=pod

=head1 NAME

PKCS5_PBE_keyivgen, PKCS5_PBE_keyivgen_ex, PKCS5_pbe2_set, PKCS5_pbe2_set_iv,
PKCS5_pbe2_set_iv_ex, PKCS5_pbe_set, PKCS5_pbe_set_ex, PKCS5_pbe2_set_scrypt,
PKCS5_pbe_set0_algor, PKCS5_pbe_set0_algor_ex,
PKCS5_v2_PBE_keyivgen, PKCS5_v2_PBE_keyivgen_ex,
PKCS5_v2_scrypt_keyivgen, PKCS5_v2_scrypt_keyivgen_ex,
PKCS5_pbkdf2_set, PKCS5_pbkdf2_set_ex, EVP_PBE_scrypt, EVP_PBE_scrypt_ex
- PKCS#5 Password based encryption routines

=head1 SYNOPSIS

 #include <openssl/evp.h>

 int PKCS5_PBE_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass, int passlen,
                        ASN1_TYPE *param, const EVP_CIPHER *cipher,
                        const EVP_MD *md, int en_de);
 int PKCS5_PBE_keyivgen_ex(EVP_CIPHER_CTX *cctx, const char *pass, int passlen,
                           ASN1_TYPE *param, const EVP_CIPHER *cipher,
                           const EVP_MD *md, int en_de, OSSL_LIB_CTX *libctx,
                           const char *propq);
 int PKCS5_v2_PBE_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass, int passlen,
                           ASN1_TYPE *param, const EVP_CIPHER *cipher,
                           const EVP_MD *md, int en_de);
 int PKCS5_v2_PBE_keyivgen_ex(EVP_CIPHER_CTX *ctx, const char *pass, int passlen,
                              ASN1_TYPE *param, const EVP_CIPHER *cipher,
                              const EVP_MD *md, int en_de,
                              OSSL_LIB_CTX *libctx, const char *propq);
 int EVP_PBE_scrypt(const char *pass, size_t passlen,
                    const unsigned char *salt, size_t saltlen,
                    uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
                    unsigned char *key, size_t keylen);
 int EVP_PBE_scrypt_ex(const char *pass, size_t passlen,
                       const unsigned char *salt, size_t saltlen,
                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
                       unsigned char *key, size_t keylen,
                       OSSL_LIB_CTX *ctx, const char *propq);
 int PKCS5_v2_scrypt_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass,
                              int passlen, ASN1_TYPE *param,
                              const EVP_CIPHER *c, const EVP_MD *md, int en_de);
 int PKCS5_v2_scrypt_keyivgen_ex(EVP_CIPHER_CTX *ctx, const char *pass,
                                 int passlen, ASN1_TYPE *param,
                                 const EVP_CIPHER *c, const EVP_MD *md, int en_de,
                                 OSSL_LIB_CTX *libctx, const char *propq);

 #include <openssl/x509.h>

 int PKCS5_pbe_set0_algor(X509_ALGOR *algor, int alg, int iter,
                          const unsigned char *salt, int saltlen);
 int PKCS5_pbe_set0_algor_ex(X509_ALGOR *algor, int alg, int iter,
                             const unsigned char *salt, int saltlen,
                             OSSL_LIB_CTX *libctx);

 X509_ALGOR *PKCS5_pbe_set(int alg, int iter,
                           const unsigned char *salt, int saltlen);
 X509_ALGOR *PKCS5_pbe_set_ex(int alg, int iter,
                              const unsigned char *salt, int saltlen,
                              OSSL_LIB_CTX *libctx);

 X509_ALGOR *PKCS5_pbe2_set(const EVP_CIPHER *cipher, int iter,
                            unsigned char *salt, int saltlen);
 X509_ALGOR *PKCS5_pbe2_set_iv(const EVP_CIPHER *cipher, int iter,
                               unsigned char *salt, int saltlen,
                               unsigned char *aiv, int prf_nid);
 X509_ALGOR *PKCS5_pbe2_set_iv_ex(const EVP_CIPHER *cipher, int iter,
                                  unsigned char *salt, int saltlen,
                                  unsigned char *aiv, int prf_nid,
                                  OSSL_LIB_CTX *libctx);
 X509_ALGOR *PKCS5_pbe2_set_scrypt(const EVP_CIPHER *cipher,
                                   const unsigned char *salt, int saltlen,
                                   unsigned char *aiv, uint64_t N, uint64_t r,
                                   uint64_t p);

 X509_ALGOR *PKCS5_pbkdf2_set(int iter, unsigned char *salt, int saltlen,
                              int prf_nid, int keylen);
 X509_ALGOR *PKCS5_pbkdf2_set_ex(int iter, unsigned char *salt, int saltlen,
                                 int prf_nid, int keylen,
                                 OSSL_LIB_CTX *libctx);

=head1 DESCRIPTION

=head2 Key Derivation

PKCS5_PBE_keyivgen() and PKCS5_PBE_keyivgen_ex() take a password I<pass> of
length I<passlen>, parameters I<param> and a message digest function I<md_type>
and performs a key derivation according to PKCS#5 PBES1. The resulting key is
then used to initialise the cipher context I<ctx> with a cipher I<cipher> for
encryption (I<en_de>=1) or decryption (I<en_de>=0).

I<pass> is an optional parameter and can be NULL. If I<passlen> is -1, then the
function will calculate the length of I<pass> using strlen().

PKCS5_v2_PBE_keyivgen() and PKCS5_v2_PBE_keyivgen_ex() are similar to the above
but instead use PKCS#5 PBES2 as the encryption algorithm using the supplied
parameters.

PKCS5_v2_scrypt_keyivgen() and PKCS5_v2_scrypt_keyivgen_ex() use SCRYPT as the
key derivation part of the encryption algorithm.

I<salt> is the salt used in the derivation of length I<saltlen>. If the
I<salt> is NULL, then I<saltlen> must be 0. The function will not
attempt to calculate the length of the I<salt> because it is not assumed to
be NULL terminated.

I<iter> is the iteration count and its value should be greater than or
equal to 1. RFC 2898 suggests an iteration count of at least 1000. Any
I<iter> less than 1 is treated as a single iteration.

I<digest> is the message digest function used in the derivation.

Functions ending in _ex() take optional parameters I<libctx> and I<propq> which
are used to select appropriate algorithm implementations.

=head2 Algorithm Identifier Creation

PKCS5_pbe_set(), PKCS5_pbe_set_ex(), PKCS5_pbe2_set(), PKCS5_pbe2_set_iv(),
PKCS5_pbe2_set_iv_ex() and PKCS5_pbe2_set_scrypt() generate an B<X509_ALGOR>
object which represents an AlgorithmIdentifier containing the algorithm OID and
associated parameters for the PBE algorithm.

PKCS5_pbkdf2_set() and PKCS5_pbkdf2_set_ex() generate an B<X509_ALGOR>
object which represents an AlgorithmIdentifier containing the algorithm OID and
associated parameters for the PBKDF2 algorithm.

PKCS5_pbe_set0_algor() and PKCS5_pbe_set0_algor_ex() set the PBE algorithm OID and
parameters into the supplied B<X509_ALGOR>.

If I<salt> is NULL, then I<saltlen> specifies the size in bytes of the random salt to
generate. If I<saltlen> is 0 then a default size is used.
For PBE related functions such as PKCS5_pbe_set_ex() the default salt length is 8 bytes.
For PBE2 related functions that use PBKDF2 such as PKCS5_pbkdf2_set(),
PKCS5_pbe2_set_scrypt() and PKCS5_pbe2_set() the default salt length is 16 bytes.

=head1 NOTES

The *_keyivgen() functions are typically used in PKCS#12 to encrypt objects.

These functions make no assumption regarding the given password.
It will simply be treated as a byte sequence.

=head1 RETURN VALUES

PKCS5_PBE_keyivgen(), PKCS5_v2_PBE_keyivgen(),
PKCS5_v2_PBE_keyivgen_ex(), PKCS5_v2_scrypt_keyivgen(),
PKCS5_v2_scrypt_keyivgen_ex(), PKCS5_pbe_set0_algor() and
PKCS5_pbe_set0_algor_ex() return 1 for success and 0 if an error occurs.

PKCS5_pbe_set(), PKCS5_pbe_set_ex(), PKCS5_pbe2_set(), PKCS5_pbe2_set_iv(),
PKCS5_pbe2_set_iv_ex(), PKCS5_pbe2_set_scrypt(),
PKCS5_pbkdf2_set() and PKCS5_pbkdf2_set_ex() return an B<X509_ALGOR> object or
NULL if an error occurs.

=head1 CONFORMING TO

IETF RFC 8018 (L<https://tools.ietf.org/html/rfc8018>)

=head1 SEE ALSO

L<EVP_PBE_CipherInit_ex(3)>,
L<PKCS12_pbe_crypt_ex(3)>,
L<passphrase-encoding(7)>

=head1 HISTORY

PKCS5_v2_PBE_keyivgen_ex(), EVP_PBE_scrypt_ex(), PKCS5_v2_scrypt_keyivgen_ex(),
PKCS5_pbe_set0_algor_ex(), PKCS5_pbe_set_ex(), PKCS5_pbe2_set_iv_ex() and
PKCS5_pbkdf2_set_ex() were added in OpenSSL 3.0.

From OpenSSL 3.0 the PBKDF1 algorithm used in PKCS5_PBE_keyivgen() and
PKCS5_PBE_keyivgen_ex() has been moved to the legacy provider as an EVP_KDF.

In OpenSSL 3.2 the default salt length changed from 8 bytes to 16 bytes for PBE2
related functions such as PKCS5_pbe2_set().
This is required for PBKDF2 FIPS compliance.

=head1 COPYRIGHT

Copyright 2021-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
