diff --git a/tests/suites/test_suite_ssl.data b/tests/suites/test_suite_ssl.data
index 20a0c6d..c344b21 100644
--- a/tests/suites/test_suite_ssl.data
+++ b/tests/suites/test_suite_ssl.data
@@ -254,23 +254,23 @@
 handshake_cipher:"TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:0
 
 Handshake, RSA-WITH-AES-128-CCM
-depends_on:MBEDTLS_CCM_C:MBEDTLS_AES_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+depends_on:MBEDTLS_CCM_C:MBEDTLS_AES_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
 handshake_cipher:"TLS-RSA-WITH-AES-128-CCM":MBEDTLS_PK_RSA:0
 
 Handshake, DHE-RSA-WITH-AES-256-CBC-SHA256
-depends_on:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_AES_C:MBEDTLS_HAS_ALG_SHA_256_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+depends_on:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_AES_C:MBEDTLS_HAS_ALG_SHA_256_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
 handshake_cipher:"TLS-DHE-RSA-WITH-AES-256-CBC-SHA256":MBEDTLS_PK_RSA:0
 
 Handshake, ECDHE-ECDSA-WITH-AES-256-CCM
-depends_on:MBEDTLS_AES_C:MBEDTLS_CCM_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+depends_on:MBEDTLS_AES_C:MBEDTLS_CCM_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 handshake_cipher:"TLS-ECDHE-ECDSA-WITH-AES-256-CCM":MBEDTLS_PK_ECDSA:0
 
 Handshake, ECDH-ECDSA-WITH-CAMELLIA-256-CBC-SHA384
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_CAMELLIA_C
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_CAMELLIA_C:MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED
 handshake_cipher:"TLS-ECDH-ECDSA-WITH-CAMELLIA-256-CBC-SHA384":MBEDTLS_PK_ECDSA:0
 
 Handshake, PSK-WITH-AES-128-CBC-SHA
-depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_HAS_ALG_SHA_1_VIA_MD_OR_PSA_BASED_ON_USE_PSA
+depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_HAS_ALG_SHA_1_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
 handshake_psk_cipher:"TLS-PSK-WITH-AES-128-CBC-SHA":MBEDTLS_PK_RSA:"abc123":0
 
 DTLS Handshake, tls1_2
@@ -282,23 +282,23 @@
 handshake_cipher:"TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:1
 
 DTLS Handshake, RSA-WITH-AES-128-CCM
-depends_on:MBEDTLS_CCM_C:MBEDTLS_AES_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS
+depends_on:MBEDTLS_CCM_C:MBEDTLS_AES_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
 handshake_cipher:"TLS-RSA-WITH-AES-128-CCM":MBEDTLS_PK_RSA:1
 
 DTLS Handshake, DHE-RSA-WITH-AES-256-CBC-SHA256
-depends_on:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_AES_C:MBEDTLS_HAS_ALG_SHA_256_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS
+depends_on:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_AES_C:MBEDTLS_HAS_ALG_SHA_256_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
 handshake_cipher:"TLS-DHE-RSA-WITH-AES-256-CBC-SHA256":MBEDTLS_PK_RSA:1
 
 DTLS Handshake, ECDHE-ECDSA-WITH-AES-256-CCM
-depends_on:MBEDTLS_AES_C:MBEDTLS_CCM_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS
+depends_on:MBEDTLS_AES_C:MBEDTLS_CCM_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 handshake_cipher:"TLS-ECDHE-ECDSA-WITH-AES-256-CCM":MBEDTLS_PK_ECDSA:1
 
 DTLS Handshake, ECDH-ECDSA-WITH-CAMELLIA-256-CBC-SHA384
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_CAMELLIA_C:MBEDTLS_SSL_PROTO_DTLS
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_CAMELLIA_C:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED
 handshake_cipher:"TLS-ECDH-ECDSA-WITH-CAMELLIA-256-CBC-SHA384":MBEDTLS_PK_ECDSA:1
 
 DTLS Handshake, PSK-WITH-AES-128-CBC-SHA
-depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_HAS_ALG_SHA_1_VIA_MD_OR_PSA_BASED_ON_USE_PSA
+depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SSL_PROTO_DTLS:MBEDTLS_HAS_ALG_SHA_1_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
 handshake_psk_cipher:"TLS-PSK-WITH-AES-128-CBC-SHA":MBEDTLS_PK_RSA:"abc123":1
 
 DTLS Handshake with serialization, tls1_2
@@ -354,27 +354,27 @@
 handshake_ciphersuite_select:"TLS-RSA-PSK-WITH-AES-256-CBC-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_CRYPT:PSA_ALG_NONE:PSA_KEY_USAGE_DECRYPT:MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:0
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, non-opaque
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_NONE:PSA_ALG_NONE:0:0:MBEDTLS_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, opaque, PSA_ALG_ANY_HASH
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_ANY_HASH):PSA_ALG_NONE:PSA_KEY_USAGE_SIGN_HASH:0:MBEDTLS_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, opaque, PSA_ALG_SHA_384
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_384):PSA_ALG_NONE:PSA_KEY_USAGE_SIGN_HASH:0:MBEDTLS_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, opaque, invalid alg
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_256):PSA_ALG_NONE:PSA_KEY_USAGE_SIGN_HASH:MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:0
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, opaque, bad alg
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_CRYPT:PSA_ALG_NONE:PSA_KEY_USAGE_SIGN_HASH:MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:0
 
 Handshake, select DHE-RSA-WITH-AES-256-GCM-SHA384, opaque, bad usage
-depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
+depends_on:MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA:MBEDTLS_AES_C:MBEDTLS_GCM_C:MBEDTLS_RSA_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED:MBEDTLS_USE_PSA_CRYPTO
 handshake_ciphersuite_select:"TLS-DHE-RSA-WITH-AES-256-GCM-SHA384":MBEDTLS_PK_RSA:"":PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_ANY_HASH):PSA_ALG_NONE:PSA_KEY_USAGE_DERIVE:MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:0
 
 Handshake, select ECDHE-RSA-WITH-AES-256-GCM-SHA384, non-opaque
@@ -3115,7 +3115,7 @@
 # - App data payload: 70696e67
 # - Complete record:  1703030015c74061535eb12f5f25a781957874742ab7fb305dd5
 # - Padding used: No (== granularity 1)
-depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C
+depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 ssl_tls13_record_protection:MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:MBEDTLS_SSL_IS_CLIENT:0:1:"0b6d22c8ff68097ea871c672073773bf":"1b13dd9f8d8f17091d34b349":"49134b95328f279f0183860589ac6707":"bc4dd5f7b98acff85466261d":"70696e67":"c74061535eb12f5f25a781957874742ab7fb305dd5"
 
 SSL TLS 1.3 Record Encryption, tls13.ulfheim.net Example #2
@@ -3126,7 +3126,7 @@
 # - App data payload: 706f6e67
 # - Complete record:  1703030015370e5f168afa7fb16b663ecdfca3dbb81931a90ca7
 # - Padding used: No (== granularity 1)
-depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C
+depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 ssl_tls13_record_protection:MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:MBEDTLS_SSL_IS_SERVER:1:1:"0b6d22c8ff68097ea871c672073773bf":"1b13dd9f8d8f17091d34b349":"49134b95328f279f0183860589ac6707":"bc4dd5f7b98acff85466261d":"706f6e67":"370e5f168afa7fb16b663ecdfca3dbb81931a90ca7"
 
 SSL TLS 1.3 Record Encryption RFC 8448 Example #1
@@ -3145,7 +3145,7 @@
 #                     62 97 4e 1f 5a 62 92 a2 97 70 14 bd 1e 3d ea e6
 #                     3a ee bb 21 69 49 15 e4
 # - Padding used: No (== granularity 1)
-depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C
+depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 ssl_tls13_record_protection:MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:MBEDTLS_SSL_IS_CLIENT:0:1:"9f02283b6c9c07efc26bb9f2ac92e356":"cf782b88dd83549aadf1e984":"17422dda596ed5d9acd890e3c63f5051":"5b78923dee08579033e523d9":"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031":"a23f7054b62c94d0affafe8228ba55cbefacea42f914aa66bcab3f2b9819a8a5b46b395bd54a9a20441e2b62974e1f5a6292a2977014bd1e3deae63aeebb21694915e4"
 
 SSL TLS 1.3 Record Encryption RFC 8448 Example #2
@@ -3164,12 +3164,12 @@
 #                     fc c4 9c 4b f2 e5 f0 a2 1c 00 47 c2 ab f3 32 54
 #                     0d d0 32 e1 67 c2 95 5d
 # - Padding used: No (== granularity 1)
-depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C
+depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 ssl_tls13_record_protection:MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:MBEDTLS_SSL_IS_SERVER:1:1:"9f02283b6c9c07efc26bb9f2ac92e356":"cf782b88dd83549aadf1e984":"17422dda596ed5d9acd890e3c63f5051":"5b78923dee08579033e523d9":"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031":"2e937e11ef4ac740e538ad36005fc4a46932fc3225d05f82aa1b36e30efaf97d90e6dffc602dcb501a59a8fcc49c4bf2e5f0a21c0047c2abf332540dd032e167c2955d"
 
 SSL TLS 1.3 Key schedule: Application secrets derivation helper
 # Vector from RFC 8448
-depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:PSA_WANT_ALG_SHA_256
+depends_on:MBEDTLS_AES_C:MBEDTLS_ECDSA_C:PSA_WANT_ALG_SHA_256:MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 ssl_tls13_derive_application_secrets:PSA_ALG_SHA_256:"e2d32d4ed66dd37897a0e80c84107503ce58bf8aad4cb55a5002d77ecb890ece":"b0aeffc46a2cfe33114e6fd7d51f9f04b1ca3c497dab08934a774a9d9ad7dbf3":"2abbf2b8e381d23dbebe1dd2a7d16a8bf484cb4950d23fb7fb7fa8547062d9a1":"cc21f1bf8feb7dd5fa505bd9c4b468a9984d554a993dc49e6d285598fb672691":"3fd93d4ffddc98e64b14dd107aedf8ee4add23f4510f58a4592d0b201bee56b4"
 
 SSL TLS 1.3 Key schedule: Resumption secrets derivation helper