134 lines
3.6 KiB
Rust
134 lines
3.6 KiB
Rust
use crate::canonicalization::canonicalize;
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use crate::ikm::InputKeyMaterial;
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use std::num::NonZeroU64;
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pub(crate) type KdfFunction = dyn Fn(&str, &[u8]) -> Vec<u8>;
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pub struct KeyContext {
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ctx: Vec<String>,
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periodicity: Option<u64>,
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}
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impl KeyContext {
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pub fn set_static(&mut self) {
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self.periodicity = None;
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}
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pub fn set_periodicity(&mut self, periodicity: NonZeroU64) {
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self.periodicity = Some(periodicity.get());
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}
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pub(crate) fn get_ctx_elems(&self, time_period: Option<u64>) -> Vec<Vec<u8>> {
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let mut ret: Vec<Vec<u8>> = self.ctx.iter().map(|s| s.as_bytes().to_vec()).collect();
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if let Some(tp) = time_period {
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ret.push(tp.to_le_bytes().to_vec());
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}
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ret
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}
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pub(crate) fn get_time_period(&self, timestamp: u64) -> Option<u64> {
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self.periodicity.map(|p| timestamp / p)
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}
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pub(crate) fn is_periodic(&self) -> bool {
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self.periodicity.is_some()
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}
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}
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impl<const N: usize> From<[&str; N]> for KeyContext {
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fn from(ctx: [&str; N]) -> Self {
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Self {
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ctx: ctx.iter().map(|s| s.to_string()).collect(),
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periodicity: Some(crate::DEFAULT_KEY_CTX_PERIODICITY),
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}
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}
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}
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pub(crate) fn derive_key(
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ikm: &InputKeyMaterial,
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ctx: &KeyContext,
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time_period: Option<u64>,
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) -> Vec<u8> {
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let elems = ctx.get_ctx_elems(time_period);
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let key_context = canonicalize(&elems);
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let kdf = ikm.scheme.get_kdf();
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kdf(&key_context, &ikm.content)
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}
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#[cfg(test)]
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mod tests {
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use crate::ikm::InputKeyMaterial;
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use crate::KeyContext;
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use std::num::NonZeroU64;
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const TEST_RAW_IKM: &[u8] = &[
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0x0a, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x7b, 0x85, 0x27, 0xef, 0xf2, 0xbd, 0x58,
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0x9f, 0x6e, 0xb1, 0x7b, 0x71, 0xc3, 0x1e, 0xf6, 0xfd, 0x7f, 0x90, 0xdb, 0xc6, 0x43, 0xea,
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0xe9, 0x9c, 0xa3, 0xb5, 0xee, 0xcc, 0xb6, 0xb6, 0x28, 0x6a, 0xbd, 0xe4, 0xd0, 0x65, 0x00,
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0x00, 0x00, 0x00, 0x3d, 0x82, 0x6f, 0x8b, 0x00, 0x00, 0x00, 0x00, 0x00,
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];
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#[test]
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fn derive_key_no_tp() {
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let ikm = InputKeyMaterial::from_bytes(TEST_RAW_IKM).unwrap();
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let ctx = KeyContext::from(["some", "context"]);
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assert_eq!(
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super::derive_key(&ikm, &ctx, None),
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vec![
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0xc1, 0xd2, 0xf0, 0xa7, 0x4d, 0xc5, 0x32, 0x6e, 0x89, 0x86, 0x85, 0xae, 0x3f, 0xdf,
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0x16, 0x0b, 0xec, 0xe6, 0x63, 0x46, 0x41, 0x8a, 0x28, 0x2b, 0x04, 0xa1, 0x23, 0x20,
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0x36, 0xe3, 0x2f, 0x0a
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]
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);
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}
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#[test]
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fn derive_key_tp_0() {
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let ikm = InputKeyMaterial::from_bytes(TEST_RAW_IKM).unwrap();
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let ctx = KeyContext::from(["some", "context"]);
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assert_eq!(
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super::derive_key(&ikm, &ctx, Some(0)),
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vec![
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0xdc, 0x6c, 0x4b, 0xed, 0xef, 0x31, 0x2a, 0x83, 0x40, 0xc0, 0xee, 0xf4, 0xd7, 0xe5,
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0xec, 0x2e, 0xcf, 0xda, 0x64, 0x0a, 0xb8, 0xb6, 0x89, 0xe4, 0x3c, 0x6e, 0xc2, 0x53,
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0x0e, 0xaa, 0x38, 0x12
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]
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);
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}
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#[test]
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fn derive_key_tp_42() {
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let ikm = InputKeyMaterial::from_bytes(TEST_RAW_IKM).unwrap();
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let ctx = KeyContext::from(["some", "context"]);
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assert_eq!(
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super::derive_key(&ikm, &ctx, Some(42)),
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vec![
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0xc7, 0xfb, 0x96, 0x6a, 0x15, 0xde, 0x5f, 0xfc, 0x66, 0xa6, 0xac, 0xda, 0x6b, 0x8e,
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0xa3, 0x66, 0xd8, 0x70, 0x5b, 0x2f, 0xf9, 0x7f, 0xfb, 0x47, 0xb1, 0xa9, 0x93, 0xfc,
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0xf5, 0x0b, 0x6d, 0x3c
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]
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);
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}
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#[test]
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fn get_time_period() {
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let test_vec = &[
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// (periodicity, timestamp, reference value)
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(1, 0, 0),
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(1, 1, 1),
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(1, 2, 2),
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(1, 35015, 35015),
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(16_777_216, 0, 0),
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(16_777_216, 16_777_215, 0),
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(16_777_216, 16_777_216, 1),
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(16_777_216, 1_709_994_382, 101),
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];
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let mut ctx = KeyContext::from([]);
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for (p, ts, ref_val) in test_vec {
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let p = NonZeroU64::new(*p).unwrap();
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ctx.set_periodicity(p);
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let tp = ctx.get_time_period(*ts);
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assert_eq!(tp, Some(*ref_val));
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}
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}
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}
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