cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing

Summarypkcs7decryptder, pkcs7decryptpem, and pkcs7decryptsmime reported theoutcome of decrypting a RecipientInfo's encryptedKey in severaldistinguishable ways, one of which disclosed the exact length recovered from theRSA operation. The same distinction was also observable by timing. Anapplicatio...