digest#

Finalise the context and return the 16-byte raw binary digest.

Synopsis#

my $bin = $ctx->digest;       # exactly 16 bytes

What you get back#

A 16-byte Perl string holding the raw digest. This is the most compact representation — handy for binary protocols or packing into fixed-width records — but it typically contains non-printable bytes, so do not paste it into log lines without encoding.

digest is destructive. After it returns, the context is automatically reset to the empty state and is immediately ready to digest a new message. To read the digest without destroying the state, use $ctx->clone->digest instead.

Examples#

Raw bytes, then convert to hex by hand:

my $bin = Digest::MD5->new->add("abc")->digest;
printf "%v02x\n", $bin;   # 90.01.50.98.3c.d2.4f.b0.d6.96.3f.7d.28.e1.7f.72

Pack into a fixed-width binary record:

my $record = pack("A16 a16", $filename, $ctx->digest);

Peek at an intermediate digest without resetting:

my $snapshot = $ctx->clone->digest;   # $ctx keeps going
$ctx->add($more);

Edge cases#

Called on a context with no data added, returns the MD5 of the empty string (d41d8cd98f00b204e9800998ecf8427e as hex).
Resets before returning, so calling digest twice in a row without adding data between the calls gives the empty-string digest the second time.

Differences from upstream#

Fully compatible with upstream Digest::MD5 2.58.