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PEM_read(3)                         OpenSSL                        PEM_read(3)



NAME
       PEM_write, PEM_write_bio, PEM_read, PEM_read_bio, PEM_do_header,
       PEM_get_EVP_CIPHER_INFO - PEM encoding routines

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/pem.h>

        int PEM_write(FILE *fp, const char *name, const char *header,
                      const unsigned char *data, long len);
        int PEM_write_bio(BIO *bp, const char *name, const char *header,
                          const unsigned char *data, long len);

        int PEM_read(FILE *fp, char **name, char **header,
                     unsigned char **data, long *len);
        int PEM_read_bio(BIO *bp, char **name, char **header,
                         unsigned char **data, long *len);

        int PEM_get_EVP_CIPHER_INFO(char *header, EVP_CIPHER_INFO *cinfo);
        int PEM_do_header(EVP_CIPHER_INFO *cinfo, unsigned char *data, long *len,
                          pem_password_cb *cb, void *u);

DESCRIPTION
       These functions read and write PEM-encoded objects, using the PEM type
       name, any additional header information, and the raw data of length
       len.

       PEM is the term used for binary content encoding first defined in IETF
       RFC 1421.  The content is a series of base64-encoded lines, surrounded
       by begin/end markers each on their own line.  For example:

        -----BEGIN PRIVATE KEY-----
        MIICdg....
        ... bhTQ==
        -----END PRIVATE KEY-----

       Optional header line(s) may appear after the begin line, and their
       existence depends on the type of object being written or read.

       PEM_write() writes to the file fp, while PEM_write_bio() writes to the
       BIO bp.  The name is the name to use in the marker, the header is the
       header value or NULL, and data and len specify the data and its length.

       The final data buffer is typically an ASN.1 object which can be decoded
       with the d2i function appropriate to the type name; see d2i_X509(3) for
       examples.

       PEM_read() reads from the file fp, while PEM_read_bio() reads from the
       BIO bp.  Both skip any non-PEM data that precedes the start of the next
       PEM object.  When an object is successfully retrieved, the type name
       from the "----BEGIN <type>-----" is returned via the name argument, any
       encapsulation headers are returned in header and the base64-decoded
       content and its length are returned via data and len respectively.  The
       name, header and data pointers are allocated via OPENSSL_malloc() and
       should be freed by the caller via OPENSSL_free() when no longer needed.

       PEM_get_EVP_CIPHER_INFO() can be used to determine the data returned by
       PEM_read() or PEM_read_bio() is encrypted and to retrieve the
       associated cipher and IV. The caller passes a pointer to structure of
       type EVP_CIPHER_INFO via the cinfo argument and the header returned via
       PEM_read() or PEM_read_bio().  If the call is successful 1 is returned
       and the cipher and IV are stored at the address pointed to by cinfo.
       When the header is malformed, or not supported or when the cipher is
       unknown or some internal error happens 0 is returned.  This function is
       deprecated, see NOTES below.

       PEM_do_header() can then be used to decrypt the data if the header
       indicates encryption.  The cinfo argument is a pointer to the structure
       initialized by the previous call to PEM_get_EVP_CIPHER_INFO().  The
       data and len arguments are those returned by the previous call to
       PEM_read() or PEM_read_bio().  The cb and u arguments make it possible
       to override the default password prompt function as described in
       PEM_read_PrivateKey(3).  On successful completion the data is decrypted
       in place, and len is updated to indicate the plaintext length.  This
       function is deprecated, see NOTES below.

       If the data is a priori known to not be encrypted, then neither
       PEM_do_header() nor PEM_get_EVP_CIPHER_INFO() need be called.

RETURN VALUES
       PEM_read() and PEM_read_bio() return 1 on success and 0 on failure, the
       latter includes the case when no more PEM objects remain in the input
       file.  To distinguish end of file from more serious errors the caller
       must peek at the error stack and check for PEM_R_NO_START_LINE, which
       indicates that no more PEM objects were found.  See
       ERR_peek_last_error(3), ERR_GET_REASON(3).

       PEM_get_EVP_CIPHER_INFO() and PEM_do_header() return 1 on success, and
       0 on failure.  The data is likely meaningless if these functions fail.

NOTES
       The PEM_get_EVP_CIPHER_INFO() and PEM_do_header() functions are
       deprecated.  This is because the underlying PEM encryption format is
       obsolete, and should be avoided.  It uses an encryption format with an
       OpenSSL-specific key-derivation function, which employs MD5 with an
       iteration count of 1!  Instead, private keys should be stored in PKCS#8
       form, with a strong PKCS#5 v2.0 PBE. See PEM_write_PrivateKey(3) and
       d2i_PKCS8PrivateKey_bio(3).

       PEM_do_header() makes no assumption regarding the pass phrase received
       from the password callback.  It will simply be treated as a byte
       sequence.

SEE ALSO
       ERR_peek_last_error(3), ERR_GET_LIB(3), d2i_PKCS8PrivateKey_bio(3),
       passphrase-encoding(7)

COPYRIGHT
       Copyright 1998-2020 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
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                       PEM_read(3)