File: //usr/local/share/man/man3/Crypt::AuthEnc::ChaCha20Poly1305.3pm
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.\" ========================================================================
.\"
.IX Title "Crypt::AuthEnc::ChaCha20Poly1305 3"
.TH Crypt::AuthEnc::ChaCha20Poly1305 3 "2022-08-21" "perl v5.26.3" "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::AuthEnc::ChaCha20Poly1305 \- Authenticated encryption in ChaCha20\-Poly1305 mode
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\& ### OO interface
\& use Crypt::AuthEnc::ChaCha20Poly1305;
\&
\& # encrypt and authenticate
\& my $ae = Crypt::AuthEnc::ChaCha20Poly1305\->new($key, $iv);
\& $ae\->adata_add(\*(Aqadditional_authenticated_data1\*(Aq);
\& $ae\->adata_add(\*(Aqadditional_authenticated_data2\*(Aq);
\& my $ct = $ae\->encrypt_add(\*(Aqdata1\*(Aq);
\& $ct .= $ae\->encrypt_add(\*(Aqdata2\*(Aq);
\& $ct .= $ae\->encrypt_add(\*(Aqdata3\*(Aq);
\& my $tag = $ae\->encrypt_done();
\&
\& # decrypt and verify
\& my $ae = Crypt::AuthEnc::ChaCha20Poly1305\->new($key, $iv);
\& $ae\->adata_add(\*(Aqadditional_authenticated_data1\*(Aq);
\& $ae\->adata_add(\*(Aqadditional_authenticated_data2\*(Aq);
\& my $pt = $ae\->decrypt_add(\*(Aqciphertext1\*(Aq);
\& $pt .= $ae\->decrypt_add(\*(Aqciphertext2\*(Aq);
\& $pt .= $ae\->decrypt_add(\*(Aqciphertext3\*(Aq);
\& my $tag = $ae\->decrypt_done();
\& die "decrypt failed" unless $tag eq $expected_tag;
\&
\& #or
\& my $result = $ae\->decrypt_done($expected_tag); # 0 or 1
\&
\& ### functional interface
\& use Crypt::AuthEnc::ChaCha20Poly1305 qw(chacha20poly1305_encrypt_authenticate chacha20poly1305_decrypt_verify);
\&
\& my ($ciphertext, $tag) = chacha20poly1305_encrypt_authenticate($key, $iv, $adata, $plaintext);
\& my $plaintext = chacha20poly1305_decrypt_verify($key, $iv, $adata, $ciphertext, $tag);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Provides encryption and authentication based on ChaCha20 + Poly1305 as defined in \s-1RFC 7539\s0 \- <https://tools.ietf.org/html/rfc7539>
.SH "EXPORT"
.IX Header "EXPORT"
Nothing is exported by default.
.PP
You can export selected functions:
.PP
.Vb 1
\& use Crypt::AuthEnc::ChaCha20Poly1305 qw(chacha20poly1305_encrypt_authenticate chacha20poly1305_decrypt_verify);
.Ve
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
.SS "chacha20poly1305_encrypt_authenticate"
.IX Subsection "chacha20poly1305_encrypt_authenticate"
.Vb 1
\& my ($ciphertext, $tag) = chacha20poly1305_encrypt_authenticate($key, $iv, $adata, $plaintext);
\&
\& # $key ..... key of proper length (128 or 256 bits / 16 or 32 bytes)
\& # $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)
\& # $adata ... additional authenticated data (optional)
.Ve
.SS "chacha20poly1305_decrypt_verify"
.IX Subsection "chacha20poly1305_decrypt_verify"
.Vb 2
\& my $plaintext = chacha20poly1305_decrypt_verify($key, $iv, $adata, $ciphertext, $tag);
\& # on error returns undef
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
.Vb 1
\& my $ae = Crypt::AuthEnc::ChaCha20Poly1305\->new($key, $iv);
\&
\& # $key ..... encryption key of proper length (128 or 256 bits / 16 or 32 bytes)
\& # $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)
.Ve
.SS "adata_add"
.IX Subsection "adata_add"
Add \fBadditional authenticated data\fR.
Can be called before the first \f(CW\*(C`encrypt_add\*(C'\fR or \f(CW\*(C`decrypt_add\*(C'\fR;
.PP
.Vb 1
\& $ae\->adata_add($aad_data); # can be called multiple times
.Ve
.SS "encrypt_add"
.IX Subsection "encrypt_add"
.Vb 1
\& $ciphertext = $ae\->encrypt_add($data); # can be called multiple times
.Ve
.SS "encrypt_done"
.IX Subsection "encrypt_done"
.Vb 1
\& $tag = $ae\->encrypt_done(); # returns $tag value
.Ve
.SS "decrypt_add"
.IX Subsection "decrypt_add"
.Vb 1
\& $plaintext = $ae\->decrypt_add($ciphertext); # can be called multiple times
.Ve
.SS "decrypt_done"
.IX Subsection "decrypt_done"
.Vb 3
\& my $tag = $ae\->decrypt_done; # returns $tag value
\& #or
\& my $result = $ae\->decrypt_done($tag); # returns 1 (success) or 0 (failure)
.Ve
.SS "set_iv"
.IX Subsection "set_iv"
.Vb 2
\& my $ae = Crypt::AuthEnc::ChaCha20Poly1305\->new($key)\->set_iv($iv);
\& # $iv ...... initialization vector (64 or 96 bits / 8 or 12 bytes)
.Ve
.SS "set_iv_rfc7905"
.IX Subsection "set_iv_rfc7905"
See <https://tools.ietf.org/html/rfc7905>
.PP
.Vb 3
\& my $ae = Crypt::AuthEnc::ChaCha20Poly1305\->new($key)\->set_iv_rfc7905($iv, $seqnum);
\& # $iv ...... initialization vector (96 bits / 12 bytes)
\& # $seqnum .. 64bit integer (sequence number)
.Ve
.SS "clone"
.IX Subsection "clone"
.Vb 1
\& my $ae_new = $ae\->clone;
.Ve
.SH "SEE ALSO"
.IX Header "SEE ALSO"
.IP "\(bu" 4
CryptX, Crypt::AuthEnc::GCM, Crypt::AuthEnc::CCM, Crypt::AuthEnc::EAX, Crypt::AuthEnc::OCB
.IP "\(bu" 4
<https://tools.ietf.org/html/rfc7539>