# rsa

# 1. rsa.1.man

# Manpage of RSA

## RSA

Section: OpenSSL (1)Updated: 2003-01-30

Index Return to Main Contents

## NAME

rsa - RSA key processing tool## SYNOPSIS

**openssl**

**rsa**[

**-inform PEM|NET|DER**] [

**-outform PEM|NET|DER**] [

**-in filename**] [

**-passin arg**] [

**-out filename**] [

**-passout arg**] [

**-sgckey**] [

**-des**] [

**-des3**] [

**-idea**] [

**-text**] [

**-noout**] [

**-modulus**] [

**-check**] [

**-pubin**] [

**-pubout**] [

**-engine id**]

## DESCRIPTION

The**rsa**command processes RSA keys. They can be converted between various forms and their components printed out.

**Note**this command uses the traditional SSLeay compatible format for private key encryption: newer applications should use the more secure PKCS#8 format using the

**pkcs8**utility.

## COMMAND OPTIONS

**-inform DER|NET|PEM**-
This specifies the input format. The
**DER**option uses an ASN1 DER encoded form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format. The**PEM**form is the default format: it consists of the**DER**format base64 encoded with additional header and footer lines. On input PKCS#8 format private keys are also accepted. The**NET**form is a format is described in the**NOTES**section. **-outform DER|NET|PEM**-
This specifies the output format, the options have the same meaning as the
**-inform**option. **-in filename**- This specifies the input filename to read a key from or standard input if this option is not specified. If the key is encrypted a pass phrase will be prompted for.
**-passin arg**-
the input file password source. For more information about the format of
**arg**see the**PASS****PHRASE****ARGUMENTS**section in*openssl*(1). **-out filename**-
This specifies the output filename to write a key to or standard output if this
option is not specified. If any encryption options are set then a pass phrase
will be prompted for. The output filename should
**not**be the same as the input filename. **-passout password**-
the output file password source. For more information about the format of
**arg**see the**PASS****PHRASE****ARGUMENTS**section in*openssl*(1). **-sgckey**- use the modified NET algorithm used with some versions of Microsoft IIS and SGC keys.
**-des|-des3|-idea**-
These options encrypt the private key with the DES, triple DES, or the
IDEA ciphers respectively before outputting it. A pass phrase is prompted for.
If none of these options is specified the key is written in plain text. This
means that using the
**rsa**utility to read in an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be use to add or change the pass phrase. These options can only be used with PEM format output files. **-text**- prints out the various public or private key components in plain text in addition to the encoded version.
**-noout**- this option prevents output of the encoded version of the key.
**-modulus**- this option prints out the value of the modulus of the key.
**-check**- this option checks the consistency of an RSA private key.
**-pubin**- by default a private key is read from the input file: with this option a public key is read instead.
**-pubout**- by default a private key is output: with this option a public key will be output instead. This option is automatically set if the input is a public key.
**-engine id**-
specifying an engine (by it's unique
**id**string) will cause**req**to attempt to obtain a functional reference to the specified engine, thus initialising it if needed. The engine will then be set as the default for all available algorithms.

## NOTES

The PEM private key format uses the header and footer lines:

-----BEGIN RSA PRIVATE KEY----- -----END RSA PRIVATE KEY-----

The PEM public key format uses the header and footer lines:

-----BEGIN PUBLIC KEY----- -----END PUBLIC KEY-----

The **NET** form is a format compatible with older Netscape servers
and Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
It is not very secure and so should only be used when necessary.

Some newer version of IIS have additional data in the exported .key
files. To use these with the utility, view the file with a binary editor
and look for the string ``private-key'', then trace back to the byte
sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
from this point onwards to another file and use that as the input
to the **rsa** utility with the **-inform ****NET** option. If you get
an error after entering the password try the **-sgckey** option.

## EXAMPLES

To remove the pass phrase on an RSA private key:

openssl rsa -in key.pem -out keyout.pem

To encrypt a private key using triple DES:

openssl rsa -in key.pem -des3 -out keyout.pem

To convert a private key from PEM to DER format:

openssl rsa -in key.pem -outform DER -out keyout.der

To print out the components of a private key to standard output:

openssl rsa -in key.pem -text -noout

To just output the public part of a private key:

openssl rsa -in key.pem -pubout -out pubkey.pem

## BUGS

The command line password arguments don't currently work with**NET**format.

There should be an option that automatically handles .key files, without having to manually edit them.

## SEE ALSO

*pkcs8*(1),

*dsa*(1),

*genrsa*(1),

*gendsa*(1)

## Index

This document was created by man2html using the manual pages.

Time: 17:32:14 GMT, October 23, 2013

# 2. rsa.3.man

# Manpage of rsa

## rsa

Section: OpenSSL (3)Updated: 2002-08-04

Index Return to Main Contents

## NAME

rsa - RSA public key cryptosystem## SYNOPSIS

#include <openssl/rsa.h> #include <openssl/engine.h>

RSA * RSA_new(void); void RSA_free(RSA *rsa);

int RSA_public_encrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa, int padding); int RSA_private_decrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa, int padding); int RSA_private_encrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa,int padding); int RSA_public_decrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa,int padding);

int RSA_sign(int type, unsigned char *m, unsigned int m_len, unsigned char *sigret, unsigned int *siglen, RSA *rsa); int RSA_verify(int type, unsigned char *m, unsigned int m_len, unsigned char *sigbuf, unsigned int siglen, RSA *rsa);

int RSA_size(const RSA *rsa);

RSA *RSA_generate_key(int num, unsigned long e, void (*callback)(int,int,void *), void *cb_arg);

int RSA_check_key(RSA *rsa);

int RSA_blinding_on(RSA *rsa, BN_CTX *ctx); void RSA_blinding_off(RSA *rsa);

void RSA_set_default_method(const RSA_METHOD *meth); const RSA_METHOD *RSA_get_default_method(void); int RSA_set_method(RSA *rsa, const RSA_METHOD *meth); const RSA_METHOD *RSA_get_method(const RSA *rsa); RSA_METHOD *RSA_PKCS1_SSLeay(void); RSA_METHOD *RSA_null_method(void); int RSA_flags(const RSA *rsa); RSA *RSA_new_method(ENGINE *engine);

int RSA_print(BIO *bp, RSA *x, int offset); int RSA_print_fp(FILE *fp, RSA *x, int offset);

int RSA_get_ex_new_index(long argl, char *argp, int (*new_func)(), int (*dup_func)(), void (*free_func)()); int RSA_set_ex_data(RSA *r,int idx,char *arg); char *RSA_get_ex_data(RSA *r, int idx);

int RSA_sign_ASN1_OCTET_STRING(int dummy, unsigned char *m, unsigned int m_len, unsigned char *sigret, unsigned int *siglen, RSA *rsa); int RSA_verify_ASN1_OCTET_STRING(int dummy, unsigned char *m, unsigned int m_len, unsigned char *sigbuf, unsigned int siglen, RSA *rsa);

## DESCRIPTION

These functions implement RSA public key encryption and signatures as defined in PKCS #1 v2.0 [RFC 2437].
The **RSA** structure consists of several BIGNUM components. It can
contain public as well as private RSA keys:

struct { BIGNUM *n; // public modulus BIGNUM *e; // public exponent BIGNUM *d; // private exponent BIGNUM *p; // secret prime factor BIGNUM *q; // secret prime factor BIGNUM *dmp1; // d mod (p-1) BIGNUM *dmq1; // d mod (q-1) BIGNUM *iqmp; // q^-1 mod p // ... }; RSA

In public keys, the private exponent and the related secret values are
**NULL**.

**p**, **q**, **dmp1**, **dmq1** and **iqmp** may be **NULL** in private
keys, but the RSA operations are much faster when these values are
available.

Note that RSA keys may use non-standard **RSA_METHOD** implementations,
either directly or by the use of **ENGINE** modules. In some cases (eg. an
ENGINE providing support for hardware-embedded keys), these BIGNUM values
will not be used by the implementation or may be used for alternative data
storage. For this reason, applications should generally avoid using RSA
structure elements directly and instead use API functions to query or
modify keys.

## CONFORMING TO

SSL, PKCS #1 v2.0## PATENTS

RSA was covered by a US patent which expired in September 2000.## SEE ALSO

*rsa*(1),

*bn*(3),

*dsa*(3),

*dh*(3),

*rand*(3),

*engine*(3),

*RSA_new*(3),

*RSA_public_encrypt*(3),

*RSA_sign*(3),

*RSA_size*(3),

*RSA_generate_key*(3),

*RSA_check_key*(3),

*RSA_blinding_on*(3),

*RSA_set_method*(3),

*RSA_print*(3),

*RSA_get_ex_new_index*(3),

*RSA_private_encrypt*(3),

*RSA_sign_ASN1_OCTET_STRING*(3),

*RSA_padding_add_PKCS1_type_1*(3)

## Index

This document was created by man2html using the manual pages.

Time: 17:32:14 GMT, October 23, 2013