scripts/sign_encrypt.py: Sign TA using PSS
Switches from the algorithm TEE_ALG_RSASSA_PKCS1_V1_5_SHA256 to
TEE_ALG_RSASSA_PKCS1_PSS_MGF1_SHA256 when signing TAs. Even though there
are no known vulnerabilities in PCKS#1 RSASSA V1.5 at this date there
has been issues in the past (for instance Bleichenbacher).
Reviewed-by: Jerome Forissier <jerome@forissier.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/scripts/sign_encrypt.py b/scripts/sign_encrypt.py
index 0b3408d..4cc9630 100755
--- a/scripts/sign_encrypt.py
+++ b/scripts/sign_encrypt.py
@@ -128,10 +128,10 @@
def main():
- from Crypto.Signature import PKCS1_v1_5
- from Crypto.Hash import SHA256
- from Crypto.PublicKey import RSA
- from Crypto.Util.number import ceil_div
+ from Cryptodome.Signature import pss
+ from Cryptodome.Hash import SHA256
+ from Cryptodome.PublicKey import RSA
+ from Cryptodome.Util.number import ceil_div
import base64
import logging
import os
@@ -167,7 +167,7 @@
img_type = 2 # SHDR_ENCRYPTED_TA
else:
img_type = 1 # SHDR_BOOTSTRAP_TA
- algo = 0x70004830 # TEE_ALG_RSASSA_PKCS1_V1_5_SHA256
+ algo = 0x70414930 # TEE_ALG_RSASSA_PKCS1_PSS_MGF1_SHA256
shdr = struct.pack('<IIIIHH',
magic, img_type, img_size, algo, digest_len, sig_len)
@@ -215,7 +215,7 @@
'please use offline-signing mode.')
sys.exit(1)
else:
- signer = PKCS1_v1_5.new(key)
+ signer = pss.new(key)
sig = signer.sign(h)
if len(sig) != sig_len:
raise Exception(("Actual signature length is not equal to ",
@@ -242,7 +242,7 @@
args.digf, args.sigf)
sys.exit(1)
else:
- verifier = PKCS1_v1_5.new(key)
+ verifier = pss.new(key)
if verifier.verify(h, sig):
write_image_with_signature(sig)
logger.info('Successfully applied signature.')
