aquatic-prime: Try to encrypt input data string

Take the data string we created and feed it through RSA encryption.
Basically following the steps used by the Aquatic Prime CLI program
written in C:
https://github.com/bdrister/AquaticPrime/blob/4f86666/Source/PHP/AquaticPrimeCLI.c

At first I tried using a `Signer`, but it looks like I'm supposed to be
encrypting the data instead. Unfortunately, I'm now getting this error
when calling `private_encrypt()`:

    'failed to encrypt: ErrorStack([Error { code: 67526721, library: "rsa
    routines", function: "RSA_EAY_PRIVATE_ENCRYPT", reason: "malloc
    failure", file: "rsa_eay.c", line: 368 }])', libcore/result.rs:945:5

Not sure what the problem is yet.

1 files changed, 39 insertions, 1 deletions

diff --git a/license-generator/aquatic-prime/src/lib.rs b/license-generator/aquatic-prime/src/lib.rs
index f92ad30..80db363 100644
--- a/license-generator/aquatic-prime/src/lib.rs
+++ b/license-generator/aquatic-prime/src/lib.rs
@@ -2,6 +2,14 @@ extern crate openssl;
 
 use std::collections::HashMap;
 
+use openssl::bn::BigNum;
+use openssl::hash::MessageDigest;
+use openssl::rsa::Padding;
+use openssl::pkey::PKey;
+use openssl::rsa::RsaPrivateKeyBuilder;
+use openssl::sha::sha1;
+use openssl::sign::Signer;
+
 struct AquaticPrime<'a> {
     public_key: &'a str,
     private_key: &'a str,
@@ -20,7 +28,37 @@ impl<'a> AquaticPrime<'a> {
             .collect::<Vec<&str>>()
             .concat();
 
-        println!("{:?}", data);
+        let public_key = BigNum::from_hex_str(self.public_key).unwrap();
+        let private_key = BigNum::from_hex_str(self.private_key).unwrap();
+        let rsa_e = BigNum::from_u32(3).unwrap();
+
+        if public_key.num_bits() != 1024 {
+            // TODO: Return Err
+        }
+
+        let digest = sha1(data.as_bytes());
+
+        let keypair = RsaPrivateKeyBuilder::new(
+            public_key,
+            rsa_e,
+            private_key,
+        ).expect("failed to build RSA key").build();
+
+        let mut signature = [0; 128];
+        keypair.private_encrypt(
+            &digest,
+            &mut signature,
+            Padding::PKCS1,
+        ).expect("failed to encrypt");
+
+
+        // let keypair = PKey::from_rsa(keypair).unwrap();
+        //
+        // let mut signer = Signer::new(MessageDigest::sha1(), &keypair).unwrap();
+        // signer.update(data.as_bytes());
+        // let signature = signer.sign_to_vec();
+
+        println!("{:?}", String::from_utf8_lossy(&signature));
 
         String::new()
     }