lsd0009

commit 61094f3cb7110248757d1aa271ff9170439bb218
parent 33e8242f0c0d4db84f57b292e91c43d4dda039a4
Author: Mikolai Gütschow <mikolai.guetschow@tu-dresden.de>
Date:   Mon, 27 Jan 2025 12:43:57 +0100

-define bigEndianAmount

Diffstat:
M
draft-guetschow-taler-protocol.md
 | 
13
++++++++++---

1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/draft-guetschow-taler-protocol.md b/draft-guetschow-taler-protocol.md
@@ -57,9 +57,14 @@ Use at your own risk!
 
 - `"abc"` denotes the literal string `abc` encoded as ASCII [RFC20]
 - `a | b` denotes the concatenation of a with b
-- `bits(x)` denotes the minimal number of bits necessary to represent the multiple precision integer x
-- `bytes(x)` denotes the minimal number of bytes necessary to represent the multiple precision integer x
+- `padZero(12, a)` denotes the byte string a, zero-padded to the length of 12 bytes
+- `bits(x)` (`bytes(x)`) denotes the minimal number of bits (bytes) necessary to represent the multiple precision integer x
 - `bigEndian(16, x)` denotes the 16 least significant bits of the integer x encoded in network byte order (big-endian)
+- `bigEndianAmount(amount)` is formed from a fixed-point representation of `amount`
+  as `bigEndian(64, amount.value) | bigEndian(32, amount.fraction) | padZero(12, amount.currency)`,
+  where `amount.value` is the non-negative integer part of the base currency,
+  `amount.fraction` is given in unites of one hundred millionth (1e-8) of the base currency,
+  and `amount.currency` are the 3-11 ASCII characters used as currency code by the exchange.
 - `random(256)` denotes a randomly generated sequence of 256 bits
 - `a * b (mod N)` denotes the multiplication, `a ** b (mod N)` the exponentiation of a and b, modulo N
 
@@ -370,7 +375,7 @@ sig = EdDSA-Sign(reserve.priv, msg)                     |
                |--- /reserves/{reserve.pub}/withdraw -->|
                |     (*SHA-512(denom.pub), *b, sig)     |
                |                                        |
-               |                        check *denom.pub valid
+               |                        check *denom.pub known and not withdrawal-expired
                |                        check EdDSA-Verify(reserve.pub, msg, sig)
                |                        check reserve.balance >= sum(*denom.valueAndFee)
                |                        reserve.balance -= sum(*denom.valueAndFee)
@@ -397,6 +402,8 @@ msg = bigEndian(32, 40) | bigEndian(32, 1200) /* TALER_SIGNATURE_WALLET_RESERVE_
 
 (for RSA, without age-restriction)
 
+// todo: add KYC check
+
 ### Implementation Details
 
 in wallet-core, `coin.priv` and `blind_secret` are derived from a random `secretSeed` as follows: