pem(3) OpenSSL pem(3) NNAAMMEE PEM, PEM_read_bio_PrivateKey, PEM_read_PrivateKey, PEM_write_bio_Pri- vateKey, PEM_write_PrivateKey, PEM_write_bio_PKCS8PrivateKey, PEM_write_PKCS8PrivateKey, PEM_write_bio_PKCS8PrivateKey_nid, PEM_write_PKCS8PrivateKey_nid, PEM_read_bio_PUBKEY, PEM_read_PUBKEY, PEM_write_bio_PUBKEY, PEM_write_PUBKEY, PEM_read_bio_RSAPrivateKey, PEM_read_RSAPrivateKey, PEM_write_bio_RSAPrivateKey, PEM_write_RSAPri- vateKey, 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_DSAPri- vateKey, 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, 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_read_bio_NET- SCAPE_CERT_SEQUENCE, PEM_read_NETSCAPE_CERT_SEQUENCE, PEM_write_bio_NETSCAPE_CERT_SEQUENCE, PEM_write_NETSCAPE_CERT_SEQUENCE - PEM routines SSYYNNOOPPSSIISS #include EVP_PKEY *PEM_read_bio_PrivateKey(BIO *bp, EVP_PKEY **x, pem_password_cb *cb, void *u); EVP_PKEY *PEM_read_PrivateKey(FILE *fp, EVP_PKEY **x, pem_password_cb *cb, void *u); int PEM_write_bio_PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc, unsigned char *kstr, int klen, pem_password_cb *cb, void *u); 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, EVP_PKEY *x, int nid, char *kstr, int klen, pem_password_cb *cb, void *u); int PEM_write_PKCS8PrivateKey_nid(FILE *fp, EVP_PKEY *x, int nid, char *kstr, int klen, pem_password_cb *cb, void *u); EVP_PKEY *PEM_read_bio_PUBKEY(BIO *bp, EVP_PKEY **x, pem_password_cb *cb, void *u); EVP_PKEY *PEM_read_PUBKEY(FILE *fp, EVP_PKEY **x, pem_password_cb *cb, void *u); int PEM_write_bio_PUBKEY(BIO *bp, EVP_PKEY *x); int PEM_write_PUBKEY(FILE *fp, EVP_PKEY *x); 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); 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); NETSCAPE_CERT_SEQUENCE *PEM_read_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp, NETSCAPE_CERT_SEQUENCE **x, pem_password_cb *cb, void *u); NETSCAPE_CERT_SEQUENCE *PEM_read_NETSCAPE_CERT_SEQUENCE(FILE *fp, NETSCAPE_CERT_SEQUENCE **x, pem_password_cb *cb, void *u); int PEM_write_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp, NETSCAPE_CERT_SEQUENCE *x); int PEM_write_NETSCAPE_CERT_SEQUENCE(FILE *fp, NETSCAPE_CERT_SEQUENCE *x); DDEESSCCRRIIPPTTIIOONN 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 PPEEMM FFUUNNCCTTIIOONN AARRGGUUMMEENNTTSS section. Each operation has four functions associated with it. For clarity the term "ffoooobbaarr functions" will be used to collectively refer to the _P_E_M___r_e_a_d___b_i_o___f_o_o_b_a_r_(_), _P_E_M___r_e_a_d___f_o_o_b_a_r_(_), _P_E_M___w_r_i_t_e___b_i_o___f_o_o_b_a_r_(_) and _P_E_M___w_r_i_t_e___f_o_o_b_a_r_(_) functions. The PPrriivvaatteeKKeeyy functions read or write a private key in PEM format using an EVP_PKEY structure. The write routines use "traditional" pri- vate key format and can handle both RSA and DSA private keys. The read functions can additionally transparently handle PKCS#8 format encrypted and unencrypted keys too. _P_E_M___w_r_i_t_e___b_i_o___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y_(_) and _P_E_M___w_r_i_t_e___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y_(_) write a private key in an EVP_PKEY structure in PKCS#8 EncryptedPrivateKeyInfo format using PKCS#5 v2.0 password based encryption algorithms. The cciipphheerr argument specifies the encryption algorithm to use: unlike all other PEM routines the encryption is applied at the PKCS#8 level and not in the PEM headers. If cciipphheerr is NULL then no encryption is used and a PKCS#8 PrivateKeyInfo structure is used instead. _P_E_M___w_r_i_t_e___b_i_o___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y___n_i_d_(_) and _P_E_M___w_r_i_t_e___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y___n_i_d_(_) also write out a private key as a PKCS#8 EncryptedPrivateKeyInfo how- ever it uses PKCS#5 v1.5 or PKCS#12 encryption algorithms instead. The algorithm to use is specified in the nniidd parameter and should be the NID of the corresponding OBJECT IDENTIFIER (see NOTES section). The PPUUBBKKEEYY functions process a public key using an EVP_PKEY structure. The public key is encoded as a SubjectPublicKeyInfo structure. The RRSSAAPPrriivvaatteeKKeeyy functions process an RSA private key using an RSA structure. It handles the same formats as the PPrriivvaatteeKKeeyy functions but an error occurs if the private key is not RSA. The RRSSAAPPuubblliiccKKeeyy functions process an RSA public key using an RSA structure. The public key is encoded using a PKCS#1 RSAPublicKey struc- ture. The RRSSAA__PPUUBBKKEEYY functions also process an RSA public key using an RSA structure. However the public key is encoded using a SubjectPublicKey- Info structure and an error occurs if the public key is not RSA. The DDSSAAPPrriivvaatteeKKeeyy functions process a DSA private key using a DSA structure. It handles the same formats as the PPrriivvaatteeKKeeyy functions but an error occurs if the private key is not DSA. The DDSSAA__PPUUBBKKEEYY functions process a DSA public key using a DSA struc- ture. The public key is encoded using a SubjectPublicKeyInfo structure and an error occurs if the public key is not DSA. The DDSSAAppaarraammss functions process DSA parameters using a DSA structure. The parameters are encoded using a Dss-Parms structure as defined in RFC2459. The DDHHppaarraammss functions process DH parameters using a DH structure. The parameters are encoded using a PKCS#3 DHparameter structure. The XX550099 functions process an X509 certificate using an X509 structure. They will also process a trusted X509 certificate but any trust set- tings are discarded. The XX550099__AAUUXX functions process a trusted X509 certificate using an X509 structure. The XX550099__RREEQQ and XX550099__RREEQQ__NNEEWW functions process a PKCS#10 certificate request using an X509_REQ structure. The XX550099__RREEQQ write functions use CCEERRTTIIFFIICCAATTEE RREEQQUUEESSTT in the header whereas the XX550099__RREEQQ__NNEEWW functions use NNEEWW CCEERRTTIIFFIICCAATTEE RREEQQUUEESSTT (as required by some CAs). The XX550099__RREEQQ read functions will handle either form so there are no XX550099__RREEQQ__NNEEWW read functions. The XX550099__CCRRLL functions process an X509 CRL using an X509_CRL structure. The PPKKCCSS77 functions process a PKCS#7 ContentInfo using a PKCS7 struc- ture. The NNEETTSSCCAAPPEE__CCEERRTT__SSEEQQUUEENNCCEE functions process a Netscape Certificate Sequence using a NETSCAPE_CERT_SEQUENCE structure. PPEEMM FFUUNNCCTTIIOONN AARRGGUUMMEENNTTSS The PEM functions have many common arguments. The bbpp BIO parameter (if present) specifies the BIO to read from or write to. The ffpp FILE parameter (if present) specifies the FILE pointer to read from or write to. The PEM read functions all take an argument TTYYPPEE ****xx and return a TTYYPPEE ** pointer. Where TTYYPPEE is whatever structure the function uses. If xx is NULL then the parameter is ignored. If xx is not NULL but **xx is NULL then the structure returned will be written to **xx. If neither xx nor **xx is NULL then an attempt is made to reuse the structure at **xx (but see BUGS and EXAMPLES sections). Irrespective of the value of xx a pointer to the structure is always returned (or NULL if an error occurred). The PEM functions which write private keys take an eenncc 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 ccbb 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 kkssttrr parameter is not NULL then kklleenn bytes at kkssttrr are used as the passphrase and ccbb is ignored. If the ccbb parameters is set to NULL and the uu parameter is not NULL then the uu parameter is interpreted as a null terminated string to use as the passphrase. If both ccbb and uu 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); bbuuff is the buffer to write the passphrase to. ssiizzee is the maximum length of the passphrase (i.e. the size of buf). rrwwffllaagg 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 rrwwffllaagg is 1. The uu parameter has the same value as the uu 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 mmuusstt return the number of charac- ters in the passphrase or -1 if an error occurred. EEXXAAMMPPLLEESS Although the PEM routines take several arguments in almost all applica- tions most of them are set to 0 or NULL. 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 an unencrypted private key to a FILE pointer: if (!PEM_write_PrivateKey(fp, key, NULL, NULL, 0, 0, NULL)) { /* 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 the pass phrase "hello": key = PEM_read_bio_PrivateKey(bp, NULL, 0, "hello"); if (key == NULL) { /* 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", 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; } NNOOTTEESS The old PPrriivvaatteeKKeeyy write routines are retained for compatibility. New applications should write private keys using the _P_E_M___w_r_i_t_e___b_i_o___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y_(_) or _P_E_M___w_r_i_t_e___P_K_C_S_8_P_r_i_v_a_t_e_K_e_y_(_) 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 PPrriivvaatteeKKeeyy 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 xx which is an uninitialised pointer. PPEEMM EENNCCRRYYPPTTIIOONN FFOORRMMAATT This old PPrriivvaatteeKKeeyy routines use a non standard technique for encryp- tion. 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 DEK-Info contains two comma separated pieces of information: the encryption algorithm name as used by _E_V_P___g_e_t___c_i_p_h_e_r_b_y_- _n_a_m_e_(_) and an 8 byte ssaalltt encoded as a set of hexadecimal digits. After this is the base64 encoded encrypted data. The encryption key is determined using _E_V_P___B_y_t_e_s_T_o_K_e_y_(_), using ssaalltt and an iteration count of 1. The IV used is the value of ssaalltt and *not* the IV returned by _E_V_P___B_y_t_e_s_T_o_K_e_y_(_). BBUUGGSS 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 xx 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. RREETTUURRNN CCOODDEESS 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. SSEEEE AALLSSOO _E_V_P___g_e_t___c_i_p_h_e_r_b_y_n_a_m_e(3), _E_V_P___B_y_t_e_s_T_o_K_e_y(3) 1.0.2u 2019-12-20 pem(3)