Need documentation for message signing/verifying

[nikita-fuchs]

As partners want to implement SH wallet as a login mechanism, they need documentation for signing messages using the wallet and verifying the signatures. I guess the only thing necessary here are the proper sdk functions, whereas the wallet part should handle itself?

[davidyuk]

would be good to have a guide about message signing/verifying

I guess the only thing necessary here are the proper sdk functions, whereas the wallet part should handle itself?

yep, except for deep links, sdk doesn't define anything there yet

related issue superhero-com/superhero-wallet#2688

Things should be mentioned there:

https://docs.aeternity.com/aepp-sdk-js/v13.2.2/api/classes/AccountBase.html#signMessage
https://docs.aeternity.com/aepp-sdk-js/v13.2.2/api/functions/verifyMessage.html

aepp-sdk-js/test/integration/contract.ts

Lines 65 to 103 in 71da12b

	it('Verify message in Sophia', async () => {
	const signContract = await aeSdk.initializeContract<{
	message_to_hash: (message: string) => Uint8Array;
	verify: (message: string, pub: Encoded.AccountAddress, sig: Uint8Array) => boolean;
	}>({
	sourceCode:
	'include "String.aes"'
	+ '\n'
	+ '\ncontract Sign ='
	+ '\n entrypoint int_to_binary (i: int): string ='
	+ '\n switch(Char.from_int(i))'
	+ '\n None => abort("Int is too big")'
	+ '\n Some(c) => String.from_list([c])'
	+ '\n'
	+ '\n entrypoint includes (str: string, pat: string): bool ='
	+ '\n switch(String.contains(str, pat))'
	+ '\n None => false'
	+ '\n Some(_) => true'
	+ '\n'
	+ '\n entrypoint message_to_hash (message: string): hash ='
	+ '\n let prefix = "aeternity Signed Message:\\n"'
	+ '\n let prefixBinary = String.concat(int_to_binary(String.length(prefix)), prefix)'
	+ '\n let messageBinary = String.concat(int_to_binary(String.length(message)), message)'
	+ '\n Crypto.blake2b(String.concat(prefixBinary, messageBinary))'
	+ '\n'
	+ '\n entrypoint verify (message: string, pub: address, sig: signature): bool ='
	+ '\n require(includes(message, "H"), "Invalid message")'
	+ '\n Crypto.verify_sig(message_to_hash(message), pub, sig)',
	});
	await signContract.$deploy([]);
	await Promise.all(['Hello', 'H'.repeat(127)].map(async (message) => {
	expect((await signContract.message_to_hash(message)).decodedResult)
	.to.be.eql(messageToHash(message));
	const signature = await aeSdk.signMessage(message);
	expect((await signContract.verify(message, aeSdk.address, signature)).decodedResult)
	.to.be.equal(true);
	}));
	});