Merge branch 'documentSKTags' of https://github.com/pgpainless/bc-java into pgpainless-documentSKTags

Author: dghgit

pg/src/main/java/org/bouncycastle/bcpg/SymmetricKeyAlgorithmTags.java

@@ -1,22 +1,75 @@
 package org.bouncycastle.bcpg;
 
 /**
- * Basic tags for symmetric key algorithms
+ * Basic tags for symmetric key algorithms.
+ *
+ * @see <a href="https://www.rfc-editor.org/rfc/rfc4880.html#section-9.2">
+ *     RFC4880 - Symmetric-Key Algorithms</a>
+ * @see <a href="https://www.ietf.org/archive/id/draft-koch-librepgp-00.html#name-symmetric-key-algorithms">
+ *     LibrePGP - Symmetric-Key Algorithms</a>
+ * @see <a href="https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-13.html#name-symmetric-key-algorithms">
+ *     Crypto-Refresh - Symmetric-Key Algorithms</a>
  */
 public interface SymmetricKeyAlgorithmTags 
 {
-    int NULL = 0;        // Plaintext or unencrypted data
-    int IDEA = 1;        // IDEA [IDEA]
-    int TRIPLE_DES = 2;  // Triple-DES (DES-EDE, as per spec -168 bit key derived from 192)
-    int CAST5 = 3;       // CAST5 (128 bit key, as per RFC 2144)
-    int BLOWFISH = 4;    // Blowfish (128 bit key, 16 rounds) [BLOWFISH]
-    int SAFER = 5;       // SAFER-SK128 (13 rounds) [SAFER]
-    int DES = 6;         // Reserved for DES/SK
-    int AES_128 = 7;     // Reserved for AES with 128-bit key
-    int AES_192 = 8;     // Reserved for AES with 192-bit key
-    int AES_256 = 9;     // Reserved for AES with 256-bit key
-    int TWOFISH = 10;    // Reserved for Twofish
-    int CAMELLIA_128 = 11;    // Reserved for Camellia with 128-bit key
-    int CAMELLIA_192 = 12;    // Reserved for Camellia with 192-bit key
-    int CAMELLIA_256 = 13;    // Reserved for Camellia with 256-bit key
+    /**
+     * Plaintext or unencrypted data.
+     */
+    int NULL = 0;
+    /**
+     * IDEA.
+     */
+    int IDEA = 1;
+    /**
+     * Triple-DES (DES-EDE, as per spec - 168-bit key derived from 192).
+     */
+    int TRIPLE_DES = 2;
+    /**
+     * CAST5 (128-bit key, as per RFC 2144).
+     */
+    int CAST5 = 3;
+    /**
+     * Blowfish (128-bit key, 16 rounds).
+     */
+    int BLOWFISH = 4;
+    /**
+     * Reserved for SAFER-SK128 (13 rounds).
+     */
+    int SAFER = 5;
+    /**
+     * Reserved for DES/SK.
+     */
+    int DES = 6;
+    /**
+     * AES with 128-bit key.
+     */
+    int AES_128 = 7;
+    /**
+     * AES with 192-bit key.
+     */
+    int AES_192 = 8;
+    /**
+     * AES with 256-bit key.
+     */
+    int AES_256 = 9;
+    /**
+     * Twofish with 256-bit key.
+     */
+    int TWOFISH = 10;
+    /**
+     * Camellia with 128-bit key.
+     */
+    int CAMELLIA_128 = 11;
+    /**
+     * Camellia with 192-bit key.
+     */
+    int CAMELLIA_192 = 12;
+    /**
+     * Camellia with 256-bit key.
+     */
+    int CAMELLIA_256 = 13;
+
+    // 100 to 110: Private/Experimental algorithms
+
+    // 253, 254, 255 reserved to avoid collision with secret key encryption
 }