|  | =pod | 
|  |  | 
|  | =head1 NAME | 
|  |  | 
|  | pem_password_cb, | 
|  | PEM_read_bio_PrivateKey_ex, PEM_read_bio_PrivateKey, | 
|  | PEM_read_PrivateKey_ex, PEM_read_PrivateKey, | 
|  | PEM_write_bio_PrivateKey_ex, PEM_write_bio_PrivateKey, | 
|  | PEM_write_bio_PrivateKey_traditional, | 
|  | PEM_write_PrivateKey_ex, PEM_write_PrivateKey, | 
|  | PEM_write_bio_PKCS8PrivateKey, PEM_write_PKCS8PrivateKey, | 
|  | PEM_write_bio_PKCS8PrivateKey_nid, PEM_write_PKCS8PrivateKey_nid, | 
|  | PEM_read_bio_PUBKEY_ex, PEM_read_bio_PUBKEY, | 
|  | PEM_read_PUBKEY_ex, PEM_read_PUBKEY, | 
|  | PEM_write_bio_PUBKEY_ex, PEM_write_bio_PUBKEY, | 
|  | PEM_write_PUBKEY_ex, PEM_write_PUBKEY, | 
|  | PEM_read_bio_RSAPrivateKey, PEM_read_RSAPrivateKey, | 
|  | PEM_write_bio_RSAPrivateKey, PEM_write_RSAPrivateKey, | 
|  | PEM_read_bio_RSAPublicKey, PEM_read_RSAPublicKey, PEM_write_bio_RSAPublicKey, | 
|  | PEM_write_RSAPublicKey, PEM_read_bio_RSA_PUBKEY, PEM_read_RSA_PUBKEY, | 
|  | PEM_write_bio_RSA_PUBKEY, PEM_write_RSA_PUBKEY, PEM_read_bio_DSAPrivateKey, | 
|  | PEM_read_DSAPrivateKey, PEM_write_bio_DSAPrivateKey, PEM_write_DSAPrivateKey, | 
|  | PEM_read_bio_DSA_PUBKEY, PEM_read_DSA_PUBKEY, PEM_write_bio_DSA_PUBKEY, | 
|  | PEM_write_DSA_PUBKEY, PEM_read_bio_Parameters_ex, PEM_read_bio_Parameters, | 
|  | PEM_write_bio_Parameters, PEM_read_bio_DSAparams, PEM_read_DSAparams, | 
|  | PEM_write_bio_DSAparams, PEM_write_DSAparams, PEM_read_bio_DHparams, | 
|  | PEM_read_DHparams, PEM_write_bio_DHparams, PEM_write_DHparams, | 
|  | PEM_read_bio_X509, PEM_read_X509, PEM_write_bio_X509, PEM_write_X509, | 
|  | PEM_read_bio_X509_AUX, PEM_read_X509_AUX, PEM_write_bio_X509_AUX, | 
|  | PEM_write_X509_AUX, PEM_read_bio_X509_REQ, PEM_read_X509_REQ, | 
|  | PEM_write_bio_X509_REQ, PEM_write_X509_REQ, PEM_write_bio_X509_REQ_NEW, | 
|  | PEM_write_X509_REQ_NEW, PEM_read_bio_X509_CRL, PEM_read_X509_CRL, | 
|  | PEM_write_bio_X509_CRL, PEM_write_X509_CRL, PEM_read_bio_PKCS7, PEM_read_PKCS7, | 
|  | PEM_write_bio_PKCS7, PEM_write_PKCS7 - PEM routines | 
|  |  | 
|  | =head1 SYNOPSIS | 
|  |  | 
|  | #include <openssl/pem.h> | 
|  |  | 
|  | typedef int pem_password_cb(char *buf, int size, int rwflag, void *u); | 
|  |  | 
|  | EVP_PKEY *PEM_read_bio_PrivateKey_ex(BIO *bp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | EVP_PKEY *PEM_read_bio_PrivateKey(BIO *bp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | EVP_PKEY *PEM_read_PrivateKey_ex(FILE *fp, EVP_PKEY **x, pem_password_cb *cb, | 
|  | void *u, OSSL_LIB_CTX *libctx, | 
|  | const char *propq); | 
|  | EVP_PKEY *PEM_read_PrivateKey(FILE *fp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PrivateKey_ex(BIO *bp, const EVP_PKEY *x, | 
|  | const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | int PEM_write_bio_PrivateKey(BIO *bp, const EVP_PKEY *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PrivateKey_traditional(BIO *bp, EVP_PKEY *x, | 
|  | const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_PrivateKey_ex(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | int PEM_write_PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PKCS8PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc, | 
|  | char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_PKCS8PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc, | 
|  | char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PKCS8PrivateKey_nid(BIO *bp, const EVP_PKEY *x, int nid, | 
|  | char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_PKCS8PrivateKey_nid(FILE *fp, const EVP_PKEY *x, int nid, | 
|  | char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  |  | 
|  | EVP_PKEY *PEM_read_bio_PUBKEY_ex(BIO *bp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | EVP_PKEY *PEM_read_bio_PUBKEY(BIO *bp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | EVP_PKEY *PEM_read_PUBKEY_ex(FILE *fp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | EVP_PKEY *PEM_read_PUBKEY(FILE *fp, EVP_PKEY **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PUBKEY_ex(BIO *bp, EVP_PKEY *x, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | int PEM_write_bio_PUBKEY(BIO *bp, EVP_PKEY *x); | 
|  | int PEM_write_PUBKEY_ex(FILE *fp, EVP_PKEY *x, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | int PEM_write_PUBKEY(FILE *fp, EVP_PKEY *x); | 
|  |  | 
|  | EVP_PKEY *PEM_read_bio_Parameters_ex(BIO *bp, EVP_PKEY **x, | 
|  | OSSL_LIB_CTX *libctx, const char *propq); | 
|  | EVP_PKEY *PEM_read_bio_Parameters(BIO *bp, EVP_PKEY **x); | 
|  | int PEM_write_bio_Parameters(BIO *bp, const EVP_PKEY *x); | 
|  |  | 
|  | X509 *PEM_read_bio_X509(BIO *bp, X509 **x, pem_password_cb *cb, void *u); | 
|  | X509 *PEM_read_X509(FILE *fp, X509 **x, pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_X509(BIO *bp, X509 *x); | 
|  | int PEM_write_X509(FILE *fp, X509 *x); | 
|  |  | 
|  | X509 *PEM_read_bio_X509_AUX(BIO *bp, X509 **x, pem_password_cb *cb, void *u); | 
|  | X509 *PEM_read_X509_AUX(FILE *fp, X509 **x, pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_X509_AUX(BIO *bp, X509 *x); | 
|  | int PEM_write_X509_AUX(FILE *fp, X509 *x); | 
|  |  | 
|  | X509_REQ *PEM_read_bio_X509_REQ(BIO *bp, X509_REQ **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | X509_REQ *PEM_read_X509_REQ(FILE *fp, X509_REQ **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_X509_REQ(BIO *bp, X509_REQ *x); | 
|  | int PEM_write_X509_REQ(FILE *fp, X509_REQ *x); | 
|  | int PEM_write_bio_X509_REQ_NEW(BIO *bp, X509_REQ *x); | 
|  | int PEM_write_X509_REQ_NEW(FILE *fp, X509_REQ *x); | 
|  |  | 
|  | X509_CRL *PEM_read_bio_X509_CRL(BIO *bp, X509_CRL **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | X509_CRL *PEM_read_X509_CRL(FILE *fp, X509_CRL **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_X509_CRL(BIO *bp, X509_CRL *x); | 
|  | int PEM_write_X509_CRL(FILE *fp, X509_CRL *x); | 
|  |  | 
|  | PKCS7 *PEM_read_bio_PKCS7(BIO *bp, PKCS7 **x, pem_password_cb *cb, void *u); | 
|  | PKCS7 *PEM_read_PKCS7(FILE *fp, PKCS7 **x, pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_PKCS7(BIO *bp, PKCS7 *x); | 
|  | int PEM_write_PKCS7(FILE *fp, PKCS7 *x); | 
|  |  | 
|  | The following functions have been deprecated since OpenSSL 3.0, and can be | 
|  | hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, | 
|  | see L<openssl_user_macros(7)>: | 
|  |  | 
|  | RSA *PEM_read_bio_RSAPrivateKey(BIO *bp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_RSAPrivateKey(BIO *bp, RSA *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_RSAPrivateKey(FILE *fp, RSA *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  |  | 
|  | RSA *PEM_read_bio_RSAPublicKey(BIO *bp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | RSA *PEM_read_RSAPublicKey(FILE *fp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_RSAPublicKey(BIO *bp, RSA *x); | 
|  | int PEM_write_RSAPublicKey(FILE *fp, RSA *x); | 
|  |  | 
|  | RSA *PEM_read_bio_RSA_PUBKEY(BIO *bp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | RSA *PEM_read_RSA_PUBKEY(FILE *fp, RSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_RSA_PUBKEY(BIO *bp, RSA *x); | 
|  | int PEM_write_RSA_PUBKEY(FILE *fp, RSA *x); | 
|  |  | 
|  | DSA *PEM_read_bio_DSAPrivateKey(BIO *bp, DSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | DSA *PEM_read_DSAPrivateKey(FILE *fp, DSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_DSAPrivateKey(BIO *bp, DSA *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_DSAPrivateKey(FILE *fp, DSA *x, const EVP_CIPHER *enc, | 
|  | unsigned char *kstr, int klen, | 
|  | pem_password_cb *cb, void *u); | 
|  |  | 
|  | DSA *PEM_read_bio_DSA_PUBKEY(BIO *bp, DSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | DSA *PEM_read_DSA_PUBKEY(FILE *fp, DSA **x, | 
|  | pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_DSA_PUBKEY(BIO *bp, DSA *x); | 
|  | int PEM_write_DSA_PUBKEY(FILE *fp, DSA *x); | 
|  | DSA *PEM_read_bio_DSAparams(BIO *bp, DSA **x, pem_password_cb *cb, void *u); | 
|  | DSA *PEM_read_DSAparams(FILE *fp, DSA **x, pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_DSAparams(BIO *bp, DSA *x); | 
|  | int PEM_write_DSAparams(FILE *fp, DSA *x); | 
|  |  | 
|  | DH *PEM_read_bio_DHparams(BIO *bp, DH **x, pem_password_cb *cb, void *u); | 
|  | DH *PEM_read_DHparams(FILE *fp, DH **x, pem_password_cb *cb, void *u); | 
|  | int PEM_write_bio_DHparams(BIO *bp, DH *x); | 
|  | int PEM_write_DHparams(FILE *fp, DH *x); | 
|  |  | 
|  | =head1 DESCRIPTION | 
|  |  | 
|  | All of the functions described on this page that have a I<TYPE> of B<DH>, B<DSA> | 
|  | and B<RSA> are deprecated. Applications should use OSSL_ENCODER_to_bio() and | 
|  | OSSL_DECODER_from_bio() instead. | 
|  |  | 
|  | The PEM functions read or write structures in PEM format. In | 
|  | this sense PEM format is simply base64 encoded data surrounded | 
|  | by header lines. | 
|  |  | 
|  | For more details about the meaning of arguments see the | 
|  | B<PEM FUNCTION ARGUMENTS> section. | 
|  |  | 
|  | Each operation has four functions associated with it. For | 
|  | brevity the term "B<I<TYPE>> functions" will be used below to collectively | 
|  | refer to the B<PEM_read_bio_I<TYPE>>(), B<PEM_read_I<TYPE>>(), | 
|  | B<PEM_write_bio_I<TYPE>>(), and B<PEM_write_I<TYPE>>() functions. | 
|  |  | 
|  | Some operations have additional variants that take a library context I<libctx> | 
|  | and a property query string I<propq>. The B<X509>, B<X509_REQ> and B<X509_CRL> | 
|  | objects may have an associated library context or property query string but | 
|  | there are no variants of these functions that take a library context or property | 
|  | query string parameter. In this case it is possible to set the appropriate | 
|  | library context or property query string by creating an empty B<X509>, | 
|  | B<X509_REQ> or B<X509_CRL> object using L<X509_new_ex(3)>, L<X509_REQ_new_ex(3)> | 
|  | or L<X509_CRL_new_ex(3)> respectively. Then pass the empty object as a parameter | 
|  | to the relevant PEM function. See the L</EXAMPLES> section below. | 
|  |  | 
|  | The B<PrivateKey> functions read or write a private key in PEM format using | 
|  | an EVP_PKEY structure. The write routines use PKCS#8 private key format and are | 
|  | equivalent to PEM_write_bio_PKCS8PrivateKey(). The read functions transparently | 
|  | handle traditional and PKCS#8 format encrypted and unencrypted keys. | 
|  |  | 
|  | PEM_write_bio_PrivateKey_traditional() writes out a private key in the | 
|  | "traditional" format with a simple private key marker and should only | 
|  | be used for compatibility with legacy programs. | 
|  |  | 
|  | PEM_write_bio_PKCS8PrivateKey() and PEM_write_PKCS8PrivateKey() write a private | 
|  | key in an EVP_PKEY structure in PKCS#8 EncryptedPrivateKeyInfo format using | 
|  | PKCS#5 v2.0 password based encryption algorithms. The I<cipher> argument | 
|  | specifies the encryption algorithm to use: unlike some other PEM routines the | 
|  | encryption is applied at the PKCS#8 level and not in the PEM headers. If | 
|  | I<cipher> is NULL then no encryption is used and a PKCS#8 PrivateKeyInfo | 
|  | structure is used instead. | 
|  |  | 
|  | PEM_write_bio_PKCS8PrivateKey_nid() and PEM_write_PKCS8PrivateKey_nid() | 
|  | also write out a private key as a PKCS#8 EncryptedPrivateKeyInfo however | 
|  | it uses PKCS#5 v1.5 or PKCS#12 encryption algorithms instead. The algorithm | 
|  | to use is specified in the I<nid> parameter and should be the NID of the | 
|  | corresponding OBJECT IDENTIFIER (see NOTES section). | 
|  |  | 
|  | The B<PUBKEY> functions process a public key using an EVP_PKEY | 
|  | structure. The public key is encoded as a SubjectPublicKeyInfo | 
|  | structure. | 
|  |  | 
|  | The B<RSAPrivateKey> functions process an RSA private key using an | 
|  | RSA structure. The write routines uses traditional format. The read | 
|  | routines handles the same formats as the B<PrivateKey> | 
|  | functions but an error occurs if the private key is not RSA. | 
|  |  | 
|  | The B<RSAPublicKey> functions process an RSA public key using an | 
|  | RSA structure. The public key is encoded using a PKCS#1 RSAPublicKey | 
|  | structure. | 
|  |  | 
|  | The B<RSA_PUBKEY> functions also process an RSA public key using | 
|  | an RSA structure. However, the public key is encoded using a | 
|  | SubjectPublicKeyInfo structure and an error occurs if the public | 
|  | key is not RSA. | 
|  |  | 
|  | The B<DSAPrivateKey> functions process a DSA private key using a | 
|  | DSA structure. The write routines uses traditional format. The read | 
|  | routines handles the same formats as the B<PrivateKey> | 
|  | functions but an error occurs if the private key is not DSA. | 
|  |  | 
|  | The B<DSA_PUBKEY> functions process a DSA public key using | 
|  | a DSA structure. The public key is encoded using a | 
|  | SubjectPublicKeyInfo structure and an error occurs if the public | 
|  | key is not DSA. | 
|  |  | 
|  | The B<Parameters> functions read or write key parameters in PEM format using | 
|  | an EVP_PKEY structure.  The encoding depends on the type of key; for DSA key | 
|  | parameters, it will be a Dss-Parms structure as defined in RFC2459, and for DH | 
|  | key parameters, it will be a PKCS#3 DHparameter structure.  I<These functions | 
|  | only exist for the B<BIO> type>. | 
|  |  | 
|  | The B<DSAparams> functions process DSA parameters using a DSA | 
|  | structure. The parameters are encoded using a Dss-Parms structure | 
|  | as defined in RFC2459. | 
|  |  | 
|  | The B<DHparams> functions process DH parameters using a DH | 
|  | structure. The parameters are encoded using a PKCS#3 DHparameter | 
|  | structure. | 
|  |  | 
|  | The B<X509> functions process an X509 certificate using an X509 | 
|  | structure. They will also process a trusted X509 certificate but | 
|  | any trust settings are discarded. | 
|  |  | 
|  | The B<X509_AUX> functions process a trusted X509 certificate using | 
|  | an X509 structure. | 
|  |  | 
|  | The B<X509_REQ> and B<X509_REQ_NEW> functions process a PKCS#10 | 
|  | certificate request using an X509_REQ structure. The B<X509_REQ> | 
|  | write functions use B<CERTIFICATE REQUEST> in the header whereas | 
|  | the B<X509_REQ_NEW> functions use B<NEW CERTIFICATE REQUEST> | 
|  | (as required by some CAs). The B<X509_REQ> read functions will | 
|  | handle either form so there are no B<X509_REQ_NEW> read functions. | 
|  |  | 
|  | The B<X509_CRL> functions process an X509 CRL using an X509_CRL | 
|  | structure. | 
|  |  | 
|  | The B<PKCS7> functions process a PKCS#7 ContentInfo using a PKCS7 | 
|  | structure. | 
|  |  | 
|  | =head1 PEM FUNCTION ARGUMENTS | 
|  |  | 
|  | The PEM functions have many common arguments. | 
|  |  | 
|  | The I<bp> BIO parameter (if present) specifies the BIO to read from | 
|  | or write to. | 
|  |  | 
|  | The I<fp> FILE parameter (if present) specifies the FILE pointer to | 
|  | read from or write to. | 
|  |  | 
|  | The PEM read functions all take an argument I<B<TYPE> **x> and return | 
|  | a I<B<TYPE> *> pointer. Where I<B<TYPE>> is whatever structure the function | 
|  | uses. If I<x> is NULL then the parameter is ignored. If I<x> is not | 
|  | NULL but I<*x> is NULL then the structure returned will be written | 
|  | to I<*x>. If neither I<x> nor I<*x> is NULL then an attempt is made | 
|  | to reuse the structure at I<*x> (but see BUGS and EXAMPLES sections). | 
|  | Irrespective of the value of I<x> a pointer to the structure is always | 
|  | returned (or NULL if an error occurred). | 
|  |  | 
|  | The PEM functions which write private keys take an I<enc> parameter | 
|  | which specifies the encryption algorithm to use, encryption is done | 
|  | at the PEM level. If this parameter is set to NULL then the private | 
|  | key is written in unencrypted form. | 
|  |  | 
|  | The I<cb> argument is the callback to use when querying for the pass | 
|  | phrase used for encrypted PEM structures (normally only private keys). | 
|  |  | 
|  | For the PEM write routines if the I<kstr> parameter is not NULL then | 
|  | I<klen> bytes at I<kstr> are used as the passphrase and I<cb> is | 
|  | ignored. | 
|  |  | 
|  | If the I<cb> parameters is set to NULL and the I<u> parameter is not | 
|  | NULL then the I<u> parameter is interpreted as a NUL terminated string | 
|  | to use as the passphrase. If both I<cb> and I<u> are NULL then the | 
|  | default callback routine is used which will typically prompt for the | 
|  | passphrase on the current terminal with echoing turned off. | 
|  |  | 
|  | The default passphrase callback is sometimes inappropriate (for example | 
|  | in a GUI application) so an alternative can be supplied. The callback | 
|  | routine has the following form: | 
|  |  | 
|  | int cb(char *buf, int size, int rwflag, void *u); | 
|  |  | 
|  | I<buf> is the buffer to write the passphrase to. I<size> is the maximum | 
|  | length of the passphrase (i.e. the size of buf). I<rwflag> is a flag | 
|  | which is set to 0 when reading and 1 when writing. A typical routine | 
|  | will ask the user to verify the passphrase (for example by prompting | 
|  | for it twice) if I<rwflag> is 1. The I<u> parameter has the same | 
|  | value as the I<u> parameter passed to the PEM routine. It allows | 
|  | arbitrary data to be passed to the callback by the application | 
|  | (for example a window handle in a GUI application). The callback | 
|  | I<must> return the number of characters in the passphrase or -1 if | 
|  | an error occurred. The passphrase can be arbitrary data; in the case where it | 
|  | is a string, it is not NUL terminated. See the L</EXAMPLES> section below. | 
|  |  | 
|  | Some implementations may need to use cryptographic algorithms during their | 
|  | operation. If this is the case and I<libctx> and I<propq> parameters have been | 
|  | passed then any algorithm fetches will use that library context and property | 
|  | query string. Otherwise the default library context and property query string | 
|  | will be used. | 
|  |  | 
|  | =head1 NOTES | 
|  |  | 
|  | The PEM reading functions will skip any extraneous content or PEM data of | 
|  | a different type than they expect. This allows for example having a certificate | 
|  | (or multiple certificates) and a key in the PEM format in a single file. | 
|  |  | 
|  | The old B<PrivateKey> write routines are retained for compatibility. | 
|  | New applications should write private keys using the | 
|  | PEM_write_bio_PKCS8PrivateKey() or PEM_write_PKCS8PrivateKey() routines | 
|  | because they are more secure (they use an iteration count of 2048 whereas | 
|  | the traditional routines use a count of 1) unless compatibility with older | 
|  | versions of OpenSSL is important. | 
|  |  | 
|  | The B<PrivateKey> read routines can be used in all applications because | 
|  | they handle all formats transparently. | 
|  |  | 
|  | A frequent cause of problems is attempting to use the PEM routines like | 
|  | this: | 
|  |  | 
|  | X509 *x; | 
|  |  | 
|  | PEM_read_bio_X509(bp, &x, 0, NULL); | 
|  |  | 
|  | this is a bug because an attempt will be made to reuse the data at I<x> | 
|  | which is an uninitialised pointer. | 
|  |  | 
|  | These functions make no assumption regarding the pass phrase received from the | 
|  | password callback. | 
|  | It will simply be treated as a byte sequence. | 
|  |  | 
|  | =head1 PEM ENCRYPTION FORMAT | 
|  |  | 
|  | These old B<PrivateKey> routines use a non standard technique for encryption. | 
|  |  | 
|  | The private key (or other data) takes the following form: | 
|  |  | 
|  | -----BEGIN RSA PRIVATE KEY----- | 
|  | Proc-Type: 4,ENCRYPTED | 
|  | DEK-Info: DES-EDE3-CBC,3F17F5316E2BAC89 | 
|  |  | 
|  | ...base64 encoded data... | 
|  | -----END RSA PRIVATE KEY----- | 
|  |  | 
|  | The line beginning with I<Proc-Type> contains the version and the | 
|  | protection on the encapsulated data. The line beginning I<DEK-Info> | 
|  | contains two comma separated values: the encryption algorithm name as | 
|  | used by EVP_get_cipherbyname() and an initialization vector used by the | 
|  | cipher encoded as a set of hexadecimal digits. After those two lines is | 
|  | the base64-encoded encrypted data. | 
|  |  | 
|  | The encryption key is derived using EVP_BytesToKey(). The cipher's | 
|  | initialization vector is passed to EVP_BytesToKey() as the I<salt> | 
|  | parameter. Internally, B<PKCS5_SALT_LEN> bytes of the salt are used | 
|  | (regardless of the size of the initialization vector). The user's | 
|  | password is passed to EVP_BytesToKey() using the I<data> and I<datal> | 
|  | parameters. Finally, the library uses an iteration count of 1 for | 
|  | EVP_BytesToKey(). | 
|  |  | 
|  | The I<key> derived by EVP_BytesToKey() along with the original initialization | 
|  | vector is then used to decrypt the encrypted data. The I<iv> produced by | 
|  | EVP_BytesToKey() is not utilized or needed, and NULL should be passed to | 
|  | the function. | 
|  |  | 
|  | The pseudo code to derive the key would look similar to: | 
|  |  | 
|  | EVP_CIPHER* cipher = EVP_des_ede3_cbc(); | 
|  | EVP_MD* md = EVP_md5(); | 
|  |  | 
|  | unsigned int nkey = EVP_CIPHER_get_key_length(cipher); | 
|  | unsigned int niv = EVP_CIPHER_get_iv_length(cipher); | 
|  | unsigned char key[nkey]; | 
|  | unsigned char iv[niv]; | 
|  |  | 
|  | memcpy(iv, HexToBin("3F17F5316E2BAC89"), niv); | 
|  | rc = EVP_BytesToKey(cipher, md, iv /*salt*/, pword, plen, 1, key, NULL /*iv*/); | 
|  | if (rc != nkey) | 
|  | /* Error */ | 
|  |  | 
|  | /* On success, use key and iv to initialize the cipher */ | 
|  |  | 
|  | =head1 BUGS | 
|  |  | 
|  | The PEM read routines in some versions of OpenSSL will not correctly reuse | 
|  | an existing structure. Therefore, the following: | 
|  |  | 
|  | PEM_read_bio_X509(bp, &x, 0, NULL); | 
|  |  | 
|  | where I<x> already contains a valid certificate, may not work, whereas: | 
|  |  | 
|  | X509_free(x); | 
|  | x = PEM_read_bio_X509(bp, NULL, 0, NULL); | 
|  |  | 
|  | is guaranteed to work. It is always acceptable for I<x> to contain a newly | 
|  | allocated, empty B<X509> object (for example allocated via L<X509_new_ex(3)>). | 
|  |  | 
|  | =head1 RETURN VALUES | 
|  |  | 
|  | The read routines return either a pointer to the structure read or NULL | 
|  | if an error occurred. | 
|  |  | 
|  | The write routines return 1 for success or 0 for failure. | 
|  |  | 
|  | =head1 EXAMPLES | 
|  |  | 
|  | Although the PEM routines take several arguments in almost all applications | 
|  | most of them are set to 0 or NULL. | 
|  |  | 
|  | To read a certificate with a library context in PEM format from a BIO: | 
|  |  | 
|  | X509 *x = X509_new_ex(libctx, NULL); | 
|  |  | 
|  | if (x == NULL) | 
|  | /* Error */ | 
|  |  | 
|  | if (PEM_read_bio_X509(bp, &x, 0, NULL) == NULL) | 
|  | /* Error */ | 
|  |  | 
|  | Read a certificate in PEM format from a BIO: | 
|  |  | 
|  | X509 *x; | 
|  |  | 
|  | x = PEM_read_bio_X509(bp, NULL, 0, NULL); | 
|  | if (x == NULL) | 
|  | /* Error */ | 
|  |  | 
|  | Alternative method: | 
|  |  | 
|  | X509 *x = NULL; | 
|  |  | 
|  | if (!PEM_read_bio_X509(bp, &x, 0, NULL)) | 
|  | /* Error */ | 
|  |  | 
|  | Write a certificate to a BIO: | 
|  |  | 
|  | if (!PEM_write_bio_X509(bp, x)) | 
|  | /* Error */ | 
|  |  | 
|  | Write a private key (using traditional format) to a BIO using | 
|  | triple DES encryption, the pass phrase is prompted for: | 
|  |  | 
|  | if (!PEM_write_bio_PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, NULL)) | 
|  | /* Error */ | 
|  |  | 
|  | Write a private key (using PKCS#8 format) to a BIO using triple | 
|  | DES encryption, using the pass phrase "hello": | 
|  |  | 
|  | if (!PEM_write_bio_PKCS8PrivateKey(bp, key, EVP_des_ede3_cbc(), | 
|  | NULL, 0, 0, "hello")) | 
|  | /* Error */ | 
|  |  | 
|  | Read a private key from a BIO using a pass phrase callback: | 
|  |  | 
|  | key = PEM_read_bio_PrivateKey(bp, NULL, pass_cb, "My Private Key"); | 
|  | if (key == NULL) | 
|  | /* Error */ | 
|  |  | 
|  | Skeleton pass phrase callback: | 
|  |  | 
|  | int pass_cb(char *buf, int size, int rwflag, void *u) | 
|  | { | 
|  |  | 
|  | /* We'd probably do something else if 'rwflag' is 1 */ | 
|  | printf("Enter pass phrase for \"%s\"\n", (char *)u); | 
|  |  | 
|  | /* get pass phrase, length 'len' into 'tmp' */ | 
|  | char *tmp = "hello"; | 
|  | if (tmp == NULL) /* An error occurred */ | 
|  | return -1; | 
|  |  | 
|  | size_t len = strlen(tmp); | 
|  |  | 
|  | if (len > size) | 
|  | len = size; | 
|  | memcpy(buf, tmp, len); | 
|  | return len; | 
|  | } | 
|  |  | 
|  | =head1 SEE ALSO | 
|  |  | 
|  | L<EVP_EncryptInit(3)>, L<EVP_BytesToKey(3)>, | 
|  | L<passphrase-encoding(7)> | 
|  |  | 
|  | =head1 HISTORY | 
|  |  | 
|  | The old Netscape certificate sequences were no longer documented | 
|  | in OpenSSL 1.1.0; applications should use the PKCS7 standard instead | 
|  | as they will be formally deprecated in a future releases. | 
|  |  | 
|  | PEM_read_bio_PrivateKey_ex(), PEM_read_PrivateKey_ex(), | 
|  | PEM_read_bio_PUBKEY_ex(), PEM_read_PUBKEY_ex() and | 
|  | PEM_read_bio_Parameters_ex() were introduced in OpenSSL 3.0. | 
|  |  | 
|  | The functions PEM_read_bio_RSAPrivateKey(), PEM_read_RSAPrivateKey(), | 
|  | PEM_write_bio_RSAPrivateKey(), PEM_write_RSAPrivateKey(), | 
|  | PEM_read_bio_RSAPublicKey(), PEM_read_RSAPublicKey(), | 
|  | PEM_write_bio_RSAPublicKey(), PEM_write_RSAPublicKey(), | 
|  | PEM_read_bio_RSA_PUBKEY(), PEM_read_RSA_PUBKEY(), | 
|  | PEM_write_bio_RSA_PUBKEY(), PEM_write_RSA_PUBKEY(), | 
|  | PEM_read_bio_DSAPrivateKey(), PEM_read_DSAPrivateKey(), | 
|  | PEM_write_bio_DSAPrivateKey(), PEM_write_DSAPrivateKey(), | 
|  | PEM_read_bio_DSA_PUBKEY(), PEM_read_DSA_PUBKEY(), | 
|  | PEM_write_bio_DSA_PUBKEY(), PEM_write_DSA_PUBKEY(); | 
|  | PEM_read_bio_DSAparams(), PEM_read_DSAparams(), | 
|  | PEM_write_bio_DSAparams(), PEM_write_DSAparams(), | 
|  | PEM_read_bio_DHparams(), PEM_read_DHparams(), | 
|  | PEM_write_bio_DHparams() and PEM_write_DHparams() were deprecated in 3.0. | 
|  |  | 
|  |  | 
|  | =head1 COPYRIGHT | 
|  |  | 
|  | Copyright 2001-2021 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 |