From 579bf0a624cd99db3c8927f68a904aa2105a9563 Mon Sep 17 00:00:00 2001
From: Moudy <m.ellaz@hotmail.com>
Date: Tue, 5 Aug 2025 13:31:57 +0200
Subject: [PATCH] encryption example with risc0

---
 .DS_Store                                     | Bin 0 -> 8196 bytes
 Cargo.toml                                    |   6 +
 encryption-demo-methods/Cargo.toml            |  15 +++
 encryption-demo-methods/build.rs              |   4 +
 .../guest/chacha20/Cargo.toml                 |  19 +++
 .../guest/chacha20/src/main.rs                |  27 +++++
 .../guest/xchacha20/Cargo.toml                |  19 +++
 .../guest/xchacha20/src/main.rs               |  21 ++++
 encryption-demo-methods/src/lib.rs            |   2 +
 encryption-demo/Cargo.toml                    |  16 +++
 encryption-demo/encryption-demo/src/main.rs   |  14 +++
 encryption-demo/src/lib.rs                    | 114 ++++++++++++++++++
 encryption-demo/src/main.rs                   |   1 +
 risc0-selective-privacy-poc/.DS_Store         | Bin 0 -> 6148 bytes
 14 files changed, 258 insertions(+)
 create mode 100644 .DS_Store
 create mode 100644 Cargo.toml
 create mode 100644 encryption-demo-methods/Cargo.toml
 create mode 100644 encryption-demo-methods/build.rs
 create mode 100644 encryption-demo-methods/guest/chacha20/Cargo.toml
 create mode 100644 encryption-demo-methods/guest/chacha20/src/main.rs
 create mode 100644 encryption-demo-methods/guest/xchacha20/Cargo.toml
 create mode 100644 encryption-demo-methods/guest/xchacha20/src/main.rs
 create mode 100644 encryption-demo-methods/src/lib.rs
 create mode 100644 encryption-demo/Cargo.toml
 create mode 100644 encryption-demo/encryption-demo/src/main.rs
 create mode 100644 encryption-demo/src/lib.rs
 create mode 100644 encryption-demo/src/main.rs
 create mode 100644 risc0-selective-privacy-poc/.DS_Store

diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000000000000000000000000000000000000..1472fea03afefdd29f856e433147c816ce7bcb5d
GIT binary patch
literal 8196
zcmeHMyKWOf6g@+1V<{k|O9agdAu5960*ObnL<`hWJ|GV}N)TRlWhdcLtthBb_yKx^
zM1w?07YZbxpoRib17E<I2kSdtZ;Bux0yEOgUC+I9&zZAh&(0cvTHNV%fH?qdR&8gd
z*-R+fuWO|ob3JEi7008$*;(#pX<ms89YKMhKu{nk5EKXs{4EM_&(@_~v+rAPXoCVl
zf&Wqg{reEHY8yLSSZjVd*q9>#ZG+vW@OnmH&_>S2&KB0v!=mg^T02y^BZjiW*&n&M
z*xABbI~>X#K9oaN?u4QYI`c;+94fXpv_XNOKve;Kc5mPUHgOBv-ub=x{E76XS(2>x
zvvu~hXV3rmbZK_~n(yx&=+C#ryMf~i9Ev9HU<3ECgQ16v=^MURVh{FKK3=rgVtks7
z&?iTD_;_sb2b}c~T`c(c=bjn-(kt=zUI}~=F~Xl5;p0Em_@_~h$2@s#pwHUHHd*cR
zY96_X*u@%q@0-sVx{~XahsBx0XOi<`mUow}u7~6$?*X%Y{=IBcud6rTGa*{kXp345
zs7+6*0G#+f?w51>vR~daFNb7Y7bAJNJ#C6Sa&$Zfjg=2%;5-uh<*C(Q>$UWb)=Jgu
z;WfY6dFvI>=c?#o%|k`|tC_d(OYEhr#BOm#l{w_R>tZ|}oUXxnfZIsPBOm|9F1;Q1
zOCHH1!9(PbJnCXR9(FfxLFc&3`3#ZzdYpVw@^F61BYHE&ql_8dk-8X<2VN5<l%T+o
zR$$7qpVR06>-F#dkMtY^`Jg~h;9vz*BUw%s8RO2@m1up|j#yV&b<uH!wPpw#9iscq
pah$gN!;sgJ^To~<*3!fB$6o~4XI$?YLOzFt{omY{(EQ^H`~<JCMehIr

literal 0
HcmV?d00001

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..d8f3b24
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[workspace]
+members = [
+    "encryption-demo",
+    "encryption-demo-methods",
+]
+workspace.resolver = "2"
diff --git a/encryption-demo-methods/Cargo.toml b/encryption-demo-methods/Cargo.toml
new file mode 100644
index 0000000..ff9c336
--- /dev/null
+++ b/encryption-demo-methods/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "encryption-demo-methods"
+version = "0.1.0"
+edition = "2021"
+publish = false
+build = "build.rs"
+
+[dependencies]
+build = "0.0.2"
+risc0-zkvm = { version = "2.2", default-features = false }
+risc0-build = { version = "2.2", default-features = false }
+
+[package.metadata.risc0]
+methods = ["guest/chacha20", "guest/xchacha20"]
+
diff --git a/encryption-demo-methods/build.rs b/encryption-demo-methods/build.rs
new file mode 100644
index 0000000..aa600df
--- /dev/null
+++ b/encryption-demo-methods/build.rs
@@ -0,0 +1,4 @@
+fn main() {
+    risc0_build::embed_methods();
+}
+
diff --git a/encryption-demo-methods/guest/chacha20/Cargo.toml b/encryption-demo-methods/guest/chacha20/Cargo.toml
new file mode 100644
index 0000000..bce8cdd
--- /dev/null
+++ b/encryption-demo-methods/guest/chacha20/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "chacha20"
+version = "0.1.0"
+edition = "2021"
+publish = false
+# Ensure staticlib for RISC-V
+crate-type = ["staticlib"]
+
+[dependencies]
+# no_std stream cipher
+chacha20 = { version = "0.9", default-features = false }
+cipher   = { version = "0.5", default-features = false }
+
+risc0-zkvm-guest = "2.2"
+
+[features]
+default = ["alloc"]    # pull in alloc inside guest
+alloc = []
+
diff --git a/encryption-demo-methods/guest/chacha20/src/main.rs b/encryption-demo-methods/guest/chacha20/src/main.rs
new file mode 100644
index 0000000..1ab9c08
--- /dev/null
+++ b/encryption-demo-methods/guest/chacha20/src/main.rs
@@ -0,0 +1,27 @@
+#![no_std]
+#![no_main]
+
+use chacha20::cipher::{KeyIvInit, StreamCipher};
+use chacha20::ChaCha20;
+use risc0_zkvm::guest::env;
+risc0_zkvm_guest::entry!(main);
+
+pub fn main() {
+    // Read 32-byte key
+    let key: [u8; 32] = env::read();
+    // Read 12-byte nonce
+    let nonce: [u8; 12] = env::read();
+    // Read plaintext length
+    let len: u32 = env::read();
+    // Read plaintext bytes
+    let mut plaintext = vec![0u8; len as usize];
+    env::read_slice(&mut plaintext).unwrap();
+
+    // Encrypt in-place
+    let mut cipher = ChaCha20::new(&key.into(), &nonce.into());
+    cipher.apply_keystream(&mut plaintext);
+
+    // Commit ciphertext
+    env::commit_slice(&plaintext);
+}
+
diff --git a/encryption-demo-methods/guest/xchacha20/Cargo.toml b/encryption-demo-methods/guest/xchacha20/Cargo.toml
new file mode 100644
index 0000000..f94e10f
--- /dev/null
+++ b/encryption-demo-methods/guest/xchacha20/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "xchacha20"
+version = "0.1.0"
+edition = "2021"
+publish = false
+# Ensure staticlib for RISC-V
+crate-type = ["staticlib"]
+
+[dependencies]
+# no_std stream cipher
+xchacha20 = { version = "0.9", default-features = false }
+cipher   = { version = "0.5", default-features = false }
+
+risc0-zkvm-guest = "2.2"
+
+[features]
+default = ["alloc"]    # pull in alloc inside guest
+alloc = []
+
diff --git a/encryption-demo-methods/guest/xchacha20/src/main.rs b/encryption-demo-methods/guest/xchacha20/src/main.rs
new file mode 100644
index 0000000..e76ec7a
--- /dev/null
+++ b/encryption-demo-methods/guest/xchacha20/src/main.rs
@@ -0,0 +1,21 @@
+#![no_std]
+#![no_main]
+
+use chacha20::cipher::{KeyIvInit, StreamCipher};
+use chacha20::XChaCha20;
+use risc0_zkvm::guest::env;
+risc0_zkvm_guest::entry!(main);
+
+pub fn main() {
+    let key: [u8; 32] = env::read();
+    let nonce: [u8; 24] = env::read();
+    let len: u32 = env::read();
+    let mut plaintext = vec![0u8; len as usize];
+    env::read_slice(&mut plaintext).unwrap();
+
+    let mut cipher = XChaCha20::new(&key.into(), &nonce.into());
+    cipher.apply_keystream(&mut plaintext);
+
+    env::commit_slice(&plaintext);
+}
+
diff --git a/encryption-demo-methods/src/lib.rs b/encryption-demo-methods/src/lib.rs
new file mode 100644
index 0000000..7b08660
--- /dev/null
+++ b/encryption-demo-methods/src/lib.rs
@@ -0,0 +1,2 @@
+include!(concat!(env!("OUT_DIR"), "/methods.rs"));
+
diff --git a/encryption-demo/Cargo.toml b/encryption-demo/Cargo.toml
new file mode 100644
index 0000000..6d6a565
--- /dev/null
+++ b/encryption-demo/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "encryption-demo"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+risc0-zkvm = "2.2"
+rand = { version = "0.8", features = ["std"]}
+hex = "0.4"
+
+encryption-demo-methods = { path = "../encryption-demo-methods" }
+
+[[bin]]
+name = "encrypt-demo"
+path = "src/main.rs"
diff --git a/encryption-demo/encryption-demo/src/main.rs b/encryption-demo/encryption-demo/src/main.rs
new file mode 100644
index 0000000..85f20af
--- /dev/null
+++ b/encryption-demo/encryption-demo/src/main.rs
@@ -0,0 +1,14 @@
+use encryption_demo::*;
+use rand::Rng;
+
+fn main() -> anyhow::Result<()> {
+    let msg = b"zk-encrypted hello world!";
+    let mut rng = rand::thread_rng();
+    let key: [u8; 32] = rng.gen();
+    let nonce: [u8; 12] = rng.gen();
+
+    let (ciphertext, _proof) = encrypt_chacha20(&key, &nonce, msg)?;
+    println!("ciphertext = {}", hex::encode(ciphertext));
+    println!("proof    OK");
+    Ok(())
+}
diff --git a/encryption-demo/src/lib.rs b/encryption-demo/src/lib.rs
new file mode 100644
index 0000000..feaab80
--- /dev/null
+++ b/encryption-demo/src/lib.rs
@@ -0,0 +1,114 @@
+//! Host-side helpers: prove encryption inside RISC Zero and verify receipts.
+
+use risc0_zkvm::{
+    default_prover, ExecutorEnv, Receipt,
+};
+use encryption_demo_methods::{
+    CHACHA20_ELF, CHACHA20_ID, XCHACHA20_ELF, XCHACHA20_ID,
+};
+
+/// Encrypt `plaintext` with ChaCha20 inside the zkVM.
+/// Returns `(ciphertext, receipt)`.
+pub fn encrypt_chacha20(
+    key: &[u8; 32],
+    nonce: &[u8; 12],
+    plaintext: &[u8],
+) -> anyhow::Result<(Vec<u8>, Receipt)> {
+    let env = ExecutorEnv::builder()
+        .write(key)?
+        .write(nonce)?
+        .write(&(plaintext.len() as u32))?
+        .write_slice(plaintext)?
+        .build()?;
+
+    let prover = default_prover();
+    let receipt = prover.prove(env, CHACHA20_ELF)?;
+    receipt.verify(CHACHA20_ID)?;
+
+    let ciphertext: Vec<u8> = receipt.journal.decode()?;
+    Ok((ciphertext, receipt))
+}
+
+/// Same API for XChaCha20 (24-byte nonce)
+pub fn encrypt_xchacha20(
+    key: &[u8; 32],
+    nonce: &[u8; 24],
+    plaintext: &[u8],
+) -> anyhow::Result<(Vec<u8>, Receipt)> {
+    let env = ExecutorEnv::builder()
+        .write(key)?
+        .write(nonce)?
+        .write(&(plaintext.len() as u32))?
+        .write_slice(plaintext)?
+        .build()?;
+
+    let prover = default_prover();
+    let receipt = prover.prove(env, XCHACHA20_ELF)?;
+    receipt.verify(XCHACHA20_ID)?;
+
+    let ciphertext: Vec<u8> = receipt.journal.decode()?;
+    Ok((ciphertext, receipt))
+}
+
+
+// Test for chacha20
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use chacha20::cipher::{KeyIvInit, StreamCipher};
+    use chacha20::ChaCha20;
+
+    // RFC 8439 test vector
+    const KEY: [u8; 32] = [
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
+    ];
+    const NONCE: [u8; 12] = [0; 12];
+    const PLAINTEXT: [u8; 16] = *b"example message!";
+
+    #[test]
+    fn chacha20_vector_matches() {
+        let (ciphertext, _) = encrypt_chacha20(&KEY, &NONCE, &PLAINTEXT).unwrap();
+
+        // host decryption
+        let mut buf = ciphertext.clone();
+        let mut cipher = ChaCha20::new(&KEY.into(), &NONCE.into());
+        cipher.apply_keystream(&mut buf);
+
+        assert_eq!(&buf, &PLAINTEXT);
+    }
+}
+
+
+// Tests for Xchacha20
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use xchacha20::cipher::{KeyIvInit, StreamCipher};
+    use xchacha20::xChaCha20;
+
+    // RFC 8439 test vector
+    const KEY: [u8; 32] = [
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
+    ];
+    const NONCE: [u8; 12] = [0; 12];
+    const PLAINTEXT: [u8; 16] = *b"example message!";
+
+    #[test]
+    fn xchacha20_vector_matches() {
+        let (ciphertext, _) = encrypt_xchacha20(&KEY, &NONCE, &PLAINTEXT).unwrap();
+
+        // host decryption
+        let mut buf = ciphertext.clone();
+        let mut cipher = xChaCha20::new(&KEY.into(), &NONCE.into());
+        cipher.apply_keystream(&mut buf);
+
+        assert_eq!(&buf, &PLAINTEXT);
+    }
+}
+
diff --git a/encryption-demo/src/main.rs b/encryption-demo/src/main.rs
new file mode 100644
index 0000000..1a4baf5
--- /dev/null
+++ b/encryption-demo/src/main.rs
@@ -0,0 +1 @@
+  
diff --git a/risc0-selective-privacy-poc/.DS_Store b/risc0-selective-privacy-poc/.DS_Store
new file mode 100644
index 0000000000000000000000000000000000000000..a84a518e783f0aeeada57137811323ced2d215d1
GIT binary patch
literal 6148
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z<_aNON<POwN$!&_iHV5om-&!rKtvUqAd6BEF&AAY7Tg1Jp5u`=%f)c|(5}{niT<KV
z_I^eix~FGa(BA$>ukSbe{#DyFvt>Jjy?Xon`nWpZULVHHcQNo?jtVjBr(d4N^)13&
zoB?OR8E^)ifuk^hJ6ojcD|+t?I0MeWjsZCz0-9hnOp5vFK$lAZpgg0qK$luVa)Mzr
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Wm=t9evFCK4KLj!%-Z=wDVBi}T2rWne

literal 0
HcmV?d00001