Add back support for RSA for legacy deployed CTLogs. (#341)

* Add back support for RSA for legacy deployed CTLogs.

Signed-off-by: Ville Aikas <vaikas@chainguard.dev>

* remove cruft, comments about cast to signer.

Signed-off-by: Ville Aikas <vaikas@chainguard.dev>

Signed-off-by: Ville Aikas <vaikas@chainguard.dev>

go.mod

@@ -1,13 +1,14 @@
 module github.com/sigstore/scaffolding
 
-go 1.18
+go 1.19
 
 require (
 	github.com/go-openapi/strfmt v0.21.3
 	github.com/go-openapi/swag v0.22.3
 	github.com/go-sql-driver/mysql v1.6.0
 	github.com/golang/glog v1.0.0
 	github.com/google/certificate-transparency-go v1.1.3
+	github.com/google/go-cmp v0.5.8
 	github.com/google/trillian v1.5.0
 	github.com/google/uuid v1.3.0
 	github.com/hashicorp/hcl v1.0.0
@@ -17,10 +18,10 @@ require (
 	github.com/sigstore/cosign v1.11.1
 	github.com/sigstore/fulcio v0.5.3
 	github.com/sigstore/rekor v0.11.0
-	github.com/sigstore/sigstore v1.4.0
-	github.com/theupdateframework/go-tuf v0.3.1
+	github.com/sigstore/sigstore v1.4.1-0.20220908184735-abe183b160e9
+	github.com/theupdateframework/go-tuf v0.5.0
 	github.com/titanous/rocacheck v0.0.0-20171023193734-afe73141d399
-	golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa
+	golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90
 	google.golang.org/genproto v0.0.0-20220805133916-01dd62135a58
 	google.golang.org/grpc v1.49.0
 	google.golang.org/protobuf v1.28.1
@@ -43,7 +44,7 @@ require (
 	contrib.go.opencensus.io/exporter/stackdriver v0.13.12 // indirect
 	github.com/Microsoft/go-winio v0.5.2 // indirect
 	github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d // indirect
-	github.com/aws/aws-sdk-go v1.44.80 // indirect
+	github.com/aws/aws-sdk-go v1.44.93 // indirect
 	github.com/benbjohnson/clock v1.1.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bgentry/speakeasy v0.1.0 // indirect
@@ -56,7 +57,7 @@ require (
 	github.com/cncf/xds/go v0.0.0-20211130200136-a8f946100490 // indirect
 	github.com/common-nighthawk/go-figure v0.0.0-20210622060536-734e95fb86be // indirect
 	github.com/containerd/stargz-snapshotter/estargz v0.12.0 // indirect
-	github.com/coreos/go-oidc/v3 v3.2.0 // indirect
+	github.com/coreos/go-oidc/v3 v3.3.0 // indirect
 	github.com/coreos/go-semver v0.3.0 // indirect
 	github.com/coreos/go-systemd/v22 v22.3.2 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
@@ -93,7 +94,6 @@ require (
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/btree v1.1.2 // indirect
-	github.com/google/go-cmp v0.5.8 // indirect
 	github.com/google/go-containerregistry v0.11.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.1.0 // indirect
@@ -156,7 +156,7 @@ require (
 	github.com/spiffe/go-spiffe/v2 v2.1.1 // indirect
 	github.com/stretchr/testify v1.8.0 // indirect
 	github.com/subosito/gotenv v1.3.0 // indirect
-	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 // indirect
+	github.com/syndtr/goleveldb v1.0.1-0.20220721030215-126854af5e6d // indirect
 	github.com/tent/canonical-json-go v0.0.0-20130607151641-96e4ba3a7613 // indirect
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20201229170055-e5319fda7802 // indirect
 	github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce // indirect
@@ -191,15 +191,15 @@ require (
 	go.uber.org/multierr v1.8.0 // indirect
 	go.uber.org/zap v1.22.0 // indirect
 	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
-	golang.org/x/net v0.0.0-20220805013720-a33c5aa5df48 // indirect
-	golang.org/x/oauth2 v0.0.0-20220722155238-128564f6959c // indirect
+	golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b // indirect
+	golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094 // indirect
 	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4 // indirect
-	golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 // indirect
+	golang.org/x/sys v0.0.0-20220907062415-87db552b00fd // indirect
 	golang.org/x/term v0.0.0-20220526004731-065cf7ba2467 // indirect
 	golang.org/x/text v0.3.8-0.20211004125949-5bd84dd9b33b // indirect
 	golang.org/x/time v0.0.0-20220722155302-e5dcc9cfc0b9 // indirect
 	golang.org/x/tools v0.1.12 // indirect
-	google.golang.org/api v0.93.0 // indirect
+	google.golang.org/api v0.95.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	gopkg.in/cheggaaa/pb.v1 v1.0.28 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect