MacOS RSA DER / OpenSSL 3.4.0 RSA256 EncodingKey::from_rsa_der broken

[ben-kaye]

Seen also #55

Description:
Using OpenSSL 3.4.0 on MacOS, EncodingKey::from_rsa_der fails to parse standard RSA DER keys.

Steps to Reproduce:
Minimal repro here: der_broken
jsonwebtoken = "9.3.1"

Shell script to generate the key:

#!/bin/zsh

if [ -z "$1" ]; then
    num_bits=3072
else
    num_bits=$1
fi

# Generate 3072-bit RSA private key directly in PEM
openssl genrsa -out private.pem $num_bits

openssl rsa -outform DER -in private.pem -out private.der
openssl rsa -RSAPublicKey_out -outform DER -in private.pem -out public.der

# Base64 encode the DER files (without newlines)
base64 < private.der | tr -d '\n' > private.der.b64
base64 < public.der | tr -d '\n' > public.der.b64

# Write to .env cleanly without extra newlines
{
  printf "JWT_PRIVATE=%s\n" "$(cat private.der.b64)"
  printf "JWT_PUBLIC=%s\n" "$(cat public.der.b64)"
} > .env

Notes:

• The DER produced is valid (can be parsed by OpenSSL and other libraries).
• Likely regression related to stricter ASN.1 parsing.
• Happens on both 2048 and 3072-bit keys.
• PEM-based loading (from_rsa_pem) still works fine.