTo(Stream& s) const;
void printTo(Stream& s) const;
size_t writeTo(uint8_t* dest, size_t max_len);
size_t writePubkeyTo(uint8_t* dest, size_t max_len);
size_t writePrvkeyTo(uint8_t* dest, size_t max_len);
size_t writeSeedTo(uint8_t* dest, size_t max_len);
/**
* \brief Set the Ed25519 keypair.
* \param src IN - the source for the key(s) or seed
* \param len IN - length of the input; if equal to SEED_SIZE, src is
* assumed to be a new seed, from which new private and public keys
* will be generated. If equal to PRV_KEY_SIZE, the corresponding
* public key will be re-generated. If equal to PRV_KEY_SIZE+
* PUB_KEY_SIZE, no key regen is needed. The seed can only later
* be obtained via the `get prv.seed` CLI if SEED_SIZE is used.
*/
void readFrom(const uint8_t* src, size_t len);
};

Expand Down
18 changes: 17 additions & 1 deletion src/helpers/CommonCLI.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -535,6 +535,17 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
} else {
strcpy(reply, "Error, bad key");
}
} else if (memcmp(config, "prv.seed ", 9) == 0) {
uint8_t seed[SEED_SIZE];
bool success = mesh::Utils::fromHex(seed, SEED_SIZE, &config[9]);
Copy link
Copy Markdown
Member

@liamcottle liamcottle Apr 28, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Since there's no length validation for the provided seed, is there any issue with providing a seed that's too short or too long? I guess the remainder would just be all zeros...

Copy link
Copy Markdown
Author

@aqua aqua Apr 28, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Utils::fromHex() does a check that strlen(src_hex)==dest_size*2, so it should give an error with a seed that's too short or too long (I'd test but I'm across an ocean from my nearest spare repeater until the weekend.)

if (success) {
mesh::LocalIdentity new_id;
new_id.readFrom(seed, SEED_SIZE);
_callbacks->saveIdentity(new_id);
strcpy(reply, "OK");
} else {
strcpy(reply, "Error, invalid seed");
}
} else if (memcmp(config, "name ", 5) == 0) {
if (isValidName(&config[5])) {
StrHelper::strncpy(_prefs->node_name, &config[5], sizeof(_prefs->node_name));
Expand Down Expand Up @@ -758,9 +769,14 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
sprintf(reply, "> %s", _prefs->guest_password);
} else if (sender_timestamp == 0 && memcmp(config, "prv.key", 7) == 0) { // from serial command line only
uint8_t prv_key[PRV_KEY_SIZE];
int len = _callbacks->getSelfId().writeTo(prv_key, PRV_KEY_SIZE);
auto len = _callbacks->getSelfId().writePrvkeyTo(prv_key, PRV_KEY_SIZE);
mesh::Utils::toHex(tmp, prv_key, len);
sprintf(reply, "> %s", tmp);
} else if (sender_timestamp == 0 && memcmp(config, "prv.seed", 8) == 0) { // from serial command line only
uint8_t seed[SEED_SIZE];
auto len = _callbacks->getSelfId().writeSeedTo(seed, SEED_SIZE);
Copy link
Copy Markdown
Member

@liamcottle liamcottle Apr 28, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

for devices that update firmware, but keep their existing identity, I'd assume this will just provide an output of full zeros. Probably fine, as you could check for full zeros to know there's no seed available. But wondering if it should return an error message instead...

Copy link
Copy Markdown
Author

@aqua aqua Apr 28, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Assuming you mean here devices that were seeded before this code: yes, LocalIdentity::readFrom() zeroes the seed and then attempts to read over it if the seed is in the identity store, so if the identity were stored from an older revision it'll stay zeroed and this will output a zero string. I suppose returning an error would be more helpful but we should have something in the docs to say more than the firmware itself can.

mesh::Utils::toHex(tmp, seed, len);
sprintf(reply, "> %s", tmp);
} else if (memcmp(config, "name", 4) == 0) {
sprintf(reply, "> %s", _prefs->node_name);
} else if (memcmp(config, "repeat", 6) == 0) {
Expand Down