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

1import "nx_gate_gn.nx"
2// nx_dr_encrypt_gate.nx -- exceed-gate for CAP-DR-ENCRYPT. Proves encryption-at-rest: seal->open round-trips
3// byte-exact, the ciphertext is NOT plaintext (confidentiality), a single-byte tamper is REJECTED (auth), and a
4// wrong key is REJECTED (the plaintext is never emitted). This is what a plain cp to /mnt/d cannot do.
5// Sovereign: nx_syscalls + nx_sha256 + nx_chacha20_poly1305. expect_exit: 0
6import "nx_syscalls.nx"
7import "nx_sha256.nx"
8import "nx_chacha20_poly1305.nx"
9
10func gp(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 }
11func g_eq(a: *u8, b: *u8, n: i64) -> i64 { var i: i64=0; while i<n { if a[i]!=b[i] { return 0 } i=i+1 } return 1 }
12
13func main(argc: i64, argv: *i64) -> i64 {
14    gp("=== nx_dr_encrypt_gate (encryption-at-rest: round-trip / confidential / tamper+wrongkey rejected) ===\n" as *u8)
15    var pass: i64=0; var fail: i64=0
16
17    let key: *u8 = sys_mmap(32); sha256_digest("my dr archive passphrase" as *u8, 24, key)
18    let pt: *u8 = "accounts: elderwesto = operator level 3 SECRET" as *u8
19    let n: i64 = 46
20    let dig: *u8 = sys_mmap(64); sha256_digest(pt, n, dig)   // convergent nonce source
21    let ct: *u8 = sys_mmap(n + 16); let tag: *u8 = sys_mmap(32)
22    nx_chacha20_poly1305_encrypt(key, dig, "" as *u8, 0, pt, n, ct, tag)
23
24    // T1 round-trip
25    let pt2: *u8 = sys_mmap(n + 16)
26    let v1: i64 = nx_chacha20_poly1305_decrypt(key, dig, "" as *u8, 0, ct, n, tag, pt2)
27    if v1 == NX_AEAD_VERDICT_OK { if g_eq(pt, pt2, n) == 1 { pass=pass+1; gp("  T1 seal->open round-trip byte-exact PASS\n" as *u8) } else { fail=fail+1; gp("  T1 FAIL bytes\n" as *u8) } } else { fail=fail+1; gp("  T1 FAIL verdict\n" as *u8) }
28
29    // T2 confidentiality: ciphertext differs from plaintext
30    if g_eq(pt, ct, n) == 0 { pass=pass+1; gp("  T2 ciphertext != plaintext (confidential) PASS\n" as *u8) } else { fail=fail+1; gp("  T2 FAIL plaintext leaked\n" as *u8) }
31
32    // T3 tamper the ciphertext -> rejected
33    ct[0] = (ct[0] as i64 ^ 1) as u8
34    let v3: i64 = nx_chacha20_poly1305_decrypt(key, dig, "" as *u8, 0, ct, n, tag, pt2)
35    if v3 != NX_AEAD_VERDICT_OK { pass=pass+1; gp("  T3 single-byte ciphertext tamper -> REJECTED PASS\n" as *u8) } else { fail=fail+1; gp("  T3 FAIL tamper accepted\n" as *u8) }
36    ct[0] = (ct[0] as i64 ^ 1) as u8   // restore
37
38    // T4 wrong key -> rejected
39    let key2: *u8 = sys_mmap(32); sha256_digest("WRONG passphrase" as *u8, 16, key2)
40    let v4: i64 = nx_chacha20_poly1305_decrypt(key2, dig, "" as *u8, 0, ct, n, tag, pt2)
41    if v4 != NX_AEAD_VERDICT_OK { pass=pass+1; gp("  T4 wrong key -> REJECTED (plaintext never emitted) PASS\n" as *u8) } else { fail=fail+1; gp("  T4 FAIL wrong key accepted\n" as *u8) }
42
43    gp("RESULT pass=" as *u8); gn(pass); gp(" fail=" as *u8); gn(fail)
44    if fail == 0 { gp(" verdict=GREEN (AEAD encryption-at-rest -- exceeds a plaintext cp)\n" as *u8); sys_exit(0); return 0 }
45    gp(" verdict=RED\n" as *u8); sys_exit(1); return 1
46}
nx_dr_encrypt_gate.nx source

`nx_dr_encrypt_gate.nx` source
