Allow session API to override encryption provider

index.js

@@ -305,10 +305,10 @@ class Hypercore extends EventEmitter {
     if (this.keyPair === null) this.keyPair = opts.keyPair || this.core.header.keyPair
 
     const parent = opts.parent || null
-    if (parent && parent.encryption) this.encryption = parent.encryption
+    const encryption = getEncryptionOption(opts)
 
-    const e = getEncryptionOption(opts)
-    if (!this.encryption) this.encryption = this._getEncryptionProvider(e)
+    if (encryption) this.encryption = this._getEncryptionProvider(encryption)
+    else if (parent && parent.encryption) this.encryption = parent.encryption
 
     this.writable = this._isWritable()
 

test/encryption.js

@@ -301,6 +301,47 @@ test('block encryption module', async function (t) {
   t.alike(await core.get(2), b4a.from('2'))
 })
 
+test('encryption provider is set on session', async function (t) {
+  class XOREncryption {
+    padding() {
+      return 0
+    }
+
+    async encrypt(index, block) {
+      await new Promise(setImmediate)
+
+      for (let i = 0; i < block.byteLength; i++) {
+        block[i] ^= (index + 1) & 0xff // +1 so no 0 xor in test
+      }
+    }
+
+    async decrypt(index, block) {
+      await new Promise(setImmediate)
+
+      for (let i = 0; i < block.byteLength; i++) {
+        block[i] ^= (index + 1) & 0xff
+      }
+    }
+  }
+
+  const encryption1 = new XOREncryption()
+  const encryption2 = new XOREncryption()
+
+  const core = await create(t, null, { encryption: encryption1 })
+  await core.ready()
+
+  await core.append('0')
+  await core.append('1')
+  await core.append('2')
+
+  const session = core.session({ encryption: encryption2 })
+  await session.ready()
+
+  t.not(core.encryption, session.encryption)
+
+  await session.close()
+})
+
 test('encryption backwards compatibility', async function (t) {
   const encryptionKey = b4a.alloc(32).fill('encryption key')