From 98d25539b99895158fe8a496a4b5419ec19b03b8 Mon Sep 17 00:00:00 2001
From: Graham <gpe@openrs2.org>
Date: Sun, 7 Feb 2021 11:15:49 +0000
Subject: [PATCH] Combine RSA encrypt and decrypt methods into a single crypt
 method

This allows us to speed up master index signing with the CRT.

Signed-off-by: Graham <gpe@openrs2.org>
---
 .../kotlin/org/openrs2/cache/Js5MasterIndex.kt     |  7 +++----
 crypto/src/main/kotlin/org/openrs2/crypto/Rsa.kt   | 14 +++-----------
 .../src/test/kotlin/org/openrs2/crypto/RsaTest.kt  | 14 +++++++-------
 3 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/cache/src/main/kotlin/org/openrs2/cache/Js5MasterIndex.kt b/cache/src/main/kotlin/org/openrs2/cache/Js5MasterIndex.kt
index fad6f308..871c3c7e 100644
--- a/cache/src/main/kotlin/org/openrs2/cache/Js5MasterIndex.kt
+++ b/cache/src/main/kotlin/org/openrs2/cache/Js5MasterIndex.kt
@@ -7,8 +7,7 @@ import org.openrs2.buffer.crc32
 import org.openrs2.buffer.use
 import org.openrs2.crypto.Rsa
 import org.openrs2.crypto.Whirlpool
-import org.openrs2.crypto.rsaDecrypt
-import org.openrs2.crypto.rsaEncrypt
+import org.openrs2.crypto.rsaCrypt
 import org.openrs2.crypto.whirlpool
 
 public data class Js5MasterIndex(
@@ -92,7 +91,7 @@ public data class Js5MasterIndex(
                     plaintext.writeByte(Rsa.MAGIC)
                     plaintext.writeBytes(digest)
 
-                    plaintext.rsaEncrypt(key).use { ciphertext ->
+                    plaintext.rsaCrypt(key).use { ciphertext ->
                         buf.writeBytes(ciphertext)
                     }
                 }
@@ -218,7 +217,7 @@ public data class Js5MasterIndex(
 
         private fun decrypt(buf: ByteBuf, key: RSAKeyParameters?): ByteBuf {
             return if (key != null) {
-                buf.rsaDecrypt(key)
+                buf.rsaCrypt(key)
             } else {
                 buf.retain()
             }
diff --git a/crypto/src/main/kotlin/org/openrs2/crypto/Rsa.kt b/crypto/src/main/kotlin/org/openrs2/crypto/Rsa.kt
index 5d9760f9..e680a04d 100644
--- a/crypto/src/main/kotlin/org/openrs2/crypto/Rsa.kt
+++ b/crypto/src/main/kotlin/org/openrs2/crypto/Rsa.kt
@@ -40,12 +40,8 @@ private fun BigInteger.toByteBuf(): ByteBuf {
     return Unpooled.wrappedBuffer(toByteArray())
 }
 
-public fun ByteBuf.rsaEncrypt(key: RSAKeyParameters): ByteBuf {
-    return Rsa.encrypt(toBigInteger(), key).toByteBuf()
-}
-
-public fun ByteBuf.rsaDecrypt(key: RSAKeyParameters): ByteBuf {
-    return Rsa.decrypt(toBigInteger(), key).toByteBuf()
+public fun ByteBuf.rsaCrypt(key: RSAKeyParameters): ByteBuf {
+    return Rsa.crypt(toBigInteger(), key).toByteBuf()
 }
 
 public fun RSAPrivateCrtKeyParameters.toKeySpec(): KeySpec {
@@ -87,10 +83,6 @@ public object Rsa {
         return Pair(keyPair.public as RSAKeyParameters, keyPair.private as RSAPrivateCrtKeyParameters)
     }
 
-    public fun encrypt(plaintext: BigInteger, key: RSAKeyParameters): BigInteger {
-        return plaintext.modPow(key.exponent, key.modulus)
-    }
-
     private fun generateBlindingFactor(m: BigInteger): Pair<BigInteger, BigInteger> {
         val max = m - BigInteger.ONE
 
@@ -105,7 +97,7 @@ public object Rsa {
         }
     }
 
-    public fun decrypt(ciphertext: BigInteger, key: RSAKeyParameters): BigInteger {
+    public fun crypt(ciphertext: BigInteger, key: RSAKeyParameters): BigInteger {
         if (key is RSAPrivateCrtKeyParameters) {
             // blind the input
             val e = key.publicExponent
diff --git a/crypto/src/test/kotlin/org/openrs2/crypto/RsaTest.kt b/crypto/src/test/kotlin/org/openrs2/crypto/RsaTest.kt
index 38c209f3..78be3038 100644
--- a/crypto/src/test/kotlin/org/openrs2/crypto/RsaTest.kt
+++ b/crypto/src/test/kotlin/org/openrs2/crypto/RsaTest.kt
@@ -51,34 +51,34 @@ object RsaTest {
         val (public, private) = Rsa.generateKeyPair(Rsa.CLIENT_KEY_LENGTH)
 
         val expectedPlaintext = BigInteger("1337")
-        val ciphertext = Rsa.encrypt(expectedPlaintext, public)
-        val actualPlaintext = Rsa.decrypt(ciphertext, private)
+        val ciphertext = Rsa.crypt(expectedPlaintext, public)
+        val actualPlaintext = Rsa.crypt(ciphertext, private)
 
         assertEquals(expectedPlaintext, actualPlaintext)
     }
 
     @Test
     fun testEncrypt() {
-        val ciphertext = Rsa.encrypt(BigInteger("65"), PUBLIC_KEY)
+        val ciphertext = Rsa.crypt(BigInteger("65"), PUBLIC_KEY)
         assertEquals(BigInteger("2790"), ciphertext)
     }
 
     @Test
     fun testDecrypt() {
-        val ciphertext = Rsa.decrypt(BigInteger("2790"), PRIVATE_KEY)
+        val ciphertext = Rsa.crypt(BigInteger("2790"), PRIVATE_KEY)
         assertEquals(BigInteger("65"), ciphertext)
     }
 
     @Test
     fun testDecryptCrt() {
-        val ciphertext = Rsa.decrypt(BigInteger("2790"), PRIVATE_KEY_CRT)
+        val ciphertext = Rsa.crypt(BigInteger("2790"), PRIVATE_KEY_CRT)
         assertEquals(BigInteger("65"), ciphertext)
     }
 
     @Test
     fun testEncryptByteBuf() {
         wrappedBuffer(65).use { plaintext ->
-            plaintext.rsaEncrypt(PUBLIC_KEY).use { ciphertext ->
+            plaintext.rsaCrypt(PUBLIC_KEY).use { ciphertext ->
                 wrappedBuffer(10, 230.toByte()).use { expectedCiphertext ->
                     assertEquals(expectedCiphertext, ciphertext)
                 }
@@ -89,7 +89,7 @@ object RsaTest {
     @Test
     fun testDecryptByteBuf() {
         wrappedBuffer(10, 230.toByte()).use { ciphertext ->
-            ciphertext.rsaDecrypt(PRIVATE_KEY).use { plaintext ->
+            ciphertext.rsaCrypt(PRIVATE_KEY).use { plaintext ->
                 wrappedBuffer(65).use { expectedPlaintext ->
                     assertEquals(expectedPlaintext, plaintext)
                 }