diff options
Diffstat (limited to 'openssl/doc/crypto/PKCS7_encrypt.pod')
| -rw-r--r-- | openssl/doc/crypto/PKCS7_encrypt.pod | 61 |
1 files changed, 38 insertions, 23 deletions
diff --git a/openssl/doc/crypto/PKCS7_encrypt.pod b/openssl/doc/crypto/PKCS7_encrypt.pod index 1a507b22a..2cd925a7e 100644 --- a/openssl/doc/crypto/PKCS7_encrypt.pod +++ b/openssl/doc/crypto/PKCS7_encrypt.pod @@ -6,7 +6,9 @@ PKCS7_encrypt - create a PKCS#7 envelopedData structure =head1 SYNOPSIS -PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags); + #include <openssl/pkcs7.h> + + PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags); =head1 DESCRIPTION @@ -16,43 +18,55 @@ B<cipher> is the symmetric cipher to use. B<flags> is an optional set of flags. =head1 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. +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. +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. +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 B<cipher> parameter must support ASN1 encoding of its -parameters. +The algorithm passed in the B<cipher> parameter must support ASN1 encoding of +its parameters. -Many browsers implement a "sign and encrypt" option which is simply an S/MIME +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 B<flags> parameter. -If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended -to the data. +If the B<PKCS7_TEXT> flag is set MIME headers for type B<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 B<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 B<PKCS7_BINARY> is set then B<PKCS7_TEXT> is ignored. +Normally the supplied content is translated into MIME canonical format (as +required by the S/MIME specifications) if B<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 B<PKCS7_BINARY> is set then +B<PKCS7_TEXT> is ignored. -=head1 RETURN VALUES +If the B<PKCS7_STREAM> flag is set a partial B<PKCS7> structure is output +suitable for streaming I/O: no data is read from the BIO B<in>. -PKCS7_encrypt() returns either a valid PKCS7 structure or NULL if an error occurred. -The error can be obtained from ERR_get_error(3). +=head1 NOTES -=head1 BUGS +If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not> +complete and outputting its contents via a function that does not +properly finalize the B<PKCS7> structure will give unpredictable +results. -The lack of single pass processing and need to hold all data in memory as -mentioned in PKCS7_sign() also applies to PKCS7_verify(). +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 B<BIO> directly using +BIO_new_PKCS7(). + +=head1 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). =head1 SEE ALSO @@ -61,5 +75,6 @@ L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_decrypt(3)|PKCS7_decrypt(3)> =head1 HISTORY PKCS7_decrypt() was added to OpenSSL 0.9.5 +The B<PKCS7_STREAM> flag was first supported in OpenSSL 1.0.0. =cut |