TL;DR: Checking that amavisd-new or sympa still work ok when dropping this change: OK All tested against the package in the ppa. A. Code Insights: No one of the packages calls directly or indirectly the added (and removed here) code. In both cases, an 'ack ed25519' search doesn't return anything. Files modified by these MP are lib/Mail/DKIM/Signature.pm lib/Mail/DKIM/Verifier.pm -- > Modified functions _check_and_verify_signature → private, called by finish_body lib/Mail/DKIM/PublicKey.pm lib/Mail/DKIM/Algorithm/ed25519_sha256.pm A.1. Sympa: sympa ------------- ❯ ack Mail::DKIM::Signature ❯ ack Mail::DKIM::PublicKey ❯ ack Mail::DKIM::Verifier cpanfile 182:recommends 'Mail::DKIM::Verifier', '>= 0.37'; 272:feature 'Mail::DKIM::Verifier', 'Required in order to use DKIM features (both for signature verification and signature insertion).' => sub { 273: requires 'Mail::DKIM::Verifier', '>= 0.37'; src/lib/Sympa/Message.pm 648: eval 'use Mail::DKIM::Verifier'; 655: return unless $Mail::DKIM::Verifier::VERSION; 668: unless ($dkim = Mail::DKIM::Verifier->new()) { 669: $log->syslog('err', 'Could not create Mail::DKIM::Verifier'); Checking Algorithm used is rsa: ❯ ack -C2 Algorithm src/lib/Sympa/Message.pm 502- # create a signer object 503- my $dkim = Mail::DKIM::Signer->new( 504: Algorithm => "rsa-sha256", 505- Method => "relaxed", 506- Domain => $dkim_d, -- 600- # create a signer object 601- my $arc = Mail::DKIM::ARC::Signer->new( 602: Algorithm => "rsa-sha256", 603- Chain => $arc_cv, 604- SrvId => $arc_srvid, A.2. amavisd-new: amavisd-new ------------------- ❯ ack Mail::DKIM::Signature lib/Amavis/Tools.pm 116: $dkim->add_signature( Mail::DKIM::Signature->new( lib/Amavis/DKIM.pm 27:use Mail::DKIM::Signature; 336:# returning them as a list of Mail::DKIM::Signature objects 694: $dkim->add_signature( Mail::DKIM::Signature->new( 838: # map a Mail::DKIM::Signature result into an RFC 7601 result value ❯ ack Mail::DKIM::PublicKey ❯ ack Mail::DKIM::Verifier lib/Amavis.pm 900: Net::Patricia Net::LDAP Mail::SpamAssassin Mail::DKIM::Verifier 6221: if (!defined $dns_resolver && Mail::DKIM::Verifier->VERSION >= 0.40) { 6223: # of Mail::DKIM::Verifier; this avoids repeating initializations 6254: $dkim_verifier = Mail::DKIM::Verifier->new; lib/Amavis/SpamControl/SpamAssassin.pm 123: push(@modules, qw(Mail::DKIM Mail::DKIM::Verifier Net::DNS::Resolver)) lib/Amavis/Tools.pm 139: my $dkim_verifier = Mail::DKIM::Verifier->new; 140: $dkim_verifier or die "Could not create a Mail::DKIM::Verifier object"; lib/Amavis/DKIM.pm 24:use Mail::DKIM::Verifier 0.31; Checking Algorithm used is rsa: ❯ ack -C2 Algorithm lib/Amavis/Tools.pm 116- $dkim->add_signature( Mail::DKIM::Signature->new( 117- Selector => $selector_ace, Domain => $domain_ace, 118: Method => 'simple/simple', Algorithm => 'rsa-sha256', 119- Timestamp => int($now), Expiration => int($now)+24*3600, Key => $key, 120- )); under; lib/Amavis/DKIM.pm 299- 300-# a CustomSigner callback routine passed to Mail::DKIM in place of a key; 301:# the routine will be called by Mail::DKIM::Algorithm::*rsa_sha* routines 302-# instead of calling their own Mail::DKIM::PrivateKey::sign_digest() B. Tests : We don't have a baseline for testing sympa. For amavisd-new it's Ok (DEP-8 and building tests). B.1. Sympa Sympa hasn't got an autopackage DEP-8 tests suite. It has the build tests marked as 'nocheck', so overrided. I removed this on d/rules to run it and I have to add more dependencies to make it works, because now is: Test Summary Report ------------------- t/DataSource_LDAP2.t (Wstat: 512 (exited 2) Tests: 0 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output t/DatabaseManager.t (Wstat: 512 (exited 2) Tests: 1 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output t/LockedFile.t (Wstat: 512 (exited 2) Tests: 0 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output t/Message_smime.t (Wstat: 512 (exited 2) Tests: 0 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output t/Message_urlize.t (Wstat: 512 (exited 2) Tests: 1 Failed: 1) Failed test: 1 Non-zero exit status: 2 Parse errors: No plan found in TAP output t/Request_Handler_add+del.t (Wstat: 512 (exited 2) Tests: 0 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output t/Scenario.t (Wstat: 65280 (exited 255) Tests: 1 Failed: 1) Failed test: 1 Non-zero exit status: 255 Parse errors: No plan found in TAP output t/WWW_Tools.t (Wstat: 65280 (exited 255) Tests: 1 Failed: 1) Failed test: 1 Non-zero exit status: 255 Parse errors: No plan found in TAP output t/compile_scenarios.t (Wstat: 512 (exited 2) Tests: 0 Failed: 0) Non-zero exit status: 2 Parse errors: No plan found in TAP output Files=24, Tests=546, 45 wallclock secs ( 0.13 usr 0.06 sys + 6.55 cusr 1.29 csys = 8.03 CPU) Result: FAIL Failed 9/24 test programs. 3/546 subtests failed. I found mention of dkim only I'm a regex on Scenario.t and it seems that it's not used in the tests conf per: dkim_feature off in t/data/sympa.conf B.2. Amavisd-new DEP8 tests: autopkgtest [14:14:59]: @@@@@@@@@@@@@@@@@@@@ summary test-config PASS qemu-system-x86_64: terminating on signal 15 from pid 144670 (/usr/bin/python3) Build tests: All tests successful. Files=67, Tests=216, 8 wallclock secs ( 0.18 usr 0.08 sys + 6.44 cusr 1.81 csys = 8.51 CPU) Result: PASS And related to DKIM: # Amavis::DKIM::CustomSignerTest->constructor t/Amavis/DKIM/CustomSignerTest.t ......... 1..4 ok 1 - use Amavis::DKIM::CustomSigner; ok 2 - Amavis::DKIM::CustomSigner->can('new') ok 3 - ... and the constructor should succeed ok 4 - '... and the object it returns' isa 'Amavis::DKIM::CustomSigner' ok # # Amavis::DKIMTest->empty t/Amavis/DKIMTest.t ...................... ok 1 - use Amavis::DKIM; 1..1 ok