smime_read_pkcs7(3ssl) [linux man page]

SMIME_read_PKCS7(3SSL)						      OpenSSL						    SMIME_read_PKCS7(3SSL)

NAME

       SMIME_read_PKCS7 - parse S/MIME message.

SYNOPSIS

	#include <openssl/pkcs7.h>

	PKCS7 *SMIME_read_PKCS7(BIO *in, BIO **bcont);

DESCRIPTION

       SMIME_read_PKCS7() parses a message in S/MIME format.

       in is a BIO to read the message from.

       If cleartext signing is used then the content is saved in a memory bio which is written to *bcont, otherwise *bcont is set to NULL.

       The parsed PKCS#7 structure is returned or NULL if an error occurred.

NOTES

       If *bcont is not NULL then the message is clear text signed. *bcont can then be passed to PKCS7_verify() with the PKCS7_DETACHED flag set.

       Otherwise the type of the returned structure can be determined using PKCS7_type().

       To support future functionality if bcont is not NULL *bcont should be initialized to NULL. For example:

	BIO *cont = NULL;
	PKCS7 *p7;

	p7 = SMIME_read_PKCS7(in, &cont);

BUGS

       The MIME parser used by SMIME_read_PKCS7() is somewhat primitive.  While it will handle most S/MIME messages more complex compound formats
       may not work.

       The parser assumes that the PKCS7 structure is always base64 encoded and will not handle the case where it is in binary format or uses
       quoted printable format.

       The use of a memory BIO to hold the signed content limits the size of message which can be processed due to memory restraints: a streaming
       single pass option should be available.

RETURN VALUES

       SMIME_read_PKCS7() returns a valid PKCS7 structure or NULL is an error occurred. The error can be obtained from ERR_get_error(3).

SEE ALSO

       ERR_get_error(3), PKCS7_type(3) SMIME_read_PKCS7(3), PKCS7_sign(3), PKCS7_verify(3), PKCS7_encrypt(3) PKCS7_decrypt(3)

HISTORY

       SMIME_read_PKCS7() was added to OpenSSL 0.9.5

1.0.0e								    2006-05-14						    SMIME_read_PKCS7(3SSL)

PKCS7_encrypt(3SSL)						      OpenSSL						       PKCS7_encrypt(3SSL)

NAME

       PKCS7_encrypt - create a PKCS#7 envelopedData structure

SYNOPSIS

	#include <openssl/pkcs7.h>

	PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags);

DESCRIPTION

       PKCS7_encrypt() creates and returns a PKCS#7 envelopedData structure. certs is a list of recipient certificates. in is the content to be
       encrypted.  cipher is the symmetric cipher to use. flags is an optional set of flags.

NOTES

       Only RSA keys are supported in PKCS#7 and envelopedData so the recipient certificates supplied to this function must all contain RSA public
       keys, though they do not have to be signed using the RSA algorithm.

       EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use because most clients will support it.

       Some old "export grade" clients may only support weak encryption using 40 or 64 bit RC2. These can be used by passing EVP_rc2_40_cbc() and
       EVP_rc2_64_cbc() respectively.

       The algorithm passed in the cipher parameter must support ASN1 encoding of its parameters.

       Many browsers implement a "sign and encrypt" option which is simply an S/MIME envelopedData containing an S/MIME signed message. This can
       be readily produced by storing the S/MIME signed message in a memory BIO and passing it to PKCS7_encrypt().

       The following flags can be passed in the flags parameter.

       If the PKCS7_TEXT flag is set MIME headers for type text/plain are prepended to the data.

       Normally the supplied content is translated into MIME canonical format (as required by the S/MIME specifications) if PKCS7_BINARY is set no
       translation occurs. This option should be used if the supplied data is in binary format otherwise the translation will corrupt it. If
       PKCS7_BINARY is set then PKCS7_TEXT is ignored.

       If the PKCS7_STREAM flag is set a partial PKCS7 structure is output suitable for streaming I/O: no data is read from the BIO in.

NOTES

       If the flag PKCS7_STREAM is set the returned PKCS7 structure is not complete and outputting its contents via a function that does not
       properly finalize the PKCS7 structure will give unpredictable results.

       Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(), PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively
       finalization can be performed by obtaining the streaming ASN1 BIO directly using BIO_new_PKCS7().

RETURN VALUES

       PKCS7_encrypt() returns either a PKCS7 structure or NULL if an error occurred.  The error can be obtained from ERR_get_error(3).

SEE ALSO

       ERR_get_error(3), PKCS7_decrypt(3)

HISTORY

       PKCS7_decrypt() was added to OpenSSL 0.9.5 The PKCS7_STREAM flag was first supported in OpenSSL 1.0.0.

1.0.0e								    2009-09-30						       PKCS7_encrypt(3SSL)