Add OAEP Encryption & Decryption

Cargo.toml

@@ -21,6 +21,10 @@ rand = "0.7.0"
 byteorder = "1.3.1"
 failure = "0.1.5"
 subtle = "2.0.0"
+digest = { version = "0.8.0", features = ["std"] }
+sha-1 = "0.8.1"
+sha2 = "0.8.0"
+sha3 = "0.8.1"
 
 [dependencies.zeroize]
 version = "1.1.0"
@@ -34,8 +38,6 @@ features = ["std", "derive"]
 
 [dev-dependencies]
 base64 = "0.11.0"
-sha-1 = "0.8.1"
-sha2 = "0.8.0"
 hex = "0.4.0"
 serde_test = "1.0.89"
 rand_xorshift = "0.2.0"

src/hash.rs

@@ -6,6 +6,7 @@ pub trait Hash {
 
     /// Returns the ASN1 DER prefix for the the hash function.
     fn asn1_prefix(&self) -> Vec<u8>;
+
 }
 
 /// A list of provided hashes, implementing `Hash`.

src/internals.rs

@@ -179,3 +179,14 @@ pub fn left_pad(input: &[u8], size: usize) -> Vec<u8> {
     out[size - n..].copy_from_slice(input);
     out
 }
+
+#[inline]
+pub fn copy_with_left_pad(dest: &mut [u8], src: &[u8]) {
+    // left pad with zeros
+    let padding_bytes = dest.len() - src.len();
+    for el in dest.iter_mut().take(padding_bytes) {
+        *el = 0;
+    }
+    dest[padding_bytes..].copy_from_slice(src);
+}
+

src/lib.rs

@@ -61,6 +61,7 @@ pub mod hash;
 pub mod padding;
 
 mod key;
+pub mod oaep;
 mod pkcs1v15;
 
 pub use self::key::{PublicKey, RSAPrivateKey, RSAPublicKey};