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Merge #854: Rename msg32 to msghash32 in ecdsa_sign/verify and add explanation

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6e85d675aaf9dc17842096f9cbf8cfab216c9331 Rename tweak to tweak32 in public API (Jonas Nick)
f587f04e35719883546afd54cb491ead18eb6fc7 Rename msg32 to msghash32 in ecdsa_sign/verify and add explanation (Jonas Nick)

Pull request description:

  This fixes #307 if there's nothing else that's confusing.

ACKs for top commit:
  real-or-random:
    ACK 6e85d675aaf9dc17842096f9cbf8cfab216c9331 I inspected the diff

Tree-SHA512: 1b0dc9dfffd497058dc39c962a512ed6d7f89218020fef9d2c03aaae1aefbf272b918c4fe6503434b62547714855fe1b8b89f2366f3ae6cde16143207c9e6b86
This commit is contained in:
Tim Ruffing 2020-12-07 20:10:20 +01:00
commit dc6e5c3a5c
No known key found for this signature in database
GPG Key ID: 8C461CCD293F6011
4 changed files with 70 additions and 63 deletions
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35
include/secp256k1.h
View File

@ -452,7 +452,14 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact(
* 0: incorrect or unparseable signature
* Args: ctx: a secp256k1 context object, initialized for verification.
* In: sig: the signature being verified (cannot be NULL)
* msg32: the 32-byte message hash being verified (cannot be NULL)
* msghash32: the 32-byte message hash being verified (cannot be NULL).
* The verifier must make sure to apply a cryptographic
* hash function to the message by itself and not accept an
* msghash32 value directly. Otherwise, it would be easy to
* create a "valid" signature without knowledge of the
* secret key. See also
* https://bitcoin.stackexchange.com/a/81116/35586 for more
* background on this topic.
* pubkey: pointer to an initialized public key to verify with (cannot be NULL)
*
* To avoid accepting malleable signatures, only ECDSA signatures in lower-S
@ -467,7 +474,7 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
const secp256k1_context* ctx,
const secp256k1_ecdsa_signature *sig,
const unsigned char *msg32,
const unsigned char *msghash32,
const secp256k1_pubkey *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
@ -534,7 +541,7 @@ SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_def
* 0: the nonce generation function failed, or the secret key was invalid.
* Args: ctx: pointer to a context object, initialized for signing (cannot be NULL)
* Out: sig: pointer to an array where the signature will be placed (cannot be NULL)
* In: msg32: the 32-byte message hash being signed (cannot be NULL)
* In: msghash32: the 32-byte message hash being signed (cannot be NULL)
* seckey: pointer to a 32-byte secret key (cannot be NULL)
* noncefp: pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used
* ndata: pointer to arbitrary data used by the nonce generation function (can be NULL)
@ -545,7 +552,7 @@ SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_def
SECP256K1_API int secp256k1_ecdsa_sign(
const secp256k1_context* ctx,
secp256k1_ecdsa_signature *sig,
const unsigned char *msg32,
const unsigned char *msghash32,
const unsigned char *seckey,
secp256k1_nonce_function noncefp,
const void *ndata
@ -626,7 +633,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_negate(
* invalid according to secp256k1_ec_seckey_verify, this
* function returns 0. seckey will be set to some unspecified
* value if this function returns 0. (cannot be NULL)
* In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to
* In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to
* secp256k1_ec_seckey_verify, this function returns 0. For
* uniformly random 32-byte arrays the chance of being invalid
* is negligible (around 1 in 2^128) (cannot be NULL).
@ -634,7 +641,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_negate(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add(
const secp256k1_context* ctx,
unsigned char *seckey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Same as secp256k1_ec_seckey_tweak_add, but DEPRECATED. Will be removed in
@ -642,7 +649,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
const secp256k1_context* ctx,
unsigned char *seckey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Tweak a public key by adding tweak times the generator to it.
@ -654,7 +661,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
* (cannot be NULL).
* In/Out: pubkey: pointer to a public key object. pubkey will be set to an
* invalid value if this function returns 0 (cannot be NULL).
* In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to
* In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to
* secp256k1_ec_seckey_verify, this function returns 0. For
* uniformly random 32-byte arrays the chance of being invalid
* is negligible (around 1 in 2^128) (cannot be NULL).
@ -662,7 +669,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
const secp256k1_context* ctx,
secp256k1_pubkey *pubkey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Tweak a secret key by multiplying it by a tweak.
@ -673,7 +680,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
* invalid according to secp256k1_ec_seckey_verify, this
* function returns 0. seckey will be set to some unspecified
* value if this function returns 0. (cannot be NULL)
* In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to
* In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to
* secp256k1_ec_seckey_verify, this function returns 0. For
* uniformly random 32-byte arrays the chance of being invalid
* is negligible (around 1 in 2^128) (cannot be NULL).
@ -681,7 +688,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_mul(
const secp256k1_context* ctx,
unsigned char *seckey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Same as secp256k1_ec_seckey_tweak_mul, but DEPRECATED. Will be removed in
@ -689,7 +696,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_mul(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul(
const secp256k1_context* ctx,
unsigned char *seckey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Tweak a public key by multiplying it by a tweak value.
@ -699,7 +706,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul(
* (cannot be NULL).
* In/Out: pubkey: pointer to a public key object. pubkey will be set to an
* invalid value if this function returns 0 (cannot be NULL).
* In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to
* In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to
* secp256k1_ec_seckey_verify, this function returns 0. For
* uniformly random 32-byte arrays the chance of being invalid
* is negligible (around 1 in 2^128) (cannot be NULL).
@ -707,7 +714,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul(
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_mul(
const secp256k1_context* ctx,
secp256k1_pubkey *pubkey,
const unsigned char *tweak
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Updates the context randomization to protect against side-channel leakage.

8
include/secp256k1_recovery.h
View File

@ -73,7 +73,7 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact(
* 0: the nonce generation function failed, or the secret key was invalid.
* Args: ctx: pointer to a context object, initialized for signing (cannot be NULL)
* Out: sig: pointer to an array where the signature will be placed (cannot be NULL)
* In: msg32: the 32-byte message hash being signed (cannot be NULL)
* In: msghash32: the 32-byte message hash being signed (cannot be NULL)
* seckey: pointer to a 32-byte secret key (cannot be NULL)
* noncefp: pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used
* ndata: pointer to arbitrary data used by the nonce generation function (can be NULL)
@ -81,7 +81,7 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact(
SECP256K1_API int secp256k1_ecdsa_sign_recoverable(
const secp256k1_context* ctx,
secp256k1_ecdsa_recoverable_signature *sig,
const unsigned char *msg32,
const unsigned char *msghash32,
const unsigned char *seckey,
secp256k1_nonce_function noncefp,
const void *ndata
@ -94,13 +94,13 @@ SECP256K1_API int secp256k1_ecdsa_sign_recoverable(
* Args: ctx: pointer to a context object, initialized for verification (cannot be NULL)
* Out: pubkey: pointer to the recovered public key (cannot be NULL)
* In: sig: pointer to initialized signature that supports pubkey recovery (cannot be NULL)
* msg32: the 32-byte message hash assumed to be signed (cannot be NULL)
* msghash32: the 32-byte message hash assumed to be signed (cannot be NULL)
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover(
const secp256k1_context* ctx,
secp256k1_pubkey *pubkey,
const secp256k1_ecdsa_recoverable_signature *sig,
const unsigned char *msg32
const unsigned char *msghash32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
#ifdef __cplusplus

12
src/modules/recovery/main_impl.h
View File

@ -120,34 +120,34 @@ static int secp256k1_ecdsa_sig_recover(const secp256k1_ecmult_context *ctx, cons
return !secp256k1_gej_is_infinity(&qj);
}
int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) {
int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) {
secp256k1_scalar r, s;
int ret, recid;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
ARG_CHECK(msg32 != NULL);
ARG_CHECK(msghash32 != NULL);
ARG_CHECK(signature != NULL);
ARG_CHECK(seckey != NULL);
ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, &recid, msg32, seckey, noncefp, noncedata);
ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, &recid, msghash32, seckey, noncefp, noncedata);
secp256k1_ecdsa_recoverable_signature_save(signature, &r, &s, recid);
return ret;
}
int secp256k1_ecdsa_recover(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msg32) {
int secp256k1_ecdsa_recover(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msghash32) {
secp256k1_ge q;
secp256k1_scalar r, s;
secp256k1_scalar m;
int recid;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
ARG_CHECK(msg32 != NULL);
ARG_CHECK(msghash32 != NULL);
ARG_CHECK(signature != NULL);
ARG_CHECK(pubkey != NULL);
secp256k1_ecdsa_recoverable_signature_load(ctx, &r, &s, &recid, signature);
VERIFY_CHECK(recid >= 0 && recid < 4); /* should have been caught in parse_compact */
secp256k1_scalar_set_b32(&m, msg32, NULL);
secp256k1_scalar_set_b32(&m, msghash32, NULL);
if (secp256k1_ecdsa_sig_recover(&ctx->ecmult_ctx, &r, &s, &q, &m, recid)) {
secp256k1_pubkey_save(pubkey, &q);
return 1;

52
src/secp256k1.c
View File

@ -422,17 +422,17 @@ int secp256k1_ecdsa_signature_normalize(const secp256k1_context* ctx, secp256k1_
return ret;
}
int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msg32, const secp256k1_pubkey *pubkey) {
int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msghash32, const secp256k1_pubkey *pubkey) {
secp256k1_ge q;
secp256k1_scalar r, s;
secp256k1_scalar m;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
ARG_CHECK(msg32 != NULL);
ARG_CHECK(msghash32 != NULL);
ARG_CHECK(sig != NULL);
ARG_CHECK(pubkey != NULL);
secp256k1_scalar_set_b32(&m, msg32, NULL);
secp256k1_scalar_set_b32(&m, msghash32, NULL);
secp256k1_ecdsa_signature_load(ctx, &r, &s, sig);
return (!secp256k1_scalar_is_high(&s) &&
secp256k1_pubkey_load(ctx, &q, pubkey) &&
@ -533,16 +533,16 @@ static int secp256k1_ecdsa_sign_inner(const secp256k1_context* ctx, secp256k1_sc
return ret;
}
int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) {
int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) {
secp256k1_scalar r, s;
int ret;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
ARG_CHECK(msg32 != NULL);
ARG_CHECK(msghash32 != NULL);
ARG_CHECK(signature != NULL);
ARG_CHECK(seckey != NULL);
ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, NULL, msg32, seckey, noncefp, noncedata);
ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, NULL, msghash32, seckey, noncefp, noncedata);
secp256k1_ecdsa_signature_save(signature, &r, &s);
return ret;
}
@ -623,26 +623,26 @@ int secp256k1_ec_pubkey_negate(const secp256k1_context* ctx, secp256k1_pubkey *p
}
static int secp256k1_ec_seckey_tweak_add_helper(secp256k1_scalar *sec, const unsigned char *tweak) {
static int secp256k1_ec_seckey_tweak_add_helper(secp256k1_scalar *sec, const unsigned char *tweak32) {
secp256k1_scalar term;
int overflow = 0;
int ret = 0;
secp256k1_scalar_set_b32(&term, tweak, &overflow);
secp256k1_scalar_set_b32(&term, tweak32, &overflow);
ret = (!overflow) & secp256k1_eckey_privkey_tweak_add(sec, &term);
secp256k1_scalar_clear(&term);
return ret;
}
int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) {
int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) {
secp256k1_scalar sec;
int ret = 0;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(seckey != NULL);
ARG_CHECK(tweak != NULL);
ARG_CHECK(tweak32 != NULL);
ret = secp256k1_scalar_set_b32_seckey(&sec, seckey);
ret &= secp256k1_ec_seckey_tweak_add_helper(&sec, tweak);
ret &= secp256k1_ec_seckey_tweak_add_helper(&sec, tweak32);
secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret);
secp256k1_scalar_get_b32(seckey, &sec);
@ -650,28 +650,28 @@ int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *s
return ret;
}
int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) {
return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak);
int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) {
return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak32);
}
static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak) {
static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak32) {
secp256k1_scalar term;
int overflow = 0;
secp256k1_scalar_set_b32(&term, tweak, &overflow);
secp256k1_scalar_set_b32(&term, tweak32, &overflow);
return !overflow && secp256k1_eckey_pubkey_tweak_add(ecmult_ctx, p, &term);
}
int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) {
int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak32) {
secp256k1_ge p;
int ret = 0;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
ARG_CHECK(pubkey != NULL);
ARG_CHECK(tweak != NULL);
ARG_CHECK(tweak32 != NULL);
ret = secp256k1_pubkey_load(ctx, &p, pubkey);
memset(pubkey, 0, sizeof(*pubkey));
ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak);
ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak32);
if (ret) {
secp256k1_pubkey_save(pubkey, &p);
}
@ -679,16 +679,16 @@ int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey
return ret;
}
int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) {
int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) {
secp256k1_scalar factor;
secp256k1_scalar sec;
int ret = 0;
int overflow = 0;
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(seckey != NULL);
ARG_CHECK(tweak != NULL);
ARG_CHECK(tweak32 != NULL);
secp256k1_scalar_set_b32(&factor, tweak, &overflow);
secp256k1_scalar_set_b32(&factor, tweak32, &overflow);
ret = secp256k1_scalar_set_b32_seckey(&sec, seckey);
ret &= (!overflow) & secp256k1_eckey_privkey_tweak_mul(&sec, &factor);
secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret);
@ -699,11 +699,11 @@ int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *s
return ret;
}
int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) {
return secp256k1_ec_seckey_tweak_mul(ctx, seckey, tweak);
int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) {
return secp256k1_ec_seckey_tweak_mul(ctx, seckey, tweak32);
}
int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) {
int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak32) {
secp256k1_ge p;
secp256k1_scalar factor;
int ret = 0;
@ -711,9 +711,9 @@ int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
ARG_CHECK(pubkey != NULL);
ARG_CHECK(tweak != NULL);
ARG_CHECK(tweak32 != NULL);
secp256k1_scalar_set_b32(&factor, tweak, &overflow);
secp256k1_scalar_set_b32(&factor, tweak32, &overflow);
ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey);
memset(pubkey, 0, sizeof(*pubkey));
if (ret) {