diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index c5125f9eb..d4be75b62 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -586,11 +586,11 @@
 /** The twisted Edwards curves Ed25519 and Ed448.
  *
  * These curves are suitable for EdDSA (#PSA_ALG_PURE_EDDSA for both curves,
- * #PSA_ALG_ED25519PH for the 256-bit curve,
+ * #PSA_ALG_ED25519PH for the 255-bit curve,
  * #PSA_ALG_ED448PH for the 448-bit curve).
  *
  * This family comprises the following twisted Edwards curves:
- * - 256-bit: Edwards25519, the twisted Edwards curve birationally equivalent
+ * - 255-bit: Edwards25519, the twisted Edwards curve birationally equivalent
  *   to Curve25519.
  *   Bernstein et al., _Twisted Edwards curves_, Africacrypt 2008.
  * - 448-bit: Edwards448, the twisted Edwards curve birationally equivalent
diff --git a/scripts/mbedtls_dev/crypto_knowledge.py b/scripts/mbedtls_dev/crypto_knowledge.py
index 642e7254f..500aceafd 100644
--- a/scripts/mbedtls_dev/crypto_knowledge.py
+++ b/scripts/mbedtls_dev/crypto_knowledge.py
@@ -78,7 +78,7 @@ class KeyType:
         'PSA_ECC_FAMILY_SECT_R2': (163,),
         'PSA_ECC_FAMILY_BRAINPOOL_P_R1': (160, 192, 224, 256, 320, 384, 512),
         'PSA_ECC_FAMILY_MONTGOMERY': (255, 448),
-        'PSA_ECC_FAMILY_TWISTED_EDWARDS': (256, 448),
+        'PSA_ECC_FAMILY_TWISTED_EDWARDS': (255, 448),
     }
     KEY_TYPE_SIZES = {
         'PSA_KEY_TYPE_AES': (128, 192, 256), # exhaustive