Cosmian KMS

The Cosmian KMS is a high-performance, source-available FIPS 140-3 compliant server application written in Rust.

Online documentation

The Cosmian KMS presents some unique features, such as:

• large-scale encryption and decryption of data see this documentation
• the ability to confidentially run in a public cloud, or any zero-trust environment, using Cosmian VM. See our cloud-ready confidential KMS on the Azure, GCP, and AWS marketplaces our deployment guide
• support of state-of-the-art authentication mechanisms (see authentication)
• out-of-the-box support of Google Workspace Client Side Encryption (CSE)
• out-of-the-box support of Microsoft Double Key Encryption (DKE)
• support for the CardContact SmartCard, Nitrokey HSM 2, Proteccio, Crypt2pay, Utimaco and other HSMs with KMS keys wrapped by the HSM
• Veracrypt and LUKS disk encryption support
• FIPS 140-3 mode gated behind the feature fips
• a binary and JSON KMIP 1.0-1.4 and 2.0-2.1 compliant interface
• MongoDB (./documentation/docs/mongodb.md)
• Oracle DB TDE support
• Percona Postgresql DB (./documentation/docs/percona.md)
• VMWare vCenter Trust Key Provider integration
• User Defined Functions for Big Data including snowflake
• a full-featured client command line and graphical interface
• a high-availability mode with simple horizontal scaling
• a support of Python, JavaScript, Dart, Rust, C/C++, and Java clients (see the cloudproof libraries on Cosmian Github)
• integrated with OpenTelemetry

The Cosmian KMS is both a Key Management System and a Public Key Infrastructure. As a KMS, it is designed to manage the lifecycle of keys and provide scalable cryptographic services such as on-the-fly key generation, encryption, and decryption operations.

The Cosmian KMS supports all the standard NIST cryptographic algorithms as well as advanced post-quantum cryptography algorithms such as Covercrypt. Please refer to the list of supported algorithms.

As a PKI it can manage root and intermediate certificates, sign and verify certificates, use their public keys to encrypt and decrypt data. Certificates can be exported under various formats, including PKCS#12 modern and legacy flavor, to be used in various applications, such as in S/MIME encrypted emails.

The KMS has extensive online documentation

• Cosmian KMS
  • Quick start
    • Example
  • Repository content
    • Binaries
    • Core Crates
      • Server Infrastructure
      • Client Libraries
      • Cryptographic Components
      • Hardware Security Module (HSM) Support
      • Database Interfaces
      • Development and Testing
    • Additional Directories
  • Building and running the KMS
    • Features
    • Linux or macOS (CPU Intel or macOS ARM)
    • Windows
    • Build the KMS
    • Build the Docker Ubuntu container
  • Running the unit and integration tests
  • Development: running the server with cargo
  • Server parameters
  • Use the KMS inside a Cosmian VM on SEV/TDX
  • Releases
  • Benchmarks
  • KMIP support by Cosmian KMS
    • KMIP coverage
      • Messages
      • Operations
      • Methodology
      • Managed Objects
      • Base Objects
      • Transparent Key Structures
      • Attributes

Quick start

Pre-built binaries are available for Linux, MacOS, and Windows, as well as Docker images. To run the server binary, OpenSSL must be available in your path (see "building the KMS" below for details); other binaries do not have this requirement.

Using Docker to quick-start a Cosmian KMS server on http://localhost:9998 that stores its data inside the container, run the following command:

docker run -p 9998:9998 --name kms ghcr.io/cosmian/kms:latest

Then, use the CLI to issue commands to the KMS. The CLI, called cosmian, can be either:

• installed with cargo install cosmian_cli

• downloaded from Cosmian packages

• built and launched from the GitHub project by running

  cargo build --bin cosmian

Example

1. Create a 256-bit symmetric key

   ➜ cosmian sym keys create --number-of-bits 256 --algorithm aes --tag my-key-file
   ...
   The symmetric key was successfully generated.
     Unique identifier: 87e9e2a8-4538-4701-aa8c-e3af94e44a9e
   
     Tags:
       - my-key-file

2. Encrypt the image.png file with AES GCM using the key

   ➜ cosmian sym encrypt --tag my-key-file --output-file image.enc image.png
   ...
   The encrypted file is available at "image.enc"

3. Decrypt the image.enc file using the key

   ➜ cosmian sym decrypt --tag my-key-file --output-file image2.png image.enc
   ...
   The decrypted file is available at "image2.png"

See the documentation for more.

Repository content

The Cosmian KMS is written in Rust and organized as a Cargo workspace with multiple crates. The repository contains the following main components:

Binaries

• KMS Server (cosmian_kms) - The main KMS server binary built from crate/server

Core Crates

Server Infrastructure

• server - Main KMS server implementation with REST API, KMIP protocol support, and web UI
• server_database - Database abstraction layer supporting SQLite, PostgreSQL, MySQL, and Redis
• access - Permission and access control management system

Client Libraries

• kms_client - High-level Rust client library for KMS server communication
• client_utils - Shared utilities for client implementations
• wasm - WebAssembly bindings for browser-based clients

Cryptographic Components

• crypto - Core cryptographic operations and algorithm implementations
• kmip - Complete implementation of the KMIP (Key Management Interoperability Protocol) standard versions 1.0-2.1
• kmip-derive - Procedural macros for KMIP protocol serialization/deserialization

Hardware Security Module (HSM) Support

• hsm/base_hsm - Base HSM abstraction layer
• hsm/smartcardhsm - Nitrokey HSM 2 resp. CardContact SmartCard-HSM
• hsm/crypt2pay - Crypt2pay HSM integration
• hsm/proteccio - Proteccio HSM integration
• hsm/softhsm2 - SoftHSM2 integration for testing and development
• hsm/utimaco - Utimaco HSM integration
• hsm/other - Other HSMs support

Database Interfaces

• interfaces - Database and storage backend abstractions

Development and Testing

• test_kms_server - Library for programmatic KMS server instantiation in tests
• cli - Legacy CLI crate (now primarily used for testing)

Additional Directories

• documentation/ - Comprehensive project documentation built with MkDocs
• examples/ - Code examples and integration samples
• scripts/ - Build and deployment scripts
• test_data/ - Test fixtures and sample data
• ui/ - Frontend web interface source code
• pkg/ - Packaging configurations for Debian and RPM distributions

Note: Each crate contains its own README with detailed information. Please refer to these files for specific implementation details and usage instructions.

Find the public documentation of the KMS in the documentation directory.

Building and running the KMS

The Cosmian KMS is built using the Rust programming language. A Rust toolchain is required to build the KMS.

Features

From version 5.4.0, the KMS runs in FIPS mode by default. The non-FIPS mode can be enabled by passing the --features non-fips flag to cargo build or cargo run.

OpenSSL v3.2.0 is required to build the KMS.

Linux or macOS (CPU Intel or macOS ARM)

Retrieve OpenSSL v3.2.0 (already built) with the following commands:

export OPENSSL_DIR=/usr/local/openssl
sudo mkdir -p ${OPENSSL_DIR}
sudo chown -R $USER ${OPENSSL_DIR}
bash .github/reusable_scripts/get_openssl_binaries.sh

Windows

1. Install Visual Studio Community with the C++ workload and clang support.

2. Install Strawberry Perl.

3. Install vcpkg following these instructions

4. Then install OpenSSL 3.2.0:

The files vcpkg.json and vcpkg_fips.json are provided in the repository to install OpenSSL v3.2.0:

vcpkg install --triplet x64-windows-static # arm64-windows-static for ARM64

vcpkg integrate install
$env:OPENSSL_DIR = "$env:VCPKG_INSTALLATION_ROOT\packages\openssl_x64-windows-static" # openssl_arm64-windows-static for ARM64

For a FIPS-compliant build, use the following commands (to build fips.dll), also run:

Copy-Item -Path "vcpkg_fips.json" -Destination "vcpkg.json"
vcpkg install
vcpkg integrate install

Build the KMS

Once OpenSSL is installed, you can build the KMS. To avoid the additive feature issues, the main artifacts - the CLI, the KMS server and the PKCS11 provider should be directly built using cargo build --release within their crate, not from the project root.

Build the server:

cd crate/server
cargo build --release

Build the Docker Ubuntu container

You can build a Docker containing the KMS server as follows:

docker buildx build . -t kms

Or:

# Example with FIPS support
docker buildx build --build-arg FIPS="true" -t kms .

Running the unit and integration tests

Pull the test data using:

git submodule update --init --recursive

By default, tests are run using cargo test and an SQLCipher backend (called sqlite). This can be influenced by setting the KMS_TEST_DB environment variable to

• sqlite, for plain SQLite
• mysql (requires a running MySQL or MariaDB server connected using a "mysql://kms:kms@localhost:3306/kms" URL)
• postgresql (requires a running PostgreSQL server connected using a "postgresql://kms:kms@127.0.0.1:5432/kms"URL)
• redis-findex (requires a running Redis server connected using a "redis://localhost:6379" URL)

Example: testing with a plain SQLite and some logging

RUST_LOG="error,cosmian_kms_server=info,cosmian_kms_cli=info" KMS_TEST_DB=sqlite cargo test

Alternatively, when writing a test or running a test from your IDE, the following can be inserted at the top of the test:

unsafe {
set_var("RUST_LOG", "error,cosmian_kms_server=debug,cosmian_kms_cli=info");
set_var("RUST_BACKTRACE", "1");
set_var("KMS_TEST_DB", "redis-findex");
}
log_init(option_env!("RUST_LOG"));

Development: running the server with cargo

To run the server with cargo, you need to set the RUST_LOG environment variable to the desired log level and select the correct backend (which defaults to sqlite).

RUST_LOG="info,cosmian_kms_server=debug" \
cargo run --bin cosmian_kms --features non-fips -- \
--database-type redis-findex --database-url redis://localhost:6379 \
--redis-master-password secret --redis-findex-label label

Server parameters

If a configuration file is provided, parameters are set following this order:

• conf file (env variable COSMIAN_KMS_CONF set by default to /etc/cosmian/kms.toml)
• default (set on struct)

Otherwise, the parameters are set following this order:

• args in the command line
• env var
• default (set on struct)

Use the KMS inside a Cosmian VM on SEV/TDX

See the Marketplace guide for more details about Cosmian VM.

Releases

All releases can be found in the public URL package.cosmian.com.

Benchmarks

To run benchmarks, go to the crate/test_kms_server directory and run:

cargo bench

Typical values for single-threaded HTTP KMIP 2.1 requests (zero network latency) are as follows

- RSA PKCSv1.5:
    - encrypt
            - 2048 bits: 128 microseconds
            - 4096 bits: 175 microseconds
    - decrypt
            - 2048 bits: 830 microseconds
            - 4096 bits: 4120 microseconds
- RSA PKCS OAEP:
    - encrypt
            - 2048 bits: 134 microseconds
            - 4096 bits: 173 microseconds
    - decrypt
            - 2048 bits: 849 microseconds
            - 4096 bits: 3823 microseconds
- RSA PKCS KEY WRP (AES):
    - encrypt
            - 2048 bits: 142 microseconds
            - 4096 bits: 198 microseconds
    - decrypt
            - 2048 bits: 824 microseconds
            - 4096 bits: 3768 microseconds
- RSA Keypair creation (saved in KMS DB)
    -  2048 bits: 33 milliseconds
    -  4096 bits: 322 milliseconds

KMIP support by Cosmian KMS

This page summarizes the KMIP coverage in Cosmian KMS. The support status is derived from the actual implementation in crate/server/src/core/operations.

Legend:

• ✅ Fully supported
• ❌ Not implemented
• 🚫 Deprecated
• 🚧 Partially supported (not used here)
• N/A Not applicable

KMIP coverage

Messages

Message	Current
Request Message	✅
Response Message	✅

Operations

Operation	Current
Create	✅
Create Key Pair	✅
Register	✅
Re-key	✅
Re-key Key Pair	✅
DeriveKey	✅
Certify	✅
Re-certify	❌
Locate	✅
Check	❌
Get	✅
Get Attributes	✅
Get Attribute List	❌
Add Attribute	✅
Set Attribute (Modify)	✅
Delete Attribute	✅
Obtain Lease	❌
Get Usage Allocation	❌
Activate	✅
Revoke	✅
Destroy	✅
Archive	❌
Recover	❌
Validate	✅
Query	✅
Cancel	❌
Poll	❌
Notify	❌
Put	❌
Discover Versions	✅
Encrypt	✅
Decrypt	✅
Sign	✅
Signature Verify	✅
MAC	✅
MAC Verify	❌
RNG Retrieve	❌
RNG Seed	❌
Hash	✅
Create Split Key	❌
Join Split Key	❌
Export	✅
Import	✅

Methodology

• Operations shown as ✅ are backed by a Rust implementation file under crate/server/src/core/operations.
• If no implementation file exists for an operation, it is marked ❌.
• This documentation is auto-generated by analyzing the source code.

If you spot a mismatch or want to extend coverage, please open an issue or PR.

Managed Objects

Managed Object	Current
Certificate	✅
Symmetric Key	✅
Public Key	✅
Private Key	✅
Split Key	❌
Template	🚫
Secret Data	✅
Opaque Object	✅
PGP Key	❌

Notes:

• Opaque Object import support is present (see import.rs).
• PGP Key types appear in digest and attribute handling but full object import/register is not implemented, hence ❌.

Base Objects

Base Object	Current
Attribute	✅
Credential	✅
Key Block	✅
Key Value	✅
Key Wrapping Data	✅
Key Wrapping Specification	✅
Transparent Key Structures	✅
Template-Attribute Structures	✅
Extension Information	✅
Data	❌
Data Length	❌
Signature Data	❌
MAC Data	❌
Nonce	✅
Correlation Value	❌
Init Indicator	❌
Final Indicator	❌
RNG Parameter	✅
Profile Information	✅
Validation Information	✅
Capability Information	✅
Authenticated Encryption Additional Data	✅
Authenticated Encryption Tag	✅

Notes:

• AEAD Additional Data and Tag are supported in encrypt/decrypt APIs.
• Nonce and RNG Parameter are used by symmetric encryption paths.

Transparent Key Structures

Structure	Current
Symmetric Key	✅
DSA Private/Public Key	❌
RSA Private/Public Key	✅
DH Private/Public Key	❌
ECDSA Private/Public Key	✅
ECDH Private/Public Key	❌
ECMQV Private/Public	❌
EC Private/Public	✅

Note: EC/ECDSA support is present; DH/DSA/ECMQV are not implemented.

Attributes

Attribute	Current
Activation Date	✅
Alternative Name	❌
Always Sensitive	❌
Application Specific Information	❌
Archive Date	❌
Attribute Index	❌
Certificate Attributes	❌
Certificate Identifier	🚫
Certificate Issuer	🚫
Certificate Length	❌
Certificate Subject	🚫
Certificate Type	✅
Comment	❌
Compromise Date	❌
Compromise Occurrence Date	✅
Contact Information	❌
Critical	❌
Cryptographic Algorithm	✅
Cryptographic Domain Parameters	✅
Cryptographic Length	✅
Cryptographic Parameters	✅
Cryptographic Usage Mask	✅
Deactivation Date	✅
Description	❌
Destroy Date	❌
Digest	✅
Digital Signature Algorithm	✅
Extractable	❌
Fresh	❌
Initial Date	✅
Key Format Type	❌
Key Value Location	❌
Key Value Present	❌
Last Change Date	✅
Lease Time	❌
Link	✅
Name	❌
Never Extractable	❌
Nist Key Type	❌
Object Group	❌
Object Group Member	❌
Object Type	✅
Opaque Data Type	❌
Operation Policy Name	🚫
Original Creation Date	✅
PKCS#12 Friendly Name	❌
Process Start Date	❌
Protect Stop Date	❌
Protection Level	❌
Protection Period	❌
Protection Storage Masks	❌
Quantum Safe	❌
Random Number Generator	❌
Revocation Reason	✅
Rotate Date	❌
Rotate Generation	❌
Rotate Interval	❌
Rotate Latest	❌
Rotate Name	❌
Rotate Offset	❌
Sensitive	✅
Short Unique Identifier	❌
State	✅
Unique Identifier	✅
Usage Limits	❌
Vendor Attribute	❌
X.509 Certificate Identifier	✅
X.509 Certificate Issuer	✅
X.509 Certificate Subject	✅

Notes:

• GetAttributes returns a union of metadata attributes and those embedded in KeyBlock structures.
• "Vendor Attributes" are available via the Cosmian vendor namespace and are accessible via GetAttributes.
• A ✅ indicates the attribute is used or updated by at least one KMIP operation implementation in crate/server/src/core/operations, explicitly excluding the attribute-only handlers (Add/Delete/Get/Set Attribute).