diff --git a/packages/phone-number-privacy/combiner/package.json b/packages/phone-number-privacy/combiner/package.json
index 1a2ea203300..9f9b7f1ba3f 100644
--- a/packages/phone-number-privacy/combiner/package.json
+++ b/packages/phone-number-privacy/combiner/package.json
@@ -24,9 +24,9 @@
     "db:migrate": "NODE_ENV=dev ts-node scripts/run-migrations.ts"
   },
   "dependencies": {
-    "@celo/contractkit": "1.0.2",
-    "@celo/phone-number-privacy-common": "1.0.33",
-    "@celo/identity": "1.0.2",
+    "@celo/contractkit": "1.2.0",
+    "@celo/phone-number-privacy-common": "1.0.34",
+    "@celo/identity": "1.2.0",
     "@celo/utils": "1.0.2",
     "blind-threshold-bls": "https://github.com/celo-org/blind-threshold-bls-wasm#e1e2f8a",
     "elliptic": "^6.5.4",
diff --git a/packages/phone-number-privacy/combiner/src/match-making/get-contact-matches.ts b/packages/phone-number-privacy/combiner/src/match-making/get-contact-matches.ts
index 6ad4fd27d43..1c10af3a68e 100644
--- a/packages/phone-number-privacy/combiner/src/match-making/get-contact-matches.ts
+++ b/packages/phone-number-privacy/combiner/src/match-making/get-contact-matches.ts
@@ -4,9 +4,9 @@ import {
   GetContactMatchesRequest,
   hasValidAccountParam,
   hasValidContactPhoneNumbersParam,
+  hasValidIdentifier,
   hasValidUserPhoneNumberParam,
   isVerified,
-  phoneNumberHashIsValidIfExists,
   WarningMessage,
 } from '@celo/phone-number-privacy-common'
 import Logger from 'bunyan'
@@ -71,7 +71,6 @@ function isValidGetContactMatchesInput(requestBody: GetContactMatchesRequest): b
     hasValidAccountParam(requestBody) &&
     hasValidUserPhoneNumberParam(requestBody) &&
     hasValidContactPhoneNumbersParam(requestBody) &&
-    !!requestBody.hashedPhoneNumber &&
-    phoneNumberHashIsValidIfExists(requestBody)
+    hasValidIdentifier(requestBody)
   )
 }
diff --git a/packages/phone-number-privacy/combiner/src/signing/get-threshold-signature.ts b/packages/phone-number-privacy/combiner/src/signing/get-threshold-signature.ts
index 9c93239f5f6..5401fdcc2ab 100644
--- a/packages/phone-number-privacy/combiner/src/signing/get-threshold-signature.ts
+++ b/packages/phone-number-privacy/combiner/src/signing/get-threshold-signature.ts
@@ -3,11 +3,10 @@ import {
   ErrorMessage,
   GetBlindedMessageSigRequest,
   hasValidAccountParam,
-  hasValidQueryPhoneNumberParam,
-  hasValidTimestamp,
+  hasValidBlindedPhoneNumberParam,
+  identifierIsValidIfExists,
   isBodyReasonablySized,
   MAX_BLOCK_DISCREPANCY_THRESHOLD,
-  phoneNumberHashIsValidIfExists,
   SignMessageResponse,
   SignMessageResponseFailure,
   SignMessageResponseSuccess,
@@ -354,10 +353,9 @@ function getMajorityErrorCode(errorCodes: Map<number, number>, logger: Logger) {
 function isValidGetSignatureInput(requestBody: GetBlindedMessageSigRequest): boolean {
   return (
     hasValidAccountParam(requestBody) &&
-    hasValidQueryPhoneNumberParam(requestBody) &&
-    phoneNumberHashIsValidIfExists(requestBody) &&
-    isBodyReasonablySized(requestBody) &&
-    hasValidTimestamp(requestBody)
+    hasValidBlindedPhoneNumberParam(requestBody) &&
+    identifierIsValidIfExists(requestBody) &&
+    isBodyReasonablySized(requestBody)
   )
 }
 
diff --git a/packages/phone-number-privacy/combiner/test/end-to-end/get-blinded-sig.test.ts b/packages/phone-number-privacy/combiner/test/end-to-end/get-blinded-sig.test.ts
index fb97ed41732..a9c599bac0c 100644
--- a/packages/phone-number-privacy/combiner/test/end-to-end/get-blinded-sig.test.ts
+++ b/packages/phone-number-privacy/combiner/test/end-to-end/get-blinded-sig.test.ts
@@ -36,7 +36,6 @@ describe('Running against a deployed service', () => {
         account: '0x1234',
         authenticationMethod: AuthenticationMethod.WALLET_KEY,
         blindedQueryPhoneNumber: BLINDED_PHONE_NUMBER,
-        timestamp: Date.now(),
         version: 'ignore',
         sessionID: genSessionID(),
       }
@@ -51,7 +50,6 @@ describe('Running against a deployed service', () => {
         account: ACCOUNT_ADDRESS,
         authenticationMethod: AuthenticationMethod.WALLET_KEY,
         blindedQueryPhoneNumber: '',
-        timestamp: Date.now(),
         version: 'ignore',
         sessionID: genSessionID(),
       }
@@ -67,7 +65,6 @@ describe('Running against a deployed service', () => {
         account: ACCOUNT_ADDRESS,
         authenticationMethod: AuthenticationMethod.WALLET_KEY,
         blindedQueryPhoneNumber: BLINDED_PHONE_NUMBER,
-        timestamp: Date.now(),
         version: 'ignore',
       }
       await expect(
@@ -92,14 +89,12 @@ describe('Running against a deployed service', () => {
   describe('With enough quota', () => {
     // if these tests are failing, it may just be that the address needs to be fauceted:
     // celotooljs account faucet --account 0x1be31a94361a391bbafb2a4ccd704f57dc04d4bb --dollar 1 --gold 1 -e <ENV> --verbose
-    const timestamp = Date.now()
     it('Returns sig when querying with unused and used request', async () => {
       await replenishQuota(ACCOUNT_ADDRESS, contractKit)
       const body: SignMessageRequest = {
         account: ACCOUNT_ADDRESS,
         authenticationMethod: AuthenticationMethod.WALLET_KEY,
         blindedQueryPhoneNumber: BLINDED_PHONE_NUMBER,
-        timestamp,
         version: 'ignore',
         sessionID: genSessionID(),
       }
diff --git a/packages/phone-number-privacy/combiner/test/index.test.ts b/packages/phone-number-privacy/combiner/test/index.test.ts
index 38bb74886eb..43ec2be930b 100644
--- a/packages/phone-number-privacy/combiner/test/index.test.ts
+++ b/packages/phone-number-privacy/combiner/test/index.test.ts
@@ -1,4 +1,4 @@
-import { isVerified, REQUEST_EXPIRY_WINDOW_MS } from '@celo/phone-number-privacy-common'
+import { isVerified } from '@celo/phone-number-privacy-common'
 import { Request, Response } from 'firebase-functions'
 import { BLSCryptographyClient } from '../src/bls/bls-cryptography-client'
 import { VERSION } from '../src/config'
@@ -146,17 +146,6 @@ describe(`POST /getBlindedMessageSig endpoint`, () => {
 
       getBlindedMessageSig(req, invalidResponseExpected(done, 400))
     })
-    it('expired timestamp returns 400', (done) => {
-      const req = {
-        body: {
-          ...validRequest,
-          timestamp: Date.now() - REQUEST_EXPIRY_WINDOW_MS,
-        },
-        headers: mockHeaders,
-      } as Request
-
-      getBlindedMessageSig(req, invalidResponseExpected(done, 400))
-    })
     it('invalid blinded phone number returns 400', (done) => {
       const req = {
         body: {
diff --git a/packages/phone-number-privacy/common/package.json b/packages/phone-number-privacy/common/package.json
index 5b604a7efa4..2feccc5385f 100644
--- a/packages/phone-number-privacy/common/package.json
+++ b/packages/phone-number-privacy/common/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@celo/phone-number-privacy-common",
-  "version": "1.0.34-dev",
+  "version": "1.0.35-dev",
   "description": "Common library for the combiner and signer libraries",
   "author": "Celo",
   "license": "Apache-2.0",
diff --git a/packages/phone-number-privacy/signer/package.json b/packages/phone-number-privacy/signer/package.json
index cdba85d7659..dafd44d6f8f 100644
--- a/packages/phone-number-privacy/signer/package.json
+++ b/packages/phone-number-privacy/signer/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@celo/phone-number-privacy-signer",
-  "version": "1.1.6-dev",
+  "version": "1.1.8-dev",
   "description": "Signing participator of ODIS",
   "author": "Celo",
   "license": "Apache-2.0",
@@ -19,9 +19,9 @@
   },
   "dependencies": {
     "@celo/base": "1.1.1",
-    "@celo/contractkit": "1.0.2",
-    "@celo/phone-number-privacy-common": "1.0.33",
-    "@celo/identity": "1.0.2",
+    "@celo/contractkit": "1.2.0",
+    "@celo/phone-number-privacy-common": "1.0.34",
+    "@celo/identity": "1.2.0",
     "@celo/utils": "1.0.2",
     "@celo/wallet-hsm-azure": "1.0.0-beta3",
     "@google-cloud/secret-manager": "3.0.0",
diff --git a/packages/phone-number-privacy/signer/src/common/metrics.ts b/packages/phone-number-privacy/signer/src/common/metrics.ts
index 97acb8aa2c3..809fcf5b153 100644
--- a/packages/phone-number-privacy/signer/src/common/metrics.ts
+++ b/packages/phone-number-privacy/signer/src/common/metrics.ts
@@ -22,8 +22,8 @@ export const Counters = {
     labelNames: ['endpoint', 'statusCode'],
   }),
   databaseErrors: new Counter({
-    name: 'database_read_errors',
-    help: 'Counter for the number of database read errors',
+    name: 'database_errors',
+    help: 'Counter for the number of database errors',
     labelNames: ['type'],
   }),
   blockchainErrors: new Counter({
diff --git a/packages/phone-number-privacy/signer/src/database/models/request.ts b/packages/phone-number-privacy/signer/src/database/models/request.ts
index 5e50f2b3d82..f8fea9db8cb 100644
--- a/packages/phone-number-privacy/signer/src/database/models/request.ts
+++ b/packages/phone-number-privacy/signer/src/database/models/request.ts
@@ -13,7 +13,7 @@ export class Request {
 
   constructor(request: GetBlindedMessagePartialSigRequest) {
     this[REQUESTS_COLUMNS.address] = request.account
-    this[REQUESTS_COLUMNS.timestamp] = new Date(request.timestamp as number)
+    this[REQUESTS_COLUMNS.timestamp] = new Date()
     this[REQUESTS_COLUMNS.blindedQuery] = request.blindedQueryPhoneNumber
   }
 }
diff --git a/packages/phone-number-privacy/signer/src/database/wrappers/request.ts b/packages/phone-number-privacy/signer/src/database/wrappers/request.ts
index 9a3b96b5742..6b4dc7b6f49 100644
--- a/packages/phone-number-privacy/signer/src/database/wrappers/request.ts
+++ b/packages/phone-number-privacy/signer/src/database/wrappers/request.ts
@@ -13,10 +13,6 @@ export async function getRequestExists(
   request: GetBlindedMessagePartialSigRequest,
   logger: Logger
 ): Promise<boolean> {
-  if (!request.timestamp) {
-    logger.debug('request does not have timestamp')
-    return false
-  }
   logger.debug({ request }, 'Checking if request exists')
   const getRequestExistsMeter = Histograms.dbOpsInstrumentation
     .labels('getRequestExists')
@@ -24,7 +20,6 @@ export async function getRequestExists(
   try {
     const existingRequest = await requests()
       .where({
-        [REQUESTS_COLUMNS.timestamp]: new Date(request.timestamp as number),
         [REQUESTS_COLUMNS.address]: request.account,
         [REQUESTS_COLUMNS.blindedQuery]: request.blindedQueryPhoneNumber,
       })
@@ -42,10 +37,6 @@ export async function getRequestExists(
 }
 
 export async function storeRequest(request: GetBlindedMessagePartialSigRequest, logger: Logger) {
-  if (!request.timestamp) {
-    logger.debug('request does not have timestamp')
-    return true
-  }
   const storeRequestMeter = Histograms.dbOpsInstrumentation.labels('storeRequest').startTimer()
   logger.debug({ request }, 'Storing salt request')
   try {
diff --git a/packages/phone-number-privacy/signer/src/signing/get-partial-signature.ts b/packages/phone-number-privacy/signer/src/signing/get-partial-signature.ts
index 10b05aec65c..7e30aea1763 100644
--- a/packages/phone-number-privacy/signer/src/signing/get-partial-signature.ts
+++ b/packages/phone-number-privacy/signer/src/signing/get-partial-signature.ts
@@ -2,10 +2,9 @@ import {
   authenticateUser,
   ErrorMessage,
   hasValidAccountParam,
-  hasValidQueryPhoneNumberParam,
-  hasValidTimestamp,
+  hasValidBlindedPhoneNumberParam,
+  identifierIsValidIfExists,
   isBodyReasonablySized,
-  phoneNumberHashIsValidIfExists,
   SignMessageResponse,
   SignMessageResponseFailure,
   WarningMessage,
@@ -203,10 +202,9 @@ export async function handleGetBlindedMessagePartialSig(
 function isValidGetSignatureInput(requestBody: GetBlindedMessagePartialSigRequest): boolean {
   return (
     hasValidAccountParam(requestBody) &&
-    hasValidQueryPhoneNumberParam(requestBody) &&
-    phoneNumberHashIsValidIfExists(requestBody) &&
-    isBodyReasonablySized(requestBody) &&
-    hasValidTimestamp(requestBody)
+    hasValidBlindedPhoneNumberParam(requestBody) &&
+    identifierIsValidIfExists(requestBody) &&
+    isBodyReasonablySized(requestBody)
   )
 }
 
diff --git a/packages/phone-number-privacy/signer/src/signing/query-quota.ts b/packages/phone-number-privacy/signer/src/signing/query-quota.ts
index bb50b01710d..7fac37179cb 100644
--- a/packages/phone-number-privacy/signer/src/signing/query-quota.ts
+++ b/packages/phone-number-privacy/signer/src/signing/query-quota.ts
@@ -6,9 +6,9 @@ import {
   FULL_NODE_TIMEOUT_IN_MS,
   GetQuotaRequest,
   hasValidAccountParam,
+  identifierIsValidIfExists,
   isBodyReasonablySized,
   isVerified,
-  phoneNumberHashIsValidIfExists,
   RETRY_COUNT,
   RETRY_DELAY_IN_MS,
   WarningMessage,
@@ -68,7 +68,7 @@ export async function handleGetQuota(
 function isValidGetQuotaInput(requestBody: GetQuotaRequest): boolean {
   return (
     hasValidAccountParam(requestBody) &&
-    phoneNumberHashIsValidIfExists(requestBody) &&
+    identifierIsValidIfExists(requestBody) &&
     isBodyReasonablySized(requestBody)
   )
 }
diff --git a/packages/phone-number-privacy/signer/test/end-to-end/get-blinded-sig.test.ts b/packages/phone-number-privacy/signer/test/end-to-end/get-blinded-sig.test.ts
index 5254e90d37a..d3ee0205eef 100644
--- a/packages/phone-number-privacy/signer/test/end-to-end/get-blinded-sig.test.ts
+++ b/packages/phone-number-privacy/signer/test/end-to-end/get-blinded-sig.test.ts
@@ -68,23 +68,16 @@ describe('Running against a deployed service', () => {
     })
 
     it('With auth header signer mismatch', async () => {
-      const timestamp = Date.now()
       // Sign body with different account
       const body = JSON.stringify({
         hashedPhoneNumber: '+1455556600',
         blindedQueryPhoneNumber: BLINDED_PHONE_NUMBER.trim(),
         ACCOUNT_ADDRESS1,
-        timestamp,
       })
       const signature = signMessage(JSON.stringify(body), PRIVATE_KEY2, ACCOUNT_ADDRESS2)
       const authHeader = serializeSignature(signature)
 
-      const response = await postToSignMessage(
-        BLINDED_PHONE_NUMBER,
-        ACCOUNT_ADDRESS1,
-        timestamp,
-        authHeader
-      )
+      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS1, authHeader)
       expect(response.status).toBe(401)
     })
 
@@ -102,50 +95,62 @@ describe('Running against a deployed service', () => {
   describe('When account address has enough quota', () => {
     // if these tests are failing, it may just be that the address needs to be fauceted:
     // celotooljs account faucet --account ACCOUNT_ADDRESS2 --dollar 1 --gold 1 -e <ENV> --verbose
-    let initialQueryCount: number
-    let timestamp: number
+
     beforeAll(async () => {
       console.log('ACCOUNT_ADDRESS1 ' + ACCOUNT_ADDRESS1)
       console.log('ACCOUNT_ADDRESS2 ' + ACCOUNT_ADDRESS2)
       console.log('ACCOUNT_ADDRESS3 ' + ACCOUNT_ADDRESS3)
 
       contractkit.defaultAccount = ACCOUNT_ADDRESS2
-
-      initialQueryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
-      timestamp = Date.now()
     })
 
-    it('Returns sig when querying succeeds with unused request', async () => {
+    it('Returns sig when querying succeeds', async () => {
       await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, timestamp)
+      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2)
       expect(response.status).toBe(200)
     })
 
-    it('Returns count when querying with unused request increments query count', async () => {
-      const queryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
-      expect(queryCount).toEqual(initialQueryCount + 1)
+    // Backwards compatibility check
+    it('Returns sig when querying succeeds w/ timestamp', async () => {
+      await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
+      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, Date.now())
+      expect(response.status).toBe(200)
     })
 
-    it('Returns sig when querying succeeds with used request', async () => {
+    it('Increments query count when querying succeeds', async () => {
       await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, timestamp)
-      expect(response.status).toBe(200)
+      const initialQueryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
+      await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2)
+      expect(initialQueryCount).toEqual((await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)) - 1)
     })
 
-    it('Returns count when querying with used request does not increment query count', async () => {
-      const queryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
-      expect(queryCount).toEqual(initialQueryCount + 1)
+    // Backwards compatibility check
+    it('Increments query count when querying succeeds w/ timestamp', async () => {
+      await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
+      const initialQueryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
+      await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, Date.now())
+      expect(initialQueryCount).toEqual((await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)) - 1)
     })
 
-    it('Returns sig when querying succeeds with missing timestamp', async () => {
+    it('Returns sig when querying succeeds with replayed request without incrementing query count', async () => {
       await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2)
-      expect(response.status).toBe(200)
+      const res1 = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2)
+      expect(res1.status).toBe(200)
+      const queryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
+      const res2 = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2)
+      expect(res2.status).toBe(200)
+      expect(queryCount).toEqual(await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER))
     })
 
-    it('Returns count when querying with missing timestamp increments query count', async () => {
+    // Backwards compatibility check
+    it('Returns sig when querying succeeds with replayed request without incrementing query count w/ timestamp', async () => {
+      await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
+      const res1 = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, Date.now())
+      expect(res1.status).toBe(200)
       const queryCount = await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER)
-      expect(queryCount).toEqual(initialQueryCount + 2)
+      const res2 = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS2, Date.now())
+      expect(res2.status).toBe(200)
+      expect(queryCount).toEqual(await getQueryCount(ACCOUNT_ADDRESS2, IDENTIFIER))
     })
   })
 
@@ -155,7 +160,6 @@ describe('Running against a deployed service', () => {
     // NOTE: DO NOT FAUCET ACCOUNT_ADDRESS3
     let initialQuota: number
     let initialQueryCount: number
-    let timestamp: number
     beforeAll(async () => {
       contractkit.defaultAccount = ACCOUNT_ADDRESS3
       await registerWalletAddress(ACCOUNT_ADDRESS3, ACCOUNT_ADDRESS2, PRIVATE_KEY2, contractkit)
@@ -163,7 +167,6 @@ describe('Running against a deployed service', () => {
       // and ACCOUNT_ADDRESS3 is account address (does not have quota on it's own, only bc of walletAddress)
       initialQuota = await getQuota(ACCOUNT_ADDRESS3, IDENTIFIER)
       initialQueryCount = await getQueryCount(ACCOUNT_ADDRESS3, IDENTIFIER)
-      timestamp = Date.now()
     })
 
     it('Check that accounts are set up correctly', async () => {
@@ -173,7 +176,7 @@ describe('Running against a deployed service', () => {
 
     it('Returns sig when querying succeeds with unused request', async () => {
       await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS3, timestamp)
+      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS3)
       expect(response.status).toBe(200)
     })
 
@@ -184,7 +187,7 @@ describe('Running against a deployed service', () => {
 
     it('Returns sig when querying succeeds with used request', async () => {
       await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS3, timestamp)
+      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS3)
       expect(response.status).toBe(200)
     })
 
@@ -192,17 +195,6 @@ describe('Running against a deployed service', () => {
       const queryCount = await getQueryCount(ACCOUNT_ADDRESS3, IDENTIFIER)
       expect(queryCount).toEqual(initialQueryCount + 1)
     })
-
-    it('Returns sig when querying succeeds with missing timestamp', async () => {
-      await replenishQuota(ACCOUNT_ADDRESS2, contractkit)
-      const response = await postToSignMessage(BLINDED_PHONE_NUMBER, ACCOUNT_ADDRESS3)
-      expect(response.status).toBe(200)
-    })
-
-    it('Returns count when querying with missing timestamp increments query count', async () => {
-      const queryCount = await getQueryCount(ACCOUNT_ADDRESS3, IDENTIFIER)
-      expect(queryCount).toEqual(initialQueryCount + 2)
-    })
   })
 })
 
diff --git a/packages/phone-number-privacy/signer/test/index.test.ts b/packages/phone-number-privacy/signer/test/index.test.ts
index 0755b618239..05dcb7b2b16 100644
--- a/packages/phone-number-privacy/signer/test/index.test.ts
+++ b/packages/phone-number-privacy/signer/test/index.test.ts
@@ -1,4 +1,4 @@
-import { authenticateUser, REQUEST_EXPIRY_WINDOW_MS } from '@celo/phone-number-privacy-common'
+import { authenticateUser } from '@celo/phone-number-privacy-common'
 import BigNumber from 'bignumber.js'
 import request from 'supertest'
 import { ErrorMessage, WarningMessage } from '../../common/src/interfaces/error-utils'
@@ -78,7 +78,6 @@ describe(`POST /getBlindedMessageSignature endpoint`, () => {
     blindedQueryPhoneNumber: BLINDED_PHONE_NUMBER,
     hashedPhoneNumber: '0x5f6e88c3f724b3a09d3194c0514426494955eff7127c29654e48a361a19b4b96',
     account: '0x78dc5D2D739606d31509C31d654056A45185ECb6',
-    timestamp: Date.now(),
   }
 
   describe('with valid input', () => {
@@ -102,6 +101,27 @@ describe(`POST /getBlindedMessageSignature endpoint`, () => {
           done
         )
     })
+    // Backwards compatibility check
+    it('provides signature w/ expired timestamp', (done) => {
+      mockGetRemainingQueryCount.mockResolvedValue({ performedQueryCount: 0, totalQuota: 10 })
+      mockGetBlockNumber.mockResolvedValue(10000)
+      request(app)
+        .post('/getBlindedMessagePartialSig')
+        .send({ ...validRequest, timestamp: Date.now() - 10 * 60 * 1000 }) // 10 minutes ago
+        .expect('Content-Type', /json/)
+        .expect(
+          200,
+          {
+            success: true,
+            signature: BLS_SIGNATURE,
+            version: getVersion(),
+            performedQueryCount: 1,
+            totalQuota: 10,
+            blockNumber: 10000,
+          },
+          done
+        )
+    })
     it('returns 403 on query count 0', (done) => {
       mockGetRemainingQueryCount.mockResolvedValue({ performedQueryCount: 10, totalQuota: 10 })
       request(app)
@@ -213,15 +233,6 @@ describe(`POST /getBlindedMessageSignature endpoint`, () => {
       request(app).post('/getBlindedMessagePartialSig').send(mockRequestData).expect(400, done)
     })
 
-    it('expired timestamp returns 400', (done) => {
-      const mockRequestData = {
-        ...validRequest,
-        timestamp: Date.now() - REQUEST_EXPIRY_WINDOW_MS,
-      }
-
-      request(app).post('/getBlindedMessagePartialSig').send(mockRequestData).expect(400, done)
-    })
-
     it('invalid blinded phone number returns 400', (done) => {
       const mockRequestData = {
         ...validRequest,
diff --git a/packages/sdk/identity/src/odis/bls-blinding-client.ts b/packages/sdk/identity/src/odis/bls-blinding-client.ts
index 9f0c688bc4b..c406b6ca1ec 100644
--- a/packages/sdk/identity/src/odis/bls-blinding-client.ts
+++ b/packages/sdk/identity/src/odis/bls-blinding-client.ts
@@ -1,7 +1,7 @@
 import { randomBytes } from 'crypto'
 
 export interface BlsBlindingClient {
-  blindMessage: (base64PhoneNumber: string) => Promise<string>
+  blindMessage: (base64PhoneNumber: string, seed?: Uint8Array) => Promise<string>
   unblindAndVerifyMessage: (blindedMessage: string) => Promise<string>
 }
 
@@ -36,8 +36,16 @@ export class WasmBlsBlindingClient implements BlsBlindingClient {
     }
   }
 
-  async blindMessage(base64PhoneNumber: string): Promise<string> {
-    const userSeed = randomBytes(32)
+  async blindMessage(base64PhoneNumber: string, seed?: Uint8Array): Promise<string> {
+    let userSeed
+    if (!seed) {
+      userSeed = randomBytes(32)
+      console.warn(
+        'Warning: Use a private deterministic seed (i.e. DEK private key) to preserve user quota when requests are replayed.'
+      )
+    } else {
+      userSeed = seed
+    }
     this.rawMessage = Buffer.from(base64PhoneNumber, 'base64')
     this.blindedValue = await this.thresholdBls.blind(this.rawMessage, userSeed)
     const blindedMessage = this.blindedValue.message
diff --git a/packages/sdk/identity/src/odis/phone-number-identifier.ts b/packages/sdk/identity/src/odis/phone-number-identifier.ts
index 542a148bf38..5315af5669b 100644
--- a/packages/sdk/identity/src/odis/phone-number-identifier.ts
+++ b/packages/sdk/identity/src/odis/phone-number-identifier.ts
@@ -49,6 +49,7 @@ export async function getPhoneNumberIdentifier(
     throw new Error(`Invalid phone number: ${e164Number}`)
   }
   // Fallback to using Wasm version if not specified
+
   if (!blsBlindingClient) {
     debug('No BLSBlindingClient found, using WasmBlsBlindingClient')
     blsBlindingClient = new WasmBlsBlindingClient(context.odisPubKey)
@@ -98,7 +99,6 @@ export async function getBlindedPhoneNumberSignature(
 ): Promise<string> {
   const body: SignMessageRequest = {
     account,
-    timestamp: Date.now(),
     blindedQueryPhoneNumber: base64BlindedMessage,
     hashedPhoneNumber: selfPhoneHash,
     version: clientVersion ? clientVersion : 'unknown',
diff --git a/packages/sdk/identity/src/odis/query.ts b/packages/sdk/identity/src/odis/query.ts
index d3a02c89edf..4989d3d8b33 100644
--- a/packages/sdk/identity/src/odis/query.ts
+++ b/packages/sdk/identity/src/odis/query.ts
@@ -43,7 +43,6 @@ export interface PhoneNumberPrivacyRequest {
 
 export interface SignMessageRequest extends PhoneNumberPrivacyRequest {
   blindedQueryPhoneNumber: string
-  timestamp?: number
   hashedPhoneNumber?: string
 }
 
diff --git a/yarn.lock b/yarn.lock
index f9f02e1d89e..8a5a432ab3d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1549,6 +1549,26 @@
     is-base64 "^1.1.0"
     libphonenumber-js "^1.9.11"
 
+"@celo/phone-number-privacy-common@1.0.34":
+  version "1.0.34"
+  resolved "https://registry.yarnpkg.com/@celo/phone-number-privacy-common/-/phone-number-privacy-common-1.0.34.tgz#59b3b4d03a0482c967f26f7638d1afd326d4115b"
+  integrity sha512-xAIusO9N66lBG11/21ro0w8BZTLcRs6sWluam2qlTCf5e1vSPAxQeDx8GaqpcAJ2500zSsvmFOzlAA1iZiAD8g==
+  dependencies:
+    "@celo/base" "1.1.1"
+    "@celo/contractkit" "1.2.0"
+    "@celo/identity" "1.2.0"
+    "@celo/utils" "1.0.2"
+    bignumber.js "^9.0.0"
+    blind-threshold-bls "https://github.com/celo-org/blind-threshold-bls-wasm#e1e2f8a"
+    btoa "1.2.1"
+    bunyan "1.8.12"
+    bunyan-debug-stream "2.0.0"
+    bunyan-gke-stackdriver "0.1.2"
+    dotenv "^8.2.0"
+    elliptic "^6.5.4"
+    is-base64 "^1.1.0"
+    libphonenumber-js "^1.9.11"
+
 "@celo/typechain-target-web3-v1-celo@0.2.0":
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/@celo/typechain-target-web3-v1-celo/-/typechain-target-web3-v1-celo-0.2.0.tgz#2560b470e348d2628debe899885724ce5b218bc3"