OPENSSL-RSAUTL(1ossl) OpenSSL OPENSSL-RSAUTL(1ossl) NAME openssl-rsautl - RSA command SYNOPSIS openssl rsautl [-help] [-in file] [-passin arg] [-rev] [-out file] [-inkey filename|uri] [-keyform DER|PEM|P12] [-pubin] [-certin] [-sign] [-verify] [-encrypt] [-decrypt] [-pkcs] [-x931] [-oaep] [-raw] [-hexdump] [-asn1parse] [-rand files] [-writerand file] [-provider name] [-provider-path path] [-provparam [name:]key=value] [-propquery propq] DESCRIPTION This command has been deprecated. The openssl-pkeyutl(1) command should be used instead. This 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. -passin arg The passphrase used in the output file. See see openssl-passphrase-op- tions(1). -revReverse the order of the input. -out filename Specifies the output filename to write to or standard output by de- fault. -inkey filename|uri The input key, by default it should be an RSA private key. -keyform DER|PEM|P12 The key format; unspecified by default. See openssl-format-options(1) for details. -pubin By default a private key is read from the key input. With this option a public key is read instead. If the input contains no public key but a private key, its public part is used. -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. -pkcs, -oaep, -x931, -raw The padding to use: PKCS#1 v1.5 (the default), PKCS#1 OAEP, ANSI X9.31, or no padding, respectively. For signatures, only -pkcs and -raw can be used. Note: because of protection against Bleichenbacher attacks, decryption using PKCS#1 v1.5 mode will not return errors in case padding check failed. Use -raw and inspect the returned value manually to check if the padding is correct. -hexdump Hex dump the output data. -asn1parse Parse the ASN.1 output data, this is useful when combined with the -verify option. -rand files, -writerand file See "Random State Options" in openssl(1) for details. -provider name -provider-path path -provparam [name:]key=value -propquery propq See "Provider Options" in openssl(1), provider(7), and property(7). NOTES Since this command uses the RSA algorithm directly, it can only be used to sign or verify small pieces of data. EXAMPLES Examples equivalent to these can be found in the documentation for the non-deprecated openssl-pkeyutl(1) command. 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 command in conjunction with openssl-asn1parse(1). Consider the self signed example in certs/pca-cert.pem. Running openssl-asn1parse(1) 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 openssl(1), openssl-pkeyutl(1), openssl-dgst(1), openssl-rsa(1), openssl-genrsa(1) HISTORY This command was deprecated in OpenSSL 3.0. The -engine option was removed in OpenSSL 4.0. COPYRIGHT Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. Licensed under the Apache License 2.0 (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>. 4.0.2 2026-08-25 OPENSSL-RSAUTL(1ossl)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | EXAMPLES | SEE ALSO | HISTORY | COPYRIGHT
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=openssl-rsautl&sektion=1&manpath=FreeBSD+Ports+15.1.quarterly>