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RSAUTL(1)			    OpenSSL			     RSAUTL(1)

NAME
       rsautl -	RSA utility

SYNOPSIS
       openssl rsautl [-in file] [-out file] [-inkey file] [-pubin] [-certin]
       [-sign] [-verify] [-encrypt] [-decrypt] [-pkcs] [-ssl] [-raw]
       [-hexdump] [-asn1parse]

DESCRIPTION
       The rsautl command can be used to sign, verify, encrypt and decrypt
       data using the RSA algorithm.

COMMAND	OPTIONS
       -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.

       -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 and
	   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.

       -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
	   asn1parse the 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 file	-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)

0.9.8za				  2014-06-05			     RSAUTL(1)

NAME | SYNOPSIS | DESCRIPTION | COMMAND OPTIONS | NOTES | EXAMPLES | SEE ALSO

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