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Minor hygiene items
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- open external links in a new tab (some via mdbook extension, others by hardcoding HTML)
- fix reference to deprecated public key announcement in PRId algorithm
- give a more useful internal link for assertionMethodPublicKeys in the Verifiable Credentials overview
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Wes Biggs committed Oct 3, 2024
1 parent 9cb0bf8 commit 44ad1a8
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2 changes: 1 addition & 1 deletion .spellcheckerdict.txt
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ cryptographically
[Cc]ryptosuites
CtxSharedSecretA
CtxSharedSecretB
CtxSharedSecretBob
Curve25519
decrypt(ed)?
Delegator
Expand Down Expand Up @@ -100,6 +99,7 @@ repo
resolvers
RFC[1-9][0-9]*
Ristretto
RootSharedSecretAB
RPC
S3
schemaless
Expand Down
5 changes: 4 additions & 1 deletion book.toml
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
[book]
authors = ["Unfinished"]
authors = ["Project Liberty Institute"]
language = "en"
multilingual = false
src = "pages"
Expand All @@ -21,3 +21,6 @@ exclude = ['en\.bitcoin\.it', 'github\.com/LibertyDSNP/spec', 'w3\.org']

[output.html.fold]
enable = true

# https://github.com/jonahgoldwastaken/mdbook-external-links
[preprocessor.external-links]
26 changes: 13 additions & 13 deletions pages/DSNP/Types/PRId.md
Original file line number Diff line number Diff line change
Expand Up @@ -41,17 +41,17 @@ Definitions:
Algorithm:

1. Both Alice and Bob generate an asymmetric key pair for use with X25519 <abbr title="Elliptic Curve Integrated Encryption Scheme">ECIES</abbr>.
Each publishes a Public Key Announcement with their generated public key with a `keyType` value of `keyAgreement`.
Each uses the [Replace User Data](../UserData.md#replace-user-data-operation) Operation to publish their generated public key in `keyAgreementPublicKeys`.

<table style="table-layout:fixed">
<tr><th>Libsodium</th><th>Algorithm</th></tr>
<tr><td>
<tt>
<pre>
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#key-pair-generation">crypto_box_keypair</a>(
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#key-pair-generation" target="_blank">crypto_box_keypair</a>(
&a_public,
&a_secret);
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#key-pair-generation">crypto_box_keypair</a>(
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#key-pair-generation" target="_blank">crypto_box_keypair</a>(
&b_public,
&b_secret);
</pre>
Expand All @@ -71,7 +71,7 @@ Algorithm:
<tr><th>Libsodium</th><th>Algorithm</th></tr>
<tr><td>
<tt><pre>
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#precalculation-interface">crypto_box_beforenm</a>(
<a href="https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption#precalculation-interface" target="_blank">crypto_box_beforenm</a>(
&root_shared_secret,
b_public,
a_secret);
Expand All @@ -83,13 +83,13 @@ RootSharedSecret<sub>AB</sub> &#8592;
</pre></tt>
</td></tr></table>

3. Alice derives a context-specific subkey <code>CtxSharedSecret<sub>Bob</sub></code> from the shared secret `RootSharedSecret` as the master key, Bob's DSNP User Id as the 64-bit key identifier, and the ASCII encoding of the [PRId Context](#contexts) string (`"PRIdCtx0"` for connections).
3. Alice derives a context-specific subkey <code>CtxSharedSecret<sub>A→B</sub></code> from the shared secret <code>RootSharedSecret<sub>AB</sub></code> as the master key, Bob's DSNP User Id as the 64-bit key identifier, and the ASCII encoding of the [PRId Context](#contexts) string (`"PRIdCtx0"` for connections).

<table style="table-layout:fixed">
<tr><th>Libsodium</th><th>Algorithm</th></tr>
<tr><td>
<tt><pre>
<a href="https://libsodium.gitbook.io/doc/key_derivation">crypto_kdf_derive_from_key</a>(
<a href="https://libsodium.gitbook.io/doc/key_derivation" target="_blank">crypto_kdf_derive_from_key</a>(
ctx_shared_secret,
32,
b_user_id,
Expand All @@ -98,7 +98,7 @@ RootSharedSecret<sub>AB</sub> &#8592;
</pre></tt>
</td><td>
<tt><pre>
CtxSharedSecret<sub>A→B</sub> &#8592
CtxSharedSecret<sub>A→B,C</sub> &#8592
Blake2b<sub>256</sub>(
key = RootSharedSecret<sub>AB</sub>,
message = {},
Expand All @@ -108,7 +108,7 @@ CtxSharedSecret<sub>A→B</sub> &#8592
</td></tr></table>

4. Alice uses Bob's DSNP User Id to form an 8-byte little-endian message.
Alice encrypts this message using [XSalsa20](http://cr.yp.to/snuffle/xsalsa-20110204.pdf) with the PRId key <code>CtxSharedSecret<sub>A→B</sub></code> and a nonce of her own User Id (little-endian) followed by 16 zero bytes.
Alice encrypts this message using [XSalsa20](http://cr.yp.to/snuffle/xsalsa-20110204.pdf) with the PRId key <code>CtxSharedSecret<sub>A→B,C</sub></code> and a nonce of her own User Id (little-endian) followed by 16 zero bytes.

<table style="table-layout:fixed">
<tr><th>Libsodium</th><th>Algorithm</th></tr>
Expand All @@ -120,7 +120,7 @@ for (i = 0; i < 8; i++) {
nonce[i] = (user_id_a >> (i*8))
& 0xff;
}<br>
<a href="https://libsodium.gitbook.io/doc/secret-key_cryptography/secretbox#detached-mode">crypto_secretbox_detached</a>(
<a href="https://libsodium.gitbook.io/doc/secret-key_cryptography/secretbox#detached-mode" target="_blank">crypto_secretbox_detached</a>(
&prid,
&mac_unused,
user_id_b,
Expand All @@ -136,7 +136,7 @@ for (i = 0; i < 8; i++) {
PRId<sub>A→B,C</sub> &#8592
XSalsa20(
message = Id<sub>B</sub>,
key = CtxSharedSecret<sub>A→B</sub>,
key = CtxSharedSecret<sub>A→B,C</sub>,
nonce = Padded24BytesLE(Id<sub>A</sub>)
)
</pre></tt>
Expand All @@ -147,7 +147,7 @@ PRId<sub>A→B,C</sub> &#8592
Similarly, Bob can calculate the same root shared secret `RootSharedSecret` using <code>Alice<sub>public</sub></code> and <code>Bob<sub>secret</sub></code> and derive the same <code>PRId<sub>A→B,C</sub></code> in order to check if it is in Alice's published PRIds.
Bob can also derive the PRId subkey for Alice's DSNP User Id and encrypt Alice's User Id, using his own as the nonce, to generate the Bob-to-Alice PRId (<code>PRId<sub>B→A,C</sub></code>), and then publish it to his own list, if desired.

If Alice or Bob wants to prove to a third party that their PRIds are in each other's PRId list, they can provide the third party with their own subkey <code>CtxSharedSecret<sub>A→B</sub></code> or <code>CtxSharedSecret<sub>B→A</sub></code>.
If Alice or Bob wants to prove to a third party that their PRIds are in each other's PRId list, they can provide the third party with their own subkey <code>CtxSharedSecret<sub>A→B,C</sub></code> or <code>CtxSharedSecret<sub>B→A,C</sub></code>.
The third party can repeat the encryption step using Alice and Bob's User Ids, and check that the output is present in the published set of PRIds. The root shared secret `RootSharedSecret` (used as a master key in this algorithm) should _not_ be divulged.

### Test Vector
Expand All @@ -169,6 +169,6 @@ An implementation of the PRId generation algorithm should produce the following
| Output | Value |
| --- | --- |
| <tt>PRId<sub>A→B</sub></tt> | `0xace4d2995b1a829c` |
| <tt>CtxSharedSecret<sub>A→B</sub></tt> | `0x37cb1a870f0c1dce06f5116faf145ac2cf7a2f7d30136be4eea70c324932e6d2` |
| <tt>CtxSharedSecret<sub>A→B,C</sub></tt> | `0x37cb1a870f0c1dce06f5116faf145ac2cf7a2f7d30136be4eea70c324932e6d2` |
| <tt>PRId<sub>B→A</sub></tt> | `0x1a53b02a26503600` |
| <tt>CtxSharedSecret<sub>B→A</sub></tt> | `0x32c45c49fcfe12f9db60e74fa66416c5a05832c298814d82032a6783a4b1fca0` |
| <tt>CtxSharedSecret<sub>B→A,C</sub></tt> | `0x32c45c49fcfe12f9db60e74fa66416c5a05832c298814d82032a6783a4b1fca0` |
2 changes: 1 addition & 1 deletion pages/VerifiableCredentials/Overview.md
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ Current usage with DSNP relies on the following specifications:
### Cryptography

The Data Integrity specification provides a generic format for expressing cryptographic proofs, where the detailed representation of each data item is defined in individual cryptosuites.
DSNP compliant applications MUST support the following cryptosuites, which correspond to the allowed algorithms for `assertionMethod` [Public Keys](../DSNP/Types/PublicKey.md):
DSNP compliant applications MUST support the following cryptosuites, which correspond to the allowed algorithms for the DSNP User Data item [`assertionMethodPublicKeys`](../DSNP/Types/PublicKeyUserData.md#allowed-key-types):

| Specification | Version/Status | Multikey codec |
| --- | --- | --- |
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