Merge pull request #220 from ricmoo/master

Add Transaction Type List

lists/signature-types/README.md

@@ -0,0 +1,68 @@
+Signature Types
+===============
+
+This is a list of existing, reserved and tentative signature types
+for payloads signed using secp256k1.
+
+Signature Types
+---------------
+
+See the sections below for additional notes on prefix bytes marked
+Reserved or Tentative.
+
+| Prefix byte | Specs or Purpose |
+|-------------|------------------|
+| 0x00  | Reserved: indicates legacy (untyped) trancactions |
+| 0x01  | Reserved: [EIP-2930](https://eips.ethereum.org/EIPS/eip-2930) *(available in Berlin)* |
+| 0x02  | Reserved: [EIP-1559](https://eips.ethereum.org/EIPS/eip-1559) *(available in London)* |
+| 0x03  | Tentative: prevents collision with [EIP-3074](https://eips.ethereum.org/EIPS/eip-3074) |
+| 0x19  | Reserved: prevents collision with [EIP-191](https://eips.ethereum.org/EIPS/eip-191) |
+| 0xc0 - 0xff  | Invalid; collides with the initial byte of valid RLP encoded transactions |
+
+
+Reserved Signature Types Motivation and History
+-----------------------------------------------
+
+Reserved prefix bytes are currently in use and should never be reused. This
+avoids signature collisions that could have unintentional consequences, such as
+authorizing unintended actions.
+
+### Type 0x00 (0)
+
+The prefix byte `0x00` is reserved to identify transactions which are untyped legacy
+transactions. It is not prefixed, but allows software to use a numeric enum
+value to indicate a legacy transaction.
+
+This was an unintentional consequence of the internal type of 0 being exposed
+in early JSON-RPC implementations, but is convenient as a canonical value to
+use within APIs or databases.
+
+### Type 0x19 (25)
+
+The prefix byte `0x19` is reserved for data payloads to be signed according to
+[EIP-191](https://eips.ethereum.org/EIPS/eip-191).
+
+The initial byte of `0x19` has long been used for the purpose of
+prefixing a series of bytes to be signed, rather than a transaction
+since a valid RLP-encoded transaction could not begin with it (prior to 
+[EIP-2718](https://eips.ethereum.org/EIPS/eip-2718)) and represents the
+Bitcoin varint length of the string `"Ethereum signed Message:\n"`.
+
+It was carried over from the technique Bitcon used to sign personal messages
+(which uses `"\18Bitcoin signed message:\n"`) but was extended with
+[EIP-191](https://eips.ethereum.org/EIPS/eip-191), which effectively
+retconned signed personal messages into a scheme that is extensible,
+allowing new types of data and structures to be safely signed with
+the same prefix byte.
+
+
+Tentative Signature Types
+-------------------------
+
+Proposed signature types to reserve for upcoming purposes, but still subject to
+change.
+
+### Type 0x03 (3)
+
+The prefix byte `0x03` is reserved for
+[EIP-3074](https://eips.ethereum.org/EIPS/eip-3074) `AUTH` payloads.