mirror of https://github.com/k3s-io/k3s
33 lines
2.3 KiB
Markdown
33 lines
2.3 KiB
Markdown
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# OCIcrypt Library
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The `ocicrypt` library is the OCI image spec implementation of container image encryption. More details of the spec can be seen in the [OCI repository](https://github.com/opencontainers/image-spec/pull/775). The purpose of this library is to encode spec structures and consts in code, as well as provide a consistent implementation of image encryption across container runtimes and build tools.
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## Usage
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There are various levels of usage for this library. The main consumers of these would be runtime/buil tools, and a more specific use would be in the ability to extend cryptographic function.
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### Runtime/Build tool usage
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The general exposed interface a runtime/build tool would use, would be to perform encryption or decryption of layers:
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```
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package "github.com/containers/ocicrypt"
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func EncryptLayer(ec *config.EncryptConfig, encOrPlainLayerReader io.Reader, desc ocispec.Descriptor) (io.Reader, EncryptLayerFinalizer, error)
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func DecryptLayer(dc *config.DecryptConfig, encLayerReader io.Reader, desc ocispec.Descriptor, unwrapOnly bool) (io.Reader, digest.Digest, error)
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```
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The settings/parameters to these functions can be specified via creation of an encryption config with the `github.com/containers/ocicrypt/config` package. We note that because setting of annotations and other fields of the layer descriptor is done through various means in different runtimes/build tools, it is the resposibility of the caller to still ensure that the layer descriptor follows the OCI specification (i.e. encoding, setting annotations, etc.).
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### Crypto Agility and Extensibility
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The implementation for both symmetric and assymetric encryption used in this library are behind 2 main interfaces, which users can extend if need be. These are in the following packages:
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- github.com/containers/ocicrypt/blockcipher - LayerBlockCipher interface for block ciphers
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- github.com/containers/ocicrypt/keywrap - KeyWrapper interface for key wrapping
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We note that adding interfaces here is risky outside the OCI spec is not recommended, unless for very specialized and confined usecases. Please open an issue or PR if there is a general usecase that could be added to the OCI spec.
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## Security Issues
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We consider security issues related to this library critical. Please report and security related issues by emailing maintainers in the [MAINTAINERS](MAINTAINERS) file.
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