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Identity and Access Management

MinIO requires clients authenticate using AWS Signature Version 4 protocol with support for the deprecated Signature Version 2 protocol. Specifically, clients must authenticate by presenting a valid access key and secret key to access any S3 or MinIO administrative API, such as PUT, GET, and DELETE operations. S3-compatible SDKs, including those provided by MinIO, typically include built-in helpers for creating the necessary signatures using an access key and secret key.

MinIO supports both internal and external identity management:

IDentity Provider (IDP)


MinIO Internal IDP

Provides built-in identity management functionality.


Supports managing identities through an OpenID Connect (OIDC) compatible service.

Active Directory / LDAP

Supports managing identities through an Active Directory or LDAP service.

Once authenticated, MinIO either allows or rejects the client request depending on whether or not the authenticated identity is authorized to perform the operation on the specified resource.

MinIO uses Policy-Based Access Control (PBAC) to define the authorized actions and resources to which an authenticated user has access. Each policy describes one or more actions and conditions that outline the permissions of a user or group of users. By default, MinIO denies access to actions or resources not explicitly referenced in a user’s assigned or inherited policies. MinIO manages the creation and storage of policies and does not support external authorization management.

MinIO PBAC is built for compatibility with AWS IAM policy syntax, structure, and behavior. The MinIO documentation makes a best-effort to cover IAM-specific behavior and functionality. Consider deferring to the IAM documentation for more complete documentation on IAM, IAM policies, or IAM JSON syntax.


MinIO supports end-to-end encryption of objects over-the-wire (network encryption) and on read/write (at-rest).

Network Encryption

MinIO supports Transport Layer Security (TLS) encryption of incoming and outgoing traffic. MinIO recommends all MinIO servers run with TLS enabled to ensure end-to-end security of client-server or server-server transmissions.

TLS is the successor to Secure Socket Layer (SSL) encryption. SSL is fully deprecated as of June 30th, 2018. MinIO uses only supported (non-deprecated) TLS protocols (TLS 1.2 and later).

See Network Encryption (TLS) for more complete documentation.

Server-Side Object Encryption (SSE)

MinIO supports Server-Side Object Encryption (SSE) of objects, where MinIO uses a secret key to encrypt and store objects on disk (encryption at-rest).

MinIO supports enabling automatic SSE-KMS encryption of all objects written to a bucket using a specific External Key (EK) stored on the external KMS. Clients can override the bucket-default EK by specifying an explicit key as part of the write operation.

For buckets without automatic SSE-KMS encryption, clients can specify an EK as part of the write operation instead.

SSE-KMS provides more granular and customizable encryption compared to SSE-S3 and SSE-C and is recommended over the other supported encryption methods.

MinIO supports enabling automatic SSE-S3 encryption of all objects written to a bucket using an EK stored on the external KMS. MinIO SSE-S3 supports one EK for the entire deployment.

For buckets without automatic SSE-S3 encryption, clients can request SSE encryption as part of the write operation instead.

Clients specify an EK as part of the write operation for an object. MinIO uses the specified EK to perform SSE-S3.

SSE-C does not support bucket-default encryption settings and requires clients perform all key management operations.

MinIO SSE requires Network Encryption (TLS).