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sm2: fix decrypt bug
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@emmansun
emmansun authored Apr 18, 2024
1 parent 15a388d commit 671e337
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Showing 2 changed files with 41 additions and 28 deletions.
61 changes: 37 additions & 24 deletions src/sm2.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -73,7 +73,7 @@ if (!rs.BigInteger.prototype.toByteArrayUnsigned) {
class EncrypterOptions {
constructor (encodingFormat) {
if (encodingFormat !== CIPHERTEXT_ENCODING_PLAIN && encodingFormat !== CIPHERTEXT_ENCODING_ASN1) {
throw new Error('SM2: unsupport ciphertext encoding format')
throw new Error('sm2: unsupport ciphertext encoding format')
}
this.encodingFormat = encodingFormat
}
Expand Down Expand Up @@ -113,7 +113,7 @@ function adaptSM2 (ecdsa) {
let md = new MessageDigest()
let count = 0
if (Q.isInfinity()) {
throw new Error('SM2: invalid public key')
throw new Error('sm2: invalid public key')
}
do {
const k = this.getBigRandom(n)
Expand All @@ -122,7 +122,7 @@ function adaptSM2 (ecdsa) {
const t = kdf(new Uint8Array(util.integerToBytes(point2.getX().toBigInteger(), SM2_BYTE_SIZE).concat(util.integerToBytes(point2.getY().toBigInteger(), SM2_BYTE_SIZE))), dataLen)
if (!t) {
if (count++ > MAX_RETRY) {
throw new Error('SM2: A5, failed to calculate valid t')
throw new Error('sm2: A5, failed to calculate valid t')
}
md = new MessageDigest()
continue
Expand Down Expand Up @@ -163,23 +163,36 @@ function adaptSM2 (ecdsa) {
const dataLen = data.length

if (data[0] !== UNCOMPRESSED) {
throw new Error('SM2: unsupport point marshal mode')
throw new Error('sm2: unsupport point marshal mode')
}
if (dataLen < 97) {
throw new Error('SM2: invalid cipher content length')
throw new Error('sm2: invalid cipher content length')
}
const point1 = rs.ECPointFp.decodeFrom(this.ecparams.curve, Array.from(data.subarray(0, 65)))
const point2 = point1.multiply(d)
const c2 = data.subarray(97)
const c3 = data.subarray(65, 97)
const t = kdf(new Uint8Array(util.integerToBytes(point2.getX().toBigInteger(), SM2_BYTE_SIZE).concat(util.integerToBytes(point2.getY().toBigInteger(), SM2_BYTE_SIZE))), dataLen - 97)
if (!t) {
throw new Error('SM2: invalid cipher content')
throw new Error('sm2: invalid cipher content')
}
for (let i = 0; i < c3.length; i++) {
c2[i] ^= t[i]
for (let i = 0; i < c2.length; i++) {
t[i] ^= c2[i]
}
return Buffer.from(c2).toString('hex')
const md = new MessageDigest()
md.update(new Uint8Array(util.integerToBytes(point2.getX().toBigInteger(), SM2_BYTE_SIZE)))
md.update(t)
md.update(new Uint8Array(util.integerToBytes(point2.getY().toBigInteger(), SM2_BYTE_SIZE)))
const hash = md.digestRaw()
let xor
for (let i = 0; i < hash.length; i++) {
xor = hash[i] ^ c3[i]
}
if (xor !== 0) {
throw new Error('sm2: decryption error')
}

return Buffer.from(t).toString('hex')
}

ecdsa.signWithMessageHash = function (hashHex) {
Expand Down Expand Up @@ -248,7 +261,7 @@ function adaptSM2 (ecdsa) {
uid = util.normalizeInput(uid)
const uidLen = uid.length
if (uidLen >= 0x2000) {
throw new Error('SM2: the uid is too long')
throw new Error('sm2: the uid is too long')
}
const entla = uidLen << 3
const md = new MessageDigest()
Expand Down Expand Up @@ -491,10 +504,10 @@ class Signature {

sm2Sign (data, uid) {
if (!data) {
throw new Error('SM2: please do not call update before sign')
throw new Error('sm2: please do not call update before sign')
}
if (this.fallbackSig || !(this.prvKey instanceof rs.ECDSA)) {
throw new Error('SM2: no valid SM2 private key')
throw new Error('sm2: no valid SM2 private key')
}
return this.signWithMessageHash(this.sm2Hash(data, uid))
}
Expand Down Expand Up @@ -532,10 +545,10 @@ class Signature {

sm2Verify (hSigVal, data, uid) {
if (!data) {
throw new Error('SM2: please do not call update before verify')
throw new Error('sm2: please do not call update before verify')
}
if (this.fallbackSig || !(this.pubKey instanceof rs.ECDSA)) {
throw new Error('SM2: no valid SM2 public key')
throw new Error('sm2: no valid SM2 public key')
}
return this.pubKey.verifyWithMessageHash(this.sm2Hash(data, uid), hSigVal)
}
Expand All @@ -557,7 +570,7 @@ function encrypt (pubkey, data, opts = DEFAULT_SM2_ENCRYPT_OPTIONS) {
})
}
if (!(pubkey instanceof rs.ECDSA) || pubkey.curveName !== SM2_CURVE_NAME) {
throw new Error('SM2: invalid ec public key')
throw new Error('sm2: invalid ec public key')
}
adaptSM2(pubkey)
return pubkey.encrypt(data, opts)
Expand All @@ -574,10 +587,10 @@ function plainCiphertext2ASN1 (data) {
const dataLen = data.length

if (data[0] !== UNCOMPRESSED) {
throw new Error('SM2: unsupport point marshal mode')
throw new Error('sm2: unsupport point marshal mode')
}
if (dataLen < 97) {
throw new Error('SM2: invalid cipher content')
throw new Error('sm2: invalid cipher content')
}
const point1 = rs.ECPointFp.decodeFrom(rs.crypto.ECParameterDB.getByName(SM2_CURVE_NAME).curve, Array.from(data.subarray(0, 65)))
const c2 = data.subarray(97)
Expand All @@ -597,7 +610,7 @@ function _getASN1Values (hexASN1Data, aIdx, aTag) {
const idx = aIdx[i]
const tag = hexASN1Data.substr(idx, 2)
if (tag !== aTag[i]) {
throw new Error('SM2: invalid asn1 format ciphertext, want ' + aTag[i] + ', get ' + tag)
throw new Error('sm2: invalid asn1 format ciphertext, want ' + aTag[i] + ', get ' + tag)
}
aValue.push(rs.ASN1HEX.getV(hexASN1Data, idx))
}
Expand All @@ -612,16 +625,16 @@ function _getASN1Values (hexASN1Data, aIdx, aTag) {
*/
function asn1Ciphertext2Plain (hexASN1Data) {
if (!hexASN1Data || !rs.ASN1HEX.isASN1HEX(hexASN1Data)) {
throw new Error('SM2: invalid asn1 format ciphertext')
throw new Error('sm2: invalid asn1 format ciphertext')
}
const idx = 0
const tag = hexASN1Data.substr(idx, 2)
if (tag !== '30') {
throw new Error('SM2: invalid asn1 format ciphertext')
throw new Error('sm2: invalid asn1 format ciphertext')
}
const aIdx = rs.ASN1HEX.getChildIdx(hexASN1Data, idx)
if (aIdx.length !== 4) {
throw new Error('SM2: invalid asn1 format ciphertext')
throw new Error('sm2: invalid asn1 format ciphertext')
}
const aValue = _getASN1Values(hexASN1Data, aIdx, ['02', '02', '04', '04'])
const curve = rs.crypto.ECParameterDB.getByName(SM2_CURVE_NAME).curve
Expand Down Expand Up @@ -661,7 +674,7 @@ function decrypt (prvKey, data) {
})
}
if (!(prvKey instanceof rs.ECDSA) || prvKey.curveName !== SM2_CURVE_NAME) {
throw new Error('SM2: invalid ec public key')
throw new Error('sm2: invalid ec public key')
}
adaptSM2(prvKey)
return prvKey.decrypt(data)
Expand All @@ -676,11 +689,11 @@ function decrypt (prvKey, data) {
*/
function decryptHex (prvKey, data) {
if (typeof data !== 'string' || data.length < 98 * 2) {
throw new Error('SM2: invalid chiphertext length')
throw new Error('sm2: invalid chiphertext length')
}
const tag = data.substr(0, 2)
if (tag !== '30' && tag !== '04') {
throw new Error(`SM2: invalid ciphertext encoding format ${tag}`)
throw new Error(`sm2: invalid ciphertext encoding format ${tag}`)
}
if (tag === '30') {
data = asn1Ciphertext2Plain(data)
Expand Down
8 changes: 4 additions & 4 deletions src/sm2_test.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -78,8 +78,8 @@ const sec1SM2PrivateKeyHex = '30770201010420857dd87970aab4328dad891c781e3b270742

test('SM2 P-256 encrypt/decrypt local', function (t) {
const ec = new rs.ECDSA({ curve: sm2.getCurveName() })
const plainText = 'emmansun'
const expected = '656d6d616e73756e'
const plainText = 'send reinforcements, we\'re going to advance'
const expected = '73656e64207265696e666f7263656d656e74732c20776527726520676f696e6720746f20616476616e6365'
const keypair = ec.generateKeyPairHex()

const ciphertext = sm2.encrypt(keypair.ecpubhex, plainText)
Expand All @@ -97,8 +97,8 @@ test('SM2 P-256 encrypt/decrypt local', function (t) {

test('SM2 P-256 encrypt, output hex asn.1 ciphertext', function (t) {
const ec = new rs.ECDSA({ curve: sm2.getCurveName() })
const plainText = 'emmansun'
const expected = '656d6d616e73756e'
const plainText = 'send reinforcements, we\'re going to advance'
const expected = '73656e64207265696e666f7263656d656e74732c20776527726520676f696e6720746f20616476616e6365'
const keypair = ec.generateKeyPairHex()
const ciphertext = sm2.encrypt(keypair.ecpubhex, plainText, sm2.asn1EncrypterOptions())
const tag = ciphertext.substr(0, 2)
Expand Down

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