NAME
PEM - PEM routines
SYNOPSIS
#include
EVPPKEY *PEMreadbioPrivateKey(BIO *bp, EVPPKEY **x,pempasswordcb *cb, void *u);
EVPPKEY *PEMreadPrivateKey(FILE *fp, EVPPKEY **x,pempasswordcb *cb, void *u);
int PEMwritebioPrivateKey(BIO *bp, EVPPKEY *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwritePrivateKey(FILE *fp, EVPPKEY *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwritebioPKCS8PrivateKey(BIO *bp, EVPPKEY *x, const EVPCIPHER *enc, char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwritePKCS8PrivateKey(FILE *fp, EVPPKEY *x, const EVPCIPHER *enc, char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwritebioPKCS8PrivateKeynid(BIO *bp, EVPPKEY *x, int nid, char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwritePKCS8PrivateKeynid(FILE *fp, EVPPKEY *x, int nid, char *kstr, int klen,pempasswordcb *cb, void *u);
EVPPKEY *PEMreadbioPUBKEY(BIO *bp, EVPPKEY **x,pempasswordcb *cb, void *u);
EVPPKEY *PEMreadPUBKEY(FILE *fp, EVPPKEY **x,pempasswordcb *cb, void *u);
int PEMwritebioPUBKEY(BIO *bp, EVPPKEY *x); int PEMwritePUBKEY(FILE *fp, EVPPKEY *x); RSA *PEMreadbioRSAPrivateKey(BIO *bp, RSA **x,pempasswordcb *cb, void *u);
RSA *PEMreadRSAPrivateKey(FILE *fp, RSA **x,pempasswordcb *cb, void *u);
int PEMwritebioRSAPrivateKey(BIO *bp, RSA *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwriteRSAPrivateKey(FILE *fp, RSA *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
RSA *PEMreadbioRSAPublicKey(BIO *bp, RSA **x,pempasswordcb *cb, void *u);
RSA *PEMreadRSAPublicKey(FILE *fp, RSA **x,pempasswordcb *cb, void *u);
int PEMwritebioRSAPublicKey(BIO *bp, RSA *x); int PEMwriteRSAPublicKey(FILE *fp, RSA *x); RSA *PEMreadbioRSAPUBKEY(BIO *bp, RSA **x,pempasswordcb *cb, void *u);
RSA *PEMreadRSAPUBKEY(FILE *fp, RSA **x,pempasswordcb *cb, void *u);
int PEMwritebioRSAPUBKEY(BIO *bp, RSA *x); int PEMwriteRSAPUBKEY(FILE *fp, RSA *x); DSA *PEMreadbioDSAPrivateKey(BIO *bp, DSA **x,pempasswordcb *cb, void *u);
DSA *PEMreadDSAPrivateKey(FILE *fp, DSA **x,pempasswordcb *cb, void *u);
int PEMwritebioDSAPrivateKey(BIO *bp, DSA *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
int PEMwriteDSAPrivateKey(FILE *fp, DSA *x, const EVPCIPHER *enc, unsigned char *kstr, int klen,pempasswordcb *cb, void *u);
DSA *PEMreadbioDSAPUBKEY(BIO *bp, DSA **x,pempasswordcb *cb, void *u);
DSA *PEMreadDSAPUBKEY(FILE *fp, DSA **x,pempasswordcb *cb, void *u);
int PEMwritebioDSAPUBKEY(BIO *bp, DSA *x); int PEMwriteDSAPUBKEY(FILE *fp, DSA *x);DSA *PEMreadbioDSAparams(BIO *bp, DSA **x, pempasswordcb *cb, void *u);
DSA *PEMreadDSAparams(FILE *fp, DSA **x, pempasswordcb *cb, void *u);
int PEMwritebioDSAparams(BIO *bp, DSA *x); int PEMwriteDSAparams(FILE *fp, DSA *x);DH *PEMreadbioDHparams(BIO *bp, DH **x, pempasswordcb *cb, void *u);
DH *PEMreadDHparams(FILE *fp, DH **x, pempasswordcb *cb, void *u);
int PEMwritebioDHparams(BIO *bp, DH *x); int PEMwriteDHparams(FILE *fp, DH *x);X509 *PEMreadbioX509(BIO *bp, X509 **x, pempasswordcb *cb, void *u);
X509 *PEMreadX509(FILE *fp, X509 **x, pempasswordcb *cb, void *u);
int PEMwritebioX509(BIO *bp, X509 *x); int PEMwriteX509(FILE *fp, X509 *x);X509 *PEMreadbioX509AUX(BIO *bp, X509 **x, pempasswordcb *cb, void *u);
X509 *PEMreadX509AUX(FILE *fp, X509 **x, pempasswordcb *cb, void *u);
int PEMwritebioX509AUX(BIO *bp, X509 *x); int PEMwriteX509AUX(FILE *fp, X509 *x); X509REQ *PEMreadbioX509REQ(BIO *bp, X509REQ **x,pempasswordcb *cb, void *u);
X509REQ *PEMreadX509REQ(FILE *fp, X509REQ **x,pempasswordcb *cb, void *u);
int PEMwritebioX509REQ(BIO *bp, X509REQ *x); int PEMwriteX509REQ(FILE *fp, X509REQ *x); int PEMwritebioX509REQNEW(BIO *bp, X509REQ *x); int PEMwriteX509REQNEW(FILE *fp, X509REQ *x); X509CRL *PEMreadbioX509CRL(BIO *bp, X509CRL **x,pempasswordcb *cb, void *u);
X509CRL *PEMreadX509CRL(FILE *fp, X509CRL **x,pempasswordcb *cb, void *u);
int PEMwritebioX509CRL(BIO *bp, X509CRL *x); int PEMwriteX509CRL(FILE *fp, X509CRL *x);PKCS7 *PEMreadbioPKCS7(BIO *bp, PKCS7 **x, pempasswordcb *cb, void *u);
PKCS7 *PEMreadPKCS7(FILE *fp, PKCS7 **x, pempasswordcb *cb, void *u);
int PEMwritebioPKCS7(BIO *bp, PKCS7 *x); int PEMwritePKCS7(FILE *fp, PKCS7 *x); NETSCAPECERTSEQUENCE *PEMreadbioNETSCAPECERTSEQUENCE(BIO *bp, NETSCAPECERTSEQUENCE **x,pempasswordcb *cb, void *u);
NETSCAPECERTSEQUENCE *PEMreadNETSCAPECERTSEQUENCE(FILE *fp, NETSCAPECERTSEQUENCE **x,pempasswordcb *cb, void *u);
int PEMwritebioNETSCAPECERTSEQUENCE(BIO *bp, NETSCAPECERTSEQUENCE *x); int PEMwriteNETSCAPECERTSEQUENCE(FILE *fp, NETSCAPECERTSEQUENCE *x);DESCRIPTION
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 PEMreadbiofoobar(), PEMreadfoobar(), PEMwritebiofoobar() and PEMwritefoobar() functions. The PPrriivvaatteeKKeeyy functions read or write a private key in PEM format using an EVPPKEY structure. The write routines use "traditional" private key format and can handle both RSA and DSA private keys. Theread functions can additionally transparently handle PKCS#8 format
encrypted and unencrypted keys too. PEMwritebioPKCS8PrivateKey() and PEMwritePKCS8PrivateKey() write aprivate key in an EVPPKEY structure in PKCS#8 EncryptedPrivateKeyInfo
format using PKCS#5 v2.0 password based encryption algorithms. The
cciipphheerr argument specifies the encryption algoritm to use: unlike allother 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 usedand a PKCS#8 PrivateKeyInfo structure is used instead.
PEMwritebioPKCS8PrivateKeynid() and PEMwritePKCS8PrivateKeynid()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 nniidd parameter and should bethe NID of the corresponding OBJECT IDENTIFIER (see NOTES section).
The PPUUBBKKEEYY functions process a public key using an EVPPKEY 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 RSAstructure. The public key is encoded using a PKCS#1 RSAPublicKey
structure. The RRSSAAPPUUBBKKEEYY 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 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 DDSSAAPPUUBBKKEEYY 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 DDSSAAppaarraammss functions process DSA parameters using a DSA structure. The parameters are encoded using a foobar structure. The DDHHppaarraammss functions process DH parameters using a DH structure. Theparameters 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 settings are discarded. The XX550099AAUUXX functions process a trusted X509 certificate using an X509 structure.The XX550099RREEQQ and XX550099RREEQQNNEEWW functions process a PKCS#10 certificate
request using an X509REQ structure. The XX550099RREEQQ write functions use CCEERRTTIIFFIICCAATTEE RREEQQUUEESSTT in the header whereas the XX550099RREEQQNNEEWW functions use NNEEWW CCEERRTTIIFFIICCAATTEE RREEQQUUEESSTT (as required by some CAs). The XX550099RREEQQ read functions will handle either form so there are no XX550099RREEQQNNEEWW read functions. The XX550099CCRRLL functions process an X509 CRL using an X509CRL structure.The PPKKCCSS77 functions process a PKCS#7 ContentInfo using a PKCS7
structure. The NNEETTSSCCAAPPEECCEERRTTSSEEQQUUEENNCCEE functions process a Netscape Certificate Sequence using a NETSCAPECERTSEQUENCE 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 seeBUGS 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 characters in the passphrase or 0 if an error occurred. EEXXAAMMPPLLEESS Although the PEM routines take several arguments in almost all applications most of them are set to 0 or NULL. Read a certificate in PEM format from a BIO: X509 *x; x = PEMreadbioX509(bp, NULL, 0, NULL); if (x == NULL) { /* Error */ } Alternative method: X509 *x = NULL; if (!PEMreadbioX509(bp, &x, 0, NULL)) { /* Error */ } Write a certificate to a BIO: if (!PEMwritebioX509(bp, x)) { /* Error */ } Write an unencrypted private key to a FILE pointer: if (!PEMwritePrivateKey(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 (!PEMwritebioPrivateKey(bp, key, EVPdesede3cbc(), 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 (!PEMwritebioPKCS8PrivateKey(bp, key, EVPdesede3cbc(), NULL, 0, 0, "hello")) { /* Error */ } Read a private key from a BIO using the pass phrase "hello": key = PEMreadbioPrivateKey(bp, NULL, 0, "hello"); if (key == NULL) { /* Error */ } Read a private key from a BIO using a pass phrase callback: key = PEMreadbioPrivateKey(bp, NULL, passcb, "My Private Key"); if (key == NULL) { /* Error */ } Skeleton pass phrase callback: int passcb(char *buf, int size, int rwflag, void *u); { int len; char *tmp; /* 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' */ tmp = "hello"; len = strlen(tmp); if (len <= 0) return 0; /* if too long, truncate */ 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 PEMwritebioPKCS8PrivateKey() or PEMwritePKCS8PrivateKey() 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; PEMreadbioX509(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 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 DEK-Info contains two comma separated pieces of
information: the encryption algorithm name as used by EVPgetcipherbyname() 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 EVPbytestokey(), using ssaalltt and an iteration count of 1. The IV used is the value of ssaalltt and *not* the IV returned by EVPbytestokey().BUGS
The PEM read routines in some versions of OpenSSL will not correctly reuse an existing structure. Therefore the following: PEMreadbioX509(bp, &x, 0, NULL); where xx already contains a valid certificate, may not work, whereas: X509free(x); x = PEMreadbioX509(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.0.9.7l 2004-03-21 pem(3)