[STUD-79136]: Configurable PGP key size, IResource inputs, paired-property normalization

[alexandru-petre]

Problem Statement

The Cryptography pack accumulated several pain points since the v2.0 release:

1. PGP key generation hardcoded to RSA-1024, considered weak since 2010 (STUD-79136 calls for configurable key size, enterprise-grade default).
2. No AEAD ciphers — only legacy CBC modes; modern interop expects AESGCM / ChaCha20-Poly1305.
3. Symmetric-cipher wire format incompatibility with third-party PGP tooling — STUD-64429 surfaced cases where ServiceNow / devglan / OpenSSL ciphertext couldn't be decrypted (and vice versa) due to the deliberate PBKDF2-salt + random-IV format.
4. No storage-resource (IResource) inputs — file activities only accepted local string paths.
5. Three different patterns for path ↔ IResource and string ↔ SecureString toggles across the pack (switch-strict, switch-fallback, HasValue-inference); [OverloadGroup] on the existing PGP sign / clear-sign / verify activities was misused (validator rejected any XAML that bound both file + key inputs).
6. NuGet packaging emits deprecation warnings on every build (NU5125, NU5048).
7. Activity class names mismatch display names for the PGP activities, hurting Studio's search experience.
8. PGP was silently treated as FIPS-compliant in IsFipsCompliant, even though the underlying PgpCore + BouncyCastle path is not a CMVP-validated module. The dropdown label and design-time warning didn't surface this either.

Analysis

The work splits into a few intertwined themes across the 39 Cryptography-scoped commits on this branch. The PGP signing primitives themselves (Sign / Clearsign / Verify / GenerateKey) were already on develop via PR #514; this PR makes them production-ready and unifies the pack:

• PGP hardening (STUD-79136) — RsaKeySize enum (2048 / 3072 / 4096) defaulting to 4096; SHA-256 hashing; AES-256 session keys; renamed PgpGenerateKeyPair.Username → UserId to match OpenPGP convention.
• AEAD cipher modernization — added AESGCM and ChaCha20-Poly1305; marked the older CBC ciphers obsolete; new default for EncryptionAlgorithm is AESGCM.
• Symmetric interop diagnostics (STUD-64429) — documented the wire format (docs/symmetric-wire-format.md) and emit a localized hint pointing at the spec when foreign-format ciphertext fails to decrypt.
• IResource storage inputs — paired path / IResource properties on every file activity (Encrypt / Decrypt / Hash / Pgp*) with viewmodel menu-action toggles and runtime resolution.
• SecureString passphrase support — paired plain / secure passphrase properties on all six PGP-passphrase-bearing activities.
• OverloadGroup fix on PGP sign / clear-sign / verify — distinct [OverloadGroup] names made the file + key pairs mutually exclusive at the validator level, which broke every valid XAML. Replaced with runtime fallback resolution.
• Paired-property normalization — every pair across the pack now follows one template: no dedicated *InputModeSwitch enum, viewmodel uses pure HasValue-inference for initial mode, runtime resolves via string-first fallback. Kept obsolete switches that existed on origin/masters/Cryptography for XAML deserialization compatibility; deleted switches that were only ever added since the last release.
• PGP activity renames for Studio search alignment: PgpGenerateKeyPair → PgpGenerateKeys (matches display "PGP Generate Keys"), PgpClearSignFile → PgpClearsignFile (matches GnuPG --clearsign spelling and RFC 9580 "cleartext signature"). PgpSignFile and PgpVerify already matched.
• FIPS classification correctness — IsFipsCompliant(PGP) now returns false (PgpCore + open-source BouncyCastle is not a CMVP-validated module). The dropdown label changed PGP (Pretty Good Privacy) → PGP - Pretty Good Privacy (Non-FIPS) to match how other non-FIPS ciphers are labeled, and the existing yellow design-time FipsComplianceWarning now also surfaces when PGP is selected (the Algorithm != PGP && short-circuit was removed from the four CacheMetadata methods).
• Packaging cleanup — removed deprecated <PackageLicenseUrl> / <PackageIconUrl> in favor of <PackageLicenseFile> (the existing LICENSE.md now ships in the .nupkg) and <PackageProjectUrl>.

Considered Use Cases

• PGP key generation: RSA-2048 / 3072 / 4096; legacy XAML omitting KeySize defaults to 4096.
• Symmetric encryption: AESGCM / ChaCha20-Poly1305 (new), AES / DES / RC2 / Rijndael / TripleDES (obsolete but still functional for back-compat).
• PGP encrypt / decrypt with optional sign / verify; passphrase as string or SecureString.
• PGP sign / clearsign / verify: binary signature, clearsign cleartext signature, public-key validation modes.
• IResource inputs: storage-bucket resource provided in place of a local file path (input file, public / private key file).
• Three customer workflows reported during development: full sign → clearsign → verify pipeline; EncryptText + DecryptText with sign + verify; EncryptFile + DecryptFile with sign + verify — all three covered by new end-to-end regression tests.
• Interop with third-party PGP tooling (STUD-64429): runtime error now hints at the wire-format spec instead of producing an opaque CryptographicException.
• FIPS-locked machines: PGP now visibly flagged as non-FIPS in the dropdown and triggers the standard design-time warning, so operators can make an informed choice before deployment.

Implementation

New files (4 truly new + 3 renamed-with-rewrite):

• UiPath.Cryptography/Enums/RsaKeySize.cs — 2048 / 3072 / 4096.
• UiPath.Cryptography.Activities/Helpers/PgpFileResolver.cs — shared string-first fallback for path ↔ IResource and string ↔ SecureString.
• Activities/Cryptography/docs/symmetric-wire-format.md — STUD-64429 spec.
• UiPath.Cryptography.Activities.Tests/Resources/ActivityMetadataTests.cs — metadata invariant checks.
• PgpGenerateKeys.cs (renamed + rewritten from PgpGenerateKeyPair.cs), PgpClearsignFile.cs (renamed + rewritten from PgpClearSignFile.cs), and the matching viewmodels.

Modified (~57 files):

• All file-based Encrypt / Decrypt / Hash / PGP activities — IResource pair properties, OutputFilePath fallback to input directory, sentence-case display-name fixes, paired-property template normalization, uniform IsFipsCompliant check (no PGP short-circuit).
• ViewModels — pure HasValue-inference for initial mode, switch handlers null the inactive side, no writes to obsolete *InputModeSwitch enums.
• CryptographyHelper.cs — added AESGCM / ChaCha20-Poly1305; documented obsolete-cipher rationale; corrected IsFipsCompliant(PGP) to return false.
• UiPath.Cryptography.resx — PGP label gets the (Non-FIPS) suffix, parens around the long form replaced with a hyphen for legibility.
• ActivitiesMetadata.json, English .resx, Designer.cs accessors — kept in lock-step with class / property renames and switch deletions.

Removed: deprecated <PackageLicenseUrl> / <PackageIconUrl> in the Packaging csproj.

Caveats / Potential Issues

• IsFipsCompliant(PGP) semantics flipped from true to false. This now produces an observable yellow design-time warning when the algorithm is selected — that's the intended behavior, but it is a new warning that didn't appear in v2.0 for workflows that had been authored against PGP.
• Locale .resx files are intentionally stale for new keys added on this branch (Passphrase / Passphrase Secure, IResource displays, UserId, normalized pair entries). The resource manager falls back to English for missing keys. A translation pass is a follow-up.
• Kept-obsolete switches (KeyInputModeSwitch on Encrypt / Decrypt / Hash, FileInputModeSwitch on Encrypt / Decrypt) are still declared on the activity class for XAML back-compat with already-published workflows. They're [Browsable(false)] [Obsolete] and never read by the viewmodel or runtime — deserialization is by construction (property exists on the class), not verified by a load-an-XAML test.
• Async PGP sign / clearsign / verify: no design-time validation for the file path ↔ IResource pair (runtime fallback handles it). Matches the rest of the pack now.
• OutputFileName + OutputFilePath both set: pre-existing behavior preserved (FileName silently ignored when FilePath is also set). Documented as an open item; no reported customer impact.

How to Test

1. dotnet build Activities/Activities.Cryptography.sln — expect 0 errors and 1 pre-existing unrelated CS1998 warning (CryptographyLocalItem.cs:73). NU5125 / NU5048 should be gone.
2. dotnet test Activities/Activities.Cryptography.sln — expect 518 / 518 passing.
3. Targeted customer-workflow regressions: dotnet test --filter "FullyQualifiedName~RoundTrip|FullyQualifiedName~EndToEnd" — 12 passing (covers the three customer XAMLs reported during development).
4. Manual smoke in Studio:
   • Drop PGP Generate Keys; verify the KeySize dropdown shows 2048 / 3072 / 4096 and defaults to 4096.
   • Sign → Verify with PGP Sign File + PGP Verify (binary mode).
   • Clearsign → Verify with PGP Clearsign File + PGP Verify (Clearsigned File mode).
   • Search the activity panel for PGP and Generate Keys — both should surface the activity (renames make the class names match the display names).
   • On Encrypt File (or any of the four symmetric activities), open the Algorithm dropdown — PGP - Pretty Good Privacy (Non-FIPS) should be visible. Select it: the yellow FipsComplianceWarning should appear in the designer next to the activity.