Off-chain message signing is a method of signing non-transaction messages with a Solana wallet. This feature can be used to authenticate users or provide proof of wallet ownership.
Sign Off-Chain Message
To sign an arbitrary off-chain message, run the following command:
solana sign-offchain-message <MESSAGE>
The message will be encoded and signed with CLI's default private key and
signature printed to the output. If you want to sign it with another key, just
solana sign-offchain-message -k <KEYPAIR> <MESSAGE>
By default, the messages constructed are version 0, the only version currently
supported. When other versions become available, you can override the default
value with the
solana sign-offchain-message -k <KEYPAIR> --version <VERSION> <MESSAGE>
The message format is determined automatically based on the version and text of the message.
0 headers specify three message formats allowing for trade-offs
between compatibility and composition of messages:
|ID||Encoding||Maximum Length||Hardware Wallet Support|
|0||Restricted ASCII *||1212||Yes|
|1||UTF-8||1212||Blind sign only|
* Those characters for which
returns true. That is,
1 are motivated by hardware wallet support where both RAM to
store the payload and font character support are limited.
To sign an off-chain message with Ledger, ensure your Ledger is running latest firmware and Solana Ledger App version 1.3.0 or later. After Ledger is unlocked and Solana Ledger App is open, run:
solana sign-offchain-message -k usb://ledger <MESSAGE>
For more information on how to setup and work with the ledger device see this link.
Please note that UTF-8 encoded messages require
Allow blind sign option
enabled in Solana Ledger App. Also, due to the lack of UTF-8 support in Ledger
devices, only the hash of the message will be displayed in such cases.
Display mode is set to
Expert, Ledger will display technical
information about the message to be signed.
Verify Off-Chain Message Signature
To verify the off-chain message signature, run the following command:
solana verify-offchain-signature <MESSAGE> <SIGNATURE>
The public key of the default CLI signer will be used. You can specify another
key with the
solana verify-offchain-signature --signer <PUBKEY> <MESSAGE> <SIGNATURE>
If the signed message has a version different from the default, you need to specify the matching version explicitly:
solana verify-offchain-signature --version <VERSION> <MESSAGE> <SIGNATURE>
To ensure that off-chain messages are not valid transactions, they are encoded
with a fixed prefix:
\xffsolana offchain, where first byte is chosen such
that it is implicitly illegal as the first byte in a transaction
MessageHeader today. More details about the payload format and other
considerations are available in the