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Code Issues Releases Activity

blidning for ECDSA

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orignal 2019-05-16 15:49:07 -04:00
parent a91641e427
commit 60ec03237e
2 changed files with 62 additions and 4 deletions
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64
libi2pd/Blinding.cpp
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@ -1,6 +1,8 @@
#include <zlib.h> // for crc32 #include <zlib.h> // for crc32
#include <openssl/sha.h> #include <openssl/sha.h>
#include <openssl/hmac.h> #include <openssl/hmac.h>
#include <openssl/ec.h>
#include <openssl/bn.h>
#include "Base.h" #include "Base.h"
#include "Crypto.h" #include "Crypto.h"
#include "Log.h" #include "Log.h"
@ -13,14 +15,70 @@ namespace i2p
{ {
namespace data namespace data
{ {
BlindedPublicKey::BlindedPublicKey (std::shared_ptr<const IdentityEx> identity, SigningKeyType blindedKeyType): const EC_POINT * BlindPublicKeyECDSA (const EC_GROUP * group, const EC_POINT * pub, const uint8_t * seed)
m_BlindedSigType (blindedKeyType) {
BN_CTX * ctx = BN_CTX_new ();
BN_CTX_start (ctx);
BIGNUM * q = BN_CTX_get (ctx);
EC_GROUP_get_order (group, q, ctx);
// calculate alpha = seed mod q
BIGNUM * alpha = BN_CTX_get (ctx);
BN_bin2bn (seed, 64, alpha); // seed is in BigEndian
BN_mod (alpha, alpha, q, ctx); // % q
// A' = BLIND_PUBKEY(A, alpha) = A + DERIVE_PUBLIC(alpha)
auto p = EC_POINT_new (group);
EC_POINT_mul (group, p, alpha, nullptr, nullptr, ctx); // B*alpha
EC_POINT_add (group, p, pub, p, ctx); // pub + B*alpha
BN_CTX_end (ctx);
BN_CTX_free (ctx);
return p;
}
static void BlindPrivateKeyECDSA (const EC_GROUP * group, const BIGNUM * priv, const uint8_t * seed, BIGNUM * blindedPriv)
{
BN_CTX * ctx = BN_CTX_new ();
BN_CTX_start (ctx);
BIGNUM * q = BN_CTX_get (ctx);
EC_GROUP_get_order (group, q, ctx);
// calculate alpha = seed mod q
BIGNUM * alpha = BN_CTX_get (ctx);
BN_bin2bn (seed, 64, alpha); // seed is in BigEndian
BN_mod (alpha, alpha, q, ctx); // % q
BN_add (alpha, alpha, priv); // alpha = alpha + priv
// a' = BLIND_PRIVKEY(a, alpha) = (a + alpha) mod q
BN_mod (blindedPriv, alpha, q, ctx); // % q
BN_CTX_end (ctx);
BN_CTX_free (ctx);
}
void BlindPrivateKeyECDSA (size_t publicKeyLen, const EC_GROUP * group, const uint8_t * priv, const uint8_t * seed, uint8_t * blindedPriv, uint8_t * blindedPub)
{
BIGNUM * a = BN_bin2bn (priv, publicKeyLen/2, NULL);
BIGNUM * a1 = BN_new ();
BlindPrivateKeyECDSA (group, a, seed, a1);
BN_free (a);
i2p::crypto::bn2buf (a1, blindedPriv, publicKeyLen/2);
auto p = EC_POINT_new (group);
BN_CTX * ctx = BN_CTX_new ();
EC_POINT_mul (group, p, a1, nullptr, nullptr, ctx); // B*a1
BN_CTX_free (ctx);
BN_free (a1);
BIGNUM * x = BN_new(), * y = BN_new();
EC_POINT_get_affine_coordinates_GFp (group, p, x, y, NULL);
EC_POINT_free (p);
i2p::crypto::bn2buf (x, blindedPub, publicKeyLen/2);
i2p::crypto::bn2buf (y, blindedPub + publicKeyLen/2, publicKeyLen/2);
BN_free (x); BN_free (y);
}
BlindedPublicKey::BlindedPublicKey (std::shared_ptr<const IdentityEx> identity)
{ {
if (!identity) return; if (!identity) return;
auto len = identity->GetSigningPublicKeyLen (); auto len = identity->GetSigningPublicKeyLen ();
m_PublicKey.resize (len); m_PublicKey.resize (len);
memcpy (m_PublicKey.data (), identity->GetSigningPublicKeyBuffer (), len); memcpy (m_PublicKey.data (), identity->GetSigningPublicKeyBuffer (), len);
m_SigType = identity->GetSigningKeyType (); m_SigType = identity->GetSigningKeyType ();
m_BlindedSigType = m_SigType;
} }
BlindedPublicKey::BlindedPublicKey (const std::string& b33) BlindedPublicKey::BlindedPublicKey (const std::string& b33)
@ -129,7 +187,7 @@ namespace data
{ {
i2p::data::IdentHash hash; i2p::data::IdentHash hash;
if (m_BlindedSigType == i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519 || if (m_BlindedSigType == i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519 ||
m_BlindedSigType == SIGNING_KEY_TYPE_EDDSA_SHA512_ED25519) m_BlindedSigType == i2p::data::SIGNING_KEY_TYPE_EDDSA_SHA512_ED25519)
{ {
uint8_t blinded[32]; uint8_t blinded[32];
if (date) if (date)

2
libi2pd/Blinding.h
View File

@ -14,7 +14,7 @@ namespace data
{ {
public: public:
BlindedPublicKey (std::shared_ptr<const IdentityEx> identity, SigningKeyType blindedKeyType = i2p::data::SIGNING_KEY_TYPE_REDDSA_SHA512_ED25519); BlindedPublicKey (std::shared_ptr<const IdentityEx> identity);
BlindedPublicKey (const std::string& b33); // from b33 without .b32.i2p BlindedPublicKey (const std::string& b33); // from b33 without .b32.i2p
std::string ToB33 () const; std::string ToB33 () const;