diff --git a/src/key.js b/src/key.js
index dd261f8d..b21a64e4 100644
--- a/src/key.js
+++ b/src/key.js
@@ -986,12 +986,14 @@ export function generate(options) {
       signaturePacket.hashAlgorithm = config.prefer_hash_algorithm;
       signaturePacket.keyFlags = [enums.keyFlags.certify_keys | enums.keyFlags.sign_data];
       signaturePacket.preferredSymmetricAlgorithms = [];
+      // prefer aes256, aes128, then aes192 (no WebCrypto support: https://www.chromium.org/blink/webcrypto#TOC-AES-support)
       signaturePacket.preferredSymmetricAlgorithms.push(enums.symmetric.aes256);
       signaturePacket.preferredSymmetricAlgorithms.push(enums.symmetric.aes128);
       signaturePacket.preferredSymmetricAlgorithms.push(enums.symmetric.aes192);
       signaturePacket.preferredSymmetricAlgorithms.push(enums.symmetric.cast5);
       signaturePacket.preferredSymmetricAlgorithms.push(enums.symmetric.tripledes);
       signaturePacket.preferredHashAlgorithms = [];
+      // prefer fast asm.js implementations (SHA-256, SHA-1)
       signaturePacket.preferredHashAlgorithms.push(enums.hash.sha256);
       signaturePacket.preferredHashAlgorithms.push(enums.hash.sha1);
       signaturePacket.preferredHashAlgorithms.push(enums.hash.sha512);