Merge branch 'master' of https://github.com/bitcoin/bips

bip-0174.mediawiki

@@ -375,7 +375,7 @@ All other data except the UTXO and unknown fields in the input key-value map sho
 ===Transaction Extractor===
 
 The Transaction Extractor must only accept a PSBT.
-It checks whether all inputs have complete scriptSigs and scriptWitnesses by checking for the presence of <tt>0x05</tt> Finalized scriptSig and <tt>0x06</tt> Finalized scriptWitness typed records. If they do, the Transaction Extractor should construct complete scriptSigs and scriptWitnesses and encode them into network serialized transactions. Otherwise the Extractor must not modify the PSBT.
+It checks whether all inputs have complete scriptSigs and scriptWitnesses by checking for the presence of <tt>0x07</tt> Finalized scriptSig and <tt>0x08</tt> Finalized scriptWitness typed records. If they do, the Transaction Extractor should construct complete scriptSigs and scriptWitnesses and encode them into network serialized transactions. Otherwise the Extractor must not modify the PSBT.
 The Extractor should produce a fully valid, network serialized transaction if all inputs are complete.
 
 The Transaction Extractor does not need to know how to interpret scripts in order to extract the network serialized transaction. However it may be able to in order to validate the network serialized transaction at the same time.

bip-0322.mediawiki

@@ -23,9 +23,9 @@ The current message signing standard only works for P2PKH (1...) addresses. By e
 
 A new structure <code>SignatureProof</code> is added, which is a simple serializable scriptSig & witness container.
 
-=== Common Header ===
+Two actions "Sign" and "Verify" are defined along with two *purposes* "SignMessage" and "ProveFunds".
 
-A common header used for signature proofs and challenges is defined as follows:
+=== SignatureProof container ===
 
 {|class="wikitable" style="text-align: center;"
 |-
@@ -43,9 +43,7 @@ A common header used for signature proofs and challenges is defined as follows:
 |Uint8||1||entries||Number of proof entries<ref><strong>Why support multiple proofs?</strong> In particular with proof of funds, it is non-trivial to check a large number of individual proofs (one per UTXO) for duplicates. Software could be written to do so, but it seems more efficient to build this check into the specification itself.</ref>
 |}
 
-=== SignatureProof container ===
-
-The signature proof begins with a common header, and is followed by [entries] number of signature entries:
+The above is followed by [entries] number of signature entries:
 
 {|class="wikitable" style="text-align: center;"
 |-
@@ -82,53 +80,54 @@ A verification call will return a result code according to the table below.
 |-
 |INVALID||One or more of the given proofs were invalid
 |-
+|SPENT||One or more of the claimed UTXO:s has been spent
+|-
 |ERROR||An error was encountered
 |}
 
-=== SignMessage serialization ===
+== Signing and Verifying ==
 
-The SignMessage challenge begins with the common header, and is followed by [entries] entries:
+Let there be an empty set `inputs` which is populated and tested at each call to one of the actions below.
 
-{|class="wikitable" style="text-align: center;"
-|-
-!Type
-!Length
-!Name
-!Comment
-|-
-|VarInt||1-8||spklen||ScriptPubKey length
-|-
-|Uint8*||[spklen]||spk||ScriptPubKey
-|}
+=== Purpose: SignMessage ===
 
-=== Proving and Verifying ===
+The "SignMessage" purpose generates a sighash based on a scriptPubKey and a message. It emits a VALID verification result code unless otherwise stated.
 
-Let there be an empty set <code>inputs</code> which is populated and tested at each call to one of the actions below.
-
-=== Common steps ===
-
-A sighash is generated based on a scriptPubKey and a message. A VALID verification result code is emitted unless otherwise stated.
-
-# Emits INVALID if scriptPubKey already exists in <code>inputs</code>set, otherwise insert it<ref><strong>Why track duplicates?</strong> Because a 3-entry proof is not proving 3 inputs unless they are all distinct</ref>
-# Emits INVALID if the message is not a UTF-8 string encoded using Normalization Form Compatibility Decomposition (NFKD); note specifically that binary messages are not supported
-# Define the message pre-image as the sequence "Bitcoin Message:" concatenated with the message, ''excluding'' the null terminating character (if any)
+# Return INVALID if scriptPubKey already exists in `inputs` set, otherwise insert it<ref><strong>Why track duplicates?</strong> Because a 3-entry proof is not proving 3 inputs unless they are all distinct</ref>
+# Define the message pre-image as the sequence "Bitcoin Message:" concatenated with the message, encoded in UTF-8 using Normalization Form Compatibility Decomposition (NFKD)
 # Let sighash = sha256(sha256(scriptPubKey || pre-image))
 
-=== Proving ===
+=== Purpose: ProveFunds ===
 
-Returns a signature or fails (emits INVALID).
+The "ProveFunds" purpose generates a sighash and a scriptPubKey from a transaction, an output index, and a message. For multiple simultaneous proofs, it also requires access to the ordered list of proofs. It emits a VALID verification result code unless otherwise stated.
 
+# Let txid be the transaction ID of the transaction, and vout be the output index corresponding to the index of the output being spent
+# Return INVALID if the txid:vout pair already exists in `inputs` set, otherwise insert it
+# Return SPENT if the txid/vout is not a valid UTXO according to a Bitcoin node<ref><strong>Synced up or not?</strong> A normal verifier would use a synced up node. An auditor checking records from a client that were submitted in the past want to use a node that is synced up to the block corresponding to the proof, or the proof will fail, even if it may have been valid at the time of creation.</ref>
+# Extract scriptPubKey from transaction output
+# Define the message pre-image as the concatenation of the following components:<ref><strong>Why not just the UTXO data?</strong> We want the verifier to be able to challenge the prover with a custom message to sign, or anyone can reuse the POF proof for a set of UTXO:s once they have seen it, and the funds have not yet been spent</ref>
+#* the string "POF:"
+#* the message, encoded in UTF-8 using Normalization Form Compatibility Decomposition (NFKD), including the null terminating character (i.e. write strlen(message) + 1 bytes, for a C string)
+#* all transactions being proven for, as binary txid (little endian uint256) followed by index (little endian uint32), each separated by a single `0x00` byte
+# Let sighash = sha256(sha256(scriptPubKey || pre-image))
+
+=== Action: Sign ===
+
+The "Sign" action takes as input a purpose. It returns a signature or fails.
+
+# Obtain the sighash and scriptPubKey from the purpose; FAIL if not VALID
 # Derive the private key privkey for the scriptPubKey; FAIL if not VALID
-# Generate a signature sig with privkey=privkey, sighash=sighash
-# Return a SignatureProof container with the given signature
+# Generate and return a signature sig with privkey=privkey, sighash=sighash
 
-=== Verifying ===
+=== Action: Verify ===
 
-Emits one of INCONCLUSIVE, VALID, or INVALID.
+The "Verify" action takes as input a standard flags value, a script sig, an optional witness, and a purpose.
+It emits one of INCONCLUSIVE, VALID, INVALID, or ERROR.
 
+# Obtain the sighash and scriptPubKey from the purpose; pass on result code if not VALID
 # If one or more of the standard flags are unknown, return INCONCLUSIVE
 # Verify Script with flags=standard flags, scriptSig=script sig, scriptPubKey=scriptPubKey, witness=witness, and sighash=sighash
-# Emit VALID if verify succeeds, otherwise emit INVALID
+# Return VALID if verify succeeds, otherwise return INVALID
 
 === Multiple Proofs ===