/opt/alt/openssl11/share/man/man1
NameSizeModeActions
asn1parse.1ssl112100644editdlrm
ca.1ssl334800644editdlrm
CA.pl.1ssl123690644editdlrm
ciphers.1ssl382080644editdlrm
cms.1ssl327160644editdlrm
crl.1ssl76790644editdlrm
crl2pkcs7.1ssl74400644editdlrm
c_rehash.1ssl87750644editdlrm
dgst.1ssl119010644editdlrm
dhparam.1ssl93180644editdlrm
dsa.1ssl100140644editdlrm
dsaparam.1ssl80020644editdlrm
ec.1ssl108930644editdlrm
ecparam.1ssl101970644editdlrm
enc.1ssl199230644editdlrm
engine.1ssl73500644editdlrm
errstr.1ssl50820644editdlrm
gendsa.1ssl71240644editdlrm
genpkey.1ssl160640644editdlrm
genrsa.1ssl82520644editdlrm
list.1ssl64980644editdlrm
nseq.1ssl63950644editdlrm
ocsp.1ssl241520644editdlrm
openssl-asn1parse.1ssl112100644editdlrm
openssl-ca.1ssl334800644editdlrm
openssl-ciphers.1ssl382080644editdlrm
openssl-cms.1ssl327160644editdlrm
openssl-crl.1ssl76790644editdlrm
openssl-crl2pkcs7.1ssl74400644editdlrm
openssl-c_rehash.1ssl87750644editdlrm
openssl-dgst.1ssl119010644editdlrm
openssl-dhparam.1ssl93180644editdlrm
openssl-dsa.1ssl100140644editdlrm
openssl-dsaparam.1ssl80020644editdlrm
openssl-ec.1ssl108930644editdlrm
openssl-ecparam.1ssl101970644editdlrm
openssl-enc.1ssl199230644editdlrm
openssl-engine.1ssl73500644editdlrm
openssl-errstr.1ssl50820644editdlrm
openssl-gendsa.1ssl71240644editdlrm
openssl-genpkey.1ssl160640644editdlrm
openssl-genrsa.1ssl82520644editdlrm
openssl-list.1ssl64980644editdlrm
openssl-nseq.1ssl63950644editdlrm
openssl-ocsp.1ssl241520644editdlrm
openssl-passwd.1ssl73480644editdlrm
openssl-pkcs7.1ssl72740644editdlrm
openssl-pkcs8.1ssl160300644editdlrm
openssl-pkcs12.1ssl183300644editdlrm
openssl-pkey.1ssl90220644editdlrm
openssl-pkeyparam.1ssl63230644editdlrm
openssl-pkeyutl.1ssl162520644editdlrm
openssl-prime.1ssl55090644editdlrm
openssl-rand.1ssl68380644editdlrm
openssl-rehash.1ssl87750644editdlrm
openssl-req.1ssl304900644editdlrm
openssl-rsa.1ssl106680644editdlrm
openssl-rsautl.1ssl109550644editdlrm
openssl-sess_id.1ssl90640644editdlrm
openssl-smime.1ssl236120644editdlrm
openssl-speed.1ssl71890644editdlrm
openssl-spkac.1ssl87330644editdlrm
openssl-srp.1ssl59330644editdlrm
openssl-storeutl.1ssl76600644editdlrm
openssl-s_client.1ssl371520644editdlrm
openssl-s_server.1ssl351190644editdlrm
openssl-s_time.1ssl123870644editdlrm
openssl-ts.1ssl286980644editdlrm
openssl-tsget.1ssl114300644editdlrm
openssl-verify.1ssl340230644editdlrm
openssl-version.1ssl54810644editdlrm
openssl-x509.1ssl384960644editdlrm
openssl.1ssl215960644editdlrm
passwd.1ssl73480644editdlrm
pkcs7.1ssl72740644editdlrm
pkcs8.1ssl160300644editdlrm
pkcs12.1ssl183300644editdlrm
pkey.1ssl90220644editdlrm
pkeyparam.1ssl63230644editdlrm
pkeyutl.1ssl162520644editdlrm
prime.1ssl55090644editdlrm
rand.1ssl68380644editdlrm
rehash.1ssl87750644editdlrm
req.1ssl304900644editdlrm
rsa.1ssl106680644editdlrm
rsautl.1ssl109550644editdlrm
sess_id.1ssl90640644editdlrm
smime.1ssl236120644editdlrm
speed.1ssl71890644editdlrm
spkac.1ssl87330644editdlrm
srp.1ssl59330644editdlrm
storeutl.1ssl76600644editdlrm
s_client.1ssl371520644editdlrm
s_server.1ssl351190644editdlrm
s_time.1ssl123870644editdlrm
ts.1ssl286980644editdlrm
tsget.1ssl114300644editdlrm
verify.1ssl340230644editdlrm
version.1ssl54810644editdlrm
x509.1ssl384960644editdlrm
Edit: /opt/alt/openssl11/share/man/man1/pkeyutl.1ssl (16252B)
.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "PKEYUTL 1" .TH PKEYUTL 1 "2023-09-11" "1.1.1w" "OpenSSL" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" openssl\-pkeyutl, pkeyutl \- public key algorithm utility .SH "SYNOPSIS" .IX Header "SYNOPSIS" \&\fBopenssl\fR \fBpkeyutl\fR [\fB\-help\fR] [\fB\-in file\fR] [\fB\-out file\fR] [\fB\-sigfile file\fR] [\fB\-inkey file\fR] [\fB\-keyform PEM|DER|ENGINE\fR] [\fB\-passin arg\fR] [\fB\-peerkey file\fR] [\fB\-peerform PEM|DER|ENGINE\fR] [\fB\-pubin\fR] [\fB\-certin\fR] [\fB\-rev\fR] [\fB\-sign\fR] [\fB\-verify\fR] [\fB\-verifyrecover\fR] [\fB\-encrypt\fR] [\fB\-decrypt\fR] [\fB\-derive\fR] [\fB\-kdf algorithm\fR] [\fB\-kdflen length\fR] [\fB\-pkeyopt opt:value\fR] [\fB\-hexdump\fR] [\fB\-asn1parse\fR] [\fB\-rand file...\fR] [\fB\-writerand file\fR] [\fB\-engine id\fR] [\fB\-engine_impl\fR] .SH "DESCRIPTION" .IX Header "DESCRIPTION" The \fBpkeyutl\fR command can be used to perform low-level public key operations using any supported algorithm. .SH "OPTIONS" .IX Header "OPTIONS" .IP "\fB\-help\fR" 4 .IX Item "-help" Print out a usage message. .IP "\fB\-in filename\fR" 4 .IX Item "-in filename" This specifies the input filename to read data from or standard input if this option is not specified. .IP "\fB\-out filename\fR" 4 .IX Item "-out filename" Specifies the output filename to write to or standard output by default. .IP "\fB\-sigfile file\fR" 4 .IX Item "-sigfile file" Signature file, required for \fBverify\fR operations only .IP "\fB\-inkey file\fR" 4 .IX Item "-inkey file" The input key file, by default it should be a private key. .IP "\fB\-keyform PEM|DER|ENGINE\fR" 4 .IX Item "-keyform PEM|DER|ENGINE" The key format \s-1PEM, DER\s0 or \s-1ENGINE.\s0 Default is \s-1PEM.\s0 .IP "\fB\-passin arg\fR" 4 .IX Item "-passin arg" The input key password source. For more information about the format of \fBarg\fR see \*(L"Pass Phrase Options\*(R" in \fBopenssl\fR\|(1). .IP "\fB\-peerkey file\fR" 4 .IX Item "-peerkey file" The peer key file, used by key derivation (agreement) operations. .IP "\fB\-peerform PEM|DER|ENGINE\fR" 4 .IX Item "-peerform PEM|DER|ENGINE" The peer key format \s-1PEM, DER\s0 or \s-1ENGINE.\s0 Default is \s-1PEM.\s0 .IP "\fB\-pubin\fR" 4 .IX Item "-pubin" The input file is a public key. .IP "\fB\-certin\fR" 4 .IX Item "-certin" The input is a certificate containing a public key. .IP "\fB\-rev\fR" 4 .IX Item "-rev" Reverse the order of the input buffer. This is useful for some libraries (such as CryptoAPI) which represent the buffer in little endian format. .IP "\fB\-sign\fR" 4 .IX Item "-sign" Sign the input data (which must be a hash) and output the signed result. This requires a private key. .IP "\fB\-verify\fR" 4 .IX Item "-verify" Verify the input data (which must be a hash) against the signature file and indicate if the verification succeeded or failed. .IP "\fB\-verifyrecover\fR" 4 .IX Item "-verifyrecover" Verify the input data (which must be a hash) and output the recovered data. .IP "\fB\-encrypt\fR" 4 .IX Item "-encrypt" Encrypt the input data using a public key. .IP "\fB\-decrypt\fR" 4 .IX Item "-decrypt" Decrypt the input data using a private key. .IP "\fB\-derive\fR" 4 .IX Item "-derive" Derive a shared secret using the peer key. .IP "\fB\-kdf algorithm\fR" 4 .IX Item "-kdf algorithm" Use key derivation function \fBalgorithm\fR. The supported algorithms are at present \fB\s-1TLS1\-PRF\s0\fR and \fB\s-1HKDF\s0\fR. Note: additional parameters and the \s-1KDF\s0 output length will normally have to be set for this to work. See \fBEVP_PKEY_CTX_set_hkdf_md\fR\|(3) and \fBEVP_PKEY_CTX_set_tls1_prf_md\fR\|(3) for the supported string parameters of each algorithm. .IP "\fB\-kdflen length\fR" 4 .IX Item "-kdflen length" Set the output length for \s-1KDF.\s0 .IP "\fB\-pkeyopt opt:value\fR" 4 .IX Item "-pkeyopt opt:value" Public key options specified as opt:value. See \s-1NOTES\s0 below for more details. .IP "\fB\-hexdump\fR" 4 .IX Item "-hexdump" hex dump the output data. .IP "\fB\-asn1parse\fR" 4 .IX Item "-asn1parse" Parse the \s-1ASN.1\s0 output data, this is useful when combined with the \&\fB\-verifyrecover\fR option when an \s-1ASN1\s0 structure is signed. .IP "\fB\-rand file...\fR" 4 .IX Item "-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 \fB;\fR for MS-Windows, \fB,\fR for OpenVMS, and \fB:\fR for all others. .IP "[\fB\-writerand file\fR]" 4 .IX Item "[-writerand file]" Writes random data to the specified \fIfile\fR upon exit. This can be used with a subsequent \fB\-rand\fR flag. .IP "\fB\-engine id\fR" 4 .IX Item "-engine id" Specifying an engine (by its unique \fBid\fR string) will cause \fBpkeyutl\fR 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. .IP "\fB\-engine_impl\fR" 4 .IX Item "-engine_impl" When used with the \fB\-engine\fR option, it specifies to also use engine \fBid\fR for crypto operations. .SH "NOTES" .IX Header "NOTES" The operations and options supported vary according to the key algorithm and its implementation. The OpenSSL operations and options are indicated below. .PP Unless otherwise mentioned all algorithms support the \fBdigest:alg\fR option which specifies the digest in use for sign, verify and verifyrecover operations. The value \fBalg\fR should represent a digest name as used in the \&\fBEVP_get_digestbyname()\fR function for example \fBsha1\fR. This value is not used to hash the input data. It is used (by some algorithms) for sanity-checking the lengths of data passed in to the \fBpkeyutl\fR and for creating the structures that make up the signature (e.g. \fBDigestInfo\fR in \s-1RSASSA\s0 PKCS#1 v1.5 signatures). .PP This utility does not hash the input data but rather it will use the data directly as input to the signature algorithm. Depending on the key type, signature type, and mode of padding, the maximum acceptable lengths of input data differ. The signed data can't be longer than the key modulus with \s-1RSA.\s0 In case of \s-1ECDSA\s0 and \s-1DSA\s0 the data shouldn't be longer than the field size, otherwise it will be silently truncated to the field size. In any event the input size must not be larger than the largest supported digest size. .PP In other words, if the value of digest is \fBsha1\fR the input should be the 20 bytes long binary encoding of the \s-1SHA\-1\s0 hash function output. .PP The Ed25519 and Ed448 signature algorithms are not supported by this utility. They accept non-hashed input, but this utility can only be used to sign hashed input. .SH "RSA ALGORITHM" .IX Header "RSA ALGORITHM" The \s-1RSA\s0 algorithm generally supports the encrypt, decrypt, sign, verify and verifyrecover operations. However, some padding modes support only a subset of these operations. The following additional \&\fBpkeyopt\fR values are supported: .IP "\fBrsa_padding_mode:mode\fR" 4 .IX Item "rsa_padding_mode:mode" This sets the \s-1RSA\s0 padding mode. Acceptable values for \fBmode\fR are \fBpkcs1\fR for PKCS#1 padding, \fBsslv23\fR for SSLv23 padding, \fBnone\fR for no padding, \fBoaep\fR for \fB\s-1OAEP\s0\fR mode, \fBx931\fR for X9.31 mode and \fBpss\fR for \s-1PSS.\s0 .Sp In PKCS#1 padding if the message digest is not set then the supplied data is signed or verified directly instead of using a \fBDigestInfo\fR structure. If a digest is set then the a \fBDigestInfo\fR structure is used and its the length must correspond to the digest type. .Sp For \fBoaep\fR mode only encryption and decryption is supported. .Sp For \fBx931\fR if the digest type is set it is used to format the block data otherwise the first byte is used to specify the X9.31 digest \s-1ID.\s0 Sign, verify and verifyrecover are can be performed in this mode. .Sp For \fBpss\fR mode only sign and verify are supported and the digest type must be specified. .IP "\fBrsa_pss_saltlen:len\fR" 4 .IX Item "rsa_pss_saltlen:len" For \fBpss\fR mode only this option specifies the salt length. Three special values are supported: \*(L"digest\*(R" sets the salt length to the digest length, \&\*(L"max\*(R" sets the salt length to the maximum permissible value. When verifying \&\*(L"auto\*(R" causes the salt length to be automatically determined based on the \&\fB\s-1PSS\s0\fR block structure. .IP "\fBrsa_mgf1_md:digest\fR" 4 .IX Item "rsa_mgf1_md:digest" For \s-1PSS\s0 and \s-1OAEP\s0 padding sets the \s-1MGF1\s0 digest. If the \s-1MGF1\s0 digest is not explicitly set in \s-1PSS\s0 mode then the signing digest is used. .IP "\fBrsa_oaep_md:\fR\fIdigest\fR" 4 .IX Item "rsa_oaep_md:digest" Sets the digest used for the \s-1OAEP\s0 hash function. If not explicitly set then \&\s-1SHA1\s0 is used. .SH "RSA-PSS ALGORITHM" .IX Header "RSA-PSS ALGORITHM" The RSA-PSS algorithm is a restricted version of the \s-1RSA\s0 algorithm which only supports the sign and verify operations with \s-1PSS\s0 padding. The following additional \fBpkeyopt\fR values are supported: .IP "\fBrsa_padding_mode:mode\fR, \fBrsa_pss_saltlen:len\fR, \fBrsa_mgf1_md:digest\fR" 4 .IX Item "rsa_padding_mode:mode, rsa_pss_saltlen:len, rsa_mgf1_md:digest" These have the same meaning as the \fB\s-1RSA\s0\fR algorithm with some additional restrictions. The padding mode can only be set to \fBpss\fR which is the default value. .Sp If the key has parameter restrictions than the digest, \s-1MGF1\s0 digest and salt length are set to the values specified in the parameters. The digest and \s-1MG\s0 cannot be changed and the salt length cannot be set to a value less than the minimum restriction. .SH "DSA ALGORITHM" .IX Header "DSA ALGORITHM" The \s-1DSA\s0 algorithm supports signing and verification operations only. Currently there are no additional \fB\-pkeyopt\fR options other than \fBdigest\fR. The \s-1SHA1\s0 digest is assumed by default. .SH "DH ALGORITHM" .IX Header "DH ALGORITHM" The \s-1DH\s0 algorithm only supports the derivation operation and no additional \&\fB\-pkeyopt\fR options. .SH "EC ALGORITHM" .IX Header "EC ALGORITHM" The \s-1EC\s0 algorithm supports sign, verify and derive operations. The sign and verify operations use \s-1ECDSA\s0 and derive uses \s-1ECDH. SHA1\s0 is assumed by default for the \fB\-pkeyopt\fR \fBdigest\fR option. .SH "X25519 and X448 ALGORITHMS" .IX Header "X25519 and X448 ALGORITHMS" The X25519 and X448 algorithms support key derivation only. Currently there are no additional options. .SH "EXAMPLES" .IX Header "EXAMPLES" Sign some data using a private key: .PP .Vb 1 \& openssl pkeyutl \-sign \-in file \-inkey key.pem \-out sig .Ve .PP Recover the signed data (e.g. if an \s-1RSA\s0 key is used): .PP .Vb 1 \& openssl pkeyutl \-verifyrecover \-in sig \-inkey key.pem .Ve .PP Verify the signature (e.g. a \s-1DSA\s0 key): .PP .Vb 1 \& openssl pkeyutl \-verify \-in file \-sigfile sig \-inkey key.pem .Ve .PP Sign data using a message digest value (this is currently only valid for \s-1RSA\s0): .PP .Vb 1 \& openssl pkeyutl \-sign \-in file \-inkey key.pem \-out sig \-pkeyopt digest:sha256 .Ve .PP Derive a shared secret value: .PP .Vb 1 \& openssl pkeyutl \-derive \-inkey key.pem \-peerkey pubkey.pem \-out secret .Ve .PP Hexdump 48 bytes of \s-1TLS1 PRF\s0 using digest \fB\s-1SHA256\s0\fR and shared secret and seed consisting of the single byte 0xFF: .PP .Vb 2 \& openssl pkeyutl \-kdf TLS1\-PRF \-kdflen 48 \-pkeyopt md:SHA256 \e \& \-pkeyopt hexsecret:ff \-pkeyopt hexseed:ff \-hexdump .Ve .PP Decrypt some data using a private key with \s-1OAEP\s0 padding using \s-1SHA256:\s0 .PP .Vb 2 \& openssl pkeyutl \-decrypt \-in file \-inkey key.pem \-out secret \e \& \-pkeyopt rsa_padding_mode:oaep \-pkeyopt rsa_oaep_md:sha256 .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBgenpkey\fR\|(1), \fBpkey\fR\|(1), \fBrsautl\fR\|(1) \&\fBdgst\fR\|(1), \fBrsa\fR\|(1), \fBgenrsa\fR\|(1), \&\fBEVP_PKEY_CTX_set_hkdf_md\fR\|(3), \fBEVP_PKEY_CTX_set_tls1_prf_md\fR\|(3) .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2006\-2021 The OpenSSL Project Authors. All Rights Reserved. .PP Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at .