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.\" ========================================================================
.\"
.IX Title "Crypt::PRNG 3pm"
.TH Crypt::PRNG 3pm "2020-11-09" "perl v5.32.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.nh
.SH "NAME"
Crypt::PRNG \- Cryptographically secure random number generator
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 3
\&   ### Functional interface:
\&   use Crypt::PRNG qw(random_bytes random_bytes_hex random_bytes_b64 random_bytes_b64u
\&                      random_string random_string_from rand irand);
\&
\&   $octets = random_bytes(45);
\&   $hex_string = random_bytes_hex(45);
\&   $base64_string = random_bytes_b64(45);
\&   $base64url_string = random_bytes_b64u(45);
\&   $alphanumeric_string = random_string(30);
\&   $string = random_string_from(\*(AqACGT\*(Aq, 64);
\&   $floating_point_number_0_to_1 = rand;
\&   $floating_point_number_0_to_88 = rand(88);
\&   $unsigned_32bit_int = irand;
\&
\&   ### OO interface:
\&   use Crypt::PRNG;
\&
\&   $prng = Crypt::PRNG\->new;
\&   #or
\&   $prng = Crypt::PRNG\->new("RC4");
\&   #or
\&   $prng = Crypt::PRNG\->new("RC4", "some data used for seeding PRNG");
\&
\&   $octets = $prng\->bytes(45);
\&   $hex_string = $prng\->bytes_hex(45);
\&   $base64_string = $prng\->bytes_b64(45);
\&   $base64url_string = $prng\->bytes_b64u(45);
\&   $alphanumeric_string = $prng\->string(30);
\&   $string = $prng\->string_from(\*(AqACGT\*(Aq, 64);
\&   $floating_point_number_0_to_1 = $prng\->double;
\&   $floating_point_number_0_to_88 = $prng\->double(88);
\&   $unsigned_32bit_int = $prng\->int32;
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Provides an interface to the ChaCha20 based pseudo random number generator (thread-safe and fork-safe).
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
.SS "random_bytes"
.IX Subsection "random_bytes"
.Vb 1
\&   $octets = random_bytes($length);
.Ve
.PP
Returns \f(CW$length\fR random octects.
.SS "random_bytes_hex"
.IX Subsection "random_bytes_hex"
.Vb 1
\&   $hex_string = random_bytes_hex($length);
.Ve
.PP
Returns \f(CW$length\fR random octects encoded as hexadecimal string.
.SS "random_bytes_b64"
.IX Subsection "random_bytes_b64"
.Vb 1
\&   $base64_string = random_bytes_b64($length);
.Ve
.PP
Returns \f(CW$length\fR random octects Base64 encoded.
.SS "random_bytes_b64u"
.IX Subsection "random_bytes_b64u"
.Vb 1
\&   $base64url_string = random_bytes_b64u($length);
.Ve
.PP
Returns \f(CW$length\fR random octects Base64 \s-1URL\s0 Safe (\s-1RFC 4648\s0 section 5) encoded.
.SS "random_string_from"
.IX Subsection "random_string_from"
.Vb 3
\&   $string = random_string_from($range, $length);
\&   #e.g.
\&   $string = random_string_from("ABCD", 10);
.Ve
.PP
Returns a random string made of \f(CW$length\fR chars randomly chosen from \f(CW$range\fR string.
.SS "random_string"
.IX Subsection "random_string"
.Vb 3
\&   $alphanumeric_string = random_string($length);
\&   #or
\&   $alphanumeric_string = random_string;  # default length = 20
.Ve
.PP
Similar to random_string_from, only \f(CW$range\fR is fixed to \f(CW\*(AqABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\*(Aq\fR.
.SS "rand"
.IX Subsection "rand"
.Vb 3
\&   $n = rand;
\&   #or
\&   $n = rand($limit);
.Ve
.PP
Returns a random floating point number from range \f(CW\*(C`[0,1)\*(C'\fR (if called without parameter) or \f(CW\*(C`[0,$limit)\*(C'\fR.
.SS "irand"
.IX Subsection "irand"
.Vb 1
\&   $i = irand;
.Ve
.PP
Returns a random unsigned 32bit integer \- range \f(CW\*(C`0 .. 0xFFFFFFFF\*(C'\fR.
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
.Vb 5
\&   $prng = Crypt::PRNG\->new;
\&   #or
\&   $prng = Crypt::PRNG\->new($alg);
\&   #or
\&   $prng = Crypt::PRNG\->new($alg, $seed);
\&
\&   # $alg  ... algorithm name \*(AqFrotuna\*(Aq (DEFAULT), \*(AqRC4\*(Aq, \*(AqSober128\*(Aq or \*(AqYarrow\*(Aq
\&   # $seed ... will be used as an initial entropy for seeding PRNG
.Ve
.PP
If \f(CW$seed\fR is not specified the \s-1PRNG\s0 is automatically seeded with 32bytes random data taken from \f(CW\*(C`/dev/random\*(C'\fR (\s-1UNIX\s0) or \f(CW\*(C`CryptGenRandom\*(C'\fR (Win32)
.SS "add_entropy"
.IX Subsection "add_entropy"
.Vb 3
\&  $prng\->add_entropy($random_data);
\&  #or
\&  $prng\->add_entropy();
.Ve
.PP
If called without parameter it uses 32bytes random data taken from \f(CW\*(C`/dev/random\*(C'\fR (\s-1UNIX\s0) or \f(CW\*(C`CryptGenRandom\*(C'\fR (Win32).
.PP
\&\fB\s-1BEWARE:\s0\fR you probably do not need this function at all as the module does automatic seeding on initialization as well as reseeding after fork and thread creation.
.SS "bytes"
.IX Subsection "bytes"
.Vb 1
\&   $octets = $prng\->bytes($length);
.Ve
.PP
See random_bytes
.SS "bytes_hex"
.IX Subsection "bytes_hex"
.Vb 1
\&   $hex_string = $prng\->bytes_hex($length);
.Ve
.PP
See random_bytes_hex
.SS "bytes_b64"
.IX Subsection "bytes_b64"
.Vb 1
\&   $base64_string = $prng\->bytes_b64($length);
.Ve
.PP
See random_bytes_b64
.SS "bytes_b64u"
.IX Subsection "bytes_b64u"
.Vb 1
\&   $base64url_string = $prng\->bytes_b64u($length);
.Ve
.PP
See random_bytes_b64u
.SS "string"
.IX Subsection "string"
.Vb 3
\&   $alphanumeric_string = $prng\->string($length);
\&   #or
\&   $alphanumeric_string = $prng\->string;
.Ve
.PP
See random_string
.SS "string_from"
.IX Subsection "string_from"
.Vb 1
\&   $string = $prng\->string_from($range, $length);
.Ve
.PP
See random_string_from
.SS "double"
.IX Subsection "double"
.Vb 3
\&   $n = $prng\->double;
\&   #or
\&   $n = $prng\->double($limit);
.Ve
.PP
See rand
.SS "int32"
.IX Subsection "int32"
.Vb 1
\&   $i = $prng\->int32;
.Ve
.PP
See irand
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Crypt::PRNG::Fortuna, Crypt::PRNG::RC4, Crypt::PRNG::Sober128, Crypt::PRNG::Yarrow