openssl-rsautl(1), rsautl(1) - RSA utility



  • RSAUTL(1)			    OpenSSL			     RSAUTL(1)
    
    
    
    NAME
           openssl-rsautl, rsautl - RSA utility
    
    SYNOPSIS
           openssl rsautl [-help] [-in file] [-out file] [-inkey file] [-keyform
           PEM|DER|ENGINE] [-pubin] [-certin] [-sign] [-verify] [-encrypt]
           [-decrypt] [-rand file...]  [-writerand file] [-pkcs] [-ssl] [-raw]
           [-hexdump] [-asn1parse]
    
    DESCRIPTION
           The rsautl command can be used to sign, verify, encrypt and decrypt
           data using the RSA algorithm.
    
    OPTIONS
           -help
    	   Print out a usage message.
    
           -in filename
    	   This specifies the input filename to read data from or standard
    	   input if this option is not specified.
    
           -out filename
    	   Specifies the output filename to write to or standard output by
    	   default.
    
           -inkey file
    	   The input key file, by default it should be an RSA private key.
    
           -keyform PEM|DER|ENGINE
    	   The key format PEM, DER or ENGINE.
    
           -pubin
    	   The input file is an RSA public key.
    
           -certin
    	   The input is a certificate containing an RSA public key.
    
           -sign
    	   Sign the input data and output the signed result. This requires an
    	   RSA private key.
    
           -verify
    	   Verify the input data and output the recovered data.
    
           -encrypt
    	   Encrypt the input data using an RSA public key.
    
           -decrypt
    	   Decrypt the input data using an RSA private key.
    
           -rand file...
    	   A file or files containing random data used to seed the random
    	   number generator.  Multiple files can be specified separated by an
    	   OS-dependent character.  The separator is ; for MS-Windows, , for
    	   OpenVMS, and : for all others.
    
           [-writerand file]
    	   Writes random data to the specified file upon exit.	This can be
    	   used with a subsequent -rand flag.
    
           -pkcs, -oaep, -ssl, -raw
    	   The padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP, special
    	   padding used in SSL v2 backwards compatible handshakes, or no
    	   padding, respectively.  For signatures, only -pkcs and -raw can be
    	   used.
    
           -hexdump
    	   Hex dump the output data.
    
           -asn1parse
    	   Parse the ASN.1 output data, this is useful when combined with the
    	   -verify option.
    
    NOTES
           rsautl because it uses the RSA algorithm directly can only be used to
           sign or verify small pieces of data.
    
    EXAMPLES
           Sign some data using a private key:
    
    	openssl rsautl -sign -in file -inkey key.pem -out sig
    
           Recover the signed data
    
    	openssl rsautl -verify -in sig -inkey key.pem
    
           Examine the raw signed data:
    
    	openssl rsautl -verify -in sig -inkey key.pem -raw -hexdump
    
    	0000 - 00 01 ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0010 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0020 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0030 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0040 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0050 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0060 - ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff	 ................
    	0070 - ff ff ff ff 00 68 65 6c-6c 6f 20 77 6f 72 6c 64	 .....hello world
    
           The PKCS#1 block formatting is evident from this. If this was done
           using encrypt and decrypt the block would have been of type 2 (the
           second byte) and random padding data visible instead of the 0xff bytes.
    
           It is possible to analyse the signature of certificates using this
           utility in conjunction with asn1parse. Consider the self signed example
           in certs/pca-cert.pem . Running asn1parse as follows yields:
    
    	openssl asn1parse -in pca-cert.pem
    
    	   0:d=0  hl=4 l= 742 cons: SEQUENCE
    	   4:d=1  hl=4 l= 591 cons:  SEQUENCE
    	   8:d=2  hl=2 l=   3 cons:   cont [ 0 ]
    	  10:d=3  hl=2 l=   1 prim:    INTEGER		 :02
    	  13:d=2  hl=2 l=   1 prim:   INTEGER		:00
    	  16:d=2  hl=2 l=  13 cons:   SEQUENCE
    	  18:d=3  hl=2 l=   9 prim:    OBJECT		 :md5WithRSAEncryption
    	  29:d=3  hl=2 l=   0 prim:    NULL
    	  31:d=2  hl=2 l=  92 cons:   SEQUENCE
    	  33:d=3  hl=2 l=  11 cons:    SET
    	  35:d=4  hl=2 l=   9 cons:	SEQUENCE
    	  37:d=5  hl=2 l=   3 prim:	 OBJECT		   :countryName
    	  42:d=5  hl=2 l=   2 prim:	 PRINTABLESTRING   :AU
    	 ....
    	 599:d=1  hl=2 l=  13 cons:  SEQUENCE
    	 601:d=2  hl=2 l=   9 prim:   OBJECT		:md5WithRSAEncryption
    	 612:d=2  hl=2 l=   0 prim:   NULL
    	 614:d=1  hl=3 l= 129 prim:  BIT STRING
    
           The final BIT STRING contains the actual signature. It can be extracted
           with:
    
    	openssl asn1parse -in pca-cert.pem -out sig -noout -strparse 614
    
           The certificate public key can be extracted with:
    
    	openssl x509 -in test/testx509.pem -pubkey -noout >pubkey.pem
    
           The signature can be analysed with:
    
    	openssl rsautl -in sig -verify -asn1parse -inkey pubkey.pem -pubin
    
    	   0:d=0  hl=2 l=  32 cons: SEQUENCE
    	   2:d=1  hl=2 l=  12 cons:  SEQUENCE
    	   4:d=2  hl=2 l=   8 prim:   OBJECT		:md5
    	  14:d=2  hl=2 l=   0 prim:   NULL
    	  16:d=1  hl=2 l=  16 prim:  OCTET STRING
    	     0000 - f3 46 9e aa 1a 4a 73 c9-37 ea 93 00 48 25 08 b5   .F...Js.7...H%..
    
           This is the parsed version of an ASN1 DigestInfo structure. It can be
           seen that the digest used was md5. The actual part of the certificate
           that was signed can be extracted with:
    
    	openssl asn1parse -in pca-cert.pem -out tbs -noout -strparse 4
    
           and its digest computed with:
    
    	openssl md5 -c tbs
    	MD5(tbs)= f3:46:9e:aa:1a:4a:73:c9:37:ea:93:00:48:25:08:b5
    
           which it can be seen agrees with the recovered value above.
    
    SEE ALSO
           dgst(1), rsa(1), genrsa(1)
    
    COPYRIGHT
           Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
    
           Licensed under the OpenSSL license (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>.
    
    
    
    1.1.1				  2018-09-11			     RSAUTL(1)
    

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