diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5fd13836b..2dbaa1d90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ All notable changes to this project will be documented in this file.
 - Matter bridge for ESP8266 remote endpoints (experimental)
 - Display descriptor for ST7735 128x160 display
 - Matter support for Occupancy via Switch (experimental)
+- Berry RS256 crypto algorithm (RSASSA-MCKS1_v1-5 with SHA256) used for JWT
 
 ### Breaking Changed
 - Matter relay number starts at 1 instead of 0 to match Tasmota numbering
diff --git a/lib/lib_ssl/bearssl-esp8266/src/t_inner.h b/lib/lib_ssl/bearssl-esp8266/src/t_inner.h
index 924486db7..d5fecd71b 100644
--- a/lib/lib_ssl/bearssl-esp8266/src/t_inner.h
+++ b/lib/lib_ssl/bearssl-esp8266/src/t_inner.h
@@ -2597,7 +2597,11 @@ br_cpuid(uint32_t mask_eax, uint32_t mask_ebx,
   #endif
 
   #define _debugBearSSL (0)
-  extern void optimistic_yield(uint32_t);
+  #ifdef ESP8266
+    extern void optimistic_yield(uint32_t);
+  #else
+    #define optimistic_yield(ignored)
+  #endif
   #ifdef __cplusplus
   }
   #endif
diff --git a/lib/libesp32/berry_tasmota/src/be_crypto_lib.c b/lib/libesp32/berry_tasmota/src/be_crypto_lib.c
index 621d17113..0162bc369 100644
--- a/lib/libesp32/berry_tasmota/src/be_crypto_lib.c
+++ b/lib/libesp32/berry_tasmota/src/be_crypto_lib.c
@@ -11,6 +11,8 @@
 extern int be_class_crypto_member(bvm *vm);
 extern int m_crypto_random(bvm *vm);
 
+extern int m_rsa_rsassa_pkcs1_v1_5(bvm *vm);
+
 extern int m_aes_ccm_init(bvm *vm);
 extern int m_aes_ccm_encryt(bvm *vm);
 extern int m_aes_ccm_decryt(bvm *vm);
@@ -56,6 +58,7 @@ extern const bclass be_class_md5;
 #include "solidify/solidified_crypto_pbkdf2_hmac_sha256.h"
 #include "solidify/solidified_crypto_spake2p_matter.h"
 
+#include "be_fixed_be_class_rsa.h"
 #include "be_fixed_be_class_aes_ccm.h"
 #include "be_fixed_be_class_aes_gcm.h"
 #include "be_fixed_be_class_aes_ctr.h"
@@ -104,6 +107,10 @@ const be_const_member_t be_crypto_members[] = {
   { "/PBKDF2_HMAC_SHA256", (intptr_t) &be_class_pbkdf2_hmac_sha256 },
 #endif // USE_BERRY_CRYPTO_PBKDF2_HMAC_SHA256
 
+#ifdef USE_BERRY_CRYPTO_RSA
+  { "/RSA", (intptr_t) &be_class_rsa },
+#endif // USE_BERRY_CRYPTO_PBKDF2_HMAC_SHA256
+
 #ifdef USE_BERRY_CRYPTO_SHA256
   { "/SHA256", (intptr_t) &be_class_sha256 },
 #endif // USE_BERRY_CRYPTO_SHA256
@@ -118,6 +125,10 @@ const size_t be_crypto_members_size = sizeof(be_crypto_members)/sizeof(be_crypto
 
 /* @const_object_info_begin
 
+class be_class_rsa (scope: global, name: RSA) {
+    rs256, static_func(m_rsa_rsassa_pkcs1_v1_5)
+}
+
 class be_class_aes_ccm (scope: global, name: AES_CCM) {
     .p1, var
     .p2, var
diff --git a/tasmota/tasmota_xdrv_driver/xdrv_52_3_berry_crypto.ino b/tasmota/tasmota_xdrv_driver/xdrv_52_3_berry_crypto.ino
index bec624546..d422f09d8 100644
--- a/tasmota/tasmota_xdrv_driver/xdrv_52_3_berry_crypto.ino
+++ b/tasmota/tasmota_xdrv_driver/xdrv_52_3_berry_crypto.ino
@@ -65,6 +65,56 @@ extern "C" {
   }
 }
 
+/*********************************************************************************************\
+ * RSA class
+ * 
+\*********************************************************************************************/
+extern "C" {
+  // crypto.RSA.rsassa_pkcs1_v1_5(private_key:bytes(), msg:bytes()) -> bytes()
+  // Parses RSA private key from DER binary
+  int32_t m_rsa_rsassa_pkcs1_v1_5(bvm *vm);
+  int32_t m_rsa_rsassa_pkcs1_v1_5(bvm *vm) {
+    int32_t argc = be_top(vm); // Get the number of arguments
+    if (argc >= 2 && be_isbytes(vm, 1)) {
+      size_t sk_len = 0;
+      uint8_t * sk_der = (uint8_t*) be_tobytes(vm, 1, &sk_len);
+      
+      // 1. decode the DER private key
+      br_skey_decoder_context sdc;
+      br_skey_decoder_init(&sdc);
+      br_skey_decoder_push(&sdc, sk_der, sk_len);
+      if (int ret = br_skey_decoder_last_error(&sdc)) {
+        be_raisef(vm, "value_error", "invalid private key %i", ret);
+      }
+      if (br_skey_decoder_key_type(&sdc) != BR_KEYTYPE_RSA) {
+        be_raise(vm, "value_error", "key is not RSA");
+      }
+      const br_rsa_private_key *sk = br_skey_decoder_get_rsa(&sdc);
+      
+      // 2. Hash the message with SHA
+      size_t msg_len = 0;
+      uint8_t * msg = (uint8_t*) be_tobytes(vm, 2, &msg_len);
+      uint8_t hash[32];
+      br_sha256_context ctx;
+      br_sha256_init(&ctx);
+      br_sha256_update(&ctx, msg, msg_len);
+      br_sha256_out(&ctx, hash);
+
+      // 3. sign the message
+      size_t sign_len = (sk->n_bitlen + 7) / 8;
+      uint8_t x[sign_len] = {};
+      int err = br_rsa_i15_pkcs1_sign(BR_HASH_OID_SHA256,	hash, sizeof(hash), sk, x);
+      if (err != 1) {
+        be_raisef(vm, "value_error", "signature failed %i", err);
+      }
+
+      be_pushbytes(vm, x, sign_len);
+      be_return(vm);
+    }
+    be_raise(vm, kTypeError, nullptr);
+  }
+}
+
 /*********************************************************************************************\
  * AES_GCM class
  *