//! The asymmetric encryption context.

//!

//! # Examples

//!

//! Encrypt data with RSA

//!

//! ```

//! use openssl::rsa::Rsa;

//! use openssl::pkey::PKey;

//! use openssl::pkey_ctx::PkeyCtx;

//!

//! let key = Rsa::generate(4096).unwrap();

//! let key = PKey::from_rsa(key).unwrap();

//!

//! let mut ctx = PkeyCtx::new(&key).unwrap();

//! ctx.encrypt_init().unwrap();

//!

//! let data = b"Some Crypto Text";

//! let mut ciphertext = vec![];

//! ctx.encrypt_to_vec(data, &mut ciphertext).unwrap();

//! ```

#![cfg_attr(

    not(boringssl),

    doc = r#"\

Generate a CMAC key

```

use openssl::pkey_ctx::PkeyCtx;

use openssl::pkey::Id;

use openssl::cipher::Cipher;

let mut ctx = PkeyCtx::new_id(Id::CMAC).unwrap();

ctx.keygen_init().unwrap();

ctx.set_keygen_cipher(Cipher::aes_128_cbc()).unwrap();

ctx.set_keygen_mac_key(b"0123456789abcdef").unwrap();

let cmac_key = ctx.keygen().unwrap();

```"#

)]

//!

//! Sign and verify data with RSA

//!

//! ```

//! use openssl::pkey_ctx::PkeyCtx;

//! use openssl::pkey::PKey;

//! use openssl::rsa::Rsa;

//!

//! // Generate a random RSA key.

//! let key = Rsa::generate(4096).unwrap();

//! let key = PKey::from_rsa(key).unwrap();

//!

//! let text = b"Some Crypto Text";

//!

//! // Create the signature.

//! let mut ctx = PkeyCtx::new(&key).unwrap();

//! ctx.sign_init().unwrap();

//! let mut signature = vec![];

//! ctx.sign_to_vec(text, &mut signature).unwrap();

//!

//! // Verify the signature.

//! let mut ctx = PkeyCtx::new(&key).unwrap();

//! ctx.verify_init().unwrap();

//! let valid = ctx.verify(text, &signature).unwrap();

//! assert!(valid);

//! ```

#[cfg(not(boringssl))]

use crate::cipher::CipherRef;

use crate::error::ErrorStack;

use crate::md::MdRef;

use crate::pkey::{HasPrivate, HasPublic, Id, PKey, PKeyRef, Private};

use crate::rsa::Padding;

use crate::sign::RsaPssSaltlen;

use crate::{cvt, cvt_p};

use foreign_types::{ForeignType, ForeignTypeRef};

#[cfg(not(boringssl))]

use libc::c_int;

use openssl_macros::corresponds;

use std::convert::TryFrom;

use std::ptr;

/// HKDF modes of operation.

#[cfg(any(ossl111, libressl360))]

pub struct HkdfMode(c_int);

#[cfg(any(ossl111, libressl360))]

impl HkdfMode {

    /// This is the default mode. Calling [`derive`][PkeyCtxRef::derive] on a [`PkeyCtxRef`] set up

    /// for HKDF will perform an extract followed by an expand operation in one go. The derived key

    /// returned will be the result after the expand operation. The intermediate fixed-length

    /// pseudorandom key K is not returned.

    pub const EXTRACT_THEN_EXPAND: Self = HkdfMode(ffi::EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND);

    /// In this mode calling [`derive`][PkeyCtxRef::derive] will just perform the extract operation.

    /// The value returned will be the intermediate fixed-length pseudorandom key K.

    ///

    /// The digest, key and salt values must be set before a key is derived or an error occurs.

    pub const EXTRACT_ONLY: Self = HkdfMode(ffi::EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY);

    /// In this mode calling [`derive`][PkeyCtxRef::derive] will just perform the expand operation.

    /// The input key should be set to the intermediate fixed-length pseudorandom key K returned

    /// from a previous extract operation.

    ///

    /// The digest, key and info values must be set before a key is derived or an error occurs.

    pub const EXPAND_ONLY: Self = HkdfMode(ffi::EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);

}

generic_foreign_type_and_impl_send_sync! {

    type CType = ffi::EVP_PKEY_CTX;

    fn drop = ffi::EVP_PKEY_CTX_free;

    /// A context object which can perform asymmetric cryptography operations.

    pub struct PkeyCtx<T>;

    /// A reference to a [`PkeyCtx`].

    pub struct PkeyCtxRef<T>;

}

impl<T> PkeyCtx<T> {

    /// Creates a new pkey context using the provided key.

    #[corresponds(EVP_PKEY_CTX_new)]

    #[inline]

    pub fn new(pkey: &PKeyRef<T>) -> Result<Self, ErrorStack> {

        unsafe {

            let ptr = cvt_p(ffi::EVP_PKEY_CTX_new(pkey.as_ptr(), ptr::null_mut()))?;

            Ok(PkeyCtx::from_ptr(ptr))

        }

    }

}

impl PkeyCtx<()> {

    /// Creates a new pkey context for the specified algorithm ID.

    #[corresponds(EVP_PKEY_new_id)]

    #[inline]

    pub fn new_id(id: Id) -> Result<Self, ErrorStack> {

        unsafe {

            let ptr = cvt_p(ffi::EVP_PKEY_CTX_new_id(id.as_raw(), ptr::null_mut()))?;

            Ok(PkeyCtx::from_ptr(ptr))

        }

    }

}

impl<T> PkeyCtxRef<T>

where

    T: HasPublic,

{

    /// Prepares the context for encryption using the public key.

    #[corresponds(EVP_PKEY_encrypt_init)]

    #[inline]

    pub fn encrypt_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_encrypt_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Prepares the context for signature verification using the public key.

    #[corresponds(EVP_PKEY_verify_init)]

    #[inline]

    pub fn verify_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_verify_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Prepares the context for signature recovery using the public key.

    #[corresponds(EVP_PKEY_verify_recover_init)]

    #[inline]

    pub fn verify_recover_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_verify_recover_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Encrypts data using the public key.

    ///

    /// If `to` is set to `None`, an upper bound on the number of bytes required for the output buffer will be

    /// returned.

    #[corresponds(EVP_PKEY_encrypt)]

    #[inline]

    pub fn encrypt(&mut self, from: &[u8], to: Option<&mut [u8]>) -> Result<usize, ErrorStack> {

        let mut written = to.as_ref().map_or(0, |b| b.len());

        unsafe {

            cvt(ffi::EVP_PKEY_encrypt(

                self.as_ptr(),

                to.map_or(ptr::null_mut(), |b| b.as_mut_ptr()),

                &mut written,

                from.as_ptr(),

                from.len(),

            ))?;

        }

        Ok(written)

    }

    /// Like [`Self::encrypt`] but appends ciphertext to a [`Vec`].

    pub fn encrypt_to_vec(&mut self, from: &[u8], out: &mut Vec<u8>) -> Result<usize, ErrorStack> {

        let base = out.len();

        let len = self.encrypt(from, None)?;

        out.resize(base + len, 0);

        let len = self.encrypt(from, Some(&mut out[base..]))?;

        out.truncate(base + len);

        Ok(len)

    }

    /// Verifies the signature of data using the public key.

    ///

    /// Returns `Ok(true)` if the signature is valid, `Ok(false)` if the signature is invalid, and `Err` if an error

    /// occurred.

    ///

    /// # Note

    ///

    /// This verifies the signature of the *raw* data. It is more common to compute and verify the signature of the

    /// cryptographic hash of an arbitrary amount of data. The [`MdCtx`](crate::md_ctx::MdCtx) type can be used to do

    /// that.

    #[corresponds(EVP_PKEY_verify)]

    #[inline]

    pub fn verify(&mut self, data: &[u8], sig: &[u8]) -> Result<bool, ErrorStack> {

        unsafe {

            let r = ffi::EVP_PKEY_verify(

                self.as_ptr(),

                sig.as_ptr(),

                sig.len(),

                data.as_ptr(),

                data.len(),

            );

            // `EVP_PKEY_verify` is not terribly consistent about how it,

            // reports errors. It does not clearly distinguish between 0 and

            // -1, and may put errors on the stack in both cases. If there's

            // errors on the stack, we return `Err()`, else we return

            // `Ok(false)`.

            if r <= 0 {

                let errors = ErrorStack::get();

                if !errors.errors().is_empty() {

                    return Err(errors);

                }

            }

            Ok(r == 1)

        }

    }

    /// Recovers the original data signed by the private key. You almost

    /// always want `verify` instead.

    ///

    /// Returns the number of bytes written to `to`, or the number of bytes

    /// that would be written, if `to` is `None.

    #[corresponds(EVP_PKEY_verify_recover)]

    #[inline]

    pub fn verify_recover(

        &mut self,

        sig: &[u8],

        to: Option<&mut [u8]>,

    ) -> Result<usize, ErrorStack> {

        let mut written = to.as_ref().map_or(0, |b| b.len());

        unsafe {

            cvt(ffi::EVP_PKEY_verify_recover(

                self.as_ptr(),

                to.map_or(ptr::null_mut(), |b| b.as_mut_ptr()),

                &mut written,

                sig.as_ptr(),

                sig.len(),

            ))?;

        }

        Ok(written)

    }

}

impl<T> PkeyCtxRef<T>

where

    T: HasPrivate,

{

    /// Prepares the context for decryption using the private key.

    #[corresponds(EVP_PKEY_decrypt_init)]

    #[inline]

    pub fn decrypt_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_decrypt_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Prepares the context for signing using the private key.

    #[corresponds(EVP_PKEY_sign_init)]

    #[inline]

    pub fn sign_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_sign_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Sets the peer key used for secret derivation.

    #[corresponds(EVP_PKEY_derive_set_peer)]

    pub fn derive_set_peer<U>(&mut self, key: &PKeyRef<U>) -> Result<(), ErrorStack>

    where

        U: HasPublic,

    {

        unsafe {

            cvt(ffi::EVP_PKEY_derive_set_peer(self.as_ptr(), key.as_ptr()))?;

        }

        Ok(())

    }

    /// Decrypts data using the private key.

    ///

    /// If `to` is set to `None`, an upper bound on the number of bytes required for the output buffer will be

    /// returned.

    #[corresponds(EVP_PKEY_decrypt)]

    #[inline]

    pub fn decrypt(&mut self, from: &[u8], to: Option<&mut [u8]>) -> Result<usize, ErrorStack> {

        let mut written = to.as_ref().map_or(0, |b| b.len());

        unsafe {

            cvt(ffi::EVP_PKEY_decrypt(

                self.as_ptr(),

                to.map_or(ptr::null_mut(), |b| b.as_mut_ptr()),

                &mut written,

                from.as_ptr(),

                from.len(),

            ))?;

        }

        Ok(written)

    }

    /// Like [`Self::decrypt`] but appends plaintext to a [`Vec`].

    pub fn decrypt_to_vec(&mut self, from: &[u8], out: &mut Vec<u8>) -> Result<usize, ErrorStack> {

        let base = out.len();

        let len = self.decrypt(from, None)?;

        out.resize(base + len, 0);

        let len = self.decrypt(from, Some(&mut out[base..]))?;

        out.truncate(base + len);

        Ok(len)

    }

    /// Signs the contents of `data`.

    ///

    /// If `sig` is set to `None`, an upper bound on the number of bytes required for the output buffer will be

    /// returned.

    ///

    /// # Note

    ///

    /// This computes the signature of the *raw* bytes of `data`. It is more common to sign the cryptographic hash of

    /// an arbitrary amount of data. The [`MdCtx`](crate::md_ctx::MdCtx) type can be used to do that.

    #[corresponds(EVP_PKEY_sign)]

    #[inline]

    pub fn sign(&mut self, data: &[u8], sig: Option<&mut [u8]>) -> Result<usize, ErrorStack> {

        let mut written = sig.as_ref().map_or(0, |b| b.len());

        unsafe {

            cvt(ffi::EVP_PKEY_sign(

                self.as_ptr(),

                sig.map_or(ptr::null_mut(), |b| b.as_mut_ptr()),

                &mut written,

                data.as_ptr(),

                data.len(),

            ))?;

        }

        Ok(written)

    }

    /// Like [`Self::sign`] but appends the signature to a [`Vec`].

    pub fn sign_to_vec(&mut self, data: &[u8], sig: &mut Vec<u8>) -> Result<usize, ErrorStack> {

        let base = sig.len();

        let len = self.sign(data, None)?;

        sig.resize(base + len, 0);

        let len = self.sign(data, Some(&mut sig[base..]))?;

        sig.truncate(base + len);

        Ok(len)

    }

}

impl<T> PkeyCtxRef<T> {

    /// Prepares the context for shared secret derivation.

    #[corresponds(EVP_PKEY_derive_init)]

    #[inline]

    pub fn derive_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_derive_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Prepares the context for key generation.

    #[corresponds(EVP_PKEY_keygen_init)]

    #[inline]

    pub fn keygen_init(&mut self) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_keygen_init(self.as_ptr()))?;

        }

        Ok(())

    }

    /// Sets which algorithm was used to compute the digest used in a

    /// signature. With RSA signatures this causes the signature to be wrapped

    /// in a `DigestInfo` structure. This is almost always what you want with

    /// RSA signatures.

    #[corresponds(EVP_PKEY_CTX_set_signature_md)]

    #[inline]

    pub fn set_signature_md(&self, md: &MdRef) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_signature_md(

                self.as_ptr(),

                md.as_ptr(),

            ))?;

        }

        Ok(())

    }

    /// Returns the RSA padding mode in use.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_get_rsa_padding)]

    #[inline]

    pub fn rsa_padding(&self) -> Result<Padding, ErrorStack> {

        let mut pad = 0;

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_get_rsa_padding(self.as_ptr(), &mut pad))?;

        }

        Ok(Padding::from_raw(pad))

    }

    /// Sets the RSA padding mode.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_set_rsa_padding)]

    #[inline]

    pub fn set_rsa_padding(&mut self, padding: Padding) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_rsa_padding(

                self.as_ptr(),

                padding.as_raw(),

            ))?;

        }

        Ok(())

    }

    /// Sets the RSA PSS salt length.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_set_rsa_pss_saltlen)]

    #[inline]

    pub fn set_rsa_pss_saltlen(&mut self, len: RsaPssSaltlen) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_rsa_pss_saltlen(

                self.as_ptr(),

                len.as_raw(),

            ))

            .map(|_| ())

        }

    }

    /// Sets the RSA MGF1 algorithm.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_set_rsa_mgf1_md)]

    #[inline]

    pub fn set_rsa_mgf1_md(&mut self, md: &MdRef) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_rsa_mgf1_md(

                self.as_ptr(),

                md.as_ptr(),

            ))?;

        }

        Ok(())

    }

    /// Sets the RSA OAEP algorithm.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_set_rsa_oaep_md)]

    #[cfg(any(ossl102, libressl310, boringssl))]

    #[inline]

    pub fn set_rsa_oaep_md(&mut self, md: &MdRef) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_rsa_oaep_md(

                self.as_ptr(),

                md.as_ptr() as *mut _,

            ))?;

        }

        Ok(())

    }

    /// Sets the RSA OAEP label.

    ///

    /// This is only useful for RSA keys.

    #[corresponds(EVP_PKEY_CTX_set0_rsa_oaep_label)]

    #[cfg(any(ossl102, libressl310, boringssl))]

    pub fn set_rsa_oaep_label(&mut self, label: &[u8]) -> Result<(), ErrorStack> {

        use crate::LenType;

        let len = LenType::try_from(label.len()).unwrap();

        unsafe {

            let p = ffi::OPENSSL_malloc(label.len() as _);

            ptr::copy_nonoverlapping(label.as_ptr(), p as *mut _, label.len());

            let r = cvt(ffi::EVP_PKEY_CTX_set0_rsa_oaep_label(

                self.as_ptr(),

                p as *mut _,

                len,

            ));

            if r.is_err() {

                ffi::OPENSSL_free(p);

            }

            r?;

        }

        Ok(())

    }

    /// Sets the cipher used during key generation.

    #[cfg(not(boringssl))]

    #[corresponds(EVP_PKEY_CTX_ctrl)]

    #[inline]

    pub fn set_keygen_cipher(&mut self, cipher: &CipherRef) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_ctrl(

                self.as_ptr(),

                -1,

                ffi::EVP_PKEY_OP_KEYGEN,

                ffi::EVP_PKEY_CTRL_CIPHER,

                0,

                cipher.as_ptr() as *mut _,

            ))?;

        }

        Ok(())

    }

    /// Sets the key MAC key used during key generation.

    #[cfg(not(boringssl))]

    #[corresponds(EVP_PKEY_CTX_ctrl)]

    #[inline]

    pub fn set_keygen_mac_key(&mut self, key: &[u8]) -> Result<(), ErrorStack> {

        let len = c_int::try_from(key.len()).unwrap();

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_ctrl(

                self.as_ptr(),

                -1,

                ffi::EVP_PKEY_OP_KEYGEN,

                ffi::EVP_PKEY_CTRL_SET_MAC_KEY,

                len,

                key.as_ptr() as *mut _,

            ))?;

        }

        Ok(())

    }

    /// Sets the digest used for HKDF derivation.

    ///

    /// Requires OpenSSL 1.1.0 or newer.

    #[corresponds(EVP_PKEY_CTX_set_hkdf_md)]

    #[cfg(any(ossl110, boringssl, libressl360))]

    #[inline]

    pub fn set_hkdf_md(&mut self, digest: &MdRef) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_hkdf_md(

                self.as_ptr(),

                digest.as_ptr(),

            ))?;

        }

        Ok(())

    }

    /// Sets the HKDF mode of operation.

    ///

    /// Defaults to [`HkdfMode::EXTRACT_THEN_EXPAND`].

    ///

    /// WARNING: Although this API calls it a "mode", HKDF-Extract and HKDF-Expand are distinct

    /// operations with distinct inputs and distinct kinds of keys. Callers should not pass input

    /// secrets for one operation into the other.

    ///

    /// Requires OpenSSL 1.1.1 or newer.

    #[corresponds(EVP_PKEY_CTX_set_hkdf_mode)]

    #[cfg(any(ossl111, libressl360))]

    #[inline]

    pub fn set_hkdf_mode(&mut self, mode: HkdfMode) -> Result<(), ErrorStack> {

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set_hkdf_mode(self.as_ptr(), mode.0))?;

        }

        Ok(())

    }

    /// Sets the input material for HKDF generation as the "key".

    ///

    /// Which input is the key depends on the "mode" (see [`set_hkdf_mode`][Self::set_hkdf_mode]).

    /// If [`HkdfMode::EXTRACT_THEN_EXPAND`] or [`HkdfMode::EXTRACT_ONLY`], this function specifies

    /// the input keying material (IKM) for HKDF-Extract. If [`HkdfMode::EXPAND_ONLY`], it instead

    /// specifies the pseudorandom key (PRK) for HKDF-Expand.

    ///

    /// Requires OpenSSL 1.1.0 or newer.

    #[corresponds(EVP_PKEY_CTX_set1_hkdf_key)]

    #[cfg(any(ossl110, boringssl, libressl360))]

    #[inline]

    pub fn set_hkdf_key(&mut self, key: &[u8]) -> Result<(), ErrorStack> {

        #[cfg(not(boringssl))]

        let len = c_int::try_from(key.len()).unwrap();

        #[cfg(boringssl)]

        let len = key.len();

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set1_hkdf_key(

                self.as_ptr(),

                key.as_ptr(),

                len,

            ))?;

        }

        Ok(())

    }

    /// Sets the salt value for HKDF generation.

    ///

    /// If performing HKDF-Expand only, this parameter is ignored.

    ///

    /// Requires OpenSSL 1.1.0 or newer.

    #[corresponds(EVP_PKEY_CTX_set1_hkdf_salt)]

    #[cfg(any(ossl110, boringssl, libressl360))]

    #[inline]

    pub fn set_hkdf_salt(&mut self, salt: &[u8]) -> Result<(), ErrorStack> {

        #[cfg(not(boringssl))]

        let len = c_int::try_from(salt.len()).unwrap();

        #[cfg(boringssl)]

        let len = salt.len();

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_set1_hkdf_salt(

                self.as_ptr(),

                salt.as_ptr(),

                len,

            ))?;

        }

        Ok(())

    }

    /// Appends info bytes for HKDF generation.

    ///

    /// If performing HKDF-Extract only, this parameter is ignored.

    ///

    /// Requires OpenSSL 1.1.0 or newer.

    #[corresponds(EVP_PKEY_CTX_add1_hkdf_info)]

    #[cfg(any(ossl110, boringssl, libressl360))]

    #[inline]

    pub fn add_hkdf_info(&mut self, info: &[u8]) -> Result<(), ErrorStack> {

        #[cfg(not(boringssl))]

        let len = c_int::try_from(info.len()).unwrap();

        #[cfg(boringssl)]

        let len = info.len();

        unsafe {

            cvt(ffi::EVP_PKEY_CTX_add1_hkdf_info(

                self.as_ptr(),

                info.as_ptr(),

                len,

            ))?;

        }

        Ok(())

    }

    /// Derives a shared secret between two keys.

    ///

    /// If `buf` is set to `None`, an upper bound on the number of bytes required for the buffer will be returned.

    #[corresponds(EVP_PKEY_derive)]

    pub fn derive(&mut self, buf: Option<&mut [u8]>) -> Result<usize, ErrorStack> {

        let mut len = buf.as_ref().map_or(0, |b| b.len());

        unsafe {

            cvt(ffi::EVP_PKEY_derive(

                self.as_ptr(),

                buf.map_or(ptr::null_mut(), |b| b.as_mut_ptr()),

                &mut len,

            ))?;

        }

        Ok(len)

    }

    /// Like [`Self::derive`] but appends the secret to a [`Vec`].

    pub fn derive_to_vec(&mut self, buf: &mut Vec<u8>) -> Result<usize, ErrorStack> {

        let base = buf.len();

        let len = self.derive(None)?;

        buf.resize(base + len, 0);

        let len = self.derive(Some(&mut buf[base..]))?;

        buf.truncate(base + len);

        Ok(len)

    }

    /// Generates a new public/private keypair.

    #[corresponds(EVP_PKEY_keygen)]

    #[inline]

    pub fn keygen(&mut self) -> Result<PKey<Private>, ErrorStack> {

        unsafe {

            let mut key = ptr::null_mut();

            cvt(ffi::EVP_PKEY_keygen(self.as_ptr(), &mut key))?;

            Ok(PKey::from_ptr(key))

        }

    }

}

#[cfg(test)]

mod test {

    use super::*;

    #[cfg(not(boringssl))]

    use crate::cipher::Cipher;

    use crate::ec::{EcGroup, EcKey};

    use crate::hash::{hash, MessageDigest};

    use crate::md::Md;

    use crate::nid::Nid;

    use crate::pkey::PKey;

    use crate::rsa::Rsa;

    use crate::sign::Verifier;

    #[test]

    fn rsa() {

        let key = include_bytes!("../test/rsa.pem");

        let rsa = Rsa::private_key_from_pem(key).unwrap();

        let pkey = PKey::from_rsa(rsa).unwrap();

        let mut ctx = PkeyCtx::new(&pkey).unwrap();

        ctx.encrypt_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        let pt = "hello world".as_bytes();

        let mut ct = vec![];

        ctx.encrypt_to_vec(pt, &mut ct).unwrap();

        ctx.decrypt_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        let mut out = vec![];

        ctx.decrypt_to_vec(&ct, &mut out).unwrap();

        assert_eq!(pt, out);

    }

    #[test]

    #[cfg(any(ossl102, libressl310, boringssl))]

    fn rsa_oaep() {

        let key = include_bytes!("../test/rsa.pem");

        let rsa = Rsa::private_key_from_pem(key).unwrap();

        let pkey = PKey::from_rsa(rsa).unwrap();

        let mut ctx = PkeyCtx::new(&pkey).unwrap();

        ctx.encrypt_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1_OAEP).unwrap();

        ctx.set_rsa_oaep_md(Md::sha256()).unwrap();

        ctx.set_rsa_mgf1_md(Md::sha256()).unwrap();

        let pt = "hello world".as_bytes();

        let mut ct = vec![];

        ctx.encrypt_to_vec(pt, &mut ct).unwrap();

        ctx.decrypt_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1_OAEP).unwrap();

        ctx.set_rsa_oaep_md(Md::sha256()).unwrap();

        ctx.set_rsa_mgf1_md(Md::sha256()).unwrap();

        let mut out = vec![];

        ctx.decrypt_to_vec(&ct, &mut out).unwrap();

        assert_eq!(pt, out);

    }

    #[test]

    fn rsa_sign() {

        let key = include_bytes!("../test/rsa.pem");

        let rsa = Rsa::private_key_from_pem(key).unwrap();

        let pkey = PKey::from_rsa(rsa).unwrap();

        let mut ctx = PkeyCtx::new(&pkey).unwrap();

        ctx.sign_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        ctx.set_signature_md(Md::sha384()).unwrap();

        let msg = b"hello world";

        let digest = hash(MessageDigest::sha384(), msg).unwrap();

        let mut signature = vec![];

        ctx.sign_to_vec(&digest, &mut signature).unwrap();

        let mut verifier = Verifier::new(MessageDigest::sha384(), &pkey).unwrap();

        verifier.update(msg).unwrap();

        assert!(matches!(verifier.verify(&signature), Ok(true)));

    }

    #[test]

    fn rsa_sign_pss() {

        let key = include_bytes!("../test/rsa.pem");

        let rsa = Rsa::private_key_from_pem(key).unwrap();

        let pkey = PKey::from_rsa(rsa).unwrap();

        let mut ctx = PkeyCtx::new(&pkey).unwrap();

        ctx.sign_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1_PSS).unwrap();

        ctx.set_signature_md(Md::sha384()).unwrap();

        ctx.set_rsa_pss_saltlen(RsaPssSaltlen::custom(14)).unwrap();

        let msg = b"hello world";

        let digest = hash(MessageDigest::sha384(), msg).unwrap();

        let mut signature = vec![];

        ctx.sign_to_vec(&digest, &mut signature).unwrap();

        let mut verifier = Verifier::new(MessageDigest::sha384(), &pkey).unwrap();

        verifier.set_rsa_padding(Padding::PKCS1_PSS).unwrap();

        verifier

            .set_rsa_pss_saltlen(RsaPssSaltlen::custom(14))

            .unwrap();

        verifier.update(msg).unwrap();

        assert!(matches!(verifier.verify(&signature), Ok(true)));

    }

    #[test]

    fn derive() {

        let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();

        let key1 = EcKey::generate(&group).unwrap();

        let key1 = PKey::from_ec_key(key1).unwrap();

        let key2 = EcKey::generate(&group).unwrap();

        let key2 = PKey::from_ec_key(key2).unwrap();

        let mut ctx = PkeyCtx::new(&key1).unwrap();

        ctx.derive_init().unwrap();

        ctx.derive_set_peer(&key2).unwrap();

        let mut buf = vec![];

        ctx.derive_to_vec(&mut buf).unwrap();

    }

    #[test]

    #[cfg(not(boringssl))]

    fn cmac_keygen() {

        let mut ctx = PkeyCtx::new_id(Id::CMAC).unwrap();

        ctx.keygen_init().unwrap();

        ctx.set_keygen_cipher(Cipher::aes_128_cbc()).unwrap();

        ctx.set_keygen_mac_key(&hex::decode("9294727a3638bb1c13f48ef8158bfc9d").unwrap())

            .unwrap();

        ctx.keygen().unwrap();

    }

    #[test]

    #[cfg(any(ossl110, boringssl, libressl360))]

    fn hkdf() {

        let mut ctx = PkeyCtx::new_id(Id::HKDF).unwrap();

        ctx.derive_init().unwrap();

        ctx.set_hkdf_md(Md::sha256()).unwrap();

        ctx.set_hkdf_key(&hex::decode("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b").unwrap())

            .unwrap();

        ctx.set_hkdf_salt(&hex::decode("000102030405060708090a0b0c").unwrap())

            .unwrap();

        ctx.add_hkdf_info(&hex::decode("f0f1f2f3f4f5f6f7f8f9").unwrap())

            .unwrap();

        let mut out = [0; 42];

        ctx.derive(Some(&mut out)).unwrap();

        assert_eq!(

            &out[..],

            hex::decode("3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865")

                .unwrap()

        );

    }

    #[test]

    #[cfg(any(ossl111, libressl360))]

    fn hkdf_expand() {

        let mut ctx = PkeyCtx::new_id(Id::HKDF).unwrap();

        ctx.derive_init().unwrap();

        ctx.set_hkdf_mode(HkdfMode::EXPAND_ONLY).unwrap();

        ctx.set_hkdf_md(Md::sha256()).unwrap();

        ctx.set_hkdf_key(

            &hex::decode("077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5")

                .unwrap(),

        )

        .unwrap();

        ctx.add_hkdf_info(&hex::decode("f0f1f2f3f4f5f6f7f8f9").unwrap())

            .unwrap();

        let mut out = [0; 42];

        ctx.derive(Some(&mut out)).unwrap();

        assert_eq!(

            &out[..],

            hex::decode("3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865")

                .unwrap()

        );

    }

    #[test]

    #[cfg(any(ossl111, libressl360))]

    fn hkdf_extract() {

        let mut ctx = PkeyCtx::new_id(Id::HKDF).unwrap();

        ctx.derive_init().unwrap();

        ctx.set_hkdf_mode(HkdfMode::EXTRACT_ONLY).unwrap();

        ctx.set_hkdf_md(Md::sha256()).unwrap();

        ctx.set_hkdf_key(&hex::decode("0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b").unwrap())

            .unwrap();

        ctx.set_hkdf_salt(&hex::decode("000102030405060708090a0b0c").unwrap())

            .unwrap();

        let mut out = vec![];

        ctx.derive_to_vec(&mut out).unwrap();

        assert_eq!(

            &out[..],

            hex::decode("077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5")

                .unwrap()

        );

    }

    #[test]

    fn verify_fail() {

        let key1 = Rsa::generate(4096).unwrap();

        let key1 = PKey::from_rsa(key1).unwrap();

        let data = b"Some Crypto Text";

        let mut ctx = PkeyCtx::new(&key1).unwrap();

        ctx.sign_init().unwrap();

        let mut signature = vec![];

        ctx.sign_to_vec(data, &mut signature).unwrap();

        let bad_data = b"Some Crypto text";

        ctx.verify_init().unwrap();

        let valid = ctx.verify(bad_data, &signature);

        assert!(matches!(valid, Ok(false) | Err(_)));

        assert!(ErrorStack::get().errors().is_empty());

    }

    #[test]

    fn verify_fail_ec() {

        let key1 =

            EcKey::generate(&EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap()).unwrap();

        let key1 = PKey::from_ec_key(key1).unwrap();

        let data = b"Some Crypto Text";

        let mut ctx = PkeyCtx::new(&key1).unwrap();

        ctx.verify_init().unwrap();

        assert!(matches!(ctx.verify(data, &[0; 64]), Ok(false) | Err(_)));

        assert!(ErrorStack::get().errors().is_empty());

    }

    #[test]

    fn test_verify_recover() {

        let key = Rsa::generate(2048).unwrap();

        let key = PKey::from_rsa(key).unwrap();

        let digest = [

            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,

            24, 25, 26, 27, 28, 29, 30, 31,

        ];

        let mut ctx = PkeyCtx::new(&key).unwrap();

        ctx.sign_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        ctx.set_signature_md(Md::sha256()).unwrap();

        let mut signature = vec![];

        ctx.sign_to_vec(&digest, &mut signature).unwrap();

        // Attempt recovery of just the digest.

        let mut ctx = PkeyCtx::new(&key).unwrap();

        ctx.verify_recover_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        ctx.set_signature_md(Md::sha256()).unwrap();

        let length = ctx.verify_recover(&signature, None).unwrap();

        let mut result_buf = vec![0; length];

        let length = ctx

            .verify_recover(&signature, Some(&mut result_buf))

            .unwrap();

        assert_eq!(length, digest.len());

        // result_buf contains the digest

        assert_eq!(result_buf[..length], digest);

        // Attempt recovery of teh entire DigestInfo

        let mut ctx = PkeyCtx::new(&key).unwrap();

        ctx.verify_recover_init().unwrap();

        ctx.set_rsa_padding(Padding::PKCS1).unwrap();

        let length = ctx.verify_recover(&signature, None).unwrap();

        let mut result_buf = vec![0; length];

        let length = ctx

            .verify_recover(&signature, Some(&mut result_buf))

            .unwrap();

        // 32-bytes of SHA256 digest + the ASN.1 DigestInfo structure == 51 bytes

        assert_eq!(length, 51);

        // The digest is the end of the DigestInfo structure.

        assert_eq!(result_buf[length - digest.len()..length], digest);

    }

}