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POST /api/v1/crypto/cipher

Select the cipher for this session.

Asks the key server to select a cipher for the calling session.

cipher is REQUIRED and must be a non-empty string, and both halves of that are refused rather than defaulted: a falsy cipher is not a default, because the binding then omits the parameter entirely and sends a different request rather than a defaulted one.

The value is matched case-insensitively against the key server's own allowed-algorithm list, and the matched spelling is what goes on the wire.

WARNING: accepted: true is not confirmation. verified is always false on this route, deliberately: the response says the key server did not refuse. The operation that reports a session's cipher is GET /api/v1/crypto/cipher (GET_CIPHER), an Encryptor operation the administrative identities are measured to be refused -- read the cipher back with it when the session holds that role.

3DES, DES, RC2 and RC4 are refused here regardless of what the key server configuration lists. The binding still carries a 3DES constant; its presence there is not permission to use it.

Authentication​

Send the session id as Authorization: Bearer <session id>, and an RFC 9449 DPoP proof in the DPoP header if your session is bound to a key. The two are required together, not as alternatives — see Authenticating and Proving you hold your key.

This surface sets no cookie

There is no session cookie on any response and none is read on any request. Do not set credentials: "include" on a browser fetch.

Request​

FieldTypeRequiredDescription
cipherstringyes

Example

{
  "cipher": "..."
}

Responses​

200​

The key server accepted the selection. It has not been read back.

FieldTypeRequiredDescription
requestedstringyes
sentstringyesThe spelling actually sent, from the server's own list.
allowedAlgorithmsarray of stringyes
acceptedtrue (constant)yes
verifiedfalse (constant)yes
detailstringyes

Example

{
  "requested": "...",
  "sent": "...",
  "allowedAlgorithms": [
    "..."
  ],
  "accepted": true,
  "verified": false,
  "detail": "..."
}

400​

BAD_REQUEST -- cipher absent, not a string, empty, prohibited by this product's crypto posture, or not in this key server's allowed list (which the detail enumerates, including the case where it lists none).

401​

No live session, a DPoP proof that did not verify, or a certificate session whose certificate the key server now refuses.

SESSION_NOT_FOUND -- the credential names no session this Gateway holds. SESSION_EXPIRED -- it aged out. Both carry reauth: true; obtain a new credential rather than retrying.

PROOF_* -- the sender constraint refused. See the DPoP section of this document for the full table; PROOF_MALFORMED is a 400 and PROOF_REPLAY_CACHE_FULL a 503, and the rest are here.

SCOPED_CREDENTIAL_EXPIRED -- a scoped browser credential passed its fixed lifetime. Use does not extend it: an idle timeout would be refreshed by exactly the traffic a stolen handle produces.

CERTIFICATE_REVOKED -- on a session established by certificate login, the key server re-checks the certificate that session was established with on its operations, and it is now named by revocation evidence. detail is the key server's sentence. The Gateway answers this once and then ENDS everything that service holds or minted here -- its sessions, the delegated sessions and the scoped credentials it minted -- so a later operation on any of them is SESSION_NOT_FOUND. Log in with a different certificate.

SSO_SESSION_EXPIRED -- a single-sign-on session (POST /api/v1/session/oidc) reached its lifetime, or was idle past its binding's idle bound; it has been ended. Sign in again.

SENDER_KEY_RETIRED -- the session's registered sender key was rotated out and its overlap has passed (see "The registered service's credential lifecycle"); the session is closed with this answer. SERVICE_REGISTRATION_ENDED -- the registration a service credential was issued under was removed or narrowed on this Gateway; it has ended. Both are final for that credential.

403​

Authenticated, and refused. The codes differ in what they say about where the refusal came from: ACCESS_DENIED (no role grants the operation), ACL_DENIED (the ACL of the key the request named refuses the principal -- ask the key's owner, not an administrator), PRINCIPAL_DISABLED and DELEGATOR_REFUSED are the key server's -- the last one on a DELEGATED session whose delegator has since been disabled, lost its DELEGATION flag, been unenrolled or had its certificate revoked; its detail is the key server's sentence naming the delegator, and no new login helps until an administrator restores it. REVOCATION_STATUS_UNAVAILABLE and REVOCATION_EVIDENCE_STALE are the key server's too, on a session established by certificate login: the same re-check found no current revocation evidence for that certificate's issuer under a policy that requires it -- the credential is not what was refused, and an operator importing a current CRL for the issuer is what helps. TRANSPORT_PRINCIPAL_REQUIRED (POST /api/v1/keys/get: the operation needs a session established by a certificate the key server has enrolled) and PRINCIPAL_MISMATCH (the request named a principal other than the session's) are the key server's too, and no role changes either -- while NOT_WRITABLE, BUILT_IN_PRINCIPAL, OWN_ACCOUNT and OBJECT_NOT_IN_CREDENTIAL_SCOPE are decided by the Gateway before anything is sent.

500​

A fault rather than a refusal.

OP_FAILED is the catch-all: the key server refused in words that match no classified pattern, so the Gateway cannot say more than that the operation did not happen. Some key server refusals that are conceptually a caller error arrive here rather than as a 4xx, because the wire carries no distinguishing code -- where a route can recognise one from its message it maps it, and each such mapping is documented on the operation.

503​

A capacity ceiling or a missing deployment prerequisite. retryable says which.

A scope of session or process names the ceiling that was hit, and the response carries Retry-After.

BUILD_NOT_ADMITTED (scope: process, retryable: true, Retry-After): the key server does not admit this Gateway's client build. Every key-server connection the Gateway opens attests the signed release it runs (TE_RELEASE_MANIFEST) right after it authenticates; while that attestation is refused -- the release is not registered at the key server's code-signing level, the level was raised under it, or the installed files no longer match the signed manifest -- every route but GET /api/v1/health and GET /api/v1/ready answers this, and detail names the cause. It is never a 401 or a 403: no credential or role of the caller's is at fault. The Gateway re-attempts on a timer and recovers without a restart once the key server admits it; GET /api/v1/ready says when.

CAPACITY_UNAVAILABLE (scope: process, retryable: true, Retry-After): this Gateway is serving its maximum number of requests at once, or cannot track another allowance, or (on a certificate login) is recording its maximum of live certificate sessions -- in which case the session the login created has been closed. Nothing else was sent to the key server. See "Rate and capacity limits" above.

413​

PAYLOAD_TOO_LARGE (retryable: false) -- the request body is larger than this deployment accepts. It was refused before it was parsed, and the connection is closed. Nothing was sent to the key server.

429​

RATE_LIMITED (retryable: true, Retry-After) -- the allowance this request is charged to is spent: the login allowance of its network source (before authentication), or the allowance, the concurrency ceiling or the live-session ceiling of the identity it was verified as -- shared by every session that identity holds, including every delegated and scoped credential a service minted. It carries no scope. Nothing was sent to the key server; on a login refused after authentication, the session it created has been closed. See "Rate and capacity limits" above.

Error handling​

Every failure answers JSON carrying at least code and detail. Match on code — detail is written for a human debugging the call and its wording is not part of the contract. See the error model.

StatusMeaning
400BAD_REQUEST -- cipher absent, not a string, empty, prohibited by this product's crypto posture, or not in this key server's allowed list (which the detail enumerates, including the case where it lists none).
401No live session, a DPoP proof that did not verify, or a certificate session whose certificate the key server now refuses. SESSION_NOT_FOUND -- the credential names no session this Gateway holds. SESSION_EXPIRED -- it aged out. Both carry reauth: true; obtain a new credential rather than retrying. PROOF_* -- the sender constraint refused. See the DPoP section of this document for the full table; PROOF_MALFORMED is a 400 and PROOF_REPLAY_CACHE_FULL a 503, and the rest are here. SCOPED_CREDENTIAL_EXPIRED -- a scoped browser credential passed its fixed lifetime. Use does not extend it: an idle timeout would be refreshed by exactly the traffic a stolen handle produces. CERTIFICATE_REVOKED -- on a session established by certificate login, the key server re-checks the certificate that session was established with on its operations, and it is now named by revocation evidence. detail is the key server's sentence. The Gateway answers this once and then ENDS everything that service holds or minted here -- its sessions, the delegated sessions and the scoped credentials it minted -- so a later operation on any of them is SESSION_NOT_FOUND. Log in with a different certificate. SSO_SESSION_EXPIRED -- a single-sign-on session (POST /api/v1/session/oidc) reached its lifetime, or was idle past its binding's idle bound; it has been ended. Sign in again. SENDER_KEY_RETIRED -- the session's registered sender key was rotated out and its overlap has passed (see "The registered service's credential lifecycle"); the session is closed with this answer. SERVICE_REGISTRATION_ENDED -- the registration a service credential was issued under was removed or narrowed on this Gateway; it has ended. Both are final for that credential.
403Authenticated, and refused. The codes differ in what they say about where the refusal came from: ACCESS_DENIED (no role grants the operation), ACL_DENIED (the ACL of the key the request named refuses the principal -- ask the key's owner, not an administrator), PRINCIPAL_DISABLED and DELEGATOR_REFUSED are the key server's -- the last one on a DELEGATED session whose delegator has since been disabled, lost its DELEGATION flag, been unenrolled or had its certificate revoked; its detail is the key server's sentence naming the delegator, and no new login helps until an administrator restores it. REVOCATION_STATUS_UNAVAILABLE and REVOCATION_EVIDENCE_STALE are the key server's too, on a session established by certificate login: the same re-check found no current revocation evidence for that certificate's issuer under a policy that requires it -- the credential is not what was refused, and an operator importing a current CRL for the issuer is what helps. TRANSPORT_PRINCIPAL_REQUIRED (POST /api/v1/keys/get: the operation needs a session established by a certificate the key server has enrolled) and PRINCIPAL_MISMATCH (the request named a principal other than the session's) are the key server's too, and no role changes either -- while NOT_WRITABLE, BUILT_IN_PRINCIPAL, OWN_ACCOUNT and OBJECT_NOT_IN_CREDENTIAL_SCOPE are decided by the Gateway before anything is sent.
500A fault rather than a refusal. OP_FAILED is the catch-all: the key server refused in words that match no classified pattern, so the Gateway cannot say more than that the operation did not happen. Some key server refusals that are conceptually a caller error arrive here rather than as a 4xx, because the wire carries no distinguishing code -- where a route can recognise one from its message it maps it, and each such mapping is documented on the operation.
503A capacity ceiling or a missing deployment prerequisite. retryable says which. A scope of session or process names the ceiling that was hit, and the response carries Retry-After. BUILD_NOT_ADMITTED (scope: process, retryable: true, Retry-After): the key server does not admit this Gateway's client build. Every key-server connection the Gateway opens attests the signed release it runs (TE_RELEASE_MANIFEST) right after it authenticates; while that attestation is refused -- the release is not registered at the key server's code-signing level, the level was raised under it, or the installed files no longer match the signed manifest -- every route but GET /api/v1/health and GET /api/v1/ready answers this, and detail names the cause. It is never a 401 or a 403: no credential or role of the caller's is at fault. The Gateway re-attempts on a timer and recovers without a restart once the key server admits it; GET /api/v1/ready says when. CAPACITY_UNAVAILABLE (scope: process, retryable: true, Retry-After): this Gateway is serving its maximum number of requests at once, or cannot track another allowance, or (on a certificate login) is recording its maximum of live certificate sessions -- in which case the session the login created has been closed. Nothing else was sent to the key server. See "Rate and capacity limits" above.
413PAYLOAD_TOO_LARGE (retryable: false) -- the request body is larger than this deployment accepts. It was refused before it was parsed, and the connection is closed. Nothing was sent to the key server.
429RATE_LIMITED (retryable: true, Retry-After) -- the allowance this request is charged to is spent: the login allowance of its network source (before authentication), or the allowance, the concurrency ceiling or the live-session ceiling of the identity it was verified as -- shared by every session that identity holds, including every delegated and scoped credential a service minted. It carries no scope. Nothing was sent to the key server; on a login refused after authentication, the session it created has been closed. See "Rate and capacity limits" above.