- Update README to point to https://sshnet.github.io/SSH.NET rather than the CHM file
- Add a CONTRIBUTING.md with some how-tos
For https://sshnet.github.io/SSH.NET:
- Use the repo README as the landing page to keep them in sync
- Combine the API-per-TFM pages to just one "API" page
- Add a couple more examples
- Add a GitHub link in the header.
* Use BCL for RSA
* Restore benchmark (with quirks for old code)
* Fixup benchmark (remove compatibility with old code)
* cosmetic tweaks
* Add a regression test for #1388
* Fix SocketAsyncEventArgsAwaitable calling continuation multiple times
* Use Interlocked.Exchange
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Add timeouts when reading from sockets in Socks5Connector
* Add a Socks5 timeout test for a connection reply
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Implement OpenSSH strict key exchange extension
* The pseudo-algorithm
is only valid in the initial SSH2_MSG_KEXINIT and MUST be ignored
if they are present in subsequent SSH2_MSG_KEXINIT packets.
* Only send strict kex pseudo algorithm for the first kex.
Strictly disable non-kex massages in strict kex mode.
* Unit tests for strict kex
* More unit tests
* More unit tests
* Correct file name
* Update SessionTest_ConnectingBase.cs
* More unit tests
* Delete SessionTest_Connecting_ServerSendsMaxIgnoreMessagesBeforeKexInit.cs
* Add a comment about throwing exception when inbound sequence number is about to wrap during init kex.
* Delete SessionTest_Connecting_ServerSendsDebugMessageAfterKexInit_NoStrictKex.cs
* Fix build
* Update test/Renci.SshNet.Tests/Classes/SessionTest_Connected.cs
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Init AeadCipher
* Move AeadCipher to parent folder. Move EncryptBlock/DecryptBlock from SymmetricCipher to BlockCipher
* simplify parameter name
* Implement AesGcmCipher
* Update README
* Remove protected IV from AeadCipher; Set offset to outbound sequence just like other ciphers
* Rename associatedData to packetLengthField
* Use Span<byte> to avoid unnecessary allocations
* Use `Span` to improve performance when `IncrementCounter()`
* Add `IsAead` property to `CipherInfo`. Include packet length field and tag field in offset and length when call AesGcm's `Decrypt(...)` method. Do not determine HMAC if cipher is AesGcm during kex.
* Fix build
* Fix UT
* Check `AesGcm.IsSupported` before add to the `Encryptions` collection.
Guard AES-GCM with `NET6_0_OR_GREATER`.
Insert AES-GCM ciphers right after AES-CTR ciphers but before AES-CBC ciphers, which is similar with OpenSSH:
```
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
```
Although Dictionary's order is not defined, from observation, it is in the same order with add. Anyway that would be another topic.
* Suppress CA1859 "Use concrete types when possible for improved performance" for `ConnectionInfo.Encryptions`.
Test `Aes128Gcm` and `Aes256Gcm` only when `NET6_0_OR_GREATER`
* Update xml doc comments. Do not treat AesGcmCipher separately in Session.cs
* Fix build
* Fix build
* Update the comment as ChaCha20Poly1305 uses a separated key to encypt the packet length and the size it 4.
* Update src/Renci.SshNet/Security/Cryptography/Cipher.cs
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Make `AesGcmCipher` internal.
Assert offset when decrypt.
* Fix nullable error in build
* typos
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Integrate `ZLibStream` from .NET 6.0+ with SSH.NET.
* OpenSSH server does not support zlib (pre-auth); OpenSSH client still supports zlib (pre-auth)
* Correct compression algorithm name; Update README.md
* Integrate `ZLibStream` from .NET 6.0+ with SSH.NET.
* OpenSSH server does not support zlib (pre-auth); OpenSSH client still supports zlib (pre-auth)
* Correct compression algorithm name; Update README.md
* Test the compression by upload/download file
* Refactor compression.
* Move delayed compression logic to base class.
* seal Zlib
* update unit test
* update unit test to see if it can trigger integration test
* Flush zlibStream
* Fix integration test
* update test
* Update ConnectionInfo.cs
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Update README.md
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Handle unknown channel messages correctly
See discussion #1218 . Some servers send custom channel messages
like 'keepalive@proftpd.org' as keep alive messages. This currently
causes a NotSupportedException.
According to the spec https://datatracker.ietf.org/doc/html/rfc4254#section-5.4 :
"If the request is not recognized or is not
supported for the channel, SSH_MSG_CHANNEL_FAILURE is returned."
Send a failure message back instead of throwing an exception.
* consider WantReply before sending failure reply
* Use RemoteChannelNumber for failure message
* fix wrong ChannelNumber in SshCommand Channel Response
not directly related to the PR, was noticed during Code Review.
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* SftpClient: handle the SFTP session being closed by the server
If the server closes the SFTP session but keeps the TCP connection open,
this currently causes IsConnected to return true, but any operation
fails with "the session is not open".
SftpClient.IsConnected now also check sftpSession.IsOpen. Connect()
and ConnectAsync() were reworked to take into account that the Session
may already/still be open, but the SFTP session may not. This is needed
so a reconnect works.
fixes#843 and #1153
* Always re-create session
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
Co-authored-by: Igor Milavec <igor.milavec@gmail.com>
* Fixed warnings in tests.
* Fixed warnings in main project.
* Fix public key.
* Further warning cleanup.
* Muted remaining warnings.
* Final cleanup.
* Fix warning.
* Fix test classes.
* Fix more internals.
* Revert "internal" in test projects
* Revert more internals.
* Revert all non-analyzer changes.
---------
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Fix CancelAsync Cause Deadlock
* Fix CancelAsync Cause Deadlock
* Support manual cancelling if exit-signal does not cancel
* Fix switch with duplicate case
* Revert wait exit response, use existing OperationCancelledException
* Not executing callback when command is cancelled
* Add `Closed` event to `ShellStream`. Lib consumer could hook to this event to detect if channel is closed by server **in time**.
* handle `Closed` event on different thread. No need to block original thread.
* Updated dependencies.
* Reverted Microsoft.Bcl.AsyncInterfaces back to version 1.0.0.
Also added a note so we no longer try to upgrade it.
* Reverted back to Moq.
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Added guard clauses to various timeouts to ensure they don't exceed an Int32 in milliseconds.
* Fixed guard clauses.
* Updated build tags.
* Added guard clauses to various timeouts to ensure they don't exceed an Int32 in milliseconds.
* Fixed tests.
* Added additional tests.
* Replaced NoWarn with .editorconfig setting
* Fixed references to parameter names.
* Restore Write/Flush tests
* Restore write buffer to ShellStream and painfully fix the mocks
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Fix a few issues with ShellStream
The main change is to replace the Queue<byte> with a byte[] and a couple of
variables which index the start and end of the data. The remainder is mainly
slightly more careful locking semantics.
It also implements Expect(string) separately so that it can work on the bytes
and skip a lot of encoding work (this is where I wish ShellStream derived from
StreamReader).
One possibly contentious point: in fixing the Write behaviour I chose to
remove the "outgoing" buffer and immediately send the data across the channel.
Write(string) and WriteLine(string) were already doing this, and I felt it
was better to change Write(byte[]) to match rather than changing the string
methods.
* Integrate expectSize (as "windowSize" parameter)
* Rename "windowSize" to "lookback"
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Support ETM (Encrypt-then-MAC) variants for HMAC
* Support ETM (Encrypt-then-MAC) variants for HMAC
* Remove `ETM` property from `HashInfo`
* Add support for HmacMd5Etm, HmacMd5_96_Etm, HmacSha1Etm and HmacSha1_96_Etm
Explicitly specify etm even if false
* Add Encrypt-then-MAC variants to README.md
* Add back empty span to prevent auto link
* Store ETM in `HashInfo`;
Change `HMAC Create[...]Hash()` to `HashAlgorithm Create[...]Hash(out bool isEncryptThenMAC)`
* Making all unit tests pass locally.
Excluded MD5 tests on net462 because I get System.InvalidOperationException: 'This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.'
SshdConfig: do not throw for "Include", just do nothing.
Modified failing dos2unix parameters in Dockerfile.TestServer.
Forceing LF line ending for key files used by integration tests, otherwise using them causes error.
SftpClientTest.Test_Sftp_Multiple_Async_Upload_And_Download_10Files_5MB_Each times out for maxFiles=10, decreasing to 2 to make the test pass.
* Added SshCommand.InputStream.
* Added an integration test for SshCommand.InputStream.
* Reverting changes made to unit tests unrelated to this PR.
* Moved ChannelInputStream's EOF sending from Write to Dispose. Replace SshCommand.InputStream with CreateInputStream to emphasise that a (disposable) resource is created here. EndExecute also closes the _inputStream to make sure that EOF is sent (in case the user forgot to dispose the input stream). Added more unit tests: sending the input one byte at a time, not disposing the input stream, calling CreateInputStream before BeginExecute or AfterEndExecute throws exception.
* Fixing review comments.
* Fix build error after #1286
---------
Co-authored-by: ferenc.vizkeleti <ferenc.vizkeleti@innopay.hu>
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
- Change _connectAndLazySemaphoreInitLock to a SemaphoreSlim and use it in
ConnectAsync.
- Rename it to _connectLock and only use it for connecting. Replace its
other usages (on SessionSemaphore and NextChannelNumber) with Interlocked
operations.
- Remove AuthenticationConnection semaphore. This static member placed a
process-wide limit on the number of connections an application can make.
I agree with the argument in
https://github.com/sshnet/SSH.NET/issues/409#issuecomment-457415542
(and in several other issues/PRs) that this should not be something
that the library attempts to control.
The last change broke a few tests which do things like making 100 connections.
I was tempted to delete these tests as I don't think they have much value, but
instead I just limited their concurrency.
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Enable trim analysis and fix warnings
* Use EnableTrimAnalyzer instead of IsTrimmable
I don't know how IsTrimmable works with references
(i.e. to SshNet.Security.Cryptography)
* Add additional aot/trimming related analyzers
* Initialise the hash instance in the constructor
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Changes _socketDisposeLock to a SemaphoreSlim so it can play nice with async/await
* Adds a SendAsync method for .NET6+
* Fix false positive analyzer error
* Formatting
---------
Co-authored-by: Robert Hague <rh@johnstreetcapital.com>
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* remove unneeded feature flags
FEATURE_SOCKET_EAP and FEATURE_DNS_SYNC were set for all
frameworks, so unneeded. The other feature flags were
only used in elif of FEATURE_SOCKET_EAP and FEATURE_DNS_SYNC,
so also unneeded.
* pass cancellationToken to Dns.GetHostAddressesAsync
* Removed DnsAbstractions
This technically fixes 2 different issues:
- previously SSH.NET would require exactly(!) version 8.0.0, which would
cause issues in the future if e.g. a project using SSH.NET would
try to update to version 9.0.0. In this case the constraint on the
exact version would cause NuGet to refuse to upgrade to 9.0.0 (#1287)
- PowerShell Core seems to have problems with Version 8.0.0, therefore
downgrade the requirement to 1.0.0 (see https://github.com/darkoperator/Posh-SSH/issues/558)
I had to re-enable AutoGenerateBindingRedirects, otherwise there is a
FileLoadException with net462 in one of the tests. I don't know why this
was disabled in 3ecbd1071d .
* Release 2023.0.0 (#1201)
* Assets/logos (#782)
* Added logo assets
* Added PNG 1260x640 with white border
Co-authored-by: 103filgualan <f.gualandi@crif.com>
* OPENSSH KeyReader for more keys (#614)
* OPENSSH KeyReader for more keys
Add support to parse OpenSSH Keys with ECDSA 256/384/521 and RSA.
https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key
Change-Id: Iaa9cce0f2522e5fee377a82cb252f81f0b7cc563
* Fix ED25519Key KeyLength
* Fix ED25519 PubKey-auth
LeadingZeros of BigInteger-Conversion have to be removed
before sending the Key.
* Add interface to SftpFile #120 (#812)
* Create ISftpFile interface. SftpFile sealed. Return ISftpFile from SftpClient instead of SftpFile. Make ISftpClient interface disposable.
Co-authored-by: Wojciech Swieboda <wswieboda@chathamfinancial.com>
* Start MessageListener with ThreadAbstraction.ExecuteThreadLongRunning (#902)
* Fix Thread pool exhaustion due to MessageListener running on ThreadPool
* Mark long running thread as background
* Add async support to SftpClient and SftpFileStream (#819)
* Add FEATURE_TAP and net472 target
* Add TAP async support to SftpClient and SftpFileStream
* Add async support to DnsAbstraction and SocketAbstraction
* Add async support to *Connector and refactor the hierarchy
* Add ConnectAsync to BaseClient
* Add CODEOWNERS file.
* Fix virus false-positive by Defender on Renci.SSHNet.Tests.dll (#867)
Co-authored-by: Pedro Fonseca <pfonseca@qti.qualcomm.com>
* Add unit tests for task-based asynchronous API (#906)
* Fix runtime and culture dependant tests.
* Set C# 7.3 in Tests.csproj to limit intellisense's suggestions under different targets
* Add SftpClientTest.*Async
* Add SftpFileStreamTest_OpenAsync_*
* Add SftpFileStreamTest_WriteAsync_*
* Add SftpFileStreamTest_ReadAsync_*
* Align AppVeyor script with Test project target frameworks
* correct 'Documenation' to 'Documentation' (#838)
in the documentation's window title
* Agent auth and Keygen (#794)
* Allow to set PrivateKeyFile Key directly
So you can add your own Key-Classes to SSH.NET
* Add ED25519 ctor for just pub key part.
* Make ECDSA Key Bits accessible
You cant export imported CngKeys. To be able to export them to agent or Key-Files make the private bits also accessible.
* Better NETFRAMEWORK vs NETSTANDARD handling
* Add Comment Property to Key
* Add IPrivateKeySource
So Extension can add own PrivateKeyFiles, e.g. PuttyKeyFile.
* Use cryptographically secure random number generator.
Fixes CVE-2022-29245.
* Remove unused import.
* Add IBaseClient for BaseClient and ISftpClient to inherit from (#975)
Add IBaseClient for BaseClient and ISftpClient to inherit from
* fix typo (#999)
* Fix Seek Operations in SftpFileStream (#910)
* Fix offset operations in SftpFileStream.Seek
* Fix seek exception message and add default case for invalid seek origin
* Use named params when throwing ArgumentException
* Add tests for seeking from end of file
* Add back copyright to license. (#1060)
Fixes#1059.
* Removing old target frameworks (#1109)
Remove support for legacy / deprecated target frameworks while adding support for .NET 6.0 (and higher).
The supported target frameworks are now:
* .NETFramework 4.6.2 (and higher)
* .NET Standard 2.0
* .NET 6.0 (and higher)
* Remove old features [Part 1] (#1117)
Remove obsolete feature switches (now that we've remove support for legacy target frameworks) and remove corresponding conditional code.
* Remove FEATURE_DIRECTORYINFO_ENUMERATEFILES (#1119)
* Remove FEATURE_DIRECTORYINFO_ENUMERATEFILES
* Add exception documentation
* Fix some (lots of) issues reported by analyzers. (#1125)
Fix some (lots of) issues reported by analyzers.
* Round 2 of analyzer fixes and general cleanup. (#1132)
* Analyzer fixes round 3. (#1135)
* Replace Array<T>.Empty with Array.Empty<T>() (#1137)
* Replace IsNullOrWhiteSpace extension (#1142)
* Use License Expression for NuGet Package
licenseUrl is deprecated, see https://github.com/NuGet/Announcements/issues/32
* Integration tests
* Remove todos
* Update CODEOWNERS
* Use correct SSH.NET
* ListDirectoryAsync return IAsyncEnumerable (#1126)
* ListDirectoryAsync return IAsyncEnumerable
* Fix documentation
* Update README.md
* Fix
* Add Sftp ListDirectoryAsync test
* Revert
* Integration tests for ListDirectoryAsync with IAsyncEnumerable
* Fix the assembly resolution build warning (#1165)
* Delete performance/longrunning tests (#1143)
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Move Integration tests (#1173)
* Renci.SshNet.IntegrationTests
* Renci.SshNet.TestTools.OpenSSH
* Move integration tests to main repo
* Move old tests to new integration tests
* Move old integration tests to new integration tests
* Move more tests
* Move authentication tests
* Move SshClientTests
* Fix some tests
* Remove duplicated test
* Poc of ProcessDisruptor
* Rename
* Some fixes
* Remove performance tests
* Small improvements
* Add a benchmarks project (#1151)
* Add a benchmarks project
* Small improvements
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Use ExceptionDispatchInfo to retain call stack in Session.WaitOnHandle() (#936)
* Use ExceptionDispatchInfo to retain call stack in Session.WaitOnHandle()
* merge
* Update src/Renci.SshNet/Session.cs
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
* Support SHA256 fingerprints for host key validation (#1098)
* Add tests for HostKeyEventArgs
* Add SHA256 fingerprint support
* Add support for RSA SHA-2 public key algorithms (#1177)
* Abstract out the hash algorithm from RsaDigitalSignature
* Add integration tests
* Add DigitalSignature property to KeyHostAlgorithm
* Add IHostAlgorithmsProvider interface
* Verify the host signature
* Fix HostKeyEventArgsTest after merge
* Remove PubkeyAcceptedAlgorithms ssh-rsa
* Add test coverage for RSA keys in PrivateKeyFile
* Obsolete IPrivateKeySource
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Improvements after #1177 (#1180)
* Use ExceptionDispatchInfo in more places (#1182)
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Try to "fix" the flaky test (#1185)
* Enable DSA tests (#1181)
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* FingerPrints (#1186)
* Use OS-agnostic socket error codes to allow tests run on different OSes (#1179)
SocketErrorCode is OS agnostic, ErrorCode is OS specific.
On Windows ErrorCode = (int) SocketErrorCode, but on Mac and Unix it is not.
For example ExitCode for HostNotFound (11001) on Windows is 11001, on Mac & Unix is -131073. So testing for ExitCode == 11001 fails on Mac & Unix.
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Fix for channel session semaphore from thread blocking (#1071)
* Merging fix from @clivetong into our own SSH.NET fork
- The following article describes some of the issues with the double check lock that we have seen issues with: https://www.sudhanshutheone.com/posts/double-check-lock-csharp
* Merging fix from @clivetong into our own SSH.NET fork
- The following article describes some of the issues with the double check lock that we have seen issues with: https://www.sudhanshutheone.com/posts/double-check-lock-csharp
* Update Channel to fix AppVeyor failure (field should be readonly)
* Update ISftpClient for #120 (#1193)
* Implement set last write and access time (#1194)
* Add/migrate hmac+cipher integration tests (#1189)
* Add/migrate hmac+cipher integration tests
* fix integration tests
---------
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
* Update tests for SetLastAccessTime(Utc) to also verify the time component and the Kind of the DateTime value returned by GetLastAccessTime(Utc). (#1198)
---------
Co-authored-by: Filippo Gualandi <filippo.gualandi@gmail.com>
Co-authored-by: 103filgualan <f.gualandi@crif.com>
Co-authored-by: Stefan Rinkes <darinkes@users.noreply.github.com>
Co-authored-by: wxtsxt <wojciech.swieboda@gmail.com>
Co-authored-by: Wojciech Swieboda <wswieboda@chathamfinancial.com>
Co-authored-by: Igor Milavec <igor.milavec@gmail.com>
Co-authored-by: drieseng <gert.driesen@telenet.be>
Co-authored-by: Pedro Fonseca <pbfonseca@gmail.com>
Co-authored-by: Pedro Fonseca <pfonseca@qti.qualcomm.com>
Co-authored-by: Maximiliano Jabase <maxijabase@gmail.com>
Co-authored-by: Owen Krueger <37021716+Owen-Krueger@users.noreply.github.com>
Co-authored-by: Masuri <psh0258@gmail.com>
Co-authored-by: LemonPi314 <49930425+LemonPi314@users.noreply.github.com>
Co-authored-by: Gert Driesen <gertdriesen@msn.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
Co-authored-by: Rob Hague <rh@johnstreetcapital.com>
Co-authored-by: Marius Thesing <marius.thesing@gmail.com>
Co-authored-by: Dāvis Mošenkovs <davikovs@gmail.com>
Co-authored-by: Dmitry Tsarevich <dimhotepus@users.noreply.github.com>
Co-authored-by: Patrick Yates <114094360+patrick-yates-redgate@users.noreply.github.com>
* Remove code examples
---------
Co-authored-by: Filippo Gualandi <filippo.gualandi@gmail.com>
Co-authored-by: 103filgualan <f.gualandi@crif.com>
Co-authored-by: Stefan Rinkes <darinkes@users.noreply.github.com>
Co-authored-by: wxtsxt <wojciech.swieboda@gmail.com>
Co-authored-by: Wojciech Swieboda <wswieboda@chathamfinancial.com>
Co-authored-by: Igor Milavec <igor.milavec@gmail.com>
Co-authored-by: drieseng <gert.driesen@telenet.be>
Co-authored-by: Pedro Fonseca <pbfonseca@gmail.com>
Co-authored-by: Pedro Fonseca <pfonseca@qti.qualcomm.com>
Co-authored-by: Maximiliano Jabase <maxijabase@gmail.com>
Co-authored-by: Owen Krueger <37021716+Owen-Krueger@users.noreply.github.com>
Co-authored-by: Masuri <psh0258@gmail.com>
Co-authored-by: LemonPi314 <49930425+LemonPi314@users.noreply.github.com>
Co-authored-by: Gert Driesen <gertdriesen@msn.com>
Co-authored-by: Rob Hague <rob.hague00@gmail.com>
Co-authored-by: Rob Hague <rh@johnstreetcapital.com>
Co-authored-by: Marius Thesing <marius.thesing@gmail.com>
Co-authored-by: Dāvis Mošenkovs <davikovs@gmail.com>
Co-authored-by: Dmitry Tsarevich <dimhotepus@users.noreply.github.com>
Co-authored-by: Patrick Yates <114094360+patrick-yates-redgate@users.noreply.github.com>
This makes it easier to reason about Key instances in e.g.
DigitalSignature implementations, because we know that the
Key is initialised with its data and will not change.
Co-authored-by: Wojciech Nagórski <wojtpl2@gmail.com>
Rob Hague