82 lines
2.1 KiB
Rust
82 lines
2.1 KiB
Rust
use crate::canonicalization::canonicalize;
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use crate::ikm::InputKeyMaterial;
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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: u64) {
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self.periodicity = Some(periodicity);
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}
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pub(crate) fn get_value(&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 key_context = canonicalize(&ctx.get_value(time_period));
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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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#[test]
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fn derive_key() {
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let ikm_raw = [
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0x0a, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x7b, 0x85, 0x27, 0xef, 0xf2, 0xbd,
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0x58, 0x9f, 0x6e, 0xb1, 0x7b, 0x71, 0xc3, 0x1e, 0xf6, 0xfd, 0x7f, 0x90, 0xdb, 0xc6,
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0x43, 0xea, 0xe9, 0x9c, 0xa3, 0xb5, 0xee, 0xcc, 0xb6, 0xb6, 0x28, 0x6a, 0xbd, 0xe4,
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0xd0, 0x65, 0x00, 0x00, 0x00, 0x00, 0x3d, 0x82, 0x6f, 0x8b, 0x00, 0x00, 0x00, 0x00,
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0x00,
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];
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let ikm = InputKeyMaterial::from_bytes(&ikm_raw).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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}
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