code wiki / _hdl_build / nx_x25519_extvec_gate.nx
`nx_x25519_extvec_gate.nx` source

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1// nx_x25519_extvec_gate.nx -- THE FIRST PROVABLY THIRD-PARTY-VALIDATED CLAIM.
2// Proven GREEN on the laptop 2026-07-31 (pass=2 fail=0). Shipped here so it runs where claims are served.
3//
4// Every other KAT in this corpus embeds its expected values as constants a developer copied out of a
5// specification. Honest work, but NOT provably external: nothing in the artifact distinguishes a value
6// transcribed from the IETF from one an author -- or an AGENT -- merely believed. This gate closes that:
7//   1 it reads the vectors FROM knowledge/extvec/rfc7748.txt AT RUN TIME. NO expected value appears in
8//     this source at all, so there is nothing here for anyone to have mistyped or invented.
9//   2 it PINS the acquisition digest: the file must sha256 to the value nx_vecfetch computed IN-PROCESS,
10//     at the socket, before the bytes ever touched disk. Edited, truncated or substituted -> pin fails.
11//   3 only then does it run x25519() and compare.
12//
13// THE PIN IS THE SECURITY PROPERTY, NOT THE RUN-TIME PARSE. Parsing from a file is necessary but NOT
14// sufficient: an agent could edit the fetched file to contain whatever answers make its implementation
15// pass, and the parse would faithfully read the forgery. Pinning to an ACQUISITION-TIME digest is what
16// turns "we read it from a file" into evidence.
17// AND THE PIN MAKES TRANSPORT UNTRUSTED-BUT-VERIFIED: whoever carries rfc7748.txt to this host -- scp, an
18// agent, a USB stick -- cannot corrupt it undetected, because sha256 preimage resistance means bytes that
19// hash to ab200228.. ARE the fetched bytes. The carrier never has to be trusted. That is the whole point
20// of content-addressing, and it is why this gate is safe to ship even though its data file is not.
21//
22// TO MAKE IT GREEN HERE: place knowledge/extvec/rfc7748.txt (any byte-exact copy; the pin checks it), or
23// build+run nx_vecfetch on this host. Until then it reports RED-and-honest: absent file, never a fallback
24// to constants. license_tier: ORIGINAL  expect_exit: 0
25import "nx_syscalls.nx"
26import "nx_sha256_wasm.nx"
27import "nx_x25519.nx"
28import "nx_gate_verdict.nx"
29
30func w(s: *u8) -> i64 { var n: i64 = 0; while s[n] != (0 as u8) { n = n + 1 } sys_write(1, s, n); return 0 }
31func wb(b: *u8, n: i64) -> i64 { sys_write(1, b, n); return 0 }
32
33func nn(v: i64) -> i64 {
34    var m: i64 = v
35    if m < 0 { w("-" as *u8); m = 0 - m }
36    let t: *u8 = sys_mmap(32)
37    var k: i64 = 0
38    if m == 0 { t[0] = 48 as u8; k = 1 }
39    while m > 0 { t[k] = (48 + (m % 10)) as u8; m = m / 10; k = k + 1 }
40    let b: *u8 = sys_mmap(32)
41    var j: i64 = 0
42    while j < k { b[j] = t[k - 1 - j]; j = j + 1 }
43    sys_write(1, b, k)
44    return 0
45}
46
47func hexnib(v: i64) -> i64 { if v < 10 { return 48 + v } return 87 + v }
48
49func hexval(c: i64) -> i64 {
50    if c >= 48 { if c <= 57 { return c - 48 } }
51    if c >= 97 { if c <= 102 { return c - 87 } }
52    if c >= 65 { if c <= 70 { return c - 55 } }
53    return 0 - 1
54}
55
56func starts(b: *u8, n: i64, at: i64, s: *u8) -> i64 {
57    var i: i64 = 0
58    while s[i] != (0 as u8) {
59        if at + i >= n { return 0 }
60        if b[at + i] != s[i] { return 0 }
61        i = i + 1
62    }
63    return 1
64}
65
66func findfrom(b: *u8, n: i64, s: *u8, from: i64) -> i64 {
67    var p: i64 = from
68    while p < n {
69        if starts(b, n, p, s) == 1 { return p }
70        p = p + 1
71    }
72    return 0 - 1
73}
74
75// Strict: refuses a short hex run, so a reflowed or truncated document fails loudly rather than yielding
76// a half-vector that would then be compared as if complete.
77func parse32(b: *u8, n: i64, from: i64, out: *u8) -> i64 {
78    var p: i64 = from
79    var got: i64 = 0
80    while p < n {
81        if got >= 32 { return p }
82        let c: i64 = b[p] as i64
83        let hv: i64 = hexval(c)
84        if hv < 0 {
85            if got > 0 { if got < 32 { got = 0 } }
86            p = p + 1
87        } else {
88            if p + 1 >= n { return 0 - 1 }
89            let hv2: i64 = hexval(b[p + 1] as i64)
90            if hv2 < 0 { p = p + 1 }
91            else {
92                out[got] = ((hv * 16) + hv2) as u8
93                got = got + 1
94                p = p + 2
95            }
96        }
97    }
98    if got >= 32 { return p }
99    return 0 - 1
100}
101
102func eq32(a: *u8, b: *u8) -> i64 {
103    var i: i64 = 0
104    while i < 32 { if a[i] != b[i] { return 0 } i = i + 1 }
105    return 1
106}
107
108func main() -> i64 {
109    w("nx_x25519_extvec_gate -- x25519 vs RFC 7748 5.2, vectors READ FROM THE FETCHED DOCUMENT\n" as *u8)
110
111    let lp: *i64 = sys_mmap(16) as *i64
112    lp[0] = 0
113    let b: *u8 = sys_read_file("knowledge/extvec/rfc7748.txt\x00" as *u8, lp)
114    if lp[0] <= 0 {
115        w("RED: fetched vector file absent -- run nx_vecfetch first. NOT falling back to constants.\n" as *u8)
116        return 1
117    }
118
119    let ctx: *u8 = sys_mmap(1024)
120    let dig: *u8 = sys_mmap(64)
121    nx_sha256_one_shot(b, lp[0], ctx, dig)
122    let hx: *u8 = sys_mmap(80)
123    var i: i64 = 0
124    while i < 32 {
125        hx[i * 2] = hexnib(((dig[i] as i64) / 16) & 15) as u8
126        hx[i * 2 + 1] = hexnib((dig[i] as i64) & 15) as u8
127        i = i + 1
128    }
129    // A MODULE-LEVEL `const NAME: *u8 = "..." as *u8` DOES NOT COMPARE CORRECTLY IN nx_cc. First run printed
130    // this digest byte-for-byte identical to the constant and STILL reported PIN FAILED -- a check
131    // disagreeing with its own displayed evidence means the INSTRUMENT is broken, not the subject. Bound as
132    // a LOCAL literal. Had I trusted that RED and loosened the pin, I would have disabled the one clause
133    // that makes this gate evidence.
134    // PIN ROTATED 2026-08-17: rfc-editor.org re-issued rfc7748.txt (immutable vectors, drifted boilerplate)
135    // since the 2026-07-31 fetch, so ab200228.. is no longer reproducible. Re-pinned to the current
136    // authoritative document: nx_vecfetch over the cert-validated sovereign TLS stack (200 OK), gunzip'd
137    // with CRC32 verified, canonical S5.2 vectors (out c3da5537..) confirmed present, 39298 bytes.
138    let want: *u8 = "279ca0ecc5e92e2962e27b846986aeb74729d9dd34bd4a04a362f80dcb596ad3\x00" as *u8
139    var pin: i64 = 1
140    i = 0
141    while i < 64 { if hx[i] != want[i] { pin = 0 } i = i + 1 }
142    w("  acquisition digest: " as *u8); wb(hx, 64); w("\n" as *u8)
143    if pin == 0 {
144        w("RED: PIN FAILED -- this file is not the one nx_vecfetch acquired.\n" as *u8)
145        w("     Refusing to read vectors from an unpinned document: an edited file would let us\n" as *u8)
146        w("     grade ourselves against answers of our own choosing.\n" as *u8)
147        return 1
148    }
149    w("  PIN OK -- bytes match the digest computed in-process at the socket\n" as *u8)
150
151    var pass: i64 = 0
152    var fail: i64 = 0
153    let sc: *u8 = sys_mmap(64)
154    let uu: *u8 = sys_mmap(64)
155    let ex: *u8 = sys_mmap(64)
156    let got: *u8 = sys_mmap(64)
157
158    var cur: i64 = 0
159    var vec: i64 = 0
160    while vec < 2 {
161        let ls: i64 = findfrom(b, lp[0], "Input scalar:" as *u8, cur)
162        if ls < 0 { w("  RED: could not locate 'Input scalar:' in the document\n" as *u8); fail = fail + 1; vec = 2 }
163        else {
164            let p1: i64 = parse32(b, lp[0], ls + 13, sc)
165            let lu: i64 = findfrom(b, lp[0], "Input u-coordinate:" as *u8, p1)
166            let p2: i64 = parse32(b, lp[0], lu + 19, uu)
167            let lo: i64 = findfrom(b, lp[0], "Output u-coordinate:" as *u8, p2)
168            let p3: i64 = parse32(b, lp[0], lo + 20, ex)
169            if p1 < 0 { fail = fail + 1 } else { if p2 < 0 { fail = fail + 1 } else { if p3 < 0 { fail = fail + 1 } else {
170                x25519(sc, uu, got)
171                if eq32(got, ex) == 1 {
172                    pass = pass + 1
173                    w("  PASS vector " as *u8); nn(vec + 1)
174                    w(": x25519(scalar,u) == the document's Output u-coordinate\n" as *u8)
175                } else {
176                    fail = fail + 1
177                    w("  FAIL vector " as *u8); nn(vec + 1); w(": output mismatch\n" as *u8)
178                }
179                cur = p3
180            } } }
181            vec = vec + 1
182        }
183    }
184
185    w("\n  refsrc=https://www.rfc-editor.org/rfc/rfc7748.txt\n" as *u8)
186    w("  refsrcdig=" as *u8); wb(hx, 64); w("\n" as *u8)
187    w("  ref=RFC7748-5.2   gate=nx_x25519_extvec_gate\n" as *u8)
188    w("nx_x25519_extvec_gate: pass=" as *u8); nn(pass); w(" fail=" as *u8); nn(fail)
189    // MIGRATED onto nx_gate_verdict by nx_gate_dry_apply (D001, minimal form): every check
190    // row above is untouched, so the PASS/FAIL vector cannot change; only the hand-rolled
191    // verdict emission is replaced by the ONE shared base class. Proven by nx_gate_migrate verify.
192    let ctr__dry: *i64 = gv_ctr()
193    ctr__dry[0] = pass
194    ctr__dry[1] = pass + fail
195    let rc__dry: i64 = gv_verdict("X25519-EXTVEC-GATE" as *u8, ctr__dry, "teeth unchanged; verdict emission migrated onto the shared base class" as *u8)
196    sys_exit(rc__dry)
197    return rc__dry
198}
nx_x25519_extvec_gate.nx source

`nx_x25519_extvec_gate.nx` source
