ThomasHoevel
commented
1 month ago Thanks for your feedback.
We sign an empty block and reserve 4 more bytes for the signature. With your signing authority, 4 bytes are not enough and we have to add at least 6 bytes.
We did not yet test with ECDSA certificates. We cannot say if it works, but theoretically all sorts of certificates should do.
I'm trying to sign PDFs using v6.2.0-preview-1.
The attached reproducer generates the same PDF 100 times and tries to sign each of them using an ECDSA certificate. In some cases it succeeds, but in others it complains that the digest length is larger than the "approximation made", which (as far as I understand) comes from signing an empty stream. It seems like the size of the digest is not fixed. In this case, the digest length seems to be 934, 935, or 936 bytes; a different certificate with a proper chain resulted in digest lengths of 2851, 2852, or 2853.
It's possible that the varying size of the digest is due to the use of ECDSA. I don't know if ECDSA is meant to be supported, I'm certainly having some trouble (which I've yet to track down) with the result even when the signing is successful. If ECDSA is not going to be supported in this version, I'd appreciate a response saying so.
Sample output below; reproducer attached.
0: success Filename='D:\data\incoming\PDFsharp.IssueSubmissionTemplate\assets\temp\IssueTemplate-WIN-CORE-6.0-CCF0D98EB7_temp.pdf' 1: success 2: success 3: success 4: success 5: success 6: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 7: success 8: success 9: success 10: success 11: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 12: success 13: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 14: success 15: success 16: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 17: success 18: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 19: success 20: success 21: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 22: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 23: success 24: success 25: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 26: success 27: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 28: success 29: success 30: success 31: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 32: success 33: success 34: success 35: success 36: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 37: success 38: success 39: success 40: success 41: success 42: success 43: success 44: success 45: success 46: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 47: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 48: success 49: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 50: success 51: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 52: success 53: success 54: success 55: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 56: success 57: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 58: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 59: success 60: success 61: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 62: success 63: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 64: success 65: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 66: success 67: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 68: success 69: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 70: success 71: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 72: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 73: success 74: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 75: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 76: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 77: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 78: success 79: success 80: success 81: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 82: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 83: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 84: success 85: success 86: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 87: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 88: success 89: success 90: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 91: success 92: success 93: success 94: success 95: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 96: The actual digest length 936 is larger than the approximation made 935. Not enough room in the placeholder to fit the signature. 97: The actual digest length 936 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 98: The actual digest length 935 is larger than the approximation made 934. Not enough room in the placeholder to fit the signature. 99: success
Issue.zip