diff --git a/Cargo.toml b/Cargo.toml
index bb82d11..7e5972a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,8 @@ edition = "2021"
 ooniprobe-core = { version = "0.1.0", path = "./ooniprobe-core" }
 ooniprobe-experiments = { version = "0.1.0", path = "./ooniprobe-experiments" }
 ooniprobe-services = { version = "0.1.0", path = "./ooniprobe-services" }
+ooniauth = { version = "0.1.0", path = "./ooniauth" }
+
 
 serde = { version = "1.0.216", features = ["serde_derive"] }
 serde_json = "1.0.133"
diff --git a/ooniauth/Cargo.toml b/ooniauth/Cargo.toml
new file mode 100644
index 0000000..0d4945a
--- /dev/null
+++ b/ooniauth/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "ooniauth"
+version = { workspace = true }
+edition = { workspace = true }
+
+[lib]
+crate_type = ["cdylib"]
+
+[dependencies]
diff --git a/ooniauth/src/lib.rs b/ooniauth/src/lib.rs
new file mode 100644
index 0000000..8612b2b
--- /dev/null
+++ b/ooniauth/src/lib.rs
@@ -0,0 +1,103 @@
+use rand::Rng;
+
+#[derive(Debug, Clone)]
+struct CredentialError;
+
+/*
+	Protocol overview: 
+	USER: “POST register/” credential_sign_request
+“create_sign_request” sends a credential request with random fields “nym_id” 
+SERVER: credential_sign_response
+Set the attributes “age” and “measurement_count” in the credential request
+Re-randomize attributes “nym_id”
+Sign the credential and send it over
+	USER: credential
+Check that the public attributes “age” and “measurement_count” are set correctly 
+“Unblind the credential and store it permanently.
+*/
+
+pub fn create_sign_request(nym_id: &[u8]) -> Result<Vec<u8>, CredentialError> {
+    // creates a sign_request with random fields `nym_id`
+    let mut rng = rand::thread_rng();
+    let sign_request: Vec<u8> = (0..nym_id.len()).map(|_| rng.gen()).collect();
+    sign_request
+}
+
+pub fn create_sign_response(sign_request: &[u8]) -> Result<Vec<u8>, CredentialError> {
+    // Set the attributes “age” and “measurement_count” in the credential request
+    // Re-randomize attributes “nym_id”
+    // Sign the credential and send it over
+    let mut rng = rand::thread_rng();
+    let blinded_sign_response: Vec<u8> = (0..sign_request.len()).map(|_| rng.gen()).collect();
+    blinded_sign_response
+}
+
+// Q(michele): what's the key we need in here to unblind this?
+pub fn unblind_sign_response(sign_response: &[u8]) -> Result<Vec<u8>, CredentialError> {
+    // “Unblind the credential and store it permanently.
+    let mut rng = rand::thread_rng();
+    let sign_response: Vec<u8> = (0..sign_response.len()).map(|_| rng.gen()).collect();
+    sign_response
+}
+
+/*
+USER: “POST submit/” submission, presentation_message
+Compute NYM = PRF(nym_id, nym_scope)
+Let measurement_count_msb = floor(UserAuthCredential.measurement_count / 2^10) 
+# leak just the most significant bits of the counter
+Let age_msb = floor(UserAuthCredential.age / 2^10)
+# leak just the most significant bits of the probe age
+Compute a credential signing request with:
+new.nym_id = old.nym_id
+new.age = old.age
+new.measurement_count = old.measurement_count + 1
+Send 
+Measurement
+NYM, age_msb, measurement_count_msb
+presentation_message for the predicate: 
+NYM is correctly computed
+PRF(UserAuthCredential.nym_id, nym_scope) = NYM
+age_msb and measurement_count are correct
+UserAuthCredential.age = age_msb * 2^10 + age_lsb
+UserAuthCredential.measurement_count = measurement_count_msb * 2^10 + measurement_count_lsb
+age_lsb < 2^10
+measurement_count_lsb < 2^10 
+
+	SERVER: decision
+Check the credential presentation_message against NYM, TOKEN, age_msb, measurement_count_msb
+Check NYM not in blocklist
+Add submission.NYM = NYM
+Add submission.measurement_count_msb = measurement_count_msb
+Add submission to log
+Respond with credential_sign_response
+
+	User: credential update
+Finalize credential_sign_response and store UserAuthCredential 
+*/
+
+pub struct SubmissionMeta {
+    nym: Vec<u8>
+    age_msb: u32
+    measurement_count_msb: u32
+}
+
+// Measurement
+// NYM, TOKEN, age_msb, measurement_count_msb
+pub fn create_submission(nym_id: &[u8], nym_scope: &[u8], current_credential: &[u8]) -> Result<SubmissionMeta, CredentialError> {
+    let mut nym = Vec::new();
+    nym.extend_from_slice(nym_id);
+    nym.extend_from_slice(nym_scope);
+    nym.extend_from_slice(current_credential);
+
+    SubmissionMeta {
+        nym,
+        age_msb: 0,
+        measurement_count_msb: 0,
+    }
+}
+
+pub fn validate_submission(submission_meta: SubmissionMeta) -> Result<Vec<u8>, CredentialError> {
+    let mut rng = rand::thread_rng();
+    let credential_sign_response: Vec<u8> = (0..submission_meta.nym.len()).map(|_| rng.gen()).collect();
+    credential_sign_response
+}
\ No newline at end of file
diff --git a/ooniprobe-core/src/lib.rs b/ooniprobe-core/src/lib.rs
index e69de29..8b13789 100644
--- a/ooniprobe-core/src/lib.rs
+++ b/ooniprobe-core/src/lib.rs
@@ -0,0 +1 @@
+