# PKCS \$111 library for AWS CloudHSM Client SDK 5
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PKCS \$111 is a standard for performing cryptographic operations on hardware security modules (HSMs). AWS CloudHSM offers implementations of the PKCS \$111 library that are compliant with PKCS \$111 version 2.40.

For information about bootstrapping, see [Connecting to the cluster](cluster-connect.md). For troubleshooting, see [Known issues for the PKCS \$111 library for AWS CloudHSMKnown issues for the PKCS \$111 library](ki-pkcs11-sdk.md).

For information on using Client SDK 3, see [Using previous SDK version to work with AWS CloudHSM](choose-client-sdk.md).

**Topics**
+ [Install the PKCS \$111 library](pkcs11-library-install.md)
+ [Authenticate to the PKCS \$111 library](pkcs11-pin.md)
+ [Key types](pkcs11-key-types.md)
+ [Mechanisms](pkcs11-mechanisms.md)
+ [API operations](pkcs11-apis.md)
+ [Key attributes](pkcs11-attributes.md)
+ [Code samples](pkcs11-samples.md)
+ [Advanced configurations](pkcs11-library-configs.md)
+ [Certificate storage](pkcs11-certificate-storage.md)