docs: add ToRistrettoPoint opcode to TariScript
Description
This updates the documentation to describe the `ToRistrettoPoint ` opcode for TariScript
Motivation and Context
This will allow TariScript to process [Point Time-Locked Contracts](https://bitcoinops.org/en/topics/ptlc/) (PTLC)
@@ -325,6 +325,13 @@ push 0.
Identical to [`CheckSig`](#checksigmsg), except that nothing is pushed to the stack if the signature is valid, and the
operation fails with `VERIFY_FAILED` if the signature is invalid.
+##### ToRistrettoPoint,
+
+Pops the top element which must be a valid Ristretto scalar, calculates the corresponding Ristretto point, and pushes this to the stack.
+
+* Fails with `EMPTY_STACK` if the stack is empty.
+* Fails with `INVALID_INPUT` if the top stack element is not a scalar.
+
### Miscellaneous
##### Return
@@ -361,12 +368,13 @@ be operated on _first_!
The types of input parameters that are accepted are:
| Type | Range / Value |
-|:----------|:-----------------------------------------------------------------------|
+|:----------------|:-----------------------------------------------------------------------|
| Integer | 64-bit signed integer |
| Hash | 32-byte hash value |
-| PublicKey | 32-byte public key |
+| PublicKey | 32-byte Ristretto public key |
| Signature | 32-byte nonce + 32-byte signature |
| Data | single byte, n, indicating length of data, followed by n bytes of data |
+| RistrettoScalar | 32-byte Ristretto secret key |
## Example scripts
