Signature differences with js-nacl

[ghost]

I've been able to produce the same public key from seed on both, but the signatures do not match up.

tonyg says that his library manages C-language interface's padding requirements. https://github.com/tonyg/js-nacl/issues/27

Do I need to compensate somehow in my c++ code? I don't think I'm converting from strings to const unsigned char*s incorrectly because couting both prints the same to the terminal.

Crosspost: http://stackoverflow.com/questions/22032282/uint8array-equivalent-of-a-c-string-converted-to-const-unsigned-char

[floodyberry]

Are you encoding the string to a Uint8Array when signing? This is producing the same signature for me in both js-nacl and ed25519-donna:

var nacl = nacl_factory.instantiate()
var s = nacl.from_hex( "7776555BE320201162A9D9AD22D933176F0A7FCFE90E3009C6644041AAECDA35" )
var hello = nacl.encode_utf8( "hello" );
var k = nacl.crypto_sign_keypair_from_seed( s )
var sig = nacl.crypto_sign_detached( hello, k.signSk );
console.log( nacl.to_hex( k.signSk ) )
console.log( "sign" )
console.log( nacl.to_hex( k.signPk ) )
console.log( "public" )
console.log( nacl.to_hex( sig ) )
console.log( "sig" )

output:

"7776555be320201162a9d9ad22d933176f0a7fcfe90e3009c6644041aaecda3529d5a572d0d289b48776702dca4d5d9473785e12bb9aa79c8932f5131069ea6c"
sign
"29d5a572d0d289b48776702dca4d5d9473785e12bb9aa79c8932f5131069ea6c"
public
"a3b1cbbd9e537556263fab92bf4df6bcc48be23e2d3430542c197080118501b70db772c0069a1a9278d51b630721a7baaa318877060f03512df1957837e3ca0a"
sig

C++:

std::string message = "hello";
ed25519_secret_key sk = {0x77,0x76,0x55,0x5B,0xE3,0x20,0x20,0x11,0x62,0xA9,0xD9,0xAD,0x22,0xD9,0x33,0x17,0x6F,0x0A,0x7F,0xCF,0xE9,0x0E,0x30,0x09,0xC6,0x64,0x40,0x41,0xAA,0xEC,0xDA,0x35};
ed25519_public_key pk;
ed25519_signature sig;
ed25519_publickey(sk, pk);
ed25519_sign((const unsigned char *)message.c_str(), message.length(), sk, pk, sig);

[ghost]

floodberry, you're a genius!

I was sizeofing the const unsigned char* instead of taking string.length().

I can't thank you enough for this lib! It is unbelievably fast!