#![allow(dead_code)] // TODO: remove use super::SymKey; use crate::{ err::{Error, Res}, hpke::{Aead, Kdf}, }; use hkdf::Hkdf as HkdfImpl; use log::trace; use sha2::{Sha256, Sha384, Sha512}; #[derive(Clone, Copy)] pub enum KeyMechanism { Aead(Aead), #[allow(dead_code)] // We don't use this one. Hkdf, } impl KeyMechanism { fn len(self) -> usize { match self { Self::Aead(a) => a.n_k(), Self::Hkdf => 0, // Let the underlying module decide. } } } pub enum Hkdf { Sha256, Sha384, Sha512, } impl Hkdf { pub fn new(kdf: Kdf) -> Self { match kdf { Kdf::HkdfSha256 => Self::Sha256, Kdf::HkdfSha384 => Self::Sha384, Kdf::HkdfSha512 => Self::Sha512, } } #[cfg(test)] #[allow(clippy::unnecessary_wraps)] pub fn import_ikm(ikm: &[u8]) -> Res { Ok(SymKey::from(ikm)) } #[allow(clippy::unnecessary_wraps)] pub fn extract(&self, salt: &[u8], ikm: &SymKey) -> Res { let prk = match self { Self::Sha256 => { SymKey::from(HkdfImpl::::extract(Some(salt), &ikm.0).0.as_slice()) } Self::Sha384 => { SymKey::from(HkdfImpl::::extract(Some(salt), &ikm.0).0.as_slice()) } Self::Sha512 => { SymKey::from(HkdfImpl::::extract(Some(salt), &ikm.0).0.as_slice()) } }; trace!( "HKDF extract: salt={} ikm={:?} prk={:?}", hex::encode(salt), ikm, prk ); Ok(prk) } pub fn expand_key(&self, prk: &SymKey, info: &[u8], key_mech: KeyMechanism) -> Res { let okm = SymKey::from(self.expand_data(prk, info, key_mech.len())?); trace!( "HKDF expand_key: prk={:?} info={} okm={:?}", prk, hex::encode(info), okm, ); Ok(okm) } pub fn expand_data(&self, prk: &SymKey, info: &[u8], len: usize) -> Res> { let mut okm = vec![0; len]; match self { Self::Sha256 => { let h = HkdfImpl::::from_prk(&prk.0).map_err(|_| Error::Internal)?; h.expand(info, &mut okm).map_err(|_| Error::Internal)?; } Self::Sha384 => { let h = HkdfImpl::::from_prk(&prk.0).map_err(|_| Error::Internal)?; h.expand(info, &mut okm).map_err(|_| Error::Internal)?; } Self::Sha512 => { let h = HkdfImpl::::from_prk(&prk.0).map_err(|_| Error::Internal)?; h.expand(info, &mut okm).map_err(|_| Error::Internal)?; } } trace!( "HKDF expand_data: prk={:?} info={} len={} okm={:?}", prk, hex::encode(info), len, hex::encode(&okm), ); Ok(okm) } } #[cfg(test)] mod test { use super::{super::super::hpke::Kdf, Hkdf}; use crate::init; fn sha256_example( ikm: &[u8], salt: &[u8], info: &[u8], l: usize, expected_prk: &[u8], expected_okm: &[u8], ) { init(); let hkdf = Hkdf::new(Kdf::HkdfSha256); let k_ikm = Hkdf::import_ikm(ikm).unwrap(); let prk = hkdf.extract(salt, &k_ikm).unwrap(); let prk_data = prk.key_data().unwrap(); assert_eq!(prk_data, expected_prk); let out = hkdf.expand_data(&prk, info, l).unwrap(); assert_eq!(&out[..], expected_okm); } /// Example 1 from #[test] fn example1() { const IKM: &[u8] = &[ 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, ]; const SALT: &[u8] = &[ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, ]; const INFO: &[u8] = &[0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9]; const L: usize = 42; const PRK: &[u8] = &[ 0x07, 0x77, 0x09, 0x36, 0x2c, 0x2e, 0x32, 0xdf, 0x0d, 0xdc, 0x3f, 0x0d, 0xc4, 0x7b, 0xba, 0x63, 0x90, 0xb6, 0xc7, 0x3b, 0xb5, 0x0f, 0x9c, 0x31, 0x22, 0xec, 0x84, 0x4a, 0xd7, 0xc2, 0xb3, 0xe5, ]; const OKM: &[u8] = &[ 0x3c, 0xb2, 0x5f, 0x25, 0xfa, 0xac, 0xd5, 0x7a, 0x90, 0x43, 0x4f, 0x64, 0xd0, 0x36, 0x2f, 0x2a, 0x2d, 0x2d, 0x0a, 0x90, 0xcf, 0x1a, 0x5a, 0x4c, 0x5d, 0xb0, 0x2d, 0x56, 0xec, 0xc4, 0xc5, 0xbf, 0x34, 0x00, 0x72, 0x08, 0xd5, 0xb8, 0x87, 0x18, 0x58, 0x65, ]; sha256_example(IKM, SALT, INFO, L, PRK, OKM); } /// Example 2 from #[test] fn example2() { const IKM: &[u8] = &[ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, ]; const SALT: &[u8] = &[ 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, ]; const INFO: &[u8] = &[ 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, ]; const L: usize = 82; const PRK: &[u8] = &[ 0x06, 0xa6, 0xb8, 0x8c, 0x58, 0x53, 0x36, 0x1a, 0x06, 0x10, 0x4c, 0x9c, 0xeb, 0x35, 0xb4, 0x5c, 0xef, 0x76, 0x00, 0x14, 0x90, 0x46, 0x71, 0x01, 0x4a, 0x19, 0x3f, 0x40, 0xc1, 0x5f, 0xc2, 0x44, ]; const OKM: &[u8] = &[ 0xb1, 0x1e, 0x39, 0x8d, 0xc8, 0x03, 0x27, 0xa1, 0xc8, 0xe7, 0xf7, 0x8c, 0x59, 0x6a, 0x49, 0x34, 0x4f, 0x01, 0x2e, 0xda, 0x2d, 0x4e, 0xfa, 0xd8, 0xa0, 0x50, 0xcc, 0x4c, 0x19, 0xaf, 0xa9, 0x7c, 0x59, 0x04, 0x5a, 0x99, 0xca, 0xc7, 0x82, 0x72, 0x71, 0xcb, 0x41, 0xc6, 0x5e, 0x59, 0x0e, 0x09, 0xda, 0x32, 0x75, 0x60, 0x0c, 0x2f, 0x09, 0xb8, 0x36, 0x77, 0x93, 0xa9, 0xac, 0xa3, 0xdb, 0x71, 0xcc, 0x30, 0xc5, 0x81, 0x79, 0xec, 0x3e, 0x87, 0xc1, 0x4c, 0x01, 0xd5, 0xc1, 0xf3, 0x43, 0x4f, 0x1d, 0x87, ]; sha256_example(IKM, SALT, INFO, L, PRK, OKM); } /// Example 3 from #[test] fn example3() { const IKM: &[u8] = &[ 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, ]; const SALT: &[u8] = &[]; const INFO: &[u8] = &[]; const L: usize = 42; const PRK: &[u8] = &[ 0x19, 0xef, 0x24, 0xa3, 0x2c, 0x71, 0x7b, 0x16, 0x7f, 0x33, 0xa9, 0x1d, 0x6f, 0x64, 0x8b, 0xdf, 0x96, 0x59, 0x67, 0x76, 0xaf, 0xdb, 0x63, 0x77, 0xac, 0x43, 0x4c, 0x1c, 0x29, 0x3c, 0xcb, 0x04, ]; const OKM: &[u8] = &[ 0x8d, 0xa4, 0xe7, 0x75, 0xa5, 0x63, 0xc1, 0x8f, 0x71, 0x5f, 0x80, 0x2a, 0x06, 0x3c, 0x5a, 0x31, 0xb8, 0xa1, 0x1f, 0x5c, 0x5e, 0xe1, 0x87, 0x9e, 0xc3, 0x45, 0x4e, 0x5f, 0x3c, 0x73, 0x8d, 0x2d, 0x9d, 0x20, 0x13, 0x95, 0xfa, 0xa4, 0xb6, 0x1a, 0x96, 0xc8, ]; sha256_example(IKM, SALT, INFO, L, PRK, OKM); } }