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Scope the ECDSA constant sizes to CPubKey / CKey classes

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This commit is contained in:
Jack Grigg 2017-10-04 14:41:40 +01:00
parent 1ce9f0a952
commit 63179d0283
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GPG key ID: 665DBCD284F7DAFF
4 changed files with 43 additions and 41 deletions
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25
src/key.cpp
View file

@ -85,16 +85,13 @@ static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *ou
* <http://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
* included.
*
* privkey must point to an output buffer of length at least PRIVATE_KEY_SIZE bytes.
* privkey must point to an output buffer of length at least CKey::PRIVATE_KEY_SIZE bytes.
* privkeylen must initially be set to the size of the privkey buffer. Upon return it
* will be set to the number of bytes used in the buffer.
* key32 must point to a 32-byte raw private key.
*/
static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
assert(*privkeylen >= PRIVATE_KEY_SIZE);
static_assert(
PRIVATE_KEY_SIZE >= COMPRESSED_PRIVATE_KEY_SIZE,
"COMPRESSED_PRIVATE_KEY_SIZE is larger than PRIVATE_KEY_SIZE");
assert(*privkeylen >= CKey::PRIVATE_KEY_SIZE);
secp256k1_pubkey pubkey;
size_t pubkeylen = 0;
if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
@ -120,11 +117,11 @@ static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *pr
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
pubkeylen = COMPRESSED_PUBLIC_KEY_SIZE;
pubkeylen = CPubKey::COMPRESSED_PUBLIC_KEY_SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
ptr += pubkeylen;
*privkeylen = ptr - privkey;
assert(*privkeylen == COMPRESSED_PRIVATE_KEY_SIZE);
assert(*privkeylen == CKey::COMPRESSED_PRIVATE_KEY_SIZE);
} else {
static const unsigned char begin[] = {
0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
@ -146,11 +143,11 @@ static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *pr
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
pubkeylen = PUBLIC_KEY_SIZE;
pubkeylen = CPubKey::PUBLIC_KEY_SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
ptr += pubkeylen;
*privkeylen = ptr - privkey;
assert(*privkeylen == PRIVATE_KEY_SIZE);
assert(*privkeylen == CKey::PRIVATE_KEY_SIZE);
}
return 1;
}
@ -183,7 +180,7 @@ CPrivKey CKey::GetPrivKey() const {
CPubKey CKey::GetPubKey() const {
assert(fValid);
secp256k1_pubkey pubkey;
size_t clen = PUBLIC_KEY_SIZE;
size_t clen = CPubKey::PUBLIC_KEY_SIZE;
CPubKey result;
int ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
assert(ret);
@ -196,8 +193,8 @@ CPubKey CKey::GetPubKey() const {
bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
if (!fValid)
return false;
vchSig.resize(SIGNATURE_SIZE);
size_t nSigLen = SIGNATURE_SIZE;
vchSig.resize(CPubKey::SIGNATURE_SIZE);
size_t nSigLen = CPubKey::SIGNATURE_SIZE;
unsigned char extra_entropy[32] = {0};
WriteLE32(extra_entropy, test_case);
secp256k1_ecdsa_signature sig;
@ -225,7 +222,7 @@ bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
if (!fValid)
return false;
vchSig.resize(COMPACT_SIGNATURE_SIZE);
vchSig.resize(CPubKey::COMPACT_SIGNATURE_SIZE);
int rec = -1;
secp256k1_ecdsa_recoverable_signature sig;
int ret = secp256k1_ecdsa_sign_recoverable(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, NULL);
@ -255,7 +252,7 @@ bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const
std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
if ((nChild >> 31) == 0) {
CPubKey pubkey = GetPubKey();
assert(pubkey.size() == COMPRESSED_PUBLIC_KEY_SIZE);
assert(pubkey.size() == CPubKey::COMPRESSED_PUBLIC_KEY_SIZE);
BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, vout.data());
} else {
assert(size() == 32);

24
src/key.h
View file

@ -16,16 +16,6 @@
#include <vector>
/**
* secp256k1:
*/
const unsigned int PRIVATE_KEY_SIZE = 279;
const unsigned int COMPRESSED_PRIVATE_KEY_SIZE = 214;
/**
* see www.keylength.com
* script supports up to 75 for single byte push
*/
/**
* secure_allocator is defined in allocators.h
* CPrivKey is a serialized private key, with all parameters included
@ -36,6 +26,20 @@ typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey;
/** An encapsulated private key. */
class CKey
{
public:
/**
* secp256k1:
*/
static const unsigned int PRIVATE_KEY_SIZE = 279;
static const unsigned int COMPRESSED_PRIVATE_KEY_SIZE = 214;
/**
* see www.keylength.com
* script supports up to 75 for single byte push
*/
static_assert(
PRIVATE_KEY_SIZE >= COMPRESSED_PRIVATE_KEY_SIZE,
"COMPRESSED_PRIVATE_KEY_SIZE is larger than PRIVATE_KEY_SIZE");
private:
//! Whether this private key is valid. We check for correctness when modifying the key
//! data, so fValid should always correspond to the actual state.

4
src/pubkey.cpp
View file

@ -252,8 +252,8 @@ void CExtPubKey::Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const {
code[5] = (nChild >> 24) & 0xFF; code[6] = (nChild >> 16) & 0xFF;
code[7] = (nChild >> 8) & 0xFF; code[8] = (nChild >> 0) & 0xFF;
memcpy(code+9, chaincode.begin(), 32);
assert(pubkey.size() == COMPRESSED_PUBLIC_KEY_SIZE);
memcpy(code+41, pubkey.begin(), COMPRESSED_PUBLIC_KEY_SIZE);
assert(pubkey.size() == CPubKey::COMPRESSED_PUBLIC_KEY_SIZE);
memcpy(code+41, pubkey.begin(), CPubKey::COMPRESSED_PUBLIC_KEY_SIZE);
}
void CExtPubKey::Decode(const unsigned char code[BIP32_EXTKEY_SIZE]) {

31
src/pubkey.h
View file

@ -14,18 +14,6 @@
#include <stdexcept>
#include <vector>
/**
* secp256k1:
*/
const unsigned int PUBLIC_KEY_SIZE = 65;
const unsigned int COMPRESSED_PUBLIC_KEY_SIZE = 33;
const unsigned int SIGNATURE_SIZE = 72;
const unsigned int COMPACT_SIGNATURE_SIZE = 65;
/**
* see www.keylength.com
* script supports up to 75 for single byte push
*/
const unsigned int BIP32_EXTKEY_SIZE = 74;
/** A reference to a CKey: the Hash160 of its serialized public key */
@ -41,6 +29,22 @@ typedef uint256 ChainCode;
/** An encapsulated public key. */
class CPubKey
{
public:
/**
* secp256k1:
*/
static const unsigned int PUBLIC_KEY_SIZE = 65;
static const unsigned int COMPRESSED_PUBLIC_KEY_SIZE = 33;
static const unsigned int SIGNATURE_SIZE = 72;
static const unsigned int COMPACT_SIGNATURE_SIZE = 65;
/**
* see www.keylength.com
* script supports up to 75 for single byte push
*/
static_assert(
PUBLIC_KEY_SIZE >= COMPRESSED_PUBLIC_KEY_SIZE,
"COMPRESSED_PUBLIC_KEY_SIZE is larger than PUBLIC_KEY_SIZE");
private:
/**
@ -48,9 +52,6 @@ private:
* Its length can very cheaply be computed from the first byte.
*/
unsigned char vch[PUBLIC_KEY_SIZE];
static_assert(
PUBLIC_KEY_SIZE >= COMPRESSED_PUBLIC_KEY_SIZE,
"COMPRESSED_PUBLIC_KEY_SIZE is larger than PUBLIC_KEY_SIZE");
//! Compute the length of a pubkey with a given first byte.
unsigned int static GetLen(unsigned char chHeader)