Help Bitcoin Public Key Why can't I convert the taproot public key through the private key?

[Xxxxxx-dot]

#include <stdio.h>
#include <stdlib.h>
#include <secp256k1.h>
#include <secp256k1_extrakeys.h>

int main() {

secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);


unsigned char privkey[32] = {
    0x7d, 0x48, 0x1e, 0x43, 0x55, 0xd5, 0x1c, 0x82,
    0x4e, 0x8d, 0x02, 0xe6, 0x17, 0xd0, 0xe1, 0x88,
    0xba, 0x97, 0x68, 0x5e, 0x55, 0xf8, 0x65, 0x57,
    0xd1, 0xd8, 0x3d, 0x64, 0xd1, 0xc8, 0x95, 0x4b
};


if (!secp256k1_ec_seckey_verify(ctx, privkey)) {
    printf("Invalid private key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


secp256k1_pubkey pubkey;


if (!secp256k1_ec_pubkey_create(ctx, &pubkey, privkey)) {
    printf("Failed to create public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


secp256k1_xonly_pubkey xonly_pubkey;
if (!secp256k1_xonly_pubkey_from_pubkey(ctx, &xonly_pubkey, NULL, &pubkey)) {
    printf("Failed to convert to x-only public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}

unsigned char output[32];
if (!secp256k1_xonly_pubkey_serialize(ctx, output, &xonly_pubkey)) {
    printf("Failed to serialize x-only public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


printf("Taproot public key (x-only): ");
for (size_t i = 0; i < 32; i++) {
    printf("%02x", output[i]);
}
printf("\n");


secp256k1_context_destroy(ctx);

return 0;

}

I need t2pr public key

I need an example, can anyone help me?

[Xxxxxx-dot]

Such a conversion is wrong taproot public key

[jonasnick]

What's the problem you're having with that code?

[Xxxxxx-dot]

Is the serialized xonly public key equal to taproot's public key? I'm willing to spend a little money to get help.

[sipa]

Taproot outputs typically have an internal public key which differs from the output public key. In outputs that wish to be spendable through both a key path and a script path, this tweaking must follow the exact consensus rules specified in BIP341 (or the script path spending will not be available). For outputs that are only intended to be spent through the key path, this tweaking is optional (but there is a still a common, standard, recommended, way of doing so described in BIP341).

Your code is not doing any tweaking. I have not verified that the public key you expect is perhaps the standard key-path-only tweaking for the private/public key you give, but I suspect that may be it.

[Xxxxxx-dot]

Hello, can you give an example? Thank you so much.

[Xxxxxx-dot]

secp256k1_context* ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);

unsigned char privkey[32] = {
0x7d, 0x48, 0x1e, 0x43, 0x55, 0xd5, 0x1c, 0x82,
0x4e, 0x8d, 0x02, 0xe6, 0x17, 0xd0, 0xe1, 0x88,
0xba, 0x97, 0x68, 0x5e, 0x55, 0xf8, 0x65, 0x57,
0xd1, 0xd8, 0x3d, 0x64, 0xd1, 0xc8, 0x95, 0x4b
};

secp256k1_keypair keypair;

if (!secp256k1_keypair_create(ctx, &keypair, privkey)) {
printf("NO-0\n");
return 1;
}

secp256k1_xonly_pubkey xonly_pubkey;
int pk_parity;
if (!secp256k1_keypair_xonly_pub(ctx, &xonly_pubkey, &pk_parity, &keypair)) {
printf("NO-1\n");
return 1;
}

unsigned char tweak[32] = { 0 }; // tweak 0 ???

secp256k1_pubkey tweaked_pubkey;
if (!secp256k1_xonly_pubkey_tweak_add(ctx, &tweaked_pubkey, &xonly_pubkey, tweak)) {
printf("NO-2\n");
return 1;
}

unsigned char tweaked_pubkey33[33];
size_t output_len = sizeof(tweaked_pubkey33);
secp256k1_ec_pubkey_serialize(ctx, tweaked_pubkey33, &output_len, &tweaked_pubkey, SECP256K1_EC_COMPRESSED);

printf("BIP341 Taproot : ");
for (int i = 0; i < output_len; i++) {
printf("%02x", tweaked_pubkey33[i]);
}
printf("\n");

secp256k1_context_destroy(ctx);

return 0;

[Xxxxxx-dot]

I adjusted it like this and the result is still wrong.

[CASABECI]

#include <stdio.h> #include <stdlib.h> #include <secp256k1.h> #include <secp256k1_extrakeys.h>

int main() {

secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);


unsigned char privkey[32] = {
    0x7d, 0x48, 0x1e, 0x43, 0x55, 0xd5, 0x1c, 0x82,
    0x4e, 0x8d, 0x02, 0xe6, 0x17, 0xd0, 0xe1, 0x88,
    0xba, 0x97, 0x68, 0x5e, 0x55, 0xf8, 0x65, 0x57,
    0xd1, 0xd8, 0x3d, 0x64, 0xd1, 0xc8, 0x95, 0x4b
};


if (!secp256k1_ec_seckey_verify(ctx, privkey)) {
    printf("Invalid private key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


secp256k1_pubkey pubkey;


if (!secp256k1_ec_pubkey_create(ctx, &pubkey, privkey)) {
    printf("Failed to create public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


secp256k1_xonly_pubkey xonly_pubkey;
if (!secp256k1_xonly_pubkey_from_pubkey(ctx, &xonly_pubkey, NULL, &pubkey)) {
    printf("Failed to convert to x-only public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}

unsigned char output[32];
if (!secp256k1_xonly_pubkey_serialize(ctx, output, &xonly_pubkey)) {
    printf("Failed to serialize x-only public key\n");
    secp256k1_context_destroy(ctx);
    return 1;
}


printf("Taproot public key (x-only): ");
for (size_t i = 0; i < 32; i++) {
    printf("%02x", output[i]);
}
printf("\n");


secp256k1_context_destroy(ctx);

return 0;

}

I need t2pr public key

I need an example, can anyone help me?

[Xxxxxx-dot]

Thank you very much, but the result is still incorrect The two results do not match
C# NBitcoin 》》FullPubKey: 9161099f0ea8b9bb631e318cb9ab0b1811319e1d2e7ac1aa68fcda9c5c85c4a3

Taproot public key (x-only): 8bd5ac9306da862cc9cd1b95ae4871dd27054e49774f6319221ab8dc262d9fd7

[NicolasDorier]

In NBitcoin

var privBytes = new byte[] { 0x7d, 0x48, 0x1e, 0x43, 0x55, 0xd5, 0x1c, 0x82,
0x4e, 0x8d, 0x02, 0xe6, 0x17, 0xd0, 0xe1, 0x88,
0xba, 0x97, 0x68, 0x5e, 0x55, 0xf8, 0x65, 0x57,
0xd1, 0xd8, 0x3d, 0x64, 0xd1, 0xc8, 0x95, 0x4b};
var key = new Key(privBytes);
Console.WriteLine("33 bytes pubkey: " + key.PubKey.ToHex());
var full = key.PubKey.GetTaprootFullPubKey();
Console.WriteLine("32 bytes output key: " + full.OutputKey.ToString());
Console.WriteLine("32 bytes internal key: " + full.InternalKey.ToString());

Result:

33 bytes pubkey: 028bd5ac9306da862cc9cd1b95ae4871dd27054e49774f6319221ab8dc262d9fd7
32 bytes output key: 9161099f0ea8b9bb631e318cb9ab0b1811319e1d2e7ac1aa68fcda9c5c85c4a3
32 bytes internal key: 8bd5ac9306da862cc9cd1b95ae4871dd27054e49774f6319221ab8dc262d9fd7

8bd... is the internal key and 91... is the output key. If you don't understand the difference, please refer to the BIPs concerning taproot.

[Xxxxxx-dot]

Thank you very much for your help sir

[Xxxxxx-dot]

The problem now is that I cannot achieve the output key

If possible can you give me an example?