Validate signatures without bouncycastle

contrib/publickeymetadata.js

@@ -0,0 +1,95 @@
+// https://www.rfc-editor.org/rfc/rfc5280.html#appendix-A.1
+// https://letsencrypt.org/docs/a-warm-welcome-to-asn1-and-der/
+// https://www.ietf.org/rfc/rfc5480.txt
+
+/*
+SubjectPublicKeyInfo  ::=  SEQUENCE  {
+     algorithm            AlgorithmIdentifier,
+     subjectPublicKey     BIT STRING  }
+
+
+AlgorithmIdentifier  ::=  SEQUENCE  {
+     algorithm               OBJECT IDENTIFIER,
+     parameters              ANY DEFINED BY algorithm OPTIONAL  }
+                                -- contains a value of the type
+                                -- registered for use with the
+                                -- algorithm object identifier value
+
+id-ecPublicKey OBJECT IDENTIFIER ::= {
+     iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
+
+secp256r1 OBJECT IDENTIFIER ::= {
+     iso(1) member-body(2) us(840) ansi-X9-62(10045) curves(3)
+     prime(1) 7 }
+*/
+
+function encodeValue(type, valueBuffer) {
+  const length = valueBuffer.length
+
+  if (length >= 128) throw new Error('long encoding not supported')
+
+  const typeBuffer = Buffer.from([type])
+  const lengthBuffer = Buffer.from([length])
+
+  return Buffer.concat([typeBuffer, lengthBuffer, valueBuffer])
+}
+
+function encodeBitstring(valueBuffer) {
+  return encodeValue(3, Buffer.concat([Buffer.from([0 /* no unused bits */]), valueBuffer]))
+}
+
+function encodeOid(value) {
+  const numbers = [
+    value[0] * 40 + value[1],
+    ...value.slice(2)
+  ]
+
+  const result = []
+
+  for (let number of numbers) {
+    const tempResult = []
+    while (number) { tempResult.push(128 | (number % 128)); number = Math.floor(number / 128) }
+    tempResult.reverse()
+    tempResult[tempResult.length - 1] &= 127
+
+    for (const item of tempResult) result.push(item)
+  }
+
+  return encodeValue(6, Buffer.from(result))
+}
+
+function encodeSequence(itemBuffers) {
+  return encodeValue(0x30, Buffer.concat(itemBuffers))
+}
+
+function encodeAlogrithmIdentifier() {
+  return encodeSequence([
+    encodeOid([1, 2, 840, 10045, 2, 1]),
+    encodeOid([1, 2, 840, 10045, 3, 1, 7])
+  ])
+}
+
+function encodePublicKeyInfo() {
+  const dummyKey = Buffer.alloc(65)
+  for (let i = 0; i < dummyKey.length; i++) dummyKey.writeUInt8(255, i)
+
+  return encodeSequence([
+    encodeAlogrithmIdentifier(),
+    encodeBitstring(dummyKey)
+  ])
+}
+
+const result = encodePublicKeyInfo()
+
+// compare result with https://github.com/ashtuchkin/u2f/blob/2e45ea40acd8c3ad6c113cd1b4e0558acc4cda3a/index.js#L21
+if (result.toString('hex') !== '3059301306072a8648ce3d020106082a8648ce3d030107034200' + ('ff'.repeat(65))) throw new Error()
+
+const prefix = result.slice(0, result.length - 65)
+
+console.log(prefix.toString('hex'))
+console.log(prefix.toString('base64'))
+
+const prefixNumbers = []; for (let i = 0; i < prefix.length; i++) prefixNumbers.push(prefix.readInt8(i))
+const kotlinByteArray = 'byteArrayOf(' + prefixNumbers.join(', ') + ')'
+
+console.log(kotlinByteArray)